Search results for: N2 adsorption/desorption isotherm

Authors: Parvaneh Eskandari, Rachel O'Reilly

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In the last years, controlling the self-assembly behavior of stimuli-responsive nano-objects, including micelles, vesicles, worm-like, etc., at different conditions is considered a pertinent challenge in the polymer community. The aim of the project was to synthesize aggregation-induced emission (AIE)-active stimuli-responsive polymeric nano-objects to control the self-assemblies morphologies of the prepared nano-objects. Two types of nanoobjects, micelle and vesicles, including PDMAEMA-b-P(BzMA-TPEMA) [PDMAEMA: poly(N,Ndimethylaminoethyl methacrylate); P(BzMA-TPEMA): poly[benzyl methacrylate-co- tetraphenylethene methacrylate]] were synthesized by using reversible addition−fragmentation chain-transfer (RAFT)- mediated polymerization-induced self-assembly (PISA), which combines polymerization and self-assembly in a single step. Transmission electron microscope and dynamic light scattering (DLS) analysis were used to confirm the formed self-assemblies morphologies. The controlled self-assemblies were applied as nitrophenolic compounds (NPCs) adsorbents from wastewater, thanks to their CO2-responsive part, PDMAEMA. Moreover, the fluorescence-active part of the prepared nano-objects, P(BzMA-TPEMA), played a key role in the detection of the NPCs at the aqueous solution. The optical properties of the prepared nano-objects were studied by UV/Vis and fluorescence spectroscopies. For responsivity investigations, the hydrodynamic diameter and Zeta-potential (ζ-potential) of the sample's aqueous solution were measured by DLS. In the end, the prepared nano-objects were used for the detection and adsorption of different NPCs.

Keywords: aggregation-induced emission polymers, stimuli-responsive polymers, reversible addition−fragmentation chain-transfer polymerization, polymerization-induced self-assembly, wastewater treatment

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Authors: Saâd Oukkass, Abderrahim Bouftou, Rachid Ouchn, L. Lebrun, Miloudi Hlaibi

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We invariably exist in a world steeped in colors, whether in our clothing, food, cosmetics, or even medications. However, most of the dyes we use pose significant problems, being both harmful to the environment and resistant to degradation. Among these dyes, methylene blue and acid yellow 61 stand out, commonly used to dye various materials such as cotton, wood, and silk. Fortunately, various methods have been developed to treat and remove these polluting dyes, among which membrane processes play a prominent role. These methods are praised for their low energy consumption, ease of operation, and their ability to achieve effective separation of components. Adsorption on activated carbon is also a widely employed technique, complementing the basic processes. It proves particularly effective in capturing and removing organic compounds from water due to its substantial specific surface area while retaining its properties unchanged. In the context of our study, we examined two crucial aspects. Firstly, we explored the possibility of selectively extracting methylene blue from a mixture containing another dye, acid yellow 61, using a polymer inclusion membrane (PIM) made of PVA. After characterizing the morphology and porosity of the membrane, we applied kinetic and thermodynamic models to determine the values of permeability (P), initial flux (J0), association constant (Kass), and apparent diffusion coefficient (D*). Subsequently, we measured activation parameters (activation energy (Ea), enthalpy (ΔH#ass), entropy (ΔS#)). Finally, we studied the effect of activated carbon on the processes carried out through the membrane, demonstrating a clear improvement. These results make the membrane developed in this study a potentially pivotal player in the field of membrane separation.

Keywords: dyes, methylene blue, membrane, activated carbon

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Authors: Vidula Shevade, B. J. Nagare, Sajeev Chacko

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First principles simulation, meaning density functional theory (DFT) calculations with plane waves and pseudopotential, has become a prized technique in condensed matter theory. Nanoparticles (NP) have been known to possess good catalytic activities, especially for molecules such as CO, O₂, etc. Among the metal NPs, Aluminium based NPs are also widely known for their catalytic properties. Aluminium metal is a lightweight, excellent electrical, and thermal abundant chemical element in the earth’s crust. Aluminium NPs, when added to solid rocket fuel, help improve the combustion speed and considerably increase combustion heat and combustion stability. Adding aluminium NPs into normal Al/Al₂O₃ powder improves the sintering processes of the ceramics, with high heat transfer performance, increased density, and enhanced thermal conductivity of the sinter. We used VASP and Gaussian 0₃ package to compute the geometries, electronic structure, and bonding properties of Al₁₂Ni as well as its interaction with O₂ and CO molecules. Several MD simulations were carried out using VASP at various temperatures from which hundreds of structures were optimized, leading to 24 unique structures. These structures were then further optimized through a Gaussian package. The lowest energy structure of Al₁₂Ni has been reported to be a singlet. However, through our extensive search, we found a triplet state to be lower in energy. In our structure, the Ni atom is found to be on the surface, which gives the non-zero magnetic moment. Incidentally, O2 and CO molecules are also triplet in nature, due to which the Al₁₂-Ni cluster is likely to facilitate the oxidation process of the CO molecule. Our results show that the most favourable site for the CO molecule is the Ni atom and that for the O₂ molecule is the Al atom that is nearest to the Ni atom. Al₁₂Ni-O₂ and Al₁₂-Ni-CO structures we extracted using VMD. Al₁₂Ni nanocluster, due to in triplet electronic structure configuration, indicates it to be a potential candidate as a catalyst for oxidation of CO molecules.

Keywords: catalyst, gaussian, nanoparticles, oxidation

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Authors: Aicha Assal, El Mostapha Lotfi

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Rapid industrialization and population growth are currently the main causes of energy and environmental problems associated with wastewater treatment. Wastewater treatment plants (WWTPs) aim to treat wastewater before discharging it into the environment, but they are not yet capable of treating non-biodegradable contaminants such as heavy metals. Toxic heavy metals can disrupt biological processes in WWTPs. Consequently, it is crucial to combine additional physico-chemical treatments with WWTPs to ensure effective wastewater treatment. In this study, the authors examined the pretreatment process for urban wastewater generated by the El Jadida WWTP in order to assess its treatment efficiency. Various physicochemical and spatiotemporal parameters of the WWTP's raw and treated water were studied, including temperature, pH, conductivity, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (SS), total nitrogen, and total phosphorus. The results showed an improvement in treatment yields, with measured performance values of 77% for BOD5, 63% for COD, and 66% for TSS. However, spectroscopic analyses revealed persistent coloration in wastewater samples leaving the WWTP, as well as the presence of heavy metals such as Zn, cadmium, chromium, and cobalt, detected by inductively coupled plasma optical emission spectroscopy (ICP-OES). To remedy these staining problems and reduce the presence of heavy metals, a new low-cost, environmentally-friendly eggshell-based solution was proposed. This method eliminated most heavy metals such as cobalt, beryllium, silver, and copper and significantly reduced the amount of cadmium, lead, chromium, manganese, aluminium, and Zn. In addition, the bioadsorbent was able to decolorize wastewater by up to 84%. This adsorption process is, therefore, of great interest for ensuring the quality of wastewater and promoting its reuse in irrigation.

Keywords: WWTP, wastewater, heavy metals, decoloration, depollution, COD, BOD5

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Authors: Hugo Carronnier, Wassim Almouallem, Eric Branquet

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Per- and polyfluoroalkyl Substances (PFAS) are a group of man-made refractory compounds that have been widely used in a variety of industrial and commercial products since the 1940s, leading to contamination of groundwater and surface water systems. They are persistent, bioaccumulative and toxic chemicals. Foam fractionation is a potential remedial technique for treating PFAS-contaminated water, taking advantage of the high surface activity to remove them from the solution by adsorption onto the surface of the air bubbles. Nevertheless, traditional foam fractionation technology developed for PFAS is challenging and found to be ineffective in treating the less surface-active compounds. Different chemicals were the subject of investigation as amendments to achieve better removal. However, most amendments are toxic, expensive and complicated to use. In this situation, patent-pending PFAS technology overcomes these challenges by using rather biological amendments. Results from the first laboratory trial showed remarkable results using a simple and cheap BioFoam Fractionation (BioFF) process based on biomimetics. The study showed that the BioFF process is effective in removing greater than 99% of PFOA (C8), PFOS (C8), PFHpS (C7) and PFHxS (C6) in PFAS-contaminated water. For other PFAS such as PFDA (C10) and 6:2 FTAB, a slightly less stable removal between 94% and 96% was achieved while between 34% and 73% removal efficiency was observed for PFBA (C4), PFBS (C4), PFHxA (C6), and Gen-X. In sum, the advantages of the BioFF presented as a low-waste production, a cost and energy-efficient operation and the use of a biodegradable amendment requiring no separation step after treatment, coupled with these first findings, suggest that the BioFF process is a highly applicable treatment technology for PFAS contaminated water. Additional investigations are currently carried on in order to optimize the process and establish a promising strategy for on-site PFAS remediation.

Keywords: PFAS, treatment, foam fractionation, contaminated amendments

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Authors: Bello Gonzalez T. D. J., Setten Van M., Essen Van A., Brouwer M., Veldman K. T.

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Resistance to fluoroquinolones (FQ) has evolved increasingly over the years, posing a significant challenge for the treatment of human infections, particularly gastrointestinal tract infections caused by zoonotic bacteria transmitted through the food chain and environment. In broiler chickens, a relatively high proportion of FQ resistance has been observed in Escherichia coli indicator, Salmonella and Campylobacter isolates. We hypothesize that flumequine (Flu), used as a secondary choice for the treatment of poultry infections, could potentially be associated with a high proportion of FQ resistance. To evaluate this hypothesis, we used an in vitro fermentation chicken caeca model. Two continuous single-stage fermenters were used to simulate in real time the physiological conditions of the chicken caeca microbial content (temperature, pH, caecal content mixing, and anoxic environment). A pool of chicken caecal content containing FQ-resistant E. coli obtained from chickens at slaughter age was used as inoculum along with a spiked FQ-susceptible Campylobacter jejuni strain isolated from broilers. Flu was added to one of the fermenters (Flu-fermenter) every 24 hours for two days to evaluate the selection and maintenance of FQ resistance over time, while the other served as a control (C-Fermenter). The experiment duration was 5 days. Samples were collected at three different time points: before, during and after Flu administration. Serial dilutions were plated on Butzler culture media with and without Flu (8mg/L) and enrofloxacin (4mg/L) and on MacConkey culture media with and without Flu (4mg/L) and enrofloxacin (1mg/L) to determine the proportion of resistant strains over time. Positive cultures were identified by mass spectrometry and matrix-assisted laser desorption/ionization (MALDI). A subset of the obtained isolates were used for Whole Genome Sequencing analysis. Over time, E. coli exhibited positive growth in both fermenters, while C. jejuni growth was detected up to day 3. The proportion of Flu-resistant E. coli strains recovered remained consistent over time after antibiotic selective pressure, while in the C-fermenter, a decrease was observed at day 5; a similar pattern was observed in the enrofloxacin-resistant E. coli strains. This suggests that Flu might play a role in the selection and persistence of enrofloxacin resistance, compared to C-fermenter, where enrofloxacin-resistant E. coli strains appear at a later time. Furthermore, positive growth was detected from both fermenters only on Butzler plates without antibiotics. A subset of C. jejuni strains from the Flu-fermenter revealed that those strains were susceptible to ciprofloxacin (MIC < 0.12 μg/mL). A selection of E. coli strains from both fermenters revealed the presence of plasmid-mediated quinolone resistance (PMQR) (qnr-B19) in only one strain from the C-fermenter belonging to sequence type (ST) 48, and in all from Flu-fermenter belonged to ST189. Our results showed that Flu selective impact on PMQR-positive E. coli strains, while no effect was observed in C. jejuni. Maintenance of Flu-resistance was correlated with antibiotic selective pressure. Further studies into antibiotic resistance gene transfer among commensal and zoonotic bacteria in the chicken caeca content may help to elucidate the resistance spread mechanisms.

Keywords: fluoroquinolone-resistance, escherichia coli, campylobacter jejuni, in vitro model

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Authors: X. Han, S. Duan, C. Liu, C. Zhou, W. Zhu, L. Kong

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The ionic imprinting technique refers to the three-dimensional rigid structure with the fixed pore sizes, which was formed by the binding interactions of ions and functional monomers and used ions as the template, it has a high level of recognition to the ionic template. The preparation of monolithic column by the in-situ polymerization need to put the compound of template, functional monomers, cross-linking agent and initiating agent into the solution, dissolve it and inject to the column tube, and then the compound will have a polymerization reaction at a certain temperature, after the synthetic reaction, we washed out the unread template and solution. The monolithic columns are easy to prepare, low consumption and cost-effective with fast mass transfer, besides, they have many chemical functions. But the monolithic columns have some problems in the practical application, such as low-efficiency, quantitative analysis cannot be performed accurately because of the peak shape is wide and has tailing phenomena; the choice of polymerization systems is limited and the lack of theoretical foundations. Thus the optimization of components and preparation methods is an important research direction. During the preparation of ionic imprinted monolithic columns, pore-forming agent can make the polymer generate the porous structure, which can influence the physical properties of polymer, what’ s more, it can directly decide the stability and selectivity of polymerization reaction. The compounds generated in the pre-polymerization reaction could directly decide the identification and screening capabilities of imprinted polymer; thus the choice of pore-forming agent is quite critical in the preparation of imprinted monolithic columns. This article mainly focuses on the research that when using different pore-forming agents, the impact of zinc ion imprinted monolithic column on the enrichment performance of zinc ion.

Keywords: high performance liquid chromatography (HPLC), ionic imprinting, monolithic column, pore-forming agent

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Authors: Emmanuelle Maria, Pierre Crançon, Gaëtane Lespes

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The knowledge of uranium migration processes within underground environments is a major issue in the environmental risk assessment associated with nuclear activities. This process is identified as strongly controlled by adsorption mechanisms, thus leading to strongly delayed migration paths. Colloidal ligands are likely to significantly increase the mobility of uranium in natural environments. The ability of colloids to mobilize and transport uranium depends on their origin, their nature, their structure, their stability and their reactivity with uranium. Thus, the colloidal mobilization and transport properties are often described as site-specific. In this work, the colloidal phases of two leachates obtained from two different horizons of the same podzolic soil were characterized with a speciation approach. For this purpose, a multi-technique strategy was used, based on Field-Flow Fractionation coupled to Ultraviolet, Multi-Angle Light Scattering and Inductively Coupled Plasma Mass Spectrometry (AF4-UV-MALS-ICPMS), Transmission Electron Microscopy (TEM), Electrospray Ionization Orbitrap Mass Spectrometry (ESI-Orbitrap), and Time-Resolved Laser Fluorescence Spectroscopy (TRLFS-EEM). Thus, elemental composition, size distribution, microscopic structure, colloidal stability and possible organic and/or inorganic content of colloids were determined, as well as their association with uranium. The leachates exhibit differences in their physical and chemical characteristics, mainly in the nature of organic matter constituents. The multi-technique investigation strategy used provides original data about colloidal phase structure and composition, offering a new vision of the way the uranium can be mobilized and transported in the considered soil. This information is a real significant contribution opening the way to our understanding and predicting of the colloidal transport.

Keywords: colloids, migration, multi-technique, speciation, transport, uranium

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Authors: Innocent O. Arukalam, Emeka E. Oguzie

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Interest in the development of eco-friendly anti-corrosion coatings using bio-based renewable materials is gaining momentum recently. To this effect, chitin biopolymer, which is non-toxic, biodegradable, and inherently possesses anti-microbial property, was successfully synthesized from snail shells and used as a filler in the preparation of epoxy coating. The chitin particles were characterized with contact angle goniometer, scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrophotometer, and X-ray diffractometer (XRD). The performance of the coatings was evaluated by immersion and electrochemical impedance spectroscopy (EIS) tests. Electronic structure properties of the coating ingredients and molecular level interaction of the corrodent and coated Q235 steel were appraised by quantum chemical computations (QCC) and molecular dynamics (MD) simulation techniques, respectively. The water contact angle (WCA) measurement of chitin particles was found to be 129.3o while that of chitin particles modified with amino trimethoxy silane (ATMS) was 149.6o, suggesting it is highly hydrophobic. Immersion and EIS analyses revealed that epoxy coating containing silane-modified chitin exhibited lowest water absorption and highest barrier as well as anti-corrosion performances. The QCC showed that quantum parameters for the coating containing silane-modified chitin are optimum and therefore corresponds to high corrosion protection. The high negative value of adsorption energies (Eads) for the coating containing silane-modified chitin indicates the coating molecules interacted and adsorbed strongly on the steel surface. The observed results have shown that silane-modified epoxy-chitin coating would perform satisfactorily for surface protection of metal structures in saline environment.

Keywords: chitin, EIS, epoxy coating, hydrophobic, molecular dynamics simulation, quantum chemical computation

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Authors: Intisar Al Busaidi, Rashid Al Maamari, Daowoud Al Mahroqi, Mahvash Karimi

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In recent years, some research studies have been performed on the hybrid application of polymer and low salinity water flooding (LSWF). Numerous technical and economic benefits of low salinity polymer flooding (LSPF) have been reported. However, as with any EOR technology, there are various risks involved in using LSPF. Ions exchange between porous media and brine is one of the Crude oil/ brine/ rocks (COBR) reactions that is identified as a potential risk in LSPF. To the best of our knowledge, this conclusion was drawn based on bulk rheology measurements, and no explanation was provided on how water chemistry changed in the presence of polymer. Therefore, this study aimed to understand rock/ brine interactions with high and low salinity brine in the absence and presence of polymer with Omani reservoir core plugs. Many single-core flooding experiments were performed with low and high salinity polymer solutions to investigate the influence of partially hydrolyzed polyacrylic amide with different brine salinities on cation exchange reactions. Ion chromatography (IC), total organic carbon (TOC), rheological, and pH measurements were conducted for produced aqueous phase. A higher increase in pH and lower polymer adsorption was observed in LSPF compared with conventional polymer flooding. In addition, IC measurements showed that all produced fluids in the absence and presence of polymer showed elevated Ca²⁺, Mg²⁺, K+, Cl- and SO₄²⁻ ions compared to the injected fluids. However, the divalent cations levels, mainly Ca²⁺, were the highest and remained elevated for several pore volumes in the presence of LSP. The results are in line with rheological measurements where the highest viscosity reduction was recorded with the highest level of Ca²⁺ production. Despite the viscosity loss due to cation exchange reactions, LSP can be an attractive alternative to conventional polymer flooding in the Marmul field.

Keywords: polymer, ions, exchange, recovery, low salinity

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Authors: K. Yu Vlasova, M. A. Abakumov, H. Wishwarsao, M. Sokolsky, N. V. Nukolova, A. G. Majouga, Y. I. Golovin, N. L. Klyachko, A. V. Kabanov

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Introduction:Nowadays pharmaceutical medicine is aimed to create systems for combined therapy, diagnostic, drug delivery and controlled release of active molecules to target cells. Magnetic nanoparticles (MNPs) are used to achieve this aim. MNPs can be applied in molecular diagnostics, magnetic resonance imaging (T1/T2 contrast agents), drug delivery, hyperthermia and could improve therapeutic effect of drugs. The most common drug containers, containing MNPs, are liposomes, micelles and polymeric molecules bonded to the MNPs surface. Usually superparamagnetic nanoparticles are used (the general diameter is about 5-6 nm) and all effects of high frequency magnetic field (MF) application are based on Neel relaxation resulting in heating of surrounded media. In this work we try to develop a new method to improve drug release from MNPs under super low frequency MF. We suppose that under low frequency MF exposures the Brown’s relaxation dominates and MNPs rotation could occur leading to conformation changes and release of bioactive molecules immobilized on MNPs surface.The aim of this work was to synthesize different systems with active drug (biopolymers coated MNPs nanoclusters with immobilized enzymes and doxorubicin (Dox) loaded magnetic liposomes/micelles) and investigate the effect of super low frequency MF on these drug containers. Methods: We have synthesized MNPs of magnetite with magnetic core diameter 7-12 nm . The MNPs were coated with block-copolymer of polylysine and polyethylene glycol. Superoxide dismutase 1 (SOD1) was electrostatically adsorbed on the surface of the clusters. Liposomes were prepared as follow: MNPs, phosphatidylcholine and cholesterol were dispersed in chloroform, dried to get film and then dispersed in distillated water, sonicated. Dox was added to the solution, pH was adjusted to 7.4 and excess of drug was removed by centrifugation through 3 kDa filters. Results: Polylysine coated MNPs formed nanosized clusters (as observed by TEM) with intensity average diameter of 112±5 nm and zeta potential 12±3 mV. After low frequency AC MF exposure we observed change of immobilized enzyme activity and hydrodynamic size of clusters. We suppose that the biomolecules (enzymes) are released from the MNPs surface followed with additional aggregation of complexes at the MF in medium. Centrifugation of the nanosuspension after AC MF exposures resulted in increase of positive charge of clusters and change in enzyme concentration in comparison with control sample without MF, thus confirming desorption of negatively charged enzyme from the positively charged surface of MNPs. Dox loaded magnetic liposomes had average diameter of 160±8 nm and polydispersity index (PDI) 0.25±0.07. Liposomes were stable in DW and PBS at pH=7.4 at 370C during a week. After MF application (10 min of exposure, 50 Hz, 230 mT) diameter of liposomes raised to 190±10 nm and PDI was 0.38±0.05. We explain this by destroying and/or reorganization of lipid bilayer, that leads to changes in release of drug in comparison with control without MF exposure. Conclusion: A new application of low frequency AC MF for drug delivery and controlled drug release was shown. Investigation was supported by RSF-14-13-00731 grant, K1-2014-022 grant.

Keywords: magnetic nanoparticles, low frequency magnetic field, drug delivery, controlled drug release

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Authors: N.Quaranta, M. Caligaris, R. Varoli, A. Cristobal, M. Unsen, H. López

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Corncobs are agricultural wastes and they can be used as fuel or as raw material in different industrial processes like cement manufacture, contaminant adsorption, chemical compound synthesis, etc. The aim of this work is to characterize this waste and analyze the feasibility of its use as a pore-forming material in the manufacture of lightweight ceramics for the civil construction industry. The characterization of raw materials is carried out by using various techniques: electron diffraction analysis X-ray, differential and gravimetric thermal analyses, FTIR spectroscopy, ecotoxicity evaluation, among others. The ground corncobs, particle size less than 2 mm, are mixed with clay up to 30% in volume and shaped by uniaxial pressure of 25 MPa, with 6% humidity, in moulds of 70mm x 40mm x 18mm. Then the green bodies are heat treated at 950°C for two hours following the treatment curves used in ceramic industry. The ceramic probes are characterized by several techniques: density, porosity and water absorption, permanent volumetric variation, loss on ignition, microscopies analysis, and mechanical properties. DTA-TGA analysis of corncobs shows in the range 20°-250°C a small loss in TGA curve and exothermic peaks at 250°-500°C. FTIR spectrum of the corncobs sample shows the characteristic pattern of this kind of organic matter with stretching vibration bands of adsorbed water, methyl groups, C–O and C–C bonds, and the complex form of the cellulose and hemicellulose glycosidic bonds. The obtained ceramic bodies present external good characteristics without loose edges and adequate properties for the market requirements. The porosity values of the sintered pieces are higher than those of the reference sample without waste addition. The results generally indicate that it is possible to use corncobs as porosity former in ceramic bodies without modifying the usual sintering temperatures employed in the industry.

Keywords: ceramic industry, biomass, recycling, hemicellulose glycosidic bonds

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Authors: Dmitry Nosik, Nickolay Nosik, Elli Kaplina, Olga Lobach, Marina Chataeva, Lev Rasnetsov

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Background and aims: Human Immunodeficiency Virus (HIV) infection is very often associated with Herpes Simplex Virus (HSV) infection but HIV patients are treated with a cocktail of antiretroviral drugs which are toxic. The use of an antiviral drug which will be active against both viruses like ferrovir found in our previous studies is rather actual. Earlier we had shown that Fullerene poly-amino capronic acid (FPACA) was active in case of monoinfection of HIV-1 or HSV-1. The aim of the study was to analyze the efficiency of FPACA against mixed infection of HIV and HSV. Methods: The peripheral blood lymphocytes, CEM, MT-4 cells were simultaneously infected with HIV-1 and HSV-1. FPACA was added 1 hour before infection. Cells viability was detected by MTT assay, virus antigens detected by ELISA, syncytium formation detected by microscopy. The different multiplicity of HIV-1/HSV-1 ratio was used. Results: The double viral HIV-1/HSV-1 infection was more cytopathic comparing with monoinfections. In mixed infection by the HIV-1/HSV-1 concentration of HIV-1 antigens and syncytium formations increased by 1,7 to 2,3 times in different cells in comparison with the culture infected with HIV-1 alone. The concentration of HSV-1 increased by 1,5-1,7 times, respectively. Administration of FPACA (1 microg/ml) protected cells: HIV-1/HSV-1 (1:1) – 80,1%; HIV-1/HSV-1 (1:4) – 57,2%; HIV-1/HSV-1 (1:8) – 46,3 %; HIV-1/HSV-1 (1:16) – 17,0%. Virus’s antigen levels were also reduced. Syncytium formation was totally inhibited in all cases of mixed infection. Conclusion: FPACA showed antiviral activity in case of mixed viral infection induced by Human Immunodeficiency Virus and Herpes Simplex Virus. The effect of viral inhibition increased with the multiplicity of HIV-1 in the inoculum. The mechanism of FPACA action is connected with the blocking of the virus particles adsorption to the cells and it could be suggested that it can have an antiviral activity against some other viruses too. Now FPACA could be considered as a potential drug for treatment of HIV disease complicated with opportunistic herpes viral infection.

Keywords: antiviral drug, human immunodeficiency virus (hiv), herpes simplex virus (hsv), mixed viral infection

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Authors: Dehni Abdellatif, Lounis Mourad

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The new approach of applied spatial geostatistics in materials sciences, agriculture accuracy, agricultural statistics, permitted an apprehension of managing and monitoring the water and groundwater qualities in a relationship with salt-affected soil. The anterior experiences concerning data acquisition, spatial-preparation studies on optical and multispectral data has facilitated the integration of correction models of electrical conductivity related with soils temperature (horizons of soils). For tomography apprehension, this physical parameter has been extracted from calibration of the thermal band (LANDSAT ETM+6) with a radiometric correction. Our study area is Oran region (Northern West of Algeria). Different spectral indices are determined such as salinity and sodicity index, the Combined Spectral Reflectance Index (CSRI), Normalized Difference Vegetation Index (NDVI), emissivity, Albedo, and Sodium Adsorption Ratio (SAR). The approach of geostatistical modeling of electrical conductivity (salinity), appears to be a useful decision support system for estimating corrected electrical resistivity related to the temperature of surface soils, according to the conversion models by substitution, the reference temperature at 25°C (where hydrochemical data are collected with this constraint). The Brightness temperatures extracted from satellite reflectance (LANDSAT ETM+) are used in consistency models to estimate electrical resistivity. The confusions that arise from the effects of salt stress and water stress removed followed by seasonal application of the geostatistical analysis in Geographic Information System (GIS) techniques investigation and monitoring the variation of the electrical conductivity in the alluvial aquifer of Es-Sénia for the salt-affected soil.

Keywords: geostatistical modelling, landsat, brightness temperature, conductivity

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Authors: Krasimira Georgieva, Yordan Denev

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Many of thermosetting resins have application only in filled state, reinforced with different mineral fillers. The co-filling of polymers with mineral filler and gases creates a possibility for production of polymer composites materials with low density. This processing leads to forming of new materials – gas-filled plastics (polymer foams). The properties of these materials are determined mainly by the shape and size of internal structural elements (pores). The interactions on the phase boundaries have influence on the materials properties too. In the present work, the gas-filled urea-formaldehyde resins were reinforced by waste phosphogypsum. The waste phosphogypsum (CaSO₄.2H₂O) is a solid by-product in wet phosphoric acid production processes. The values of the interactions polymer-filler were increased by using two modifying agents: polyvinyl acetate for polymer matrix and sodium metasilicate for filler. Technological methods for gas-filling and recipes of urea-formaldehyde based materials with apparent density 20-120 kg/m³ were developed. The heat conductivity of the samples is between 0.024 and 0.029 W/m^oK. Tensile analyses were carried out at 10 and 50% deformation and show values 0.01-0.14 MPa and 0.01-0.09 MPa, respectively. The apparent density of obtained materials is between 20 and 92 kg/m³. The changes in the tensile properties and density of these materials according to sodium metasilicate content were studied too. The mechanism of phosphogypsum adsorption modification was studied using methods of FT-IR spectroscopy. The structure of the gas-filled urea-formaldehyde resins was described by results of electron scanning microscopy at three different magnification ratios – x50, x150 and x 500. The aim of present work is to study the possibility of the usage of phosphogypsum as mineral filler for urea-formaldehyde resins and development of a technology for the production of gas-filled reinforced polymer composite materials. The structure and the properties of obtained composite materials are suitable for thermal and sound insulation applications.

Keywords: urea formaldehyde resins, gas-filled thermostes, phosphogypsum, mechanical properties

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Authors: N. Porzionato, M. Mantiñan, E. Bussi, S. Grinberg, R. Gutierrez, G. Curutchet

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This work sets out to debate the tensions involved in the processes of contamination and self-purification in the urban space, particularly in the streams that run through the Buenos Aires metropolitan area. For much of their course, those streams are piped; their waters do not come into contact with the outdoors until they have reached deeply impoverished urban areas with high levels of environmental contamination. These are peripheral zones that, until thirty years ago, were marshlands and fields. They are now densely populated areas largely lacking in urban infrastructure. The Cárcova neighborhood, where this project is underway, is in the José León Suárez section of General San Martín country, Buenos Aires province. A stretch of José León Suarez canal crosses the neighborhood. Starting upstream, this canal carries pollutants due to the sewage and industrial waste released into it. Further downstream, in the neighborhood, domestic drainage is poured into the stream. In this paper, we formulate a hypothesis diametrical to the one that holds that these neighborhoods are the primary source of contamination, suggesting instead that in the stretch of the canal that runs through the neighborhood the stream’s waters are actually cleaned and the sediments accumulate pollutants. Indeed, the stretches of water that runs through these neighborhoods act as water processing plants for the metropolis. This project has studied the different organic-load polluting contributions to the water in a certain stretch of the canal, the reduction of that load over the course of the canal, and the incorporation of pollutants into the sediments. We have found that the surface water has considerable ability to self-purify, mostly due to processes of sedimentation and adsorption. The polluting load is accumulated in the sediments where that load stabilizes slowly by means of anaerobic processes. In this study, we also investigated the risks of sediment management and the use of the processes studied here in controlled conditions as tools of environmental restoration.

Keywords: bioremediation, pollutants, sediments, urban streams

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Authors: Youcef Serhane, Abdelkrim Bouzaza, Dominique Wolbert, Aymen Amin Assadi

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Throughout history, the use of chemical weapons is not exclusive to combats between army corps; some of these weapons are also found in very targeted intelligence operations (political assassinations), organized crime, and terrorist organizations. To improve the speed of action, important technological devices have been developed in recent years, in particular in the field of protection and decontamination techniques to better protect and neutralize a chemical threat. In order to assess certain protective, decontaminating technologies or to improve medical countermeasures, tests must be conducted. In view of the great toxicity of toxic chemical agents from (real) wars, simulants can be used, chosen according to the desired application. Here, we present an investigation about using a photocatalytic filtering reactor (PFR) for highly contaminated environments containing diethyl sulfide (DES). This target pollutant is used as a simulant of CWA, namely of Yperite (Mustard Gas). The influence of the inlet concentration (until high concentrations of DES (1200 ppmv, i.e., 5 g/m³ of air) has been studied. Also, the conversion rate was monitored under different relative humidity and different flow rates (respiratory flow - standards: ISO / DIS 8996 and NF EN 14387 + A1). In order to understand the efficacity of pollutant neutralization by PFR, a kinetic model based on the Langmuir–Hinshelwood (L–H) approach and taking into account the mass transfer step was developed. This allows us to determine the adsorption and kinetic degradation constants with no influence of mass transfer. The obtained results confirm that this small configuration of reactor presents an extremely promising way for the use of photocatalysis for treatment to deal with highly contaminated environments containing real chemical warfare agents. Also, they can give birth to an individual protection device (an autonomous cartridge for a gas mask).

Keywords: photocatalysis, photocatalytic filtering reactor, diethylsulfide, chemical warfare agents

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Authors: Farzaneh Shayeganfar, Ali Ramazani

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Exciton (strong electronic interaction of electron-hole) and hot carriers created by surface plasmon polaritons has been demonstrated in nanoscale optoelectronic devices, enhancing the photoresponse of the system. Herein, we employ a quantum framework to consider coupled exciton- hot carriers effects on photovoltaiv energy distribution, scattering process, polarizability and light emission of 2D-semicnductor. We use density functional theory (DFT) to design computationally a semi-functionalized 2D honeycomb silicon boride (SiB) monolayer with H atoms, suitable for photovoltaics. The dynamical stability, electronic and optical properties of SiB and semi-hydrogenated SiB structures were investigated utilizing the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The calculated phonon dispersion shows that while an unhydrogenated SiB monolayer is dynamically unstable, surface semi-hydrogenation improves the stability of the structure and leads to a transition from metallic to semiconducting conductivity with a direct band gap of about 1.57 eV, appropriate for photovoltaic applications. The optical conductivity of this H-SiB structure, determined using the random phase approximation (RPA), shows that light adsorption should begin at the boundary of the visible range of light. Additionally, due to hydrogenation, the reflectivity spectrum declines sharply with respect to the unhydrogenated reflectivity spectrum in the IR and visible ranges of light. The energy band gap remains direct, increasing from 0.9 to 1.8 eV, upon increasing the strain from -6% (compressive) to +6% (tensile). Additionally, compressive and tensile strains lead, respectively, to red and blue shifts of optical the conductivity threshold around the visible range of light. Overall, this study suggests that H-SiB monolayers are suitable as two-dimensional solar cell materials.

Keywords: surface plasmon, hot carrier, strain engineering, valley polariton

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Authors: Musawira Iftikhar

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The field of membrane materials is the most dynamic due to the constantly evolving requirements advancement of materials, to address challenges such as biocompatibility, protein-bound uremic toxins, blood coagulation, auto-immune responses, oxidative stress, and poor clearance of uremic toxins. Hemodialysis is a membrane filtration processes that is currently necessary for daily living of the patients with ESRD. Tens of millions of people with ESRD have benefited from hemodialysis over the past 60–70 years, both in terms of safeguarding life and a longer lifespan. Beyond challenges associated with the efficiency and separative properties of the membranes, ensuring hemocompatibility, or the safe circulation of blood outside the body for four hours every two days, remains a persistent challenge. This review explores the ongoing field of metal–Organic Frameworks (MOFs) and their applications in hemodialysis, offering a comprehensive examination of various MOFs employed to address challenges inherent in traditional hemodialysis methodologies. this This review included includes the experimental work done with various MOFs as a filler such as UiO-66, HKUST-1, MIL-101, and ZIF-8, which together lead to improved adsorption capacities for a range of uremic toxins and proteins. Furthermore, this review highlights how effectively MOF-based hemodialysis membranes remove a variety of uremic toxins, including p-cresol, urea, creatinine, and indoxyl sulfate and potential filler choices for the future. Future research efforts should focus on refining synthesis techniques, enhancing toxin selectivity, and investigating the long-term durability of MOF-based membranes. With these considerations, MOFs emerge as transformative materials in the quest to develop advanced and efficient hemodialysis technologies, holding the promise to significantly enhance patient outcomes and redefine the landscape of renal therapy.

Keywords: membrane, hemodailysis, metal organic frameworks, seperation, protein adsorbtion

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Authors: Omkar Gaonkar, Indumathi Nambi, Suresh G. Kumar

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The functional and morphological aspects of soil structure determine the soil quality. The dispersion of colloidal soil particles, especially the clay fraction and rupture of soil aggregates, both of which play an important role in soil structure development, lead to degradation of soil quality. The main objective of this work was to determine the effect of the behaviour of soil colloids on the agricultural soil structure and quality. The effect of commercial humic acid and soil natural organic matter on the electrical and structural properties of the soil colloids was also studied. Agricultural soil, belonging to the sandy loam texture class from northern part of India was considered in this study. In order to understand the changes in the soil quality in the presence and absence of humic acids, the soil fabric and structure was analyzed by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). Electrical properties of natural soil colloids in aqueous suspensions were assessed by zeta potential measurements at varying pH values with and without the presence of humic acids. The influence of natural organic matter was analyzed by oxidizing the natural soil organic matter with hydrogen peroxide. The zeta potential of the soil colloids was found to be negative in the pH range studied. The results indicated that hydrogen peroxide treatment leads to deflocculation of colloidal soil particles. In addition, the humic acids undergoes effective adsorption onto the soil surface imparting more negative zeta potential to the colloidal soil particles. The soil hydrophilicity decreased in the presence of humic acids which was confirmed by surface free energy determination. Thus, it can be concluded that the presence of humic acids altered the soil fabric and structure, thereby affecting the soil quality. This study assumes significance in understanding soil aggregation and the interactions at soil solid-liquid interface.

Keywords: humic acids, natural organic matter, zeta potential, soil quality

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Authors: Poojan Kothari, Yash Madhani, Chayan Jani, Bharti Saini

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The requirements for quality drinking and industrial water are increasing and water resources are depleting. Moreover large amount of wastewater is being generated and dumped into water bodies without treatment. These have made improvement in water treatment efficiency and its reuse, an important agenda. Membrane technology for wastewater treatment is an advanced process and has become increasingly popular in past few decades. There are many traditional methods for tertiary treatment such as chemical coagulation, adsorption, etc. However recent developments in membrane technology field have led to manufacturing of better quality membranes at reduced costs. This along with the high costs of conventional treatment processes, high separation efficiency and relative simplicity of the membrane treatment process has made it an economically viable option for municipal and industrial purposes. Ultrafiltration polymeric membranes can be used for wastewater treatment and drinking water applications. The proposed work focuses on preparation of one such UF membrane - Polyvinylidene fluoride (PVDF) doped with LiBr for wastewater treatment. Majorly all polymeric membranes are hydrophobic in nature. This property leads to repulsion of water and hence solute particles occupy the pores, decreasing the lifetime of a membrane. Thus modification of membrane through addition of small amount of salt such as LiBr helped us attain certain characteristics of membrane, which can then be used for wastewater treatment. The membrane characteristics are investigated through measuring its various properties such as porosity, contact angle and wettability to find out the hydrophilic nature of the membrane and morphology (surface as well as structure). Pure water flux, solute rejection and permeability of membrane is determined by permeation experiments. A study of membrane characteristics with various concentration of LiBr helped us to compare its effectivity.

Keywords: Lithium bromide (LiBr), morphology, permeability, Polyvinylidene fluoride (PVDF), solute rejection, wastewater treatment

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Authors: S. Toufigh Bararpour, Amir H. Soleimanisalim, Davood Karami, Nader Mahinpey

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The continued increase in the atmospheric concentration of CO2 is expected to have great impacts on the climate. In order to reduce CO2 emission to the atmosphere, an efficient and cost-effective technique is required. Using regenerable solid sorbents, especially K2CO3 is a promising method for low-temperature CO2 capture. Pure K2CO3 is a delinquent substance that requires modifications before it can be used for cyclic operations. For this purpose, various types of additives and supports have been used to improve the structure of K2CO3. However, hydrophilicity and reactivity of the support materials with K2CO3 have a negative effect on the CO2 capture capacity of the sorbents. In this research, two kinds of alumina supports (γ-Alumina and Boehmite) were used. In order to decrease the supports' hydrophilicity and reactivity with K2CO3, nonreactive additives such as Titania, Zirconia and Silisium were incorporated into their structures. These materials provide a shell around the alumina to protect it from undesirable reactions and improve its properties. K2CO3-based core/shell-supported sorbents were fabricated using two preparation steps. The sol-gel method was applied for shelling the supports. Then the shelled supports were impregnated on K2CO3. The physicochemical properties of the sorbents were determined using SEM and BET analyses, and their CO2 capture capacity was quantified using a thermogravimetric analyzer. It was shown that type of the shell's material had an important effect on the water adsorption capacity of the sorbents. Supported K2CO3 modified by Titania shell showed the lowest hydrophilicity among the prepared samples. Based on the obtained results, incorporating nonreactive additives in Boehmite had an outstanding impact on the CO2 capture performance of the sorbent. Incorporation of Titania into the Boehmite-supported K2CO3 enhanced its CO2 capture capacity significantly. Therefore, further study of this novel fabrication technique is highly recommended. In the second phase of this research project, the CO2 capture performance of the sorbents in fixed and fluidized bed reactors will be investigated.

Keywords: CO₂ capture, core/shell support, K₂CO₃, post-combustion

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Authors: Sung-Jun Yoo, Kazuhide Ito

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In this study, a comprehensive computer simulated person (CSP) that integrates computational human model (virtual manikin) and respiratory tract model (virtual airway), was applied for estimation of indoor environmental quality. Moreover, an inclusive prediction method was established by integrating computational fluid dynamics (CFD) analysis with advanced CSP which is combined with physiologically-based pharmacokinetic (PBPK) model, unsteady thermoregulation model for analysis targeting micro-climate around human body and respiratory area with high accuracy. This comprehensive method can estimate not only the contaminant inhalation but also constant interaction in the contaminant transfer between indoor spaces, i.e., a target area for indoor air quality (IAQ) assessment, and respiratory zone for health risk assessment. This study focused on the usage of the CSP as an air/thermal quality sensor in indoors, which means the application of comprehensive model for assessment of IAQ and thermal environmental quality. Demonstrative analysis was performed in order to examine the applicability of the comprehensive model to the heating, ventilation, air conditioning (HVAC) control scheme. CSP was located at the center of the simple model room which has dimension of 3m×3m×3m. Formaldehyde which is generated from floor material was assumed as a target contaminant, and flow field, sensible/latent heat and contaminant transfer analysis in indoor space were conducted by using CFD simulation coupled with CSP. In this analysis, thermal comfort was evaluated by thermoregulatory analysis, and respiratory exposure risks represented by adsorption flux/concentration at airway wall surface were estimated by PBPK-CFD hybrid analysis. These Analysis results concerning IAQ and thermal comfort will be fed back to the HVAC control and could be used to find a suitable ventilation rate and energy requirement for air conditioning system.

Keywords: CFD simulation, computer simulated person, HVAC control, indoor environmental quality

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Authors: Umashankar Morya, Somnath Basu

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Metalloids like arsenic are often present as contaminants in industrial effluents. Removal of the same is essential before the safe discharge of the wastewater into the environment. Otherwise, these pollutants tend to percolate into aquifers over a period of time and contaminate drinking water sources. Several adsorbents, including metal powders, carbon nanotubes and zeolites, are being used for this purpose, with varying degrees of success. However, most of these solutions are not only costly but also not always readily available. This restricts their use, especially among financially weaker communities. Slag generated globally from primary steelmaking operations exceeds 200 billion kg every year. Some of it is utilized for applications like road construction, filler in reinforced concrete, railway track ballast and recycled into iron ore agglomeration processes. However, these usually involve low-value addition, and a significant amount of the slag still ends up in a landfill. However, there is a strong possibility that the constituents in the steelmaking slag may immobilize metalloid contaminants present in wastewater through a combination of adsorption and precipitation of insoluble product(s). Preliminary experiments have already indicated that exposure to basic oxygen steelmaking slag does reduce pollutant concentration in wastewater. In addition, the slag is relatively inexpensive and available in large quantities and in several countries across the world. Investigations on the mechanism of interactions at the water-solid interfaces have been in progress for some time. However, at the same time, there are concerns about the possibility of leaching of metal ions from the slag particles in concentrations greater than what exists in the water bodies where the “treated” wastewater would eventually be discharged. The effect of such leached ions on the aquatic flora and fauna is yet uncertain. This has prompted the present investigation, which focuses on the leaching of metal ions from steelmaking slag particles in contact with wastewater, and the influence of these ions on the removal of contaminant species. Experiments were carried out to quantify the leaching behavior of different ionic species upon exposure of the slag particles to simulated wastewater, both with and without specific metalloid contaminants.

Keywords: slag, water, metalloid, heavy metal, wastewater

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Authors: S. L. J. Tan, N. Billa, C. J. Roberts

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Oral delivery of amphotericin B (AmpB) potentially eliminates constraints and side effects associated with intravenous administration, but remains challenging due to the physicochemical properties of the drug such that it results in meagre bioavailability (0.3%). In an advanced formulation, 1) nanostructured lipid carriers (NLC) were formulated as they can accommodate higher levels of cargoes and restrict drug expulsion and 2) a mucoadhesion feature was incorporated so as to impart sluggish transit of the NLC along the gastrointestinal tract and hence, maximize uptake and improve bioavailability of AmpB. The AmpB-loaded NLC formulation was successfully formulated via high shear homogenisation and ultrasonication. A chitosan coating was adsorbed onto the formed NLC. Physical properties of the formulations; particle size, zeta potential, encapsulation efficiency (%EE), aggregation states and mucoadhesion as well as the effect of the variable pH on the integrity of the formulations were examined. The particle size of the freshly prepared AmpB-loaded NLC was 163.1 ± 0.7 nm, with a negative surface charge and remained essentially stable over 120 days. Adsorption of chitosan caused a significant increase in particle size to 348.0 ± 12 nm with the zeta potential change towards positivity. Interestingly, the chitosan-coated AmpB-loaded NLC (ChiAmpB NLC) showed significant decrease in particle size upon storage, suggesting 'anti-Ostwald' ripening effect. AmpB-loaded NLC formulation showed %EE of 94.3 ± 0.02 % and incorporation of chitosan increased the %EE significantly, to 99.3 ± 0.15 %. This suggests that the addition of chitosan renders stability to the NLC formulation, interacting with the anionic segment of the NLC and preventing the drug leakage. AmpB in both NLC and ChiAmpB NLC showed polyaggregation which is the non-toxic conformation. The mucoadhesiveness of the ChiAmpB NLC formulation was observed in both acidic pH (pH 5.8) and near-neutral pH (pH 6.8) conditions as opposed to AmpB-loaded NLC formulation. Hence, the incorporation of chitosan into the NLC formulation did not only impart mucoadhesive property but also protected against the expulsion of AmpB which makes it well-primed as a potential oral delivery system for AmpB.

Keywords: Amphotericin B, mucoadhesion, nanostructured lipid carriers, oral delivery

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Authors: Howaida I. Abd-Alla, Omnia Kutkat, Yassmin Moatasim, Magda T. Ibrahim, Marwa A. Mostafa, Mohamed GabAllah, Mounir M. El-Safty

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Artemisia judaica (known shih-balady), Azadirachta indica and Sophora tomentosa (known yellow necklace pod) are members of available medicinal plants well-known for their traditional medical use in Egypt which suggests that they probably harbor broad-spectrum antiviral, immunostimulatory and anti-inflammatory functions. Their ethyl acetate-dichloromethane (1:1, v/v) extracts were evaluated for the potential anti-Middle East respiratory syndrome-related coronavirus (anti-MERS-CoV) activity. Their cytotoxic activity was tested in Vero-E6 cells using 3-(4,-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method with minor modification. The plot of percentage cytotoxicity for each extract concentration has calculated the concentration which exhibited 50% cytotoxic concentration (TC50). A plaque reduction assay was employed using safe dose of extract to evaluate its effect on virus propagation. The highest inhibition percentage was recorded for the yellow necklace pod, followed by Shih-balady. The possible mode of action of virus inhibition was studied at three different levels viral replication, viral adsorption and virucidal activity. The necklace pod leaves have induced virucidal effects and direct effects on the replication of virus. Phytochemical investigation of the promising necklace pod led to the isolation and structure determination of nine compounds. The structure of each compound was determined by a variety of spectroscopic methods. Compounds 4-O-methyl sorbitol 1, 8-methoxy daidzin 6 and 6-methoxy apigenin-7-O-β-D-glucopyranoside 8 were isolated for the first time from the Sophora genus and the other six compounds were the first time that they were isolated from this species according to available works of literature. Generally, the highest anti-CoV 2 activity of S. tomentosa was associated with the crude ethanolic extract, indicating the possibility of synergy among the antiviral phytochemical constituents (1-9).

Keywords: coronavirus, MERS-CoV, mode of action, necklace pod, shih-balady

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Authors: Kailas L. Wasewar

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Biobutanol has been considered as a potential and alternative biofuel relative to the most popular biodiesel and bioethanol. End product toxicity is the major problems in commercialization of fermentation based process which can be reduce to some possible extent by removing biobutanol simultaneously. Several techniques have been investigated for removing butanol from fermentation broth such as stripping, adsorption, liquid–liquid extraction, pervaporation, and membrane solvent extraction. Liquid–liquid extraction can be performed with high selectivity and is possible to carry out inside the fermenter. Conventional solvents have few drawbacks including toxicity, loss of solvent, high cost etc. Hence alternative solvents must be explored for the same. Room temperature ionic liquids (RTILs) composed entirely of ions are liquid at room temperature having negligible vapor pressure, non-flammability, and tunable physiochemical properties for a particular application which term them as “designer solvents”. Ionic liquids (ILs) have recently gained much attention as alternatives for organic solvents in many processes. In particular, ILs have been used as alternative solvents for liquid–liquid extraction. Their negligible vapor pressure allows the extracted products to be separated from ILs by conventional low pressure distillation with the potential for saving energy. Morpholinium, imidazolium, ammonium, phosphonium etc. based ionic liquids have been employed for the separation biobutanol. In present chapter, basic concepts of ionic liquids and application in separation have been presented. Further, type of ionic liquids including, conventional, functionalized, polymeric, supported membrane, and other ionic liquids have been explored. Also the effect of various performance parameters on separation of biobutanol by ionic liquids have been discussed and compared for different cation and anion based ionic liquids. The typical methodology for investigation have been adopted such as contacting the equal amount of biobutanol and ionic liquids for a specific time say, 30 minutes to confirm the equilibrium. Further, biobutanol phase were analyzed using GC to know the concentration of biobutanol and material balance were used to find the concentration in ionic liquid.

Keywords: biobutanol, separation, ionic liquids, sustainability, biorefinery, waste biomass

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Authors: Luciana P. Mazur, Tatiana A. Pozdniakova, Rui A. R. Boaventura, Vitor J. P. Vilar

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The principal mechanism of metal ions sequestration by brown algae involves the formation of complexes between the metal ion and functional groups present on the cell wall of the biological material. To understand the role of functional groups on copper(II) uptake by Ascophyllum nodosum, some functional groups were chemically modified. The esterification of carboxylic groups was carried out by suspending the biomass in a methanol/HCl solution under stirring for 48 h and the blocking of the sulfonic groups was performed by repeating the same procedure for 4 cycles of 48 h. The methylation of amines was conducted by suspending the biomass in a formaldehyde/formic acid solution under shaking for 6 h and the chemical modification of sulfhydryl groups on the biomass surface was achieved using dithiodipyridine for 1 h. Equilibrium sorption studies for Cu2+ using the raw and esterified algae were performed at pH 2.0 and 4.0. The experiments were performed using an initial copper concentration of 300 mg/L and algae dose of 1.0 g/L. After reaching the equilibrium, the metal in solution was quantified by atomic absorption spectrometry. The biological material was analyzed by Fourier Transform Infrared Spectroscopy and Potentiometric Titration techniques for functional groups identification and quantification, respectively. The results using unmodified algae showed that the maximum copper uptake capacity at pH 4.0 and 2.0 was 1.17 and 0.52 mmol/g, respectively. At acidic pH values most carboxyl groups are protonated and copper sorption suffered a significant reduction of 56%. Blocking the carboxylic, sulfonic, amines and sulfhydryl functional groups, copper uptake decreased by 24/26%, 69/81%, 1/23% and 40/27% at pH 2.0/4.0, respectively, when compared to the unmodified biomass. It was possible to conclude that the carboxylic and sulfonic groups are the main functional groups responsible for copper binding (>80%). This result is supported by the fact that the adsorption capacity is directly related to the presence of carboxylic groups of the alginate polymer, and the second most abundant acidic functional group in brown algae is the sulfonic acid of fucoidan that contributes, to a lower extent, to heavy metal binding, particularly at low pH.

Keywords: biosorption, brown marine macroalgae, copper, ion-exchange

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Authors: Maria Altamirano, Alfonso Duran

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Biostimulation has recently become important in order to improve the stability and performance of the anaerobic digestion (AD) process. This strategy involves the addition of nutrients or supplements to improve the rate of degradation of a native microbial consortium. With the aim of biostimulate sytrophism between secondary fermenting bacteria and methanogenic archaea, improving metabolite degradation and efficient conversion to methane, the addition of conductive materials, mainly carbon based have been studied. This research seeks to highlight the effect that coconut biochar (CBC) has on the metanogenic conversion of the organic fraction of municipal solid waste (OFMSW), analyzing the surface chemistry properties that give biochar its capacity to serve as a redox mediator in the anaerobic digestion process. The biochar characterization techniques were electrical conductivity (EC) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier Transform Infrared Transmission Spectroscopy (FTIR) and Cyclic Voltammetry (CV). Effect of coconut biochar addition was studied using Authomatic Methane Potential Test System (AMPTS II) applying a one-way variance analysis to determine the dose that leads to higher methane performance. The surface chemistry of the CBC could confer properties that enhance the AD process, such as the presence of alkaline and alkaline earth metals and their hydrophobicity that may be related to their buffering capacity and the adsorption of polar and non-polar compounds, such as NH4+ and CO2. It also has aromatic functional groups, just as quinones, whose potential as a redox mediator has been demonstrated and its morphology allows it to form an immobilizing matrix that favors a closer activity among the syntrophic microorganisms, which directly contributed in the oxidation of secondary metabolites and the final reduction to methane, whose yield is increased by 39% compared to controls, with a CBC dose of 1 g/L.

Keywords: anaerobic digestion, biochar, biostimulation, syntrophic metabolism

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Authors: Shalini Arora, Sri Sivakumar

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The deep removal of high molecular weight sulphur compounds (e.g., 4,6, dimethyl dibenzothiophene) is challenging due to their steric hindrance. Hydrogenation desulfurization (HYD) pathway is the main pathway to remove these sulfur compounds, and it is mainly governed by the number of type 2 sites. The formation of type 2 sites can be enhanced by modulating the pore structure and the interaction between the active metal and support. To this end, we report the enhanced HDS catalytic activity of ultrasmall NiMo supported on amorphous alumina (A-Al₂O₃) catalysts by one pot colloidal synthesis method followed by calcination and sulfidation. The amorphous alumina (A-Al₂O₃) was chosen as the support due to its lower surface energy, better physicochemical properties, and enhanced acidic sites (due to the dominance of tetra and penta coordinated [Al] sites) than crystalline alumina phase. At 20% metal oxide composition, NiMo supported on A-Al₂O₃ catalyst showed 1.4 and 1.2 times more reaction rate constant and turn over frequency (TOF) respectively than the conventional catalyst (wet impregnated NiMo catalysts) for HDS reaction of dibenzothiophene reactant molecule. A-Al₂O₃ supported catalysts represented enhanced type 2 sites formation (because this catalystpossesses higher sulfidation degree (80%) and NiMoS sites (19.3 x 10¹⁷ sites/mg) with desired optimum stacking degree (2.5) than wet impregnated catalyst at same metal oxide composition 20%) along with higher active metal dispersion, Mo edge site fraction. The experimental observations were also supported by DFT simulations. Lower heat of adsorption (< 4.2 ev for MoS2 interaction and < 3.15 ev for Ni doped MoS2 interaction) values for A-Al₂O₃ confirmed the presence of weaker metal-support interaction in A-Al₂O₃ in contrast to crystalline ℽ-Al₂O3. The weak metal-support interaction for prepared catalysts clearly suggests the higher formation of type 2 sites which leads to higher catalytic activity for HDS reaction.

Keywords: amorphous alumina, colloidal, desulfurization, metal-support interaction

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