Search results for: biogenic amine

Authors: Amandeep Kaur, Sangeeta Sharma

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Keeping in view the serious entanglement of heavy metals ( Pb+2 and Ni+2) ions in an aqueous environment, a rapid search for efficient adsorbents for the adsorption of heavy metals has become highly desirable. In this quest, green synthesized Fe np’s have gathered attention because of their excellent adsorption capability of heavy metals from aqueous solution. This research report aims at the fabrication of Fe np’s using the fruit Cucumis melo and leaves of Ficus virens via a biogenic synthesis route. Further, synthesized CM-Fe-np’s and FV-Fe-np’s have been tested as potential bio-adsorbents for the removal of Pb+2 and Ni+2 by carrying out adsorption batch experiments. The influence of myriad parameters like initial concentration of Pb/Ni (5,10,15,20,25 mg/L), contact time (10 to 200 min.), adsorbent dosage (0.5, 0.10, 0.15 mg/L), shaking speed (120 to 350 rpm) and pH value (6,7,8,9) has been investigated. The maximum removal with CM-Fe-np’s and FV-Fe-np’s has been achieved at pH 7, metal conc. 5 mg/L, dosage 0.9 g/L, shaking speed 200 rpm and reaction contact time 200 min during the adsorption experiment. The results obtained are found to be in accordance with Freundlich and Langmuir's adsorption models; consequently, they could be highly applicable to the wastewater treatment plant.

Keywords: adsorption, biogenic synthesis, nanoparticles, nickel, lead

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Authors: Po-Sheng Kuo, Che-Wei Lu, Ssu-Ching Chen

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Chlorinated ethenes (CEs) constitute a predominant contaminant in Taiwan's native polluted sites, particularly in groundwater inundated with sulfate salts that substantially impede remediation efforts. The reduction of sulfate by sulfate-reducing bacteria (SRB) impairs the dechlorination efficiency of Dehalococcoides by generating hydrogen sulfide (H₂S), resulting in incomplete chloride degradation and thereby leading to the failure of bioremediation. In order to elucidate interactions between sulfate reduction and dechlorination, this study aims to establish a co-culture system of Dehalococcoides and SRB, overcoming H₂S inhibition by employing the synthesis of ferrous sulfide (FeS), which is commonly utilized in chemical remediation due to its high reduction potential. Initially, the study demonstrates that the addition of ferrous chloride (FeCl₂) effectively removed H₂S production from SRB and enhanced the degradation of trichloroethylene to ethene. This process overcomes the inhibition caused by H₂S produced by SRB in high sulfate environments. Compared to different concentrations of ferrous dosages for the biogenic generation of FeS, the efficiency was optimized by adding FeCl₂ at an equal ratio to the concentration of sulfate in the environment. This was more effective in removing H₂S and crystal particles under 10 times smaller than those synthesized under excessive FeCl₂ dosages, addressing clogging issues in situ remediation. Finally, utilizing Taiwan's indigenous dechlorinating consortium in a simulated high sulfate-contaminated environment, the biodiversity of microbial species was analyzed to reveal a higher species richness within the FeS group, conducive to ecological stability. This study validates the potential of the co-culture system in generating biogenic FeS under sulfate and CEs co-contamination, removing sulfate-reducing products, and improving CE remediation through integrated chemical and biological remediations.

Keywords: biogenic ferrous sulfide, chlorinated ethenes, Dehalococcoides, sulfate-reducing bacteria, sulfide inhibition

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Authors: Wan-Tzu Yen, Yu-Chen Luo, I-Ping Liu, Po-Hsuan Yeh, Sheng-Hsun Fu, Yuh-Lang Lee

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Self-assembled characteristics and adsorption performance of 1-dodecylamine molecules on gold (Au) (111) surfaces were characterized via cyclic voltammetry (CV), surface-enhanced infrared absorption spectroscopy (SEIRAS) and scanning tunneling microscopy (STM). The present study focused on the formation of 1-dodecylamine (DDA) on a gold surface with respect to the ex-situ arrangement of an adlayer on the Au(111) surface, and phase transition at potential dynamics carried out by EC-STM. This study reveals that alkyl amine molecules were formed an adsorption pattern with highly regular “lie down shape” on Au(111) surface, even in an extreme acid system (pH = 1). Acidic electrolyte (HClO₄) could protonate the surface of alkyl amine of a monolayer of the gold surface when potential shifts to negative. The quite stability of 1-dodecylamine on the gold surface maintained the monolayer across the potential window (0.1-0.8V). This transform model was confirmed by EC-STM. In addition, amine-modified Au(111) electrode adlayer used to examine how to affect an electron transfer across an interface using [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox pair containing 0.1 M HClO₄ solution.

Keywords: cyclic voltammetry, dodecylamine, gold (Au)(111), scanning tunneling microscopy, self-assembled monolayer, surface-enhanced infrared absorption spectroscopy

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Authors: Abdallah Sofiane Berrouk, Dara Satyadileep

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This paper investigates the feasibility of retrofitting a middle-east based commercial amine sweetening unit with a split-flow scheme which involves withdrawing a portion of partially stripped semi-lean solvent from the stripping column and re-injecting it in the absorption column to reduce the overall energy consumption of the unit. This method is comprehensively explored by performing parametric analysis of the split fraction of the semi-lean solvent using a kinetics based process simulator ProMax V 3.2. Re-boiler duty, condenser duty, solvent cooling and pumping loads are analysed as functions of a split fraction of the semi-lean solvent from the stripper. It is shown that the proposed method significantly reduces the overall energy consumption of the unit resulting in an annual savings of 325,000 USD. The thorough economic analysis is performed using Aspen Economic Evaluation V 8.4 to reveal that the retrofit scheme pays back the capital cost in less than eight years and is highly recommended for any commercial plant having suitable provisions for solvent inlet/withdrawal on the columns.

Keywords: split flow, Amine, gas processing, optimization

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Authors: Sneha Singh, Abhimanyu Dev, Vinod Nigam

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The major issue which decides the impending use of gold nanoparticles (AuNPs) in nanobiotechnological applications is their particle size and stability. Often the AuNPs obtained biomimetically are considered useless owing to their instability in the aqueous medium and thereby limiting the widespread acceptance of this facile green synthesis procedure. So, the use of nontoxic surfactants is warranted to stabilize the biogenic nanoparticles (NPs). But does the surfactant only play a role in stabilizing by being adsorbed to the NPs surface or can it have any other significant contribution in synthesis process and controlling their size as well as shape? Keeping this idea in mind, AuNPs were synthesized by using surfactant treated (lechate) and untreated (cell lysate supernatant) Bacillus licheniformis cell extract. The cell extracts mediated reduction of chloroauric acid (HAuCl 4) in the presence of non-ionic surfactant, Tween 20 (TW20), and its effect on the AuNPs stability was studied. Interestingly, the surfactant used in the study served as potential alternative to harvest cellular enzymes involved in bioreduction process in a hassle free condition. The surfactants ability to solubilize/leach membrane proteins and simultaneously stabilizing the AuNPs could have advantage from process point of view as it will reduce the time and economics involve in the nanofabrication of biogenic NPs. The synthesis was substantiated with UV-Vis spectroscopy, Dynamic light scattering study, FTIR spectroscopy, and Transmission electron microscopy. The Zeta potential of AuNPs solutions was measured routinely to corroborate the stability observations recorded visually. Highly stable, ultra-small AuNPs of 2.6 nm size were obtained from the study. Further, the biological efficacy of the obtained AuNPs as potential antibacterial agent was evaluated against Bacilllus subtilis, Pseudomonas aeruginosa, and Escherichia coli by observing the zone of inhibition. This potential of AuNPs of size < 3 nm as antibacterial agent could pave way for development of new antimicrobials and overcoming the problems of antibiotics resistance

Keywords: antibacterial, bioreduction, nanoparticles, surfactant

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Authors: Nuray Yılmaz Baran

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The conjugated Schiff base polymers which are also called as polyazomethines are promising materials for various applications due to their good thermal resistance semiconductive, liquid crystal, fiber forming, nonlinear optical outstanding photo- and electroluminescence and antimicrobial properties. In recent years, polyazomethines have attracted intense attention of researchers especially due to optoelectronic properties which have made its usage possible in organic light emitting diodes (OLEDs), solar cells (SCs), organic field effect transistors (OFETs), and photorefractive holographic materials (PRHMs). In this study, N-(pyridin-2-ylmethylidene)pyridin-2-amine Schiff base was synthesized from condensation reaction of 2-aminopyridine with 2-pyridine carbaldehyde. Polymerization of Schiff base was achieved by polycondensation reaction using NaOCl oxidant in methanol medium at various time and temperatures. The synthesized Schiff base monomer and polymer (Poly(N-(pyridin-2-ylmethylidene)pyridin-2-amine)) was characterized by UV-vis, FT-IR, 1H-NMR, XRD techniques. Molecular weight distribution and the surface morphology of the polymer was determined by GPC and SEM-EDAX techniques. Thermal behaviour of the monomer and polymer was investigated by TG/DTG, DTA and DSC techniques.

Keywords: polyazomethines, polycondensation reaction, Schiff base polymers, thermal stability

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Authors: Rihana Hadjeb, Djamel Barkat

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Schiff bases derived from o-hydroxybenzaldehyde has attracted a great interest not only for its promising applications towards linear and non-linear optical properties, biological activity and technological applications but also used as model compounds for the theory of hydrogen bonding. Due to its intramolecular hydrogen bonding, depending on the position of proton in the hydrogen bond o-hydroxy salicylidene Schiff bases exhibit two tautomeric forms, enol-imine (E-form) and keto-enamine (K-form) both in solution and in crystalline state. A zwitterionic structure also appears due to a proton transfer in enol – imine and keto – amine tautomer. These classes of compounds also exhibit thermochromic and photochromic behavior. We undertook in this study the synthesis of ten compounds of hydroxy Schiff bases from the condensation of salicylic aldehyde and aniline substituted in the ortho, meta and para by the methyl, chloro and nitro groups. To study the keto-enol equilibrium of the compounds; UV-VIS spectra were studied in different polarity solvents. The compounds were in tautomeric equilibrium (enol imine O–H•••N, keto-amine O•••H–N forms). For some derivatives of salicylideneanilines the keto-amine form was observed in both ethanol and dioxane. IR results showed that all Schiff bases studied favor the enol-imine form over the keto form.

Keywords: salicylideneaniline, tautomerism, keto-enol equilibrium, UV-VIS spectroscopy, solvent effect

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Authors: Ben Yahia Nouha, Harris Chris, Sebei Abdelaziz, Boussen Slim, Chaabani Fredj

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The present work has set itself the objective of studying non-detritic siliceous rocks of the extreme northwest Tunisia. It aims to examine the origin and their sedimentary depositional environment based on mineralogical and geochemical characteristics. The different sections were located in the area of Babouch and the area of Tabarka. The collected samples were subjected to mineralogical and geochemical characterization using different analytical methods: X-ray diffraction (XRD), geochemical analysis (ICP- AES), isotopic geochemistry (δ18O), to assess their suitability for industrial use. X-ray powder diffraction of the pure siliceous rock indicates quartz as the major mineral, with the total lack of amorphous silica. Trace impurities, such as carbonate and clay minerals, are concealed in the analytical results. The petrographic examination revealed allowed us to deduce that this rock was deriving from tests of siliceous organisms (the radiolarians). The chemical composition shows that SiO2, Al2O3, and Fe2O3 represent the most abundant oxides. The other oxides are present in negligible quantities. Geochemical data support a biogenic and non-hydrothermal origin of babouchite silica. Oxygen isotopic has shown that babouchites were formed in an environment with a high temperature ranging from 56 °C to 73 °C.

Keywords: biogenic silica, babouchite formation, XRD, chemical analysis, oxygen isotopic, northwest tunisia

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Authors: Xiaohua Jing

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Efficient extraction for separation of V and Cr in the leaching/aqueous solution is essential to the reuse of V and Cr in the V-Cr slag. Trioctylamine, a common tertiary amine extractant, with some good characters (e.g., weak base, insoluble in water and good stability) different from N1923, was investigated in this paper. The separation factor of Cr and V can be reached to 230.71 when initial pH of the aqueous solution is 0.5, so trioctylamine can be used for extracting Cr from the leaching/aqueous solution contained V and Cr. The highest extraction percentages of Cr and V were 98.73% and 90.22% when the initial pH values were 0.5 and 1.5, respectively. Via FT-IR spectra of loaded organic phase and trioctylamine, the hydrogen bond association mechanism of extracting V and Cr was investigated, which was the same with the way of extracting the two metals with primary amine N1923.

Keywords: selective extraction, trioctylamine, V and Cr, separation factor, hydrogen bond association

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Authors: K. F. Khan, Samsuddin Khan

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The Paleoproterozoic phosphorite deposit of Sallopat block of Banswara district of Rajasthan belongs to kalinjara formation of lunavada group of Aravalli Super Group. The phosphorites are found to occur as massive, brecciated, laminated and stromatolitic associated with calcareous quartzite, interbedded dolomite and multi coloured chert. The phosphorites are showing alternate brown and grey coloured concentric rims which are composed of phosphate, calcite and quartz minerals. Petro-mineralogical studies of phosphorite samples using petrological microscope, XRD, FEG- SEM and EDX reveal that apatite-(CaF) and apatite-(CaOH) are phosphate minerals which are intermixed with minor amount of carbonate materials. Sporadic findings of the uniform tiny granules of partially anisotropic apatite-(CaF) along with dolomite, calcite, quartz, muscovite, zeolite and other gangue minerals have been observed with the replacement of phosphate material by quartz and carbonate. The presence of microbial filaments of organic matter and alternate concentric rims of stromatolitic structure may suggest that the deposition of the phosphate took place in shallow marine oxidizing environmental conditions leading to the formation of phosphorite layers as primary biogenic precipitates by bacterial or algal activities. Different forms and texture of phosphate minerals may be due to environmental vicissitudes at the time of deposition followed by some replacement processes and biogenic activities.

Keywords: apatite, petro-mineralogy, phosphorites, sallopat, stromatolites

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Authors: Ali Zein Aalabiden Tlais, Alessio Da Ros, Pasquale Filannino, Olimpia Vincentini, Marco Gobbetti, Raffaella Di Cagno

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This study is an example of apple by-products (AP) recycling through a designed fermentation by selected autochthonous Lactobacillus plantarum AFI5 and Lactobacillus fabifermentans ALI6 used singly or as binary cultures with the selected Saccharomyces cerevisiae AYI7. Compared to Raw-, Unstarted- and Chemically Acidified-AP, Fermented-AP promoted the highest levels of total and insoluble dietary fibers, antioxidant activity, and free phenolics. The binary culture of L. plantarum AFI5 and S. cerevisiae AYI7 had the best effect on the bioavailability phenolic compounds as resulted by the Liquid chromatography-mass spectrometry validated method. The accumulation of phenolic acid derivatives highlighted microbial metabolism during AP fermentation. Bio-converted phenolic compounds were likely responsible for the increased antioxidant activity. The potential health-promoting effects of Fermented-AP were highlighted using Caco-2 cells. With variations among single and binary cultures, fermented-AP counteracted the inflammatory processes and the effects of oxidative stress in Caco-2 cells and preserved the integrity of tight junctions. An alternative and suitable model for food by-products recycling to manufacture a dietary supplement fortified with biogenic compounds was proposed. Highlighting the microbial metabolism of several phenolic compounds, undoubted additional value to such downstream wastes was created.

Keywords: apple by-products, antioxidant, fermentation, phenolic compounds

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Authors: Arash Esmaeili, Zhibang Liu, Yang Xiang, Jimmy Yun, Lei Shao

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A high-pressure carbon dioxide (CO₂) absorption from a specific off-gas in a conventional column has been evaluated for the environmental concerns by the Aspen HYSYS simulator using a wide range of single absorbents and piperazine (PZ) blended solutions to estimate the outlet CO₂ concentration, CO₂ loading, reboiler power supply, and regeneration heat duty to choose the most efficient solution in terms of CO₂ removal and required heat duty. The property package, which is compatible with all applied solutions for the simulation in this study, estimates the properties based on the electrolyte non-random two-liquid (E-NRTL) model for electrolyte thermodynamics and Peng-Robinson equation of state for vapor phase and liquid hydrocarbon phase properties. The results of the simulation indicate that piperazine, in addition to the mixture of piperazine and monoethanolamine (MEA), demands the highest regeneration heat duty compared with other studied single and blended amine solutions, respectively. The blended amine solutions with the lowest PZ concentrations (5wt% and 10wt%) were considered and compared to reduce the cost of the process, among which the blended solution of 10wt%PZ+35wt%MDEA (methyldiethanolamine) was found as the most appropriate solution in terms of CO₂ content in the outlet gas, rich-CO₂ loading, and regeneration heat duty.

Keywords: absorption, amine solutions, aspen HYSYS, CO₂ loading, piperazine, regeneration heat duty

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Authors: Dara Satyadileep, Abdallah S. Berrouk

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Selective absorption of Hydrogen Sulphide (H2S) using methyldiethanol amine (MDEA) has become a point of interest as means of minimizing capital and operating costs of gas sweetening plants. This paper discusses the prominence of optimum design of column internals to best achieve H2S selectivity using MDEA. To this end, a kinetics-based process simulation model has been developed for a commercial gas sweetening unit. Trends of sweet gas H2S & CO2 contents as function of fraction active area (and hence residence time) have been explained through analysis of interdependent heat and mass transfer phenomena. Guidelines for column internals design in order to achieve desired degree of H2S selectivity are provided. Also the effectiveness of various operating conditions in achieving H2S selectivity for an industrial absorber with fixed internals is investigated.

Keywords: gas sweetening, H2S selectivity, methyldiethanol amine, process simulation, residence time

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Authors: Mudawi M. Nour

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Background: Now a days, the multidisciplinary scientific research conception in the field of nanotechnology has witnessed development with regard to the numerous applications and synthesis of nanomaterials. Objective: The current investigation has been conducted with the main focus on the green synthesis of silver nanoparticles from the leaves of Salvadora persica and its antibacterial activity against MDR pathogens E. coli and S. aureus. Methodology: Silver nanoparticles (AgNPs) were prepared after addition of aqueous extract of Salvadora persica leaves. The UV-Vis spectrophotometer, Transmission Electron Microscopy (TEM), zeta potential and Scanning Electron Microscopy (SEM) were employed to detect the particle size and morphology, besides Fourier transform infra-red spectrometer (FTIR) analysis was performed to determine the capping and stabilizing agents in the extract. Antibacterial assay for the biogenic AgNPs was conducted against E. coli and S. aureus. Results: Color change of the mixture from yellow to dark brown is the first indication to AgNPs formation. Furthermore, 420 nm was the peak value for UV-Vis spectroscopy absorption of the mixture. Besides, TEM and SEM micrographs showed wide variability in the diameter of smaller NPs aggregated together with spherical shapes, and zeta sizer showed about 153.3 nm as an average size of nanoparticles. Microbial suppression was noticed for the tested microorganisms. Furthermore, with the help of FTIR analysis, the biomolecules that act as capping and stabilizing agents of AgNPs are proteins and phenols present in the plant extract. Conclusion: Salvadora persica leaves extract act as a reducing and stabilizing agent for the synthesis of AgNPs, keeping its ability to suppress the MDR pathogen.

Keywords: green synthesis, FTIR, MDR pathogen, salvadora persica

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Authors: Adrien Cornille, Sylvain Caillol, Bernard Boutevon

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The development of polyurethanes began in 1937 at I. G. Farbenindustrie where Bayer with coworkers discovered the addition polymerization reaction between diisocyanates and diols. Since their discovery, the demand in PU has continued to increase and it will attain in 2016 a production of 18 million tons. However, isocyanates compounds are harmful to human and environment. Methylene diphenyl 4,4’-diisocyanate (MDI) and toluene diisocyanate (TDI), the most widely used isocyanates in PU industry, are classified as CMR (Carcinogen, Mutagen, and Reprotoxic). In order to design isocyanate-free materials, an interesting alternative is the use of Polyhydroxyurethanes (PHUs) by reaction between cyclic carbonate and polyfunctional amines. The main problem concerning PHUs synthesis relates to the low reactivity of carbonate/amine reaction. To solve this issue, many studies in the literature have been conducted to design PHU from more reactive cyclic-carbonates, bearing electro-withdrawing substituent or by using six-membered, seven-membered or thio-cyclic carbonate. The main drawback of all these systems remains the low molar masses obtained for the synthesized PHUs, which hinders their use for material applications. Therefore, we developed another strategy to afford new hybrid PHU with high conversion. This very innovative two-step approach consists in the first step in the synthesis of aminotelechelic PHU oligomers with different chain length from bis-cyclic carbonate with different excess of primary amine functions. In the second step, these aminotelechelic PHU oligomers were used in formulation with biobased epoxy monomers (from cashew nut shell liquid and tannins) to synthesize hybrid polyepoxyurethane polymers. These materials were then characterized by thermal and mechanical analyses.

Keywords: polyurethane, polyhydroxyurethane, aminotelechelic NIPU oligomers, carbonates, epoxy, amine, epoxyurethane polymers, hybrid polymers

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Authors: Muhammad Shahzad Tufail, Iram Liaqat, Umer Sohail Meer, Muhammad Ishtaiq, Muhammad Sattar

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Nanotechnology is a vibrant field with numerous applications in many different branches of science and technology. Several methods are used to synthesize nanoparticles (NPs), which have multiple range of applications. Comparatively, the biogenic synthesis of NPs is a more economical and environmentally favourable method than the traditional chemical method. The current study aims to synthesize biogenically silver nanoparticles (AgNPs) using bacterial isolates. Four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the synthesis of AgNPs from silver nitrate (AgNO3) solution. The biofilm time kinetics of four bacterial isolates (P. aeruginosa, E. coli, B. licheniformis and B. subtilis) was analysed by incubating bacterial cultures at 37◦C in test tubes over a period of different time intervals i.e., 2, 3, 5 and 7 days following crystal violet staining method. All the four strains had ability to form strong biofilms between 48 to 72 hours of incubation. Two strains (B. subtilis and B. licheniformis) formed significant (p < 0.05) biofilm after 3 days of incubation period. The other two strains (E. coli and P. aeruginosa) showed strong biofilm formation after 2 days of incubation. Next, the antibiofilm activity of biogenically synthesized AgNPs (10 - 100 µgmL-1) was analysed against biofilm forming human pathogenic bacteria. Findings of the work revealed that 60-90% inhibition was observed at 60 µgmL-1 of AgNPs, while maximum inhibition (i.e.,100%) was found at highest concentration (90 µgmL-1). It was evident that highly significant (p < 0.05) decrease in biofilm formation was observed with increasing concentration of AgNPs.

Keywords: antibiofilm, biofilm formation, nanotechnology, pathogenic bacteria, silver nanoparticles

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Authors: Yan Bachtiar Muslih, Hangga Wijaya, Trio Fani, Putri Agustin

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Demand of Energy in Indonesia always increases 5-6% a year, but production of conventional energy always decreases 3-5% a year, it means that conventional energy in 20-40 years ahead will not able to complete all energy demand in Indonesia, one of the solve way is using unconventional energy that is gas hydrate, gas hydrate is gas that form by biogenic process, gas hydrate stable in condition with extremely depth and low temperature, gas hydrate can form in two condition that is in pole condition and in deep-sea condition, wherein this research will focus in gas hydrate that association with methane form methane hydrate in deep-sea condition and usually form in depth between 150-2000 m, this research will focus in process of methane hydrate formation that is biogenic process and the important role of deep-sea sediment so can produce accumulation of methane hydrate, methane hydrate usually will be accumulated in find sediment in deep-sea environment with condition high-pressure and low-temperature this condition too usually make methane hydrate change into white nodule, methodology of this research is geology field work and laboratory analysis, from geology field work will get sample data consist of 10-15 samples from Kerek Formation outcrops as random for imagine the condition of deep-sea environment that influence the methane hydrate formation and also from geology field work will get data of measuring stratigraphy in outcrops Kerek Formation too from this data will help to imagine the process in deep-sea sediment like energy flow, supply sediment, and etc, and laboratory analysis is activity to analyze all data that get from geology field work, the result of this research can used to exploration activity of methane hydrate in another prospect deep-sea environment in Indonesia.

Keywords: methane hydrate, deep-sea sediment, kerek formation, sub-basin of kendeng, central java, Indonesia

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Authors: Rahim Shahrokhi, Junboum Park

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Per- and Polyfluoroalkyl Substances (PFASs) are environmentally persistent halogenated hydrocarbons that have been widely used in many industrial and commercial applications. Recently, contaminating the soil and groundwater due to the ubiquity of PFAS in environments has raised great concern. Adsorption technology is one of the most promising methods for PFAS removal. Chitosan is a biopolymer substance with abundant amine and hydroxyl functional groups, which render it a good adsorbent. This study has tried to enhance the adsorption capacity of chitosan by grafting more amine functional groups on its surface for the removal of two long (PFOA and PFOS) and two short-chain (PFBA, PFBS) PFAS substances from the aqueous phase. A series of batch adsorption tests have been performed to evaluate the adsorption capacity of the used sorbent. Also, the sorbent was analyzed by SEM, FT-IR, zeta potential, and XRD tests. The results demonstrated that both chitosan beads have good potential for adsorbing short and long-chain PFAS from the aqueous phase.

Keywords: PFAS, chitosan beads, adsorption, grafted chitosan

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Authors: Arash Esmaeili, Zhibang Liu, Yang Xiang, Jimmy Yun, Lei Shao

Abstract:

A high pressure carbon dioxide (CO₂) absorption from a specific gas in a conventional column has been evaluated by the Aspen HYSYS simulator using a wide range of single absorbents and blended solutions to estimate the outlet CO₂ concentration, absorption efficiency and CO₂ loading to choose the most proper solution in terms of CO₂ capture for environmental concerns. The property package (Acid Gas-Chemical Solvent) which is compatible with all applied solutions for the simulation in this study, estimates the properties based on an electrolyte non-random two-liquid (E-NRTL) model for electrolyte thermodynamics and Peng-Robinson equation of state for the vapor and liquid hydrocarbon phases. Among all the investigated single amines as well as blended solutions, piperazine (PZ) and the mixture of piperazine and monoethanolamine (MEA) have been found as the most effective absorbents respectively for CO₂ absorption with high reactivity based on the simulated operational conditions.

Keywords: absorption, amine solutions, Aspen HYSYS, carbon dioxide, simulation

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Authors: Avinash Thakur, Parmjit S. Panesar, Manohar Singh

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The distribution coefficient, KD for the reactive extraction of lactic acid from aqueous solutions of lactic acid using 10-30% (v/v) tri-n-octyl amine (extractant) dissolved in n-hexane (inert diluent) and 20% (v/v) oleyl alcohol (modifier) was optimized by using response surface methodology (RSM). A three level Box-Behnken design was employed for experimental design, analysis of the results and to depict the combined interactive effect of seven independent variables, viz lactic acid concentration (cl), pH, TOA concentration in organic phase (ψ), treat ratio (φ), temperature (T), agitation speed (ω) and batch agitation time (τ) on distribution coefficient of lactic acid. The regression analysis recommended that the quadratic model is significant (R2 and adjusted R2 are 98.72 % and 98.69 % respectively) for analysis. A numerical optimization had resulted in maximum lactic acid distribution coefficient (KD) of 3.16 at the optimized values for test variables, cl, pH, ψ, φ, T, ω and τ as 0.15 [M], 3.0, 22.75% (v/v), 1.0 (v/v), 26°C, 145 rpm and 23 min respectively. A good agreement between the predicted and experimentally obtained values for distribution coefficient using the optimized conditions was exhibited.

Keywords: Distribution coefficient, tri-n-octylamine, lactic acid, response surface methodology

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Authors: Natalia Alzate-Carvajal, Diego A. Acevedo-Guzman, Victor Meza-Laguna, Mario H. Farias, Luis A. Perez-Rey, Edgar Abarca-Morales, Victor A. Garcia-Ramirez, Vladimir A. Basiuk, Elena V. Basiuk

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Direct covalent functionalization of prefabricated free-standing graphene oxide paper (GOP) is considered as the only approach suitable for systematic tuning of thermal, mechanical and electronic characteristics of this important class of carbon nanomaterials. At the same time, the traditional liquid-phase functionalization protocols can compromise physical integrity of the paper-like material up to its total disintegration. To avoid such undesirable effects, we explored the possibility of employing an alternative, solvent-free strategy for facile and nondestructive functionalization of GOP with two representative aliphatic amines, 1-octadecylamine (ODA) and 1,12-diaminododecane (DAD), as well as with two aromatic amines, 1-aminopyrene (AP) and 1,5-diaminonaphthalene (DAN). The functionalization was performed under moderate heating at 150-180 °C in vacuum. Under such conditions, it proceeds through both amidation and epoxy ring opening reactions. Comparative characterization of pristine and amine-functionalized GOP mats was carried out by using Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopy (XPS), thermogravimetric (TGA) and differential thermal analysis, scanning electron and atomic force microscopy (SEM and AFM, respectively). Besides that, we compared the stability in water, wettability, electrical conductivity and elastic (Young's) modulus of GOP mats before and after amine functionalization. The highest content of organic species was obtained in the case of GOP-ODA, followed by GOP-DAD, GOP-AP and GOP-DAN samples. The covalent functionalization increased mechanical and thermal stability of GOP, as well as its electrical conductivity. The magnitude of each effect depends on the particular chemical structure of amine employed, which allows for tuning a given GOP property. Morphological characterization by using SEM showed that, compared to pristine graphene oxide paper, amine-modified GOP mats become relatively ordered layered assemblies, in which individual GO sheets are organized in a near-parallel pattern. Financial support from the National Autonomous University of Mexico (grants DGAPA-IN101118 and IN200516) and from the National Council of Science and Technology of Mexico (CONACYT, grant 250655) is greatly appreciated. The authors also thank David A. Domínguez (CNyN of UNAM) for XPS measurements and Dr. Edgar Alvarez-Zauco (Faculty of Science of UNAM) for the opportunity to use TGA equipment.

Keywords: amines, covalent functionalization, gas-phase, graphene oxide paper

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Authors: Chia-Yu Chang, Yi-Feng Lin

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CO2 capture has attracted significant research attention due to global warming. Among the various CO2 capture methods, membrane technology has proven to be highly efficient in capturing CO2 due to the ease at which this technology can be scaled up, its low energy consumptions, small area requirements and overall environmental friendliness for use by industrial plants. Capturing CO2 is to use a membrane contactor with a combination of water-repellent porous membranes and chemical absorption processes. In a CO2 membrane contactor system, CO2 passes through a hydrophobic porous membrane in the gas phase to contact the amine absorbent in the liquid phase. Consequently, additional CO2 gas is absorbed by amine absorbents. This study examines highly porous Polydimethylsiloxane (PDMS)/Polystyrene (PS) Nanofibrous Membranes and successfully coated onto a macroporous Al2O3 membrane. The performance of these materials in a membrane contactor system for CO2 absorption is also investigated. Compared with pristine PS nanofibrous membranes, the PDMS/PS nanofibrous membranes exhibit greater solvent resistance and mechanical strength, making them more suitable for use in CO2 capture by the membrane contactor. The resulting hydrophobic membrane contactor also demonstrates the potential for large-scale CO2 absorption during post-combustion processes in power plants.

Keywords: CO2 capture, polystyrene, polydimethylsiloxane, superhydrophobic

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Authors: Silvana Caglieri

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Theoretical study of acetylation of p-methylaniline catalyzed by Cu2+ ions from the analysis of intermediate of the reaction was carried out. The study of acetylation of amines is of great interest by the utility of its products of reaction and is one of the most frequently used transformations in organic synthesis as it provides an efficient and inexpensive means for protecting amino groups in a multistep synthetic process. Acetylation of amine is a nucleophilic substitution reaction. This reaction can be catalyzed by Lewis acid, metallic ion. In reaction mechanism, the metallic ion formed a complex with the oxygen of the acetic anhydride carbonyl, facilitating the polarization of the same and the successive addition of amine at the position to form a tetrahedral intermediate, determining step of the rate of the reaction. Experimental work agreed that this reaction takes place with the formation of a tetrahedral intermediate. In the present theoretical work were investigated the structure and energy of the tetrahedral intermediate of the reaction catalyzed by Cu2+ ions. Geometries of all species involved in the acetylation were made and identified. All of the geometry optimizations were performed by the method at the DFT/B3LYP level of theory and the method MP2. Were adopted the 6-31+G* basis sets. Energies were calculated using the Mechanics-UFF method. Following the same procedure it was identified the geometric parameters and energy of reaction intermediate. The calculations show 61.35 kcal/mol of energy for the tetrahedral intermediate and the energy of activation for the reaction was 15.55 kcal/mol.

Keywords: amides, amines, DFT, MP2

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Authors: El-Sohaimy Sobhy A., Androsova Natalia, Toshev Abuvali Djabarovec

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The conditions of the isolation of proteins from the hemp seeds were optimized in the current work. Moreover, the physicochemical and functional properties of hemp protein isolate were evaluated for its potential application in food manufacturing. The elastin protein is the most predominant protein in the protein profile with a molecular weight of 58.1 KDa, besides albumin, with a molecular weight of 31.5 KDa. The FTIR spectrum detected the absorption peaks of the amide I in 1750 and 1600 cm⁻¹, which pointed to C=O stretching while N-H was stretching at 1650-1580 cm⁻¹. The peak at 3250 was related to N-H stretching of primary aliphatic amine (3400-3300 cm⁻¹), and the N-H stretching for secondary (II) amine appeared at 3350-3310 cm⁻¹. Hemp protein isolate (HPI) was showed high content of arginine (15.52 g/100 g), phenylalanine+tyrosine (9.63 g/100 g), methionine + cysteine (5.49 g/100 g), leucine + isoleucine (5.21 g/100 g) and valine (4.53 g/100 g). It contains a moderate level of threonine (3.29 g/100 g) and lysine (2.50 g/100 g), with the limiting amino acid being a tryptophan (0.22 g/100 g HPI). HPI showed high water-holding capacity (4.5 ± 2.95 ml/g protein) and oil holding capacity (2.33 ± 1.88 ml/g) values. The foaming capacity of HPI was increased with increasing the pH values to reach the maximum value at pH 11 (67.23±3.20 %). The highest emulsion ability index of HPI was noted at pH 9 (91.3±2.57 m2/g) with low stability (19.15±2.03).

Keywords: Cannabis sativa ssp., protein isolate, isolation conditions, amino acid composition, chemical properties, functional properties

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Authors: Li Chin Law, Epaminondas Mastorakos, Mohd Roslee Othman, Antonis Trakakis

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The paper introduces an alternative concept of carbon capture for shipping by using pre-combustion carbon capture technology (Pre-CCS), which was proven to be less energy intensive than post-combustion carbon capture from the engine exhaust. Energy assessment on amine-based post-combustion CCS on LNG-fuelled ships showed that the energy efficiency of CCS ships reduced from 48% to 36.6%. Then, an energy assessment was carried out to compare the power and heat requirements of the most used hydrogen production methods and carbon capture technologies. Steam methane reformer (SMR) was found to be 20% more energy efficient and achieved a higher methane conversion than auto thermal reaction and methane decomposition. Next, pressure swing adsorber (PSA) has shown a lower energy requirement than membrane separation, cryogenic separation, and amine absorption in pre-combustion carbon capture. Hence, an integrated system combining SMR and PSA (SMR-PSA) with waste heat integration (WHR) was proposed. This optimized SMR-based integrated system has achieved 65% of CO₂ reduction with less than 7-percentage point of energy penalty (41.7% of energy efficiency). Further integration of post-combustion CCS with the SMR-PSA integrated system improved carbon capture rate to 86.3% with 9-percentage points of energy penalty (39% energy efficiency). The proposed system was shown to be able to meet the carbon reduction targets set by International Maritime Organization (IMO) with certain energy penalties.

Keywords: shipping, decarbonisation, alternative fuels, low carbon, hydrogen, carbon capture

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Authors: William E. Bauta, Jennifer Rebeles, Reggie Jacob

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Porphyrins are noteworthy in biomedical science for their cancer tissue accumulation and photophysical properties. The preferential accumulation of some porphyrins in cancerous tissue has been known for many years. This, combined with their characteristic photophysical and photochemical properties, including their strong fluorescence and their ability to generate reactive oxygen species in vivo upon laser irradiation, has led to much research into the application of porphyrins as cancer diagnostic and therapeutic agents. Porphyrins have been used as dyes to detect cancer cells both in vivo and, less commonly, in vitro. In one example, human sputum samples from lung cancer patients and patients without the disease were dissociated and stained with the porphyrin TCPP (5,10,15,20-tetrakis-(4-carboxyphenyl)-porphine). Cells were analyzed by flow cytometry. Cancer samples were identified by their higher TCPP fluorescence intensity relative to the no-cancer controls. However, quantitative analysis of fluorescence in cell suspensions stained with multiple fluorophores requires particles stained with each of the individual fluorophores as controls. Fluorescent control particles must be compatible in size with flow cytometer fluidics and have favorable hydrodynamic properties in suspension. They must also display fluorescence comparable to the cells of interest and be stable upon storage amine-functionalized spherical polystyrene beads in the 5 to 20-micron diameter range that was reacted with TCPP and EDC in aqueous pH six buffer overnight to form amide bonds. Beads were isolated by centrifugation and tested by flow cytometry. The 10-micron amine-functionalized beads displayed the best combination of fluorescence intensity and hydrodynamic properties, such as lack of clumping and remaining in suspension during the experiment. These beads were further optimized by varying the stoichiometry of EDC and TCPP relative to the amine. The reaction was accompanied by the formation of a TCPP-related particulate, which was removed, after bead centrifugation, using a microfiltration process. The resultant TCPP-functionalized beads were compatible with flow cytometry conditions and displayed a fluorescence comparable to that of stained cells, which allowed their use as fluorescence standards. The beads were stable in refrigerated storage in the dark for more than eight months. This work demonstrates the first preparation of porphyrin-functionalized flow cytometry control beads.

Keywords: tetraaryl porphyrin, polystyrene beads, flow cytometry, peptide coupling

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Authors: Mohamed Amine Bouraoui

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The aim of this paper is to realize the importance of a CRM approach, to detect the degree of awareness of Tunisian managers of this importance and analyse the degree of integration of CRM in the Tunisian companies. Initially, we focus on the definition and components of CRM, then we focus on the level of integration of CRM within Tunisian enterprises.

Keywords: CRM, operational tools, analytical tools, Tunisian company

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Authors: Aida Rafat, Ramazan Kahraman, Mert Atilhan

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The aggressive corrosion behavior of conventional amine solvents is one of main barriers against large scale commerizaliation of amine absorption process for carbon capture application. Novel CO2 absorbents that exhibit minimal corrosivity against operation conditions are essential to lower corrosion damage and control and ensure more robustness in the capture plant. This work investigated corrosion behavior of carbon steel CS1018 in various CO2 absrobent solvents. The tested solvents included the classical amines MEA, DEA and MDEA, piperazine activated solvents MEA/PZ, MDEA/PZ and MEA/MDEA/PZ as well as mixtures of MEA and Room Temperature Ionic Liquids RTIL, namely MEA/[C4MIM][BF4] and MEA/[C4MIM][Otf]. Electrochemical polarization technique was used to determine the system corrosiveness in terms of corrosion rate and polarization behavior. The process parameters of interest were CO2 loading and solution temperature. Electrochemical resulted showed corrosivity order of classical amines at 40°C is MDEA> MEA > DEA wherase at 80°C corrosivity ranking changes to MEA > DEA > MDEA. Corrosivity rankings were mainly governed by CO2 absorption capacity at the test temperature. Corrosivity ranking for activated amines at 80°C was MEA/PZ > MDEA/PZ > MEA/MDEA/PZ. Piperazine addition seemed to have a dual advanatge in terms of enhancing CO2 absorption capacity as well as nullifying corrosion. For MEA/RTIL mixtures, the preliminary results showed that the partial repalcement of aqueous phase in MEA solution by the more stable nonvolatile RTIL solvents reduced corrosion rates considerably.

Keywords: corrosion, amines, CO2 capture, piperazine, ionic liquids

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Authors: Hammad Majeed, Hanna Knuutila, Magne Hilestad, Hallvard Svendsen

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Formation of aerosols can cause serious complications in industrial exhaust gas CO2 capture processes. SO3 present in the flue gas can cause aerosol formation in an absorption based capture process. Small mist droplets and fog formed can normally not be removed in conventional demisting equipment because their submicron size allows the particles or droplets to follow the gas flow. As a consequence of this aerosol based emissions in the order of grams per Nm3 have been identified from PCCC plants. In absorption processes aerosols are generated by spontaneous condensation or desublimation processes in supersaturated gas phases. Undesired aerosol development may lead to amine emissions many times larger than what would be encountered in a mist free gas phase in PCCC development. It is thus of crucial importance to understand the formation and build-up of these aerosols in order to mitigate the problem.Rigorous modelling of aerosol dynamics leads to a system of partial differential equations. In order to understand mechanics of a particle entering an absorber an implementation of the model is created in Matlab. The model predicts the droplet size, the droplet internal variable profiles and the mass transfer fluxes as function of position in the absorber. The Matlab model is based on a subclass method of weighted residuals for boundary value problems named, orthogonal collocation method. The model comprises a set of mass transfer equations for transferring components and the essential diffusion reaction equations to describe the droplet internal profiles for all relevant constituents. Also included is heat transfer across the interface and inside the droplet. This paper presents results describing the basic simulation tool for the characterization of aerosols formed in CO2 absorption columns and gives examples as to how various entering droplets grow or shrink through an absorber and how their composition changes with respect to time. Below are given some preliminary simulation results for an aerosol droplet composition and temperature profiles. Results: As an example a droplet of initial size of 3 microns, initially containing a 5M MEA, solution is exposed to an atmosphere free of MEA. Composition of the gas phase and temperature is changing with respect to time throughout the absorber.

Keywords: amine solvents, emissions, global climate change, simulation and modelling, aerosol generation

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Authors: Laura Norfolk, Georgina Zimbitas, Jan Sefcik, Sarah Staniland

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Magnetite nanoparticles (MNP) have been an area of increasing research interest due to their extensive applications in industry, such as in carbon capture, water purification, and crucially, the biomedical industry. The use of MNP in the biomedical industry is rising, with studies on their effect as Magnetic resonance imaging contrast agents, drug delivery systems, and as hyperthermic cancer treatments becoming prevalent in the nanomaterial research community. Particles used for biomedical purposes must meet stringent criteria; the particles must have consistent shape and size between particles. Variation between particle morphology can drastically alter the effective surface area of the material, making it difficult to correctly dose particles that are not homogeneous. Particles of defined shape such as octahedral and cubic have been shown to outperform irregular shaped particles in some applications, leading to the need to synthesize particles of defined shape. In nature, highly homogeneous MNP are found within magnetotactic bacteria, a unique bacteria capable of producing magnetite nanoparticles internally under ambient conditions. Biomineralisation proteins control the properties of the MNPs, enhancing their homogeneity. One of these proteins, Mms6, has been successfully isolated and used in vitro as an additive in room-temperature co-precipitation reactions (RTCP) to produce particles of defined mono-dispersed size & morphology. When considering future industrial scale-up it is crucial to consider the costs and feasibility of an additive, as an additive that is not readily available or easily synthesized at a competitive price will not be sustainable. As such, additives selected for this research are inspired by the functional groups of biomineralisation proteins, but cost-effective, environmentally friendly, and compatible with scale-up. Diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine (PEHA) have been successfully used in RTCP to modulate the properties of particles synthesized, leading to the formation of octahedral nanoparticles with no use of organic solvents, heating, or toxic precursors. By extending this principle to a fluidic system, ongoing research will reveal whether the amine additives can also exert morphological control in an environment which is suited toward higher particle yield. Two fluidic systems have been employed; a peristaltic turbulent flow mixing system suitable for the rapid production of MNP, and a macrofluidic system for the synthesis of tailored nanomaterials under a laminar flow regime. The presence of the amine additives in the turbulent flow system in initial results appears to offer similar morphological control as observed under RTCP conditions, with higher proportions of octahedral particles formed. This is a proof of concept which may pave the way to green synthesis of tailored MNP on an industrial scale. Mms6 and amine additives have been used in the macrofluidic system, with Mms6 allowing magnetite to be synthesized at unfavourable ferric ratios, but no longer influencing particle size. This suggests this synthetic technique while still benefiting from the addition of additives, may not allow additives to fully influence the particles formed due to the faster timescale of reaction. The amine additives have been tested at various concentrations, the results of which will be discussed in this paper.

Keywords: bioinspired, green synthesis, fluidic, magnetite, morphological control, scale-up

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