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The Science of the Total Environment Feb 2022The contamination of natural resources by hexavalent chromium (Cr(VI)) originating from natural and anthropogenic activities is a serious environmental concern. Although... (Review)
Review
The contamination of natural resources by hexavalent chromium (Cr(VI)) originating from natural and anthropogenic activities is a serious environmental concern. Although many articles on chromium remediation have been published, a comprehensive understanding of the mechanisms involved in remediation with different sorbents is not yet available. In this systematic review, the performance and applicability of several adsorptive materials for Cr(VI) removal from aqueous media are discussed, along with a detailed analysis of the mechanisms involved. Statistical analysis is applied to compare the efficacies of different adsorbents, while a similar approach is used to determine the effects of sorbent properties and experimental conditions on the adsorption capacity. A detailed analysis of the factors involved in fixed-bed column studies is also presented. A suitable desorption approach to the regeneration of the spent adsorbent and its adsorption performance in reuse is also examined. Among the different sorbents, nanoparticles and mineral-doped biochar were found to be the most effective sorbents, while the adsorption was higher at low pH (~4.0) than that at intermediate pH (6-8). Contrary to our expectation, adsorption was high for sorbents with low specific surface areas, suggesting that the adsorption of Cr(VI) is largely influenced by the chemical properties of the sorbents. The optimum adsorption in fixed-bed column systems is obtained at a lower Cr(VI) ion concentration, a lower influent flow rate, and a higher bed height. Since most of the studies reviewed herein were merely experimental and utilized ideal conditions with the presence of a single contaminant, i.e. Cr(VI) in water, further studies on adsorption dynamics with the presence of other interfering ions are suggested. This review is promising for the further development of Cr(VI) removal strategies and closes the research gaps pertaining to their challenges.
Topics: Adsorption; Anthropogenic Effects; Chromium; Hydrogen-Ion Concentration; Kinetics; Water; Water Pollutants, Chemical
PubMed: 34871684
DOI: 10.1016/j.scitotenv.2021.152055 -
Environmental Science and Pollution... Mar 2021Water pollution by emerging pollutants such as pharmaceutical and personal care products is one of today's biggest challenges. The presence of these emerging...
Water pollution by emerging pollutants such as pharmaceutical and personal care products is one of today's biggest challenges. The presence of these emerging contaminants in water has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and threat to health and safety. The antidiabetic drug glimepiride, GPD, is among these compounds, and it possesses adverse effects on human health if not carefully administered. Several conventional processes were proposed for the elimination of these persistent contaminants, and adsorption is among them. Therefore, in this study, the adsorptive removal of GPD from water using multi-walled carbon nanotubes (MWCNT) supported on silica was explored on a fixed-bed column. The effects of bed-height, solution pH, and flow rate on the adsorptive removal of GPD were investigated. The obtained adsorption parameters using Sips, Langmuir, and Freundlich models were used to investigate the continuous adsorption. The results showed that the drug removal is improved with the increasing bed height; however, it decreased with the flow rate. The effect of pH indicated that the adsorption is significantly affected and increased in acidic medium. The convection-dispersion model coupled with Freundlich isotherm was developed and used to describe the adsorption breakthrough curves. The maximum adsorption capacity (q) was 275.3 mg/g, and the axial dispersion coefficients were ranged between 3.5 and 9.0 × 10 m/s. The spent adsorbent was successfully regenerated at high pH by flushing with NaOH.
Topics: Adsorption; Ecosystem; Humans; Kinetics; Nanotubes, Carbon; Sulfonylurea Compounds; Water Pollutants, Chemical; Water Purification
PubMed: 33219502
DOI: 10.1007/s11356-020-11679-y -
ACS Applied Bio Materials Mar 2023Current antimicrobial challenges in hospitals, pharmaceutical production units, and food packaging have motivated the development of antimicrobial agents, among them the...
Current antimicrobial challenges in hospitals, pharmaceutical production units, and food packaging have motivated the development of antimicrobial agents, among them the antimicrobial compounds based on cellulose and peptides. Herein, we develop molecular dynamics (MD) models to dissect and characterize the adsorption process of antimicrobial peptides (AMPs) such as protegrin 1, magainin 2, and cyclic indolicidin on various surfaces of cellulose including [-1-10], [1-10], [-100], [100], [-110], and [110]. Our results suggest that the magainin 2 antimicrobial peptide loses most of its initial helix form, spreads on the cellulose surface, and makes the most rigid structure with [110] surface. The cyclic indolicidin peptide has the lowest affinity to adsorb on the cellulose surfaces, and the protegrin 1 peptide successfully adsorbs on all the proposed cellulose surfaces. Our MD simulations confirmed that cellulose can improve the corresponding peptides' structural stability and change their secondary structures during adsorption. The [-1-10] and [100] surfaces of cellulose show considerable affinity against the AMPs, exhibiting greater interactions with and adsorption to the peptides. Our data imply that the stronger adsorptions are caused by a set of H-bonds, van der Waals, and electrostatic interactions, where van der Waals interactions play a prominent role in the stability of the AMP-cellulose structures. Our energy analysis results suggest that glutamic acid and arginine amino acids have key roles in the stability of AMPs on cellulose surfaces due largely to stronger interactions with the cellulose surfaces as compared with other residues. Our results can provide useful insight at the molecular level that can help design better antimicrobial biomaterials based on cellulose.
Topics: Antimicrobial Peptides; Adsorption; Magainins; Cellulose; Anti-Infective Agents
PubMed: 36935640
DOI: 10.1021/acsabm.2c00905 -
Environmental Science and Pollution... Apr 2023The adsorption and degradation of seven commercially available neonicotinoid insecticides in four types of agricultural soils from three states (Mississippi, Arkansas,...
The adsorption and degradation of seven commercially available neonicotinoid insecticides in four types of agricultural soils from three states (Mississippi, Arkansas, and Tennessee) in the USA were studied. The adsorptions of all the neonicotinoids fit a linear isotherm. The adsorption distribution coefficients (K) were found to be below 2.0 L/kg for all the neonicotinoids in all the soils from Mississippi and Arkansas. Only in the Tennessee soil samples, the K ranged from 0.96 to 4.21 L/kg. These low values indicate a low affinity and high mobility of these insecticides in the soils. The soil organic carbon-water partitioning coefficient K ranged from 349 to 2569 L/kg. These K values showed strong positive correlations with organic carbon content of the soils. The calculated Gibbs energy change (ΔG) of these insecticides in all the soils ranged from - 14.6 to - 19.5 kJ/mol, indicating that physical process was dominant in the adsorptions. The degradations of all these neonicotinoids in the soils followed a first-order kinetics with half-lives ranging from 33 to 305 days. The order of the insecticides with decreasing degradation rate is as follows: clothianidin > thiamethoxam > imidacloprid > acetamiprid > dinotefuran > thiacloprid > nitenpyram. The moisture content, clay content, and cation exchange capacity showed positive effects on the degradation rate of all the neonicotinoids. The Groundwater Ubiquity Score (GUS) calculated from the adsorption distribution coefficient, organic content, and half-life indicates that, except for thiacloprid, all the neonicotinoids in all the soils are possible leachers, having potentials to permeate into and through groundwater zones.
Topics: Insecticides; Soil; Adsorption; Carbon; Neonicotinoids; Nitro Compounds
PubMed: 36746858
DOI: 10.1007/s11356-023-25671-9 -
Environmental Research Sep 2023This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The...
This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The characterization analyses of the pre- and post-process material by XPS, TG/DTG, FT-IR, SEM/EDS, and XRD helped in the elucidation of the mechanisms, indicating greater involvement of n-n and π -π interactions. In the kinetic studies, the simple systems with CIP and OFL were similar, both showed equilibrium time around 20/30 min and increased adsorptive capacity with increasing initial drug concentration. In the multicomponent system, different fractions of CIP and OFL were tested and the time to reach equilibrium also varied between 20 and 30 min. In general, the adsorption capacity of CIP is slightly lower than that of OFL under the conditions tested. The selectivity analysis of the system showed that the selectivity's of the two drugs are identical in equimolar fractions. The mathematical modeling of the kinetic data indicated that in monocomponent systems, the model of pseudo-second order (PSO) adequately described both CIP and OFL kinetics. Furthermore, with the implementation of Artificial Neural Networks (ANN), it was possible to obtain a more assertive prediction of the behavior of single and binary systems.
Topics: Ofloxacin; Ciprofloxacin; Nanotubes, Carbon; Kinetics; Adsorption; Spectroscopy, Fourier Transform Infrared; Water Pollutants, Chemical
PubMed: 37356533
DOI: 10.1016/j.envres.2023.116503 -
Transfusion and Apheresis Science :... Oct 2017Apheresis therapy was first introduced into Japan from the United State as plasmapheresis by a centrifuge method. However, the invention of hollow fiber has subsequently... (Review)
Review
Apheresis therapy was first introduced into Japan from the United State as plasmapheresis by a centrifuge method. However, the invention of hollow fiber has subsequently lead to a membrane plasma separation. Selective removal of the plasma or cell component has been improved and matured in clinical application. Therapeutic apheresis has progressed and diversified with the development of technology for membrane separation by hollow fiber and adsorption with a physicochemical adsorbent in Japan.
Topics: Adsorption; Blood Component Removal; Humans; Japan
PubMed: 28927700
DOI: 10.1016/j.transci.2017.08.007 -
Journal of Hazardous Materials Feb 2023Undesired discharge of various effluents directly into the aquatic ecosystem can adversely affect water quality, endangering aquatic and terrestrial flora and fauna.... (Review)
Review
Undesired discharge of various effluents directly into the aquatic ecosystem can adversely affect water quality, endangering aquatic and terrestrial flora and fauna. Therefore, the conceptual design and fabrication of a sustainable system for alleviating the harmful toxins that are discharged into the atmosphere and water bodies using a green sustainable approach is a fundamental standpoint. Adsorptive removal of toxins (∼99% removal efficacy) is one of the most attractive and facile approaches for cleaner technologies that remediate the environmental impacts and provide a safe operating space. Recently, the introduction of biopolymers for the adsorptive abstraction of toxins from water has received considerable attention due to their eclectic accessibility, biodegradability, biocompatibility, non-toxicity, and enhanced removal efficacy (∼ 80-90% for electrospun fibers). This review summarizes the recent literature on the biosorption of various toxins by biopolymers and the possible interaction between the adsorbent and adsorbate, providing an in-depth perspective of the adsorption mechanism. Most of the observed results are explained in terms of (1) biopolymers classification and application, (2) toxicity of various effluents, (3) biopolymers in wastewater treatment and their removal mechanism, and (4) regeneration, reuse, and biodegradation of the adsorbent biopolymer.
Topics: Water Pollutants, Chemical; Ecosystem; Water Purification; Adsorption; Biopolymers; Wastewater
PubMed: 36302289
DOI: 10.1016/j.jhazmat.2022.130168 -
Chemosphere Jan 2022The ubiquitous presence of inorganic and organic phosphorus in wastewater and natural water bodies has deteriorated the water environment qualities and exerted...
The ubiquitous presence of inorganic and organic phosphorus in wastewater and natural water bodies has deteriorated the water environment qualities and exerted significant influences on ecosystems. In this study, an effective polypyrrole modified red mud adsorbent (PRM) was optimized for the adsorptive removal of inorganic and organic phosphorus from aqueous solutions. The addition of ferric chloride and pyrrole was optimized for complete oxidation and modification of polypyrrole onto red mud. Kinetic studies illustrated that the adsorption progress was accomplished by physical and chemical adsorption. The experimental data of the optimized PRM were described well by Langmuir isotherm, and the equilibrium adsorption capacity was 32.9 and 54.7 mg/g for inorganic and organic phosphorus, respectively. The PRM showed commendable adsorption performance despite the pH conditions ranging from 3 to 11. From the effect of ion strength and X-ray photoelectron spectroscopy (XPS) tests, we found that ligand exchange is the main mechanism of orthophosphate adsorption onto PRM, while electrostatic attraction played an important role in organic phosphorus adsorption. The adsorption performance from column studies showed that the velocity of flow influenced the breakthrough time of the column but the initial concentration had minor impacts. This study would extend the potential application of polypyrrole modified red mud, acting as an efficient adsorbent for inorganic and organic phosphorus adsorption in water treatment.
Topics: Adsorption; Ecosystem; Hydrogen-Ion Concentration; Kinetics; Phosphorus; Polymers; Pyrroles; Water Pollutants, Chemical; Water Purification
PubMed: 34403899
DOI: 10.1016/j.chemosphere.2021.131862 -
Journal of Environmental Management Jan 2021A series of metal-organic frameworks (MOFs) based on aluminum-benzene dicarboxylates (MIL-53, NH-MIL-53, and NH-MIL-101) at different ratios have been synthesized, and...
A series of metal-organic frameworks (MOFs) based on aluminum-benzene dicarboxylates (MIL-53, NH-MIL-53, and NH-MIL-101) at different ratios have been synthesized, and their adsorption performances for methotrexate (MTX), an anti-cancer drug, have been investigated in terms of adsorption kinetics, isotherms, solution pH, thermodynamics, mechanism, and recyclability. Maximum adsorption values of 374.97, 387.82, and 457.69 mg/g were observed for MIL-53, NH-MIL-53, and NH-MIL-101 , respectively. Our study shows that adsorption capacity of MTX depends not only on surface area and pore volume but also on the zeta potential and the presence of suitable functional groups. Higher adsorption of NH-MIL-101 observed for MTX than the other synthesized MOFs may be attributed to its large surface area, large total pore volume, high positive zeta potential, and polar amino functional groups located on its surface, which are responsible for its increased interactions with MTX molecules. Adsorption isotherms and kinetics of MTX onto NH-MIL-101 followed the Langmuir and pseudo-second-order kinetic equations. Thermodynamic data suggest that adsorption of MTX onto NH-MIL-101 is spontaneous and exothermic, while the adsorption mechanism is governed by electrostatic interactions, π-π stacking interactions, and H-bonding. Regeneration and recyclability of NH-MIL-101 were also investigated by washing with ethanol to observe its decreased adsorption performance towards MTX. It was slightly decreased after seven adsorption-desorption cycles, indicating excellent regeneration and good structural stability under the chosen experimental conditions.
Topics: Adsorption; Aluminum; Humans; Metal-Organic Frameworks; Methotrexate; Neoplasms
PubMed: 33254841
DOI: 10.1016/j.jenvman.2020.111448 -
Bioresource Technology Jan 2021A Fe/Mn oxides loaded biochar (FeMn-BC) was prepared to enhance the adsorption of tetracycline (TC). γ-FeO and MnO were assigned to the Fe and Mn oxides, respectively....
A Fe/Mn oxides loaded biochar (FeMn-BC) was prepared to enhance the adsorption of tetracycline (TC). γ-FeO and MnO were assigned to the Fe and Mn oxides, respectively. The enhanced adsorption of TC was dominated by the loaded γ-FeO and MnO. According to Akaike-Information-Criteria evaluation, Elovich kinetic and Langmuir isotherm models could best describe the adsorption with a maximum capacity of 14.24 mg/g. During adsorption process, the γ-FeO and MnO hydrolyzed into hydroxides (FeOOH and MnOOH) which acted as bases to complex with TC ion under alkaline condition (pH = 11). After the adsorption, the concentrations of leached Fe and Mn could meet the requirements PRC standards GB13456-2012 and GB8978-1996, respectively. The FeMn-BC had ~24% on TC removal (initial concentration of 20 mg/L) after four-cycles regeneration. The FeMn-BC was also available for TC adsorptions in column tests and actual wastewater.
Topics: Adsorption; Charcoal; Iron; Kinetics; Manganese; Manganese Compounds; Oxides; Tetracycline; Water Pollutants, Chemical
PubMed: 33130541
DOI: 10.1016/j.biortech.2020.124264