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Environmental Science and Pollution... Nov 2020Arsenic (As) toxicity is a global phenomenon, and it is continuously threatening human life. Arsenic remains in the Earth's crust in the forms of rocks and minerals,... (Review)
Review
Arsenic (As) toxicity is a global phenomenon, and it is continuously threatening human life. Arsenic remains in the Earth's crust in the forms of rocks and minerals, which can be released into water. In addition, anthropogenic activity also contributes to increase of As concentration in water. Arsenic-contaminated water is used as a raw water for drinking water treatment plants in many parts of the world especially Bangladesh and India. Based on extensive literature study, adsorption is the superior method of arsenic removal from water and Fe is the most researched periodic element in different adsorbent. Oxides and hydroxides of Fe-based adsorbents have been reported to have excellent adsorptive capacity to reduce As concentration to below recommended level. In addition, Fe-based adsorbents were found less expensive and not to have any toxicity after treatment. Most of the available commercial adsorbents were also found to be Fe based. Nanoparticles of Fe-, Ti-, Cu-, and Zr-based adsorbents have been found superior As removal capacity. Mixed element-based adsorbents (Fe-Mn, Fe-Ti, Fe-Cu, Fe-Zr, Fe-Cu-Y, Fe-Mg, etc.) removed As efficiently from water. Oxidation of AsO to AsOand adsorption of oxidized As on the mixed element-based adsorbent occurred by different adsorbents. Metal organic frameworks have also been confirmed as good performance adsorbents for As but had a limited application due to nano-crystallinity. However, using porous materials having extended surface area as carrier for nano-sized adsorbents could alleviate the separation problem of the used adsorbent after treatment and displayed outstanding removal performances.
Topics: Adsorption; Arsenic; Bangladesh; India; Water Pollutants, Chemical; Water Purification
PubMed: 32772289
DOI: 10.1007/s11356-020-10323-z -
Chemosphere Jan 2023The removal of poly- and perfluoroalkyl substances (PFAS) from the aquatic environment is a universal concern due to the adverse effects of these substances on both the... (Review)
Review
The removal of poly- and perfluoroalkyl substances (PFAS) from the aquatic environment is a universal concern due to the adverse effects of these substances on both the environment and public health. Different adsorbents, including carbon-based materials, ion exchange resins, biomaterials, and polymers, have been used for the removal of short-chain (C < 6) and long-chain (C > 7) PFAS from water with varying performance. Metal-organic frameworks (MOFs), as a new generation of adsorbents, have also been recently used to remove PFAS from water. MOFs provide unique properties such as significantly enhanced surface area, structural tunability, and improved selectivity compared to conventional adsorbents. However, due to various types of MOFs, their complex chemistry and morphology, different PFAS compounds, lack of standard adsorption test, and different testing conditions, there are inconclusive and contradictory findings in the literature. Therefore, this review aims to provide critical analysis of the performance of different types of MOFs in the removal of long-chain (C > 7), short-chain (C < 6), and ultra-short-chain (C < 3) PFAS and comprehensively study the efficiency of MOFs for PFAS removal in comparison with other adsorbents. In addition, the adsorption mechanisms and kinetics of PFAS components on different MOFs, including Materials of Institute Lavoisier (MIL), Universiteit of Oslo (UiO), Zeolitic imidazolate frameworks (ZIFs), Hong Kong University of Science and Technology (HKUST), and other hybrid types of MOF were discussed. The study also discussed the effect of environmental factors such as pH and ionic strength on the adsorption of PFAS on MOFs. In addition to the adsorption process, the reusability and regeneration of MOFs in the PFAS removal process are discussed. Finally, challenges and future outlooks of the utility of MOFs for PFAS removal were discussed to inspire future critical research efforts in removing PFAS.
Topics: Adsorption; Metal-Organic Frameworks; Fluorocarbons; Ion Exchange Resins; Polymers; Carbon; Water
PubMed: 36280122
DOI: 10.1016/j.chemosphere.2022.136933 -
Journal of Environmental Management Dec 2018There is a large amount of studies surrounding the usage of agro-industrial waste (AIW) for the adsorptions of organic pollutants (dyes) and inorganic pollutants (heavy... (Review)
Review
There is a large amount of studies surrounding the usage of agro-industrial waste (AIW) for the adsorptions of organic pollutants (dyes) and inorganic pollutants (heavy metals) in water/wastewater. This method is normally treated as an alternative approach to the conventional water/wastewater treatment. However, there are some increasing interests for investigators to identify novel adsorption materials for pollutants removal. It is particularly noteworthy that most AIW wastes are not currently used at the original state, but modified in a variety of ways to reinforce the porosity and adsorption surface area of the material. Nanostructuring, activation, carbonization, and grafting are some common modification technologies of agricultural waste adsorbents. Besides, the characteristic, preparation and application of adsorbents from various industrial wastes, including natural materials and biosorbents, were summarized. Additionally, the challenges and perspectives for future researches of waste-derived adsorbents were studied. This review provides an important insight on using AIWs as precursor materials for preparing adsorbents in water/wastewater treatment.
Topics: Adsorption; Industrial Waste; Waste Disposal, Fluid; Wastewater; Water; Water Pollutants, Chemical; Water Purification
PubMed: 30212686
DOI: 10.1016/j.jenvman.2018.08.069 -
Environmental Science and Pollution... Nov 2021The rate of environmental pollution augmenting at an alarming rate due to the continuous disposal of toxic dyes directly into the environment and water streams. The...
The rate of environmental pollution augmenting at an alarming rate due to the continuous disposal of toxic dyes directly into the environment and water streams. The direct contact of dyes with water resources directly affects the living beings. The identification of superior methods for the treatment of water pollution caused due to effluent dyes needs higher consideration among researchers for the well-being of living flora and fauna. The available methods for controlling the decontamination of water through toxic dyes have various drawbacks. So, it is highly significant to develop such materials which can easily adsorb the dyes without causing any toxic effect on the environment and living beings. While keeping all the facts in mind, the current work highlights the comparative enhancement in adsorption capacity and selectivity of Brij-58-coated selenium nanoparticles (Brij-58@Se NPs) towards the removal of bromophenol blue (BB) dye from series of chosen dyes in aqueous media. The fabricated Se NPs were methodically characterized and the adsorption behaviour displayed fast adsorption efficiency (98% within 6 min) for BB dye out of series of chosen dyes. The optimization studies were carried out to verify the influence of working variables such as pH (2.0-12.0), response time (1-10 min), dosage amount (0.1-80 mg/l) and concentration of BB dye (1-70 ppm). The adsorption process found to be best fitted for Freundlich adsorption isotherm and pseudo first-order kinetic model. The interference studies of different cationic, anionic species including dyes or metal ions suggested the higher efficiency of Brij-58@Se NPs for adsorptive removal of BB dye from aqueous media. The efficacy of the adsorbent was further tested in six different water resources and displayed 95% adsorption efficiency for BB dye in different wastewater samples. Therefore, Brij-58@Se NP is expected as a potential adsorbent for the adsorption of organic dyes from wastewater samples.
Topics: Adsorption; Coloring Agents; Nanoparticles; Selenium; Surface-Active Agents; Water Pollutants, Chemical
PubMed: 34173952
DOI: 10.1007/s11356-021-15024-9 -
Journal of Contaminant Hydrology Jan 2021Surface tension isotherms and calculated air-water interfacial (AWI) adsorption data are presented for solution mixtures of per- and polyfluoroalkyl substances (PFAS),...
Surface tension isotherms and calculated air-water interfacial (AWI) adsorption data are presented for solution mixtures of per- and polyfluoroalkyl substances (PFAS), specifically a series of binary and one ternary mixtures of homologous linear perfluorocarboxylic acids (PFCAs) in a simulated groundwater, and two 8-component mixtures containing both PFCAs and linear perfluoroalkane sulfonates (PFSAs). In all cases, non-ideal competitive adsorption was observed that favored the most surface-active component(s) of the solution mixture. The multi-component extended Langmuir (EL) isotherm model was observed to accurately predict the competitive adsorption observed in the binary and ternary PFCA solution mixtures. However, the predictive utility of the EL model was observed to diminish when mixtures contained both PFCAs and PFSAs, which differ in their hydrophile structure, resulting in overpredictions and underpredictions of the AWI adsorption isotherms derived from measured data depending on the specific components present in the solution mixtures. Observations indicate that the individual component adsorptive affinities for the AWI can change in response to competitive preferential adsorption as their solution concentrations increase that is not being captured by the EL model. Our results demonstrate that alternative mathematical models are needed that support concentration dependent affinity coefficients for non-similar mixtures of PFAS, such that the transport of individual target PFAS components within a larger mixture of components can be accurately predicted across a wider range of solution concentration.
Topics: Adsorption; Fluorocarbons; Groundwater; Surface Tension; Water
PubMed: 33183849
DOI: 10.1016/j.jconhyd.2020.103731 -
Physical Chemistry Chemical Physics :... Jun 2022With an inspiration of sensing toxic gases, this study is aimed at exploring the potential of a Janus MoSSe monolayer as a gas sensor. Here, we focused on the adsorption...
With an inspiration of sensing toxic gases, this study is aimed at exploring the potential of a Janus MoSSe monolayer as a gas sensor. Here, we focused on the adsorption mechanism after the exposure to NH, NO, NO, HCN, CO, CO, H, HS and SO on both the S and Se sites of MoSSe. We investigated the structural geometries and electronic, sensing and electron-transport properties before and after adsorption of the aforementioned gases by applying DFT calculations. The results revealed the higher binding strength of NO/SO and NO on Se and S sites, respectively, among all the gas adsorptions on the MoSSe monolayer. Moreover, DOS revealed strong orbital contributions at , which confirmed the n/p-type semiconducting character for the NO/NO adsorbed MoSSe monolayer. Further, the specific work function alteration after the adsorption of NO, SO and NO indicated that the MoSSe monolayer could be a potential candidate for -type gas sensor at 300 K. Additionally, the higher electron transmission and prominent electrical response values of 76.4/56 μA and 82 μA suggested a maximum sensitivity of 98%/89% and 93% at a particular voltage for NO/SO and NO on Se and S sites, respectively. Thus, our results promote surface selectivity, S or Se site, and better sensitivity with recycling potential could enable sensing application of the Janus MoSSe monolayer for toxic gases detection.
Topics: Adsorption; Bryophyta; Density Functional Theory; Gases; Nitrogen Dioxide
PubMed: 35703165
DOI: 10.1039/d2cp01648f -
Bioresource Technology Dec 2019The endocarp of Wodyetia bifurcata was used to produce biochar by vacuum pyrolysis as an alternative adsorbent for methylene blue (MB) removal. The influence of...
The endocarp of Wodyetia bifurcata was used to produce biochar by vacuum pyrolysis as an alternative adsorbent for methylene blue (MB) removal. The influence of different pyrolysis temperatures, particle diameters and activation agents in the adsorption process was studied. Kinetics and adsorption equilibrium were also evaluated. Biochar obtained at higher pyrolysis temperatures and activated with HPO showed the best adsorptive capacities, achieving 83% of MB removal. The experimental data fitted better with pseudo-second order model. Isotherms performed at 25, 40, 50 and 60 °C showed that the adsorption of MB onto the activated biochar had no concentration dependence in the range studied. Experimental isotherms fitted well with the Freundlich and Sips models and the thermodynamic parameters suggested a physical adsorption mechanism in a heterogeneous surface, spontaneous at all temperatures evaluated. In brief, the activated carbon obtained from Wodyetia bifurcata can be a promising material for MB removal from aqueous solutions.
Topics: Adsorption; Charcoal; Hydrogen-Ion Concentration; Kinetics; Methylene Blue; Water Pollutants, Chemical
PubMed: 31518818
DOI: 10.1016/j.biortech.2019.122093 -
Water Research Oct 2023While rare earth elements (REEs) play key roles in many modern technologies, the selectivity of recovering of REEs from mining wastewater remains a critical problem. In...
While rare earth elements (REEs) play key roles in many modern technologies, the selectivity of recovering of REEs from mining wastewater remains a critical problem. In this study, iron nanoparticles (FeNPs) synthesized from euphorbia cochinchinensis extracts were successfully used for selective recovery of REEs from real mining wastewater with removal efficiencies of 89.4% for Y(III), 79.8% for Ce(III) and only 6.15% for Zn(Ⅱ). FTIR and XPS analysis suggested that the high selective removal efficiency of Y(III) and Ce(III) relative to Zn(Ⅱ) on FeNPs was due to a combination of selective REEs adsorption via complexing with O or N, ion exchange with H present in functional groups contained within the capping layer and electrostatic interactions. Adsorptions of Y(III) and Ce(III) on FeNPs conformed to pseudo second-order kinetics and the Langmuir isotherm model with maximum adsorption capacities of 5.10 and 0.695 mg∙g, respectively. The desorption efficiencies of Y(III) and Ce(III) were, respectively, 95.0 and 97.9% in 0.05 M acetic acid, where desorption involved competitive ion exchange between Y(III), Ce(III) and Zn(Ⅱ) with H contained in acetic acid and intraparticle diffusion. After four consecutive adsorption-desorption cycles, adsorption efficiencies for Y(III) and Ce(III) remained relatively high at 52.7% and 50.1%, respectively, while desorption efficiencies of Y(III) and Ce(III) were > 80.0% and 95.0%, respectively. Overall, excellent reusability suggests that FeNPs can practically serve as a potential high-quality selectivity material for recovering REEs from mining wastewaters.
Topics: Wastewater; Iron; Metals, Rare Earth; Nanoparticles; Acetic Acid; Mining; Adsorption
PubMed: 37633210
DOI: 10.1016/j.watres.2023.120486 -
Journal of Colloid and Interface Science Jan 2022In this study, an iron(III)-loaded magnetic chitosan/graphene oxide composite (Fe-MCG) was synthesized and applied for the adsorptive removal of sulfosalicylic acid...
In this study, an iron(III)-loaded magnetic chitosan/graphene oxide composite (Fe-MCG) was synthesized and applied for the adsorptive removal of sulfosalicylic acid (SSA) in aqueous solution. The results obtained from the application of various characterization techniques such as scanning electron microscopy (SEM), vibrating-sample magnetometry (VSM), and X-ray photoelectron spectroscopy (XPS) prove the successful formation of the composite with enhanced microstructure and superparamagnetic properties. The adsorption capacity of Fe-MCG towards SSA via batch mode reaches up to 135 mg/g at 293 K. The adsorption of SSA onto Fe-MCG is driven by monolayer adsorption with the chemical and physical adsorption processes both playing active roles. The Langmuir isotherm and pseudo-second-order kinetic models were observed to best describe the equilibrium adsorption and kinetic processes, respectively. The values obtained for the associated thermodynamic parameters confirm that the adsorptive process is spontaneous, exothermic and entropy-increasing. The efficacy and reusability of the spent Fe-MCG was studied using 0.01 mol/L NaOH solution. The kinetic process for the desorption of SSA from Fe-MCG is well described by the pseudo-second-order kinetic model. Based on the experimental results and XPS analysis, the underlying mechanisms for the uptake of SSA onto Fe-MCG involve electrostatic forces, complexation, π-π stacking, and hydrogen bonding. Overall, the excellent features of Fe-MCG enhance its potential as an adsorbent for the sequestration of SSA in environmental media.
Topics: Adsorption; Benzenesulfonates; Chitosan; Graphite; Hydrogen-Ion Concentration; Iron; Kinetics; Magnetic Phenomena; Salicylates; Thermodynamics; Water Pollutants, Chemical
PubMed: 34492463
DOI: 10.1016/j.jcis.2021.08.097 -
Small (Weinheim An Der Bergstrasse,... Nov 2023The vigorous nanomedicine offers significant possibilities for effective therapeutics of various diseases, and nanovesicles (NVs) represented by artificial liposomes and...
The vigorous nanomedicine offers significant possibilities for effective therapeutics of various diseases, and nanovesicles (NVs) represented by artificial liposomes and natural exosomes and cytomembranes especially show great potential. However, their complex interactions with cells, particularly the heterogeneous extracellular adsorptions, are difficult to analyze spatiotemporally due to the transient dynamics. In this study, by single NVs tracking, the extracellular NVs adsorptions are directly observed and their heterogeneous characteristics are revealed. Briefly, plenty of NVs adsorbed on HCT116 cells are tracked and classified, and it is discovered that they exhibit various diffusion properties from different extracellular regions: stable adsorptions on the rear surface and restricted adsorptions on the front protrusion. After the hydrolysis of hyaluronic acid in the extracellular matrix by hyaluronidase, the restricted adsorptions are further weakened and manifested as dissociative adsorptions, which demonstrated reduced total NVs adsorptions from a single-cell and single-particle perspective. Compared with traditional static analysis, the spatiotemporal tracking and heterogeneous results not only reveal the extracellular NVs-cell interactions but also inspire a wide variety of nanomedicine and their nano-investigations.
Topics: Adsorption; Exosomes; Extracellular Vesicles
PubMed: 37467296
DOI: 10.1002/smll.202301888