Search results for: water vapor adsorption

Authors: Nomthandazo Precious Sibiya, Thembisile Patience Mahlangu, Sudesh Rathilal

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Heavy metal removal is critical in the wastewater treatment process due to its numerous harmful effects on human and aquatic life. There are several chemical and physical techniques for removing heavy metals from wastewater, including ion exchange, reverse osmosis, adsorption, electrodialysis, and ultrafiltration. However, adsorption technology has captivated researchers for years due to its low cost, high efficiency, and compatible with the environment. In this study, the adsorption effectiveness of three modified agro-waste materials was explored for the removal of lead from synthetic wastewater: banana peels (BP), orange peels (OP), and sugarcane bagasse (SB). The magnetite (Fe₃O₄) is incorporated with BP, OP, and SB at a ratio of 1:1 to create magnetic biosorbents. Characterization of biosorbents was carried out using and scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) to investigate surface morphology and elemental compositions, respectively. A series of batch experiments were carried out to investigate the effects of adsorbent mass, agitation time, and initial pH concentration on adsorption behaviour, as well as adsorption isotherms and kinetics. The removal efficiency of lead by the modified agro-waste materials proved to be superior to that of non-modified agro-waste materials. The proof of concept was achieved, and agro-waste materials can be paired with adsorption technology to effectively remove lead from aqueous media. The use of agricultural waste as biosorbents will aid in waste reduction and management.

Keywords: adsorption, isotherms, kinetics, agro waste, nanoparticles, batch

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Authors: Mozhgan Mohammadi, Arezoo Ghadi

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Arsenic is known as a potential threat to the environment. Therefore, the aim of this research is to assess the arsenic removal efficiency from an aqueous solution, with a new biosorbent composed of a black seed pulp (BSP). To treat BSP, the combination of two methods (i.e. treating with mineral acids and use at high temperature) was used and designed bio-sorbent called BSP-activated/carbonized. The BSP-activated and BSP-carbonized were also prepared using HCL and 400°C temperature, respectively, to compare the results of each three methods. Followed by, adsorption parameters such as pH, initial ion concentration, biosorbent dosage, contact time, and temperature were assessed. It was found that the combination method has provided higher adsorption capacity so that up to ~99% arsenic removal was observed with BSP-activated/carbonized at pH of 7.0 and 40°C. The adsorption capacity for BSP-carbonized and BSP-activated were 87.92% (pH: 7, 60°C) and 78.50% (pH: 6, 90°C), respectively. Moreover, adsorption kinetics data indicated the best fit with the pseudo-second-order model. The maximum biosorption capacity, by the Langmuir isotherm model, was also recorded for BSP-activated/carbonized (53.47 mg/g). It is notable that arsenic adsorption on studied bio sorbents takes place as spontaneous and through chemisorption along with the endothermic nature of the biosorption process and reduction of random collision in the solid-liquid phase.

Keywords: black seed pulp, bio-sorbents, treatment of sorbents, adsorption isotherms

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Authors: Hossam El-Sayed Emam

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As an essential issue for life, water while it’s important for all living organisms. However, the world is dangerously facing the serious problem for the deficiency of the sources of drinking water. Within the aquatic systems, there are various gases, microbes, and other toxic ingredients (chemical compounds and heavy metals) occurred owing to the draining of agricultural and industrial wastewater, resulting in water pollution. On the other hand, fuel (gaseous, liquid, or in solid phase) is one of the extensively consumable energy sources, and owing to its origin from fossil, it contains some sulfur-, nitrogen- and oxygen-based compounds that cause serious problems (toxicity, catalyst poisoning, corrosion, and gum formation andcarcinogenic effects), to be ascribed as undesirable pollutants.MOFs as porous coordinating polymers are superiorly exploited in the adsorption and separationof contaminants for wastewater treatment and fuel purification. The inclusion of highly adsorbent materials like MOFs to be immobilized within cellulosic materialscould be investigated as a new challenge for the separation of contaminants with high efficiency and opportunity for recyclability. Therefore, the current approach ascribes the exploitation of different MOFsimmobilized within cellulose (powder, films, and fabrics)for applications in environmental. Herein, using cellulose containing MOFs in dye removal (degradation and adsorption), pharmaceutical intermediates removal, and fuel purification were summarized.

Keywords: cellulose, MOFs, dye removal, pharmaceutical intermediates, fuel purification

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Authors: Nouacer Imane, Benalia Mokhtar, Djedid Mabrouk

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The adsorption ability of a powdered activated carbons (PAC) derived from Luffa cylindrica investigated in an attempt to produce more economic and effective sorbents for the control of Cu(II) ion from industrial liquid streams. Carbonaceous sorbents derived from local luffa cylindrica, were prepared by chemical activation methods using ZnCl2 as activating reagents. Adsorption of Cu (II) from aqueous solutions was investigated. The effects of pH, initial adsorbent concentration, the effect of particle size, initial metal ion concentration and temperature were studied in batch experiments. The maximum adsorption capacity of copper onto grafted Luffa cylindrica fiber was found to be 14.23 mg/g with best fit for Langmuir adsorption isotherm. The values of thermodynamic parameters such as enthalpy change, ∆H (-0.823 kJ/mol), entropy change, ∆S (-9.35 J/molK) and free energy change, ∆G (−1.56 kJ/mol) were also calculated. Adsorption process was found spontaneous and exothermic in nature. Finally, the luffa cylindrica has been evaluated by FTIR, MO and x-ray diffraction in order to determine if the biosorption process modifies its chemical structure and morphology, respectively. Luffa cylindrica has been proven to be an efficient biomaterial useful for heavy metal separation purposes that is not altered by the process.

Keywords: adsorption, cadmium, isotherms, thermodynamic, luffa sponge

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Authors: Bienvenu Gael Fouda Mbanga, Zikhona Tywabi-Ngeva, Kriveshini Pillay

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This work highlighted a new method for preparing Nitrogen carbon nanoparticles fused on zinc oxide nanoparticle nanocomposite (N-CNPs/ZnONPsNC) to remove copper ions (Cu²+) from wastewater by sol-gel method and applying the metal-loaded adsorbent in latent fingerprint application. The N-CNPs/ZnONPsNC showed to be an effective sorbent for optimum Cu²+ sorption at pH 8 and 0.05 g dose. The Langmuir isotherm was found to best fit the process, with a maximum adsorption capacity of 285.71 mg/g, which was higher than most values found in other research for Cu²+ removal. Adsorption was spontaneous and endothermic at 25oC. In addition, the Cu²+-N-CNPs/ZnONPsNC was found to be sensitive and selective for latent fingerprint (LFP) recognition on a range of porous surfaces. As a result, in forensic research, it is an effective distinguishing chemical for latent fingerprint detection.

Keywords: latent fingerprint, nanocomposite, adsorption, copper ions, metal loaded adsorption, adsorbent

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Authors: Glykeria A. Visvini, George Ν. Mathioudakis, Amaia Soto Beobide, George A. Voyiatzis

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Polymer nanocomposites are materials in which a polymer matrix is reinforced with nanoscale inclusions, such as nanoparticles, nanoplates, or nanofibers. These nanoscale inclusions can significantly enhance the mechanical, thermal, electrical, and other properties of the polymer matrix, making them attractive for a wide range of industrial applications. These properties can be tailored by adjusting the type and the concentration of the nanoinclusions, which provides a high degree of flexibility in their design and development. An important property that polymeric membranes can exhibit is water vapor permeability (WVP). This can be accomplished by various methods, including the incorporation of micro/nano-fillers into the polymer matrix. In this way, a micro/nano-pore network can be formed, allowing water vapor to permeate through the membrane. At the same time, the membrane can be stretched uni- or bi-axially, creating aligned or cross-linked micropores in the composite, respectively, which can also increase the WVP. Nowadays, in industry, stretched films reinforced with CaCO3 develop micro-porosity sufficient to give them breathability characteristics. Carbon-based nanomaterials, such as graphene oxide (GO), are tentatively expected to be able to effectively improve the WVP of corresponding composite polymer films. The presence in the GO structure of various functional oxidizing groups enhances its ability to attract and channel water molecules, exploiting the unique large surface area of graphene that allows the rapid transport of water molecules. Polypropylene (PP) is widely used in various industrial applications due to its desirable properties, including good chemical resistance, excellent thermal stability, low cost, and easy processability. The specific properties of PP are highly influenced by its crystalline behavior, which is determined by its processing conditions. The development of the β-crystalline phase in PP, in combination with stretching, is anticipating improving the microporosity of the polymer matrix, thereby enhancing its WVP. The aim of present study is to create breathable PP composite membranes using carbon-based nanomaterials, such as graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanoplatelets (GNPs). Unlike traditional methods that rely on the drawing process to enhance the WVP of PP, this study intents to develop a low-cost approach using melt mixing with β-nucleating agents and carbon fillers to create highly breathable PP composite membranes. The study aims to investigate how the concentration of these additives affects the water vapor transport properties of the resulting PP films/membranes. The presence of β-nucleating agents and carbon fillers is expected to enhance β-phase growth in PP, while an alternation between β- and α-phase is expected to lead to improved microporosity and WVP. Our ambition is to develop highly breathable PP composite films with superior performance and at a lower cost compared to the benchmark. Acknowledgment: This research has been co‐financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call «Special Actions "AQUACULTURE"-"INDUSTRIAL MATERIALS"-"OPEN INNOVATION IN CULTURE"» (project code: Τ6YBP-00337)

Keywords: carbon based nanomaterials, nanocomposites, nucleating agent, polypropylene, water vapor permeability

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Authors: Yufan Mu

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The selective depression of pyrite in the flotation of copper minerals is difficult due to the activation of pyrite surface by copper ions. Novel depressants for pyrite are needed to responsibly extract copper resources for a greener and cleaner future. In this paper, the non-toxic sodium alginate was employed as a depressant to selectively separate chalcopyrite from pyrite in flotation using potassium amyl xanthate as the collector. The results from flotation tests showed that sodium alginate significantly depressed pyrite flotation while had slight influence on chalcopyrite flotation. The adsorption tests showed that the adsorption amount of sodium alginate on pyrite surface was much higher than that on chalcopyrite surface. The pre-adsorbed sodium alginate could effectively hinder the subsequent adsorption of collector on pyrite surface, thereby inhibiting pyrite flotation. The selective adsorption of sodium alginate on pyrite surface was caused by the interactions between the activating cuprous ions on pyrite surface and the carboxyl groups in sodium alginate. The paper shows that sodium alginate is a promising depressant for pyrite in the flotation of chalcopyrite.

Keywords: chalcopyrite flotation, pyrite depression, sodium alginate, copper-activated pyrite, adsorption

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Authors: Maritza Estela Garay-Rodriguez, Mirella Gutierrez-Arzaluz, Miguel Torres-Rodriguez, Violeta Mugica-Alvarez

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Arsenic is an element present in the earth's crust and is dispersed in the environment through natural processes and some anthropogenic activities. Naturally released into the environment through the weathering and erosion of sulphides mineral, some activities such as mining, the use of pesticides or wood preservatives potentially increase the concentration of arsenic in air, water, and soil. The natural arsenic release of a geological material is a threat to the world's drinking water sources. In aqueous phase is found in inorganic form, as arsenate and arsenite mainly, the contamination of groundwater by salts of this element originates what is known as endemic regional hydroarsenicism. The International Agency for Research on Cancer (IARC) categorizes the inorganic As within group I, as a substance with proven carcinogenic action for humans. It has been found the presence of As in groundwater in several countries such as Argentina, Mexico, Bangladesh, Canada and the United States. Regarding the concentration of arsenic in drinking water according to the World Health Organization (WHO) and the Environmental Protection Agency (EPA) establish maximum concentrations of 10 μg L⁻¹. In Mexico, in some states as Hidalgo, Morelos and Michoacán concentrations of arsenic have been found in bodies of water around 1000 μg L⁻¹, a concentration that is well above what is allowed by Mexican regulations with the NOM-127- SSA1-1994 that establishes a limit of 25 μg L⁻¹. Given this problem in Mexico, this research proposes the use of a natural Mexican zeolite (clinoptilolite type) native to the district of Etla in the central valley region of Oaxaca, as an adsorbent for the removal of arsenic. The zeolite was subjected to a conditioning with iron oxide by the precipitation-impregnation method with 0.5 M iron nitrate solution, in order to increase the natural adsorption capacity of this material. The removal of arsenic was carried out in a column with a fixed bed of conditioned zeolite, since it combines the advantages of a conventional filter with those of a natural adsorbent medium, providing a continuous treatment, of low cost and relatively easy to operate, for its implementation in marginalized areas. The zeolite was characterized by XRD, SEM/EDS, and FTIR before and after the arsenic adsorption tests, the results showed that the modification methods used are adequate to prepare adsorbent materials since it does not modify its structure, the results showed that with a particle size of 1.18 mm, an initial concentration of As (V) ions of 1 ppm, a pH of 7 and at room temperature, a removal of 98.7% was obtained with an adsorption capacity of 260 μg As g⁻¹ zeolite. The results obtained indicated that the conditioned zeolite is favorable for the elimination of arsenate in water containing up to 1000 μg As L⁻¹ and could be suitable for removing arsenate from pits of water.

Keywords: adsorption, arsenic, iron conditioning, natural zeolite

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Authors: Kiurski S. Jelena, Oros B. Ivana, Kecić S. Vesna, Kovačević M. Ilija, Aksentijević M. Snežana

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The adsorption efficiency of various adsorbents for the removal of Zn(II) ions from the waste printing developer was studied in laboratory batch mode. The maximum adsorption efficiency of 94.1% was achieved with unfired clay pellets size (d≈15 mm). The obtained values of adsorption efficiency was subjected to the independent samples t-test in order to investigate the statistically significant differences of the investigated adsorbents for the effective removal of Zn(II) ions from the waste printing developer. The most statistically significant differences of adsorption efficiencies for Zn(II) ions removal were obtained between unfired clay pellets size (d≈15 mm) and activated carbon (|t|= 6.909), natural zeolite (|t|= 10.380), mixture of activated carbon and natural zeolite (|t|= 9.865), bentonite (|t|= 6.159), fired clay (|t|= 6.641), fired clay pellets size (d≈5 mm) (|t|= 6.678), fired clay pellets size (d≈8 mm) (|t|= 3.422), respectively.

Keywords: Adsorption efficiency, adsorbent, statistical analysis, zinc ion.

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Authors: H. Hajmohammadi , A. H. Jafari, M. Eskandari Nasab

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The ion exchange method was used to assess the absorption of sulfate media from laboratory-grade materials. The Taguchi method was employed for determining the optimum conditions for scandium adsorption. Results show that optimum conditions for scandium adsorption from sulfate were obtained by Purolite C100 cationic resin in 0.1 g/l sulfuric acid and scandium concentration of 2 g/l at 25 °C. Studies also showed that lowering H₂SO₄ concentration and aqueous phase temperature leads to an increase in Sc adsorption. Visual Minteq software was used to ascertain the various possible cation types and the effect of concentration of scandium ion species on scandium adsorption by cationic resins. The simulation results of the above software show that scandium ion species are often cationic species that are consistent with experimental data.

Keywords: scandium, ion exchange resin, simulation, leach copper

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Authors: P. R. Rahul, A. Kannan

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Ultrasound-aided adsorption of phenol by Granular Activated Carbon (GAC) was investigated at different frequencies ranging from 35 kHz, 58 kHz, and 192 kHz. Other factors influencing adsorption such as Adsorbent dosage (g/L), the initial concentration of the phenol solution (ppm) and RPM was also considered along with the frequency variable. However, this study involved calorimetric measurements which helped is determining the effect of frequency on the % removal of phenol from the power dissipated to the system was normalized. It was found that low frequency (35 kHz) cavitation effects had a profound influence on the % removal of phenol per unit power. This study also had cavitation mapping of the ultrasonic baths, and it showed that the effect of cavitation on the adsorption system is irrespective of the position of the vessel. Hence, the vessel was placed at the center of the bath. In this study, novel temperature control and monitoring system to make sure that the system is under proper condition while operations. From the BET studies, it was found that there was only 5% increase in the surface area and hence it was concluded that ultrasound doesn’t profoundly alter the equilibrium value of the adsorption system. DOE studies indicated that adsorbent dosage has a higher influence on the % removal in comparison with other factors.

Keywords: ultrasound, adsorption, granulated activated carbon, phenol

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Authors: Palash Soni, Vivek Kumar Gaba, Shubhankar Bhowmick, Bidyut Mazumdar

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Refrigeration technology is a fast developing field at the present era since it has very wide application in both domestic and industrial areas. It started from the usage of simple ice coolers to store food stuffs to the present sophisticated cold storages along with other air conditioning system. A variety of techniques are used to bring down the temperature below the ambient. Adsorption refrigeration technology is a novel, advanced and promising technique developed in the past few decades. It gained attention due to its attractive property of exploiting unlimited natural sources like solar energy, geothermal energy or even waste heat recovery from plants or from the exhaust of locomotives to fulfill its energy need. This will reduce the exploitation of non-renewable resources and hence reduce pollution too. This work is aimed to develop a model for a solar adsorption refrigeration system and to simulate the same for different operating conditions. In this system, the mechanical compressor is replaced by a thermal compressor. The thermal compressor uses renewable energy such as solar energy and geothermal energy which makes it useful for those areas where electricity is not available. Refrigerants normally in use like chlorofluorocarbon/perfluorocarbon have harmful effects like ozone depletion and greenhouse warming. It is another advantage of adsorption systems that it can replace these refrigerants with less harmful natural refrigerants like water, methanol, ammonia, etc. Thus the double benefit of reduction in energy consumption and pollution can be achieved. A thermodynamic model was developed for the proposed adsorber, and a universal MATLAB code was used to simulate the model. Simulations were carried out for a different operating condition for the silicagel-methanol working pair. Various graphs are plotted between regeneration temperature, adsorption capacities, the coefficient of performance, desorption rate, specific cooling power, adsorption/desorption times and mass. The results proved that adsorption system could be installed successfully for refrigeration purpose as it has saving in terms of power and reduction in carbon emission even though the efficiency is comparatively less as compared to conventional systems. The model was tested for its compliance in a cold storage refrigeration with a cooling load of 12 TR.

Keywords: adsorption, refrigeration, renewable energy, silicagel-methanol

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Authors: Rashad Al-Gaashani, Viktor Kochkodan, Jenny Lawler

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Physico-chemical activation method wasused to produce high-quality activated carbon (AC) with a large surface area of about 2000 m2/g from low-cost and abundant biomasswastes in Qatar, namely date seeds. X-Ray diffraction (XRD), scanning electron spectroscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were used to evaluate the AC samples. AC produced from date seeds have a wide range of the pores available, including micro- andnano-pores. This type of AC with a well-developed pore structure may be very attractive for different applications, including air and water purification from micro and nano pollutants. Heavy metalsiron (III) and copper (II) ions were removed from wastewater using the AC producedusinga batch adsorption technique. The AC produced from date seeds biomass wastes show high removal of heavy metals such as iron (III) ions (100%) and copper (II) ions (97.25%). The highest removal of copper (II) ions (100%) with AC produced from date seeds was found at pH 8, whereas the lowest removal (22.63%) occurred at pH 2. The effect of adsorption time, adsorbent dose, pH on the removal of heavy metalswere studied.

Keywords: activated carbon, date seeds, biomass, heavy metals removal, water treatment

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Authors: Veerakumar Arumugam, Rajesh Mishra, Jiri Militky, Jana Salacova

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The thermo-physiological comfort and compression properties of knitted spacer fabrics have been evaluated by varying the different spacer fabric parameters. Air permeability and water vapor transmission of the fabrics were measured using the Textest FX-3300 air permeability tester and PERMETEST. Then thermal behavior of fabrics was obtained by Thermal conductivity analyzer and overall moisture management capacity was evaluated by moisture management tester. Spacer Fabrics compression properties were also tested using Kawabata Evaluation System (KES-FB3). In the KES testing, the compression resilience, work of compression, linearity of compression and other parameters were calculated from the pressure-thickness curves. Analysis of Variance (ANOVA) was performed using new statistical software named QC expert trilobite and Darwin in order to compare the influence of different fabric parameters on thermo-physiological and compression behavior of samples. This study established that the raw materials, type of spacer yarn, density, thickness and tightness of surface layer have significant influence on both thermal conductivity and work of compression in spacer fabrics. The parameter which mainly influence on the water vapor permeability of these fabrics is the properties of raw material i.e. the wetting and wicking properties of fibers. The Pearson correlation between moisture capacity of the fabrics and water vapour permeability was found using statistical software named QC expert trilobite and Darwin. These findings are important requirements for the further designing of clothing for extreme environmental conditions.

Keywords: 3D spacer fabrics, thermal conductivity, moisture management, work of compression (WC), resilience of compression (RC)

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Authors: R. C. Ferreira, H. H. C. De Lima, A. A. Cândido, O. M. Couto Junior, P. A. Arroyo, K. Q De Carvalho, G. F. Gauze, M. A. S. D. Barros

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Removal of the widespread used drug paracetamol from water was investigated using activated carbon originated from dende coconut mesocarp and babassu coconut mesocarp. Kinetic and equilibrium data were obtained at different values of pH. Babassu activated carbon showed higher efficiency due to its acidity and higher microporosity. Pseudo-second order model was better adjusted to the kinetic results. Equilibrium data may be represented by Langmuir equation. Lower solution pH provided better removal efficiency as the carbonil groups may be attracted by the positively charged carbon surface.

Keywords: adsorption, activated carbon, babassu, dende

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Authors: Roman Knizek, Denisa Knizkova

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This paper describes the development of a nanofiber membrane for sport and outdoor use at the Technical University of Liberec (TUL) and the following cooperation with a private Czech company which launched this product onto the market. For making this membrane, Polyurethan was electrospun on the Nanospider spinning machine, and a wire string electrode was used. The created nanofiber membrane with a nanofiber diameter of 150 nm was subsequently hydrophobisied using a low vacuum plasma and Fluorocarbon monomer C6 type. After this hydrophobic treatment, the nanofiber membrane contact angle was higher than 125o, and its oleophobicity was 6. The last step was a lamination of this nanofiber membrane with a woven or knitted fabric to create a 3-layer laminate. Gravure printing technology and polyurethane hot-melt adhesive were used. The gravure roller has a mesh of 17. The resulting 3-layer laminate has a water vapor permeability Ret of 1.6 [Pa.m2.W-1] (– measured in compliance with ISO 11092), it is 100% windproof (– measured in compliance with ISO 9237), and the water column is above 10 000 mm (– measured in compliance with ISO 20811). This nanofiber membrane which was developed in the laboratories of the Technical University of Liberec was then produced industrially by a private company. A low vacuum plasma line and a lamination line were needed for industrial production, and the process had to be fine-tuned to achieve the same parameters as those achieved in the TUL laboratories. The result of this work is a newly developed nanofiber membrane which offers much better properties, especially water vapor permeability, than other competitive membranes. It is an example of product development and the consequent fine-tuning for industrial production; it is also an example of the cooperation between a Czech state university and a private company.

Keywords: nanofiber membrane, start-up, state university, private company, product

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Authors: Sheng Huang, Xin Zhao, Xiaofeng Gao, Tao Zhou, Shijin Dai, Youcai Zhao

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Adsorption of heavy metal pollutants (Zn, Cd, Pb, Cr, Cu) and organic pesticide (phorate, dithiophosphate diethyl, triethyl phosphorothioate), along with their multi-contamination on the surface of industrial construction & demolition waste (C&D waste) was investigated. Brick powder was selected as the appropriate waste while its maximum equilibrium adsorption amount of heavy metal under single controlled contamination matrix reached 5.41, 0.81, 0.45, 1.13 and 0.97 mg/g, respectively. Effects of pH and spiking dose of ICDW was also investigated. Equilibrium adsorption amount of organic pesticide varied from 0.02 to 0.97 mg/g, which was negatively correlated to the size distribution and hydrophilism. Existence of organic pesticide on surface of ICDW caused various effects on the heavy metal adsorption, mainly due to combination of metal ions and the floccule formation along with wrapping behaviors by pesticide pollutants. Adsorption of Zn was sharply decreased from 7.1 to 0.15 mg/g compared with clean ICDW and phorate contaminated ICDW, while that of Pb, Cr and Cd experienced an increase- then decrease procedure. On the other hand, runoff of pesticide contaminants was investigated under 25 mm/h simulated rainfall. Results showed that the cumulative runoff amount fitted well with curve obtained from a power function, of which r2=0.95 and 0.91 for 1DAA (1 day between contamination and runoff) and 7DAA, respectively. This study helps provide evaluation of industrial construction and demolition waste contamination into aquatic systems.

Keywords: adsorption mechanism, industrial construction waste, metals, pesticide, runoff

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Authors: Tarun Jain, Lovnish Gupta, Soumen Basu

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Organic pollutants like phenols and organic dyes present in industrial waste water are posing a hazardous threat to aquatic ecosystem. Several measures have been adopted for the neutralization and photodecomposition of these harmful organic moieties, among these semiconductor photocatalysis has been provided a major thrust after the discovery of Honda-Fujishema effect. Present study demonstrates the adsorption of TiO2- P25 in nano size (~36 nm) on cement balls for effective photodegradation of Alizarin and penta chlorophenol (PCP) under UV light illumination. Triton-X was used as a stabilizer for effective adsorption of TiO2 on cement balls (TCB) followed by calcination at ~300oC for 4 h. The TCB’s were dispersed randomly in a self designed reactor for phototcatalytic performance as shown in scheme 1. The change in concentration of alizarin and PCP was observed under UV-Vis spectroscopy, PCP was detoxified within 40 min while alizarin photodecomposed within 15 min of UV light irradiation. Taking into consideration the go green slogan and future prospective this technique can be also utilized under visible light and on mass scale because this is an effective tool for environmental remediation and waste water treatment.

Keywords: organic pollutants, TiO2 cement balls, photodegradation, UV light irradiation

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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: Zamouche Meriem, Mehcene Ismahan, Temmine Manel, Bencheikh Lehocine Mosaab, Meniai Abdeslam Hassen

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In this study, the adsorption of Malachite Green (MG) by chemical treated sewage sludge has been studied. The sewage sludge, collected from drying beds of the municipal wastewater treatment station of IBN ZIED, Constantine, Algeria, was treated by different acids such us HNO₃, H₂SO₄, H₃PO₄ for modifying its aptitude to removal the MG from aqueous solutions. The results obtained shows that the sewage sludge activated by sulfuric acid give the highest elimination amounts of MG (9.52 mg/L) compared by the other acids used. The effects of operation parameters have been investigated, the results obtained show that the adsorption capacity per unit of adsorbent mass decreases from 18.69 to 1.20 mg/g when the mass of the adsorbent increases from 0.25 to 4 g respectively, the optimum mass for which a maximum of elimination of the dye is equal to 0.5g. The increasing in the temperature of the solution results in a slight decrease in the adsorption capacity of the chemically treated sludge. The highest amount of dye adsorbed by CSSS (9.56 mg/g) was observed for the optimum temperature of 25°C. The chemical activated sewage sludge proved its effectiveness for the removal of the Red Congo (RC), but by comparison the adsorption of the two dyes studies, we noted that the sludge has more affinity to adsorb the (MG).

Keywords: adsorption, chemical activation, malachite green, sewage sludge

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Authors: Preeti Pal, Anjali Pal

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Chitosan is an effective sorbent for removal of contaminants from wastewater. However, the ability of pure chitosan is specific because of its cationic charge. It causes repulsion in the removal process of various cationic charged molecules. The present study has been carried out for the successful removal of Pb²⁺ ions from aqueous solution by modified chitosan beads. Surface modification of chitosan (CS) beads was performed by using the anionic surfactant (AS), sodium dodecyl sulfate (SDS). Micelle aggregation property of SDS has been utilized for the formation of bilayer over the CS beads to produce surfactant modified chitosan (SMCS) beads. Prepared adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) in order to find out their composition and surface morphology. SMCS beads, when compared to the pure CS beads, showed three times higher adsorption. This higher adsorption is believed to be due to the adsolubilization of Pb²⁺ ions on SDS bilayer. This bilayer provides more adsorption sites for quick and effective removal of Pb²⁺ ions from the aqueous phase. Moreover, the kinetic and adsorption isotherm models were employed to the obtained data for the description of the lead adsorption processes. It was found that the removal kinetics follows pseudo-second order model. Adsorption isotherm data fits well to the Langmuir model. The maximum adsorption capacity obtained is 100 mg/g at the dosage of 0.675 g/L for 50 mg/L of Pb²⁺. The adsorption capacity is subject to increase with increasing the Pb²⁺ ions concentration in the solution. The results indicated that the prepared hydrogel beads are efficient adsorbent for removal of Pb²⁺ ions from the aqueous medium.

Keywords: adsolubilisation, anionic surfactant, bilayer, chitosan, Pb²⁺

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Authors: Betina Luiza Koop, Lenilton Santos Soares, Karina Cesca, Germán Ayala Valencia, Alcilene Rodrigues Monteiro

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Active and smart food packaging has been studied to control and extend the food shelf-life. However, active compounds such as anthocyanins (ACNs) are unstable to high temperature, light, and pH changes. Several alternatives to stabilize and protect the anthocyanins have been researched, such as adsorption on nanoclays. Thus, this work aimed to stabilize anthocyanin extracted from jambolan fruit (Syzygium cumini), a noncommercial fruit, to development of food package sensors. The anthocyanin extract from jambolan pulp was concentrated by ultrafiltration and adsorbed on montmorillonite. The final biohybrid material was characterized by pH and color. Anthocyanins were adsorbed on nanoclay at pH 1.5, 2.5, and 3.5 and temperatures of 10 and 20 °C. The highest adsorption values were obtained at low pH at high temperatures. The color and antioxidant activity of the biohybrid was maintained for 60 days. A test of the color stability at pH from 1 to 13, simulating spoiled food using ammonia vapor, was performed. At pH from 1 to 5, the ACNs pink color was maintained, indicating that the flavylium cation form was preserved. At pH 13, the biohybrid presented yellow color due to the ACN oxidation. These results showed that the biohybrid material developed has potential application as a sensor to indicate the freshness of meat products.

Keywords: anthocyanin, biohybrid, food, smart packaging

Procedia PDF Downloads 47

Authors: Hatem I. Mokhtar, Randa A. Abd-El-Salam, Ghada M. Hadad

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An improved nano-composite of self-doped polyaniline nanofibers and silica-coated magnetite nanoparticles were prepared and evaluated for suitability to magnetic dispersive micro solid-phase extraction. The work focused on optimization of the composite capacity to extract four fluoroquinolones (FQs) antibiotics, ciprofloxacin, enrofloxacin, danofloxacin, and difloxacin from water and improvement of composite stability towards acid and atmospheric degradation. Self-doped polyaniline nanofibers were prepared by oxidative co-polymerization of aniline with anthranilic acid. Magnetite nanopariticles were prepared by alkaline co-precipitation and coated with silica by silicate hydrolysis on magnetite nanoparticles surface at pH 6.5. The composite was formed by self-assembly by mixing self-doped polyaniline nanofibers with silica-coated magnetite nanoparticles dispersions in ethanol. The composite structure was confirmed by transmission electron microscopy (TEM). Self-doped polyaniline nanofibers and magnetite chemical structures were confirmed by FT-IR while silica coating of the magnetite was confirmed by Energy Dispersion X-ray Spectroscopy (EDS). Improved stability of the composite magnetic component was evidenced by resistance to degrade in 2N HCl solution. The adsorption capacity of self-doped polyaniline nanofibers based composite was higher than previously reported corresponding composite prepared from polyaniline nanofibers instead of self-doped polyaniline nanofibers. Adsorption-pH profile for the studied FQs on the prepared composite revealed that the best pH for adsorption was in range of 6.5 to 7. Best extraction recovery values were obtained at pH 7 using phosphate buffer. The best solvent for FQs desorption was found to be 0.1N HCl in methanol:water (8:2; v/v) mixture. 20 mL of Spiked water sample with studied FQs were preconcentrated using 4.8 mg of composite and resulting extracts were analysed by HPLC-UV method. The prepared composite represented a suitable adsorbent phase for magnetic dispersive micro-solid phase application.

Keywords: fluoroquinolones, magnetic dispersive micro extraction, nano-composite, self-doped polyaniline nanofibers

Procedia PDF Downloads 102

Authors: Vipan Kumar Sohpal

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Temperature effect on the adsorption of crystal violet dye (CVD) was investigated using a castor leaf powder (CLP) that was prepared from the mature leaves of castor trees, through chemical reaction. The optimum values of pH (8), adsorbent dose (10g/L), initial dye concentration (10g/L), time (2hrs), and stirrer speed (120 rpm) were fixed to investigate the influence of temperature on adsorption capacity, percentage of removal of dye and free energy. A central composite design (CCD) was successfully employed for experimental design and analysis of the results. The combined effect of temperature, absorbance, and concentration on the dye adsorption was studied and optimized using response surface methodology. The optimum values of adsorption capacity, percentage of removal of dye and free energy were found to be 0.965(mg/g), 93.38 %, -8202.7(J/mol) at temperature 55.97 °C having desirability > 90% for removal of crystal violet dye respectively. The experimental values were in good agreement with predicted values.

Keywords: crystal violet dye, CVD, castor leaf powder, CLP, response surface methodology, temperature, optimization

Procedia PDF Downloads 108

Authors: Asim Olgun, Ali Kara, Vural Butun, Pelin Sevinc, Merve Gungor, Orhan Ornek

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In this study, we investigated the possibility of using waste containing boron impurity (BW) as an adsorbent for the removal of Orange 16 from aqueous solution. Surface properties of the BW, heat treated BW, and diblock copolymer coated BW were examined by using Zeta Meter and scanning electron microscopy (SEM). The polymer modified sample having the highest positive zeta potential was used as an adsorbent. Batch adsorption studies were carried out. The operating variables studied were the initial dye concentration, contact time, solution pH, and adsorbent dosage. It was found that the dye adsorption largely depends on the initial pH of the solution with maximum uptake occurring at pH 3. The adsorption followed pseudo-second-order kinetics and the isotherm fit well to the Langmuir model.

Keywords: zeta potential, adsorption, Orange 16, isotherms

Procedia PDF Downloads 182

Authors: F. Chigondo, G. Chitabati

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Hexavalent chromium is toxic and is widely used in many industries hence efficient and economical methods must be explored to remove the chromium(VI) from the environment. The removal of Cr (VI) from aqueous solutions onto polyaniline coated maize tassel was studied in batch mode at varying initial metal concentrations, adsorbent doses, pH and contact times. The residual Cr (VI) concentrations before and after adsorption were analyzed by Ultraviolet–visible spectroscopy. FTIR analysis of the polyaniline coated maize tassel showed the presence of C=C, C=N, C-H, C-N and N-H groups. Adsorption conditions were deduced to be pH of 2, adsorbent dosage 1g/L, Cr(VI) initial concentration of 40mg/L contact time of 150 minutes and agitation speed of 140rpm. Data obtained fitted best to the Langmuir isotherm (R2 = 0.972) compared to the Freundlich isotherm (R2 0.671. The maximum adsorption capacity was found to be 125mg/L. Correlation coefficients for pseudo first order and pseudo second order were 0.952 and 0.971 respectively. The adsorption process followed the pseudo-second order kinetic model. The studied polyaniline coated maize tassel can therefore be used as a promising adsorbent for the removal of Cr (VI) ion from aqueous solution.

Keywords: polyaniline-coated, maize tassels, adsorption, hexavalent chromium

Procedia PDF Downloads 183

Authors: Xincheng Jiang, Yanyan An, Yaoyao Huang, Wei Ding, Manli Sun, Hong Li, Huaili Zheng

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The residual antibiotics in the environment will pose a threat to the environment and human health. Thus, efficient removal and rapid detection of norfloxacin (NOR) in wastewater is very important. The main sources of NOR pollution are the agricultural, pharmaceutical industry and hospital wastewater. The total consumption of NOR in China can reach 5440 tons per year. It is found that neither animals nor humans can totally absorb and metabolize NOR, resulting in the excretion of NOR into the environment. Therefore, residual NOR has been detected in water bodies. The hazards of NOR in wastewater lie in three aspects: (1) the removal capacity of the wastewater treatment plant for NOR is limited (it is reported that the average removal efficiency of NOR in the wastewater treatment plant is only 68%); (2) NOR entering the environment will lead to the emergence of drug-resistant strains; (3) NOR is toxic to many aquatic species. At present, the removal and detection technologies of NOR are applied separately, which leads to a cumbersome operation process. The development of simultaneous adsorption-flocculation removal and FTIR detection of pollutants has three advantages: (1) Adsorption-flocculation technology promotes the detection technology (the enrichment effect on the material surface improves the detection ability); (2) The integration of adsorption-flocculation technology and detection technology reduces the material cost and makes the operation easier; (3) FTIR detection technology endows the water treatment agent with the ability of molecular recognition and semi-quantitative detection for pollutants. Thus, it is of great significance to develop a smart water treatment material with high removal capacity and detection ability for pollutants. This study explored the feasibility of combining NOR removal method with the semi-quantitative detection method. A magnetic Cu-Ni-S/Ni foam was synthesized by in-situ loading Cu-Ni-S nanostructures on the surface of Ni foam. The novelty of this material is the combination of adsorption-flocculation technology and semi-quantitative detection technology. Batch experiments showed that Cu-Ni-S/Ni foam has a high removal rate of NOR (96.92%), wide pH adaptability (pH=4.0-10.0) and strong ion interference resistance (0.1-100 mmol/L). According to the Langmuir fitting model, the removal capacity can reach 417.4 mg/g at 25 °C, which is much higher than that of other water treatment agents reported in most studies. Characterization analysis indicated that the main removal mechanisms are surface complexation, cation bridging, electrostatic attraction, precipitation and flocculation. Transmission FTIR detection experiments showed that NOR on Cu-Ni-S/Ni foam has easily recognizable FTIR fingerprints; the intensity of characteristic peaks roughly reflects the concentration information to some extent. This semi-quantitative detection method has a wide linear range (5-100 mg/L) and a low limit of detection (4.6 mg/L). These results show that Cu-Ni-S/Ni foam has excellent removal performance and semi-quantitative detection ability of NOR molecules. This paper provides a new idea for designing and preparing multi-functional water treatment materials to achieve simultaneous removal and semi-quantitative detection of organic pollutants in water.

Keywords: adsorption-flocculation, antibiotics detection, Cu-Ni-S/Ni foam, norfloxacin

Procedia PDF Downloads 55

Authors: L. Sasikala, Bhaarathi Dhurai

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Increase in antibiotic resistance bacteria leads to the development of active wound dressings, which absorb any bodily fluid, evaporation of moisture at a certain rate and can be easily removed after healing. Natural materials like chitosan, herbs, and honey have number of active materials present in them to accelerate wound healing and to arrest wound in infections. Hence with the advantages of biomaterials, a film was prepared using chitosan and honey. There are a lot of practical considerations with respect to honey. Honey exerts many beneficial actions on the wound surface only when it remains. The attempts to hold honey on the surface of the wound remain a question because honey becomes a very runny liquid when it comes to body temperature. Hence, this research was focused on development of a new form of wound dressing, by holding honey on the wound surface in different form and also which has a combined effect of manuka (Leptospermum scoparium) honey and chitosan. Chitosan-honey film was prepared using casting technique. Films were prepared in different variations; with acetic acid and with lactic acid; with and without honey. In summary, the film produced from 2% chitosan- 1% lactic acid as a solvent, with 10% honey shows optimum inclined values in all the tests, like thickness, folding endurance, weight, water vapor transmission, tensile strength, swelling ratio and antimicrobial activity, with specific reference to wound dressings. The film has water vapor transmission of 1680 g/m²/day, water absorption of 225%, tensile strength of 39.1N/mm² and elongation of 50.3%. There is a notable inhibition zone of 29 mm against S. aureus and 24 mm against E. coli in the case of chitosan-lactic acid-honey film. The film also arrests, microbes transmitting from the outside environment to wound bed, which can be used as an effective wound dressing material.

Keywords: casting technique, chitosan, honey, film, wound dressings

Procedia PDF Downloads 219

Authors: Saad Mohamed Elsaid Onaizah

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One of the reasons for the intensive use of pesticides is to protect agricultural crops and orchards from pests or agricultural worms. The period of time that pesticides stay inside the soil is estimated at about (2) to (12) weeks. Perhaps the most important reason that led to groundwater pollution is the easy leakage of these harmful pesticides from the soil into the aquifers. This research aims to find the best ways to use trated activated charcoal with gold nitrate solution; For the purpose of removing the deadly pesticides from the aqueous solution by adsorption phenomenon. The most used pesticides in Egypt were selected, such as Malathion, Methomyl Abamectin and, Thiamethoxam. Activated charcoal doped with gold ions was prepared by applying chemical and thermal treatments to activated charcoal using gold nitrate solution. Adsorption of studied pesticide onto activated carbon /Au was mainly by chemical adsorption forming complex with the gold metal immobilised on activated carbon surfaces. Also, gold atom was considered as a catalyst to cracking the pesticide molecule. Gold activated charcoal is a low cost material due to the use of very low concentrations of gold nitrate solution. its notice the great ability of activated charcoal in removing selected pesticides due to the presence of the positive charge of the gold ion, in addition to other active groups such as functional oxygen and lignin cellulose. The presence of pores of different sizes on the surface of activated charcoal is the driving force for the good adsorption efficiency for the removal of the pesticides under study The surface area of the prepared char as well as the active groups were determined using infrared spectroscopy and scanning electron microscopy. Some factors affecting the ability of activated charcoal were applied in order to reach the highest adsorption capacity of activated charcoal, such as the weight of the charcoal, the concentration of the pesticide solution, the time of the experiment, and the pH. Experiments showed that the maximum limit revealed by the batch adsorption study for the adsorption of selected insecticides was in contact time (80) minutes at pH (7.70). These promising results were confirmed, and by establishing the practical application of the developed system, the effect of various operating factors with equilibrium, kinetic and thermodynamic studies is evident, using the Langmuir application on the effectiveness of the absorbent material with absorption capacities higher than most other adsorbents.

Keywords: waste water, pesticides pollution, adsorption, activated carbon

Procedia PDF Downloads 56

Authors: N. Allouache, O. Rahli

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Solar radiation is by far the largest and the most world’s abundant, clean, and permanent energy source. In recent years, many promising technologies have been developed to harness the sun's energy. These technologies help in environmental protection, economizing energy, and sustainable development, which are the major issues of the world. One of these important technologies is the solar refrigerating machines that make use of either absorption or adsorption technologies. In this present work, the adsorbent bed is modelized and optimized using different working pairs, such as zeolite-water, silica gel-water, activated carbon-ammonia, calcium chlorid-ammonia, activated carbon fiber- methanol and activated carbon AC35-methanol. The results show that the enhancement of the heat and mass transfer depends on the properties of the working pair; the performances of the adsorption cycle are essentially influenced by the choice of the adsorbent-adsorbate pair. The system can operate successfully for optimal parameters such as the evaporator, condenser, and generating temperatures. The activated carbon is the best adsorbent due to its high surface area and micropore volume.

Keywords: adsorbent bed, heat and mass transfer, numerical analysis, working pairs

Procedia PDF Downloads 133