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Journal of Environmental Management Jul 2023The current paper refers to the study of a new approach to optimizing the adsorptive properties of geopolymers by varying the aluminosilicate precursors from kaolin (K),...
The current paper refers to the study of a new approach to optimizing the adsorptive properties of geopolymers by varying the aluminosilicate precursors from kaolin (K), metakaolin (MK), and coal fly ash (CFA) as internal synthesis factors. The simplex-augmented-centroid mixture design was applied to identify the optimal formulation from the three aluminosilicate precursors to develop a geopolymer (GP) with a distinctive structure that positively affects its dye adsorption efficiency. The variously formulated GP samples were tested for the removal of both methylene blue (MB-dye) and crystal violet dye (CV-dye) from an aqueous solution. The mathematical-statistical analysis of the experimental readings suggested that the generated special cubic models were significant, and thus the chosen approach was adequate for determining the optimum blending proportion. The optimization tools indicated that the optimal mixture from the three aluminosilicate precursors for developing a GP with high adsorption efficiency was 58% MK, 42% K, and 0% CFA. The optimized geopolymer (GP) was synthesized and then analyzed using a variety of physicochemical techniques, which revealed the presence of an amorphous N-A-S-H gel-rich porous structure as an influencing property on the geopolymer's organic dye adsorption efficiency. The dependence of the adsorption mechanism of both MB-dye and CV-dye by GP on the adsorbent dosage, contact time, initial dye concentration, temperature, and solution pH was evaluated. The isothermic and kinetic experimental readings for MB and CV-dyes adsorption by GP were well fitted to the pseudo-second-order and Freundlich models, with an exothermic, favorable, and spontaneous adsorption reaction thermodynamically. The experimental studies in the lab scale on GP produce comparable results. From these results, it has been concluded that the accuracy and feasibility of the mixture design simulation succeeded in optimizing and developing a geopolymeric sorbent material with great potential as an excellent economical agent for removing cationic dyes from aqueous media. This point represents an added value compared to traditional non-optimized geopolymer absorbents. Besides, this geopolymer material represents a significant application possibility for water treatment and remediation of hazardous dye pollutants.
Topics: Water Pollutants, Chemical; Coal Ash; Aluminum Silicates; Coloring Agents; Adsorption; Kinetics; Hydrogen-Ion Concentration
PubMed: 37015145
DOI: 10.1016/j.jenvman.2023.117853 -
Environmental Monitoring and Assessment Aug 2023The recovery of organophosphate pesticides (OPPs) from aqueous solutions is imperative considering their agricultural and environmental implications. Among various...
The recovery of organophosphate pesticides (OPPs) from aqueous solutions is imperative considering their agricultural and environmental implications. Among various mitigation approaches used for OPPs' removal, adsorption offers many advantageous features for OPPs abatement owing to its benign nature, cost-effective processing, and non-requirement of excessive equipment. This research describes the adsorptive removal of three organophosphate pesticides (OPPs) namely chlorpyrifos (CPF), methyl parathion (MP), and malathion (MAL) by HKUST-1 (HKUST = Hong Kong University of Science and Technology) metal-organic framework (MOF). The synthesis of HKUST-1 MOFs was confirmed by various spectroscopic and microscopic techniques. The adsorption kinetics was systematically investigated by varying three parameters to include solution pH, contact time, and initial pesticide concentration. Among all the three pesticides, HKUST-1 showed enhanced removal of CPF in terms of pH, resulting in an adsorption capacity of 1.82 mg·g. However, under the effect of contact time at 60 min, the adsorption capacity of HKUST-1 for PM, MAL, and CPF were computed to be 1.83, 1.79, and 0.44 mg·g, respectively. Besides, HKUST-1 showed a remarkable performance towards adsorptive removal of MAL (14.01 mg·g at 10 mg·L concentration) with linear increase in adsorption capacity as the function of initial pesticide concentration. The MOFs were also able to retain ca. 50% of their adsorption efficiency over the course of five cycles of adsorptive removal of CP. In the future, a comprehensive data table showing the performance of various MOFs against various OPPs can be constructed on the basis of parameters used in this study.
Topics: Metal-Organic Frameworks; Adsorption; Environmental Monitoring; Insecticides; Chlorpyrifos; Malathion; Pesticides; Organophosphorus Compounds
PubMed: 37592149
DOI: 10.1007/s10661-023-11662-3 -
Viruses Aug 2023The preservative qualities of individual ionic compounds impacting the infectivity of T4 virions were elucidated. T4 virions were immersed in quasi-pure ionic solutions...
The preservative qualities of individual ionic compounds impacting the infectivity of T4 virions were elucidated. T4 virions were immersed in quasi-pure ionic solutions prior to the adsorption process, and the plaque forming unit (pfu) values of these were measured following the conventional method. In neutral ionic solutions, the minimum and the optimum concentrations of preservative qualities corresponded with the results obtained from the multi-ionic media/buffers. In acid and alkali solutions, phages show tolerances at a pH range of 5-11 in multi-ionic media/buffers. T4 virions show no tolerance in quasi-pure acid, neutral, and weak alkaline conditions. The preservative quality of T4 virions increased in over 10 mM OH solution, equivalent to a pH value over 10, which corresponds to the pKa of the deprotonation of the DNA bases G and T. Infectivity was lost below 10 mM OH and higher than 10 mM OH. These results imply that maintaining infectivity of a virion may need the flexibility of the intra-capsid DNA by deprotonation.
Topics: Adsorption; Bacteriophage T4; Capsid; Capsid Proteins
PubMed: 37632079
DOI: 10.3390/v15081737 -
Environmental Science and Pollution... Aug 2023In this study, conventional and Graphene Oxide-engineered biochars were produced and thoroughly characterized, in order to investigate their potential as adsorptive...
In this study, conventional and Graphene Oxide-engineered biochars were produced and thoroughly characterized, in order to investigate their potential as adsorptive materials. Two types of biomass, Rice Husks (RH) and Sewage Sludge (SS), two Graphene Oxide (GO) doses, 0.1% and 1%, and two pyrolysis temperatures, 400 °C and 600 °C were investigated. The produced biochars were characterized in physicochemical terms and the effect of biomass, GO functionalization and pyrolysis temperature on biochar properties was studied. The produced samples were then applied as adsorbents for the removal of six organic micro-pollutants from water and treated secondary wastewater. Results showed that the main factors affecting biochar structure was biomass type and pyrolysis temperature, while GO functionalization caused significant changes on biochar surface by increasing the available C- and O- based functional groups. Biochars produced at 600 °C showed higher C content and Specific Surface Area, presenting more stable graphitic structure, compared to biochars produced at 400 °C. Micro-pollutant adsorption rates were in the range of 39.9%-98.3% and 9.4%-97.5% in table water and 28.3%-97.5% and 0.0%-97.5% in treated municipal wastewater, for the Rice Husk and Sewage Sludge biochars respectively. The best biochars, in terms of structural properties and adsorption efficiency were the GO-functionalized biochars, produced from Rice Husks at 600 °C, while the most difficult pollutant to remove was 2.4-Dichlorophenol.
Topics: Sewage; Environmental Pollutants; Adsorption; Wastewater; Charcoal; Water
PubMed: 37430083
DOI: 10.1007/s11356-023-28549-y -
Chemosphere Mar 2024Per- and polyfluoroalkyl substances (PFAS) (also known as 'forever chemicals') have emerged as trace pollutants of global concern, attributing to their persistent and... (Review)
Review
Per- and polyfluoroalkyl substances (PFAS) (also known as 'forever chemicals') have emerged as trace pollutants of global concern, attributing to their persistent and bio-accumulative nature, pervasive distribution, and adverse public health and environmental impacts. The unregulated discharge of PFAS into aquatic environments represents a prominent threat to the wellbeing of humans and marine biota, thereby exhorting unprecedented action to tackle PFAS contamination. Indeed, several noteworthy technologies intending to remove PFAS from environmental compartments have been intensively evaluated in recent years. Amongst them, adsorption and photocatalysis demonstrate remarkable ability to eliminate PFAS from different water matrices. In particular, carbon-based materials, because of their diverse structures and many exciting properties, offer bountiful opportunities as both adsorbent and photocatalyst, for the efficient abatement of PFAS. This review, therefore, presents a comprehensive summary of the diverse array of carbonaceous materials, including biochar, activated carbon, carbon nanotubes, and graphene, that can serve as ideal candidates in adsorptive and photocatalytic treatment of PFAS contaminated water. Specifically, the efficacy of carbon-mediated PFAS removal via adsorption and photocatalysis is summarised, together with a cognizance of the factors influencing the treatment efficiency. The review further highlights the neoteric development on the novel innovative approach 'concentrate and degrade' that integrates selective adsorption of trace concentrations of PFAS onto photoactive surface sites, with enhanced catalytic activity. This technique is way more energy efficient than conventional energy-intensive photocatalysis. Finally, the review speculates the cardinal challenges associated with the practical utility of carbon-based materials, including their scalability and economic feasibility, for eliminating exceptionally stable PFAS from water matrices.
Topics: Humans; Adsorption; Nanotubes, Carbon; Bioaccumulation; Water; Fluorocarbons; Water Pollutants, Chemical
PubMed: 38215829
DOI: 10.1016/j.chemosphere.2024.141164 -
International Journal of Biological... Dec 2023In this study, a porous polyamine lignin microsphere (PPALM) was prepared through the inverse suspension polymerization combined with freeze-drying, during which sodium...
In this study, a porous polyamine lignin microsphere (PPALM) was prepared through the inverse suspension polymerization combined with freeze-drying, during which sodium lignosulfonate and polyetheramine (PEA) were crosslinked with epichlorohydrin (ECH) as the cross-linker. By adjusting the amount of ECH and PEA, the optimized PPALM exhibited suitable crosslinking degree, ensuring a balance of framework flexibility and rigidity, thereby facilitating the formation of abundant and fine pores. PPALM demonstrated good mechanical properties comparable to commercial sulfonated polystyrene cationic resin, with a porosity of 61.12 % and an average pore size of 283.51 nm. The saturation adsorption capacity of PPALM for Pb was measured to be 156.82 mg/g, and it remained above 120 mg/g after five cycles of regeneration. Particularly, the concentration of 50 mg/L Pb solution could be reduced to 0.98 mg/L after flowing through the PPALM packed bed, indicating the great potential of PPALM for application in wastewater treatment.
Topics: Adsorption; Lignin; Porosity; Microspheres; Lead; Water Pollutants, Chemical
PubMed: 37751818
DOI: 10.1016/j.ijbiomac.2023.127026 -
Chemosphere Feb 2024Aged microplastics are ubiquitous in the aquatic environment, which inevitably accumulate metals, and then alter their migration. Whereas, the synergistic behavior and...
Aged microplastics are ubiquitous in the aquatic environment, which inevitably accumulate metals, and then alter their migration. Whereas, the synergistic behavior and effect of microplastics and Hg(II) were rarely reported. In this context, the adsorptive behavior of Hg(II) by pristine/aged microplastics involving polystyrene, polyethylene, polylactic acid, and tire microplastics were investigated via kinetic (pseudo-first and second-order dynamics, the internal diffusion model), Langmuir, and Freundlich isothermal models; the adsorption and desorption behavior was also explored under different conditions. Microplastics aged by ozone exhibited a rougher surface attached with abundant oxygen-containing groups to enhance hydrophilicity and negative surface charge, those promoted adsorption capacity of 4-20 times increment compared with the pristine microplastics. The process (except for aged tire microplastics) was dominated by a monolayer chemical reaction, which was significantly impacted by pH, salinity, fulvic acid, and co-existing ions. Furthermore, the adsorbed Hg(II) could be effectively eluted in 0.04% HCl, simulated gastric liquids, and seawater with a maximum desorption amount of 23.26 mg/g. An artificial neural network model was used to predict the performance of microplastics in complex media and accurately capture the main influencing factors and their contributions. This finding revealed that aged microplastics had the affinity to trap Hg(II) from freshwater, whereafter it released the Hg(II) once transported into the acidic medium, the organism's gastrointestinal system, or the estuary area. These indicated that aged microplastics could be the sink or the source of Hg(II) depending on the surrounding environment, meaning that aged microplastics could be the vital carrier to Hg(II).
Topics: Microplastics; Plastics; Adsorption; Deep Learning; Mercury; Water Pollutants, Chemical
PubMed: 38163463
DOI: 10.1016/j.chemosphere.2023.141067 -
Environmental Research Nov 2023Adsorptive removal of heavy metal ions from water is an energy- and cost-effective water decontamination technology. Schiff base functionalities can be incorporated into... (Review)
Review
Adsorptive removal of heavy metal ions from water is an energy- and cost-effective water decontamination technology. Schiff base functionalities can be incorporated into the pore cages of metal-organic frameworks (MOFs) via direct synthesis, post-synthetic modification, and composite formation. Such incorporation can efficiently enhance the interactions between the MOF adsorbent and target heavy metal ions to promote the selective adsorption of the latter. Accordingly, Schiff base-functionalized MOFs have great potential to selectively remove a particular metal ion from the aqueous solutions in the presence of coexisting (interfering) metal ions through the binding sites within their pore cages. Schiff base-functionalized MOFs can bind divalent metal ions (e.g., Pb(II), Co(II), Cu(II), Cd (II), and Hg (II)) more strongly than trivalent metal ions (e.g., Cr(III)). The adsorption capacity range of Schiff base-functionalized MOFs for divalent ions is thus much more broad (22.4-713 mg g) than that of trivalent metal ions (118-127 mg g). To evaluate the adsorption performance between different adsorbents, the two parameters (i.e., adsorption capacity and partition coefficient (PC)) are derived and used for comparison. Further, the possible interactions between the Schiff base sites and the target heavy metal ions are discussed to help understand the associated removal mechanisms. This review delivers actionable knowledge for developing Schiff-base functionalized MOFs toward the adsorptive removal of heavy metal ions in water in line with their performance evaluation and associated removal mechanisms. Finally, this review highlights the challenges and forthcoming research and development needs of Schiff base-functionalized MOFs for diverse fields of operations.
Topics: Metal-Organic Frameworks; Water; Schiff Bases; Decontamination; Metals, Heavy; Adsorption; Water Pollutants, Chemical
PubMed: 37541413
DOI: 10.1016/j.envres.2023.116811 -
Chemosphere Nov 2023Development of membrane with improved carbon dioxide (CO) gas separation capability is a significant challenge. However, the fabrication of membrane that efficiently...
Development of membrane with improved carbon dioxide (CO) gas separation capability is a significant challenge. However, the fabrication of membrane that efficiently separate and purification CO-containing gases has been the focus of global attention. Cellulose Acetate (CA) has robust reinforcing characteristics when incorporated within a suitable polymer matrix. This work focus on the synthesis of novel mixed matrix membranes (MMMs) by introducing Graphene-grafted bimetallic MOFs in Cellulose Acetate polymer. The graphene-grafted bimetallic MOF (GG-BM MOFs) was prepared by a hydrothermal technique. Whereas, the solution casting approach used to fabricate membranes. The 1-5 wt% of GG-BM MOFs incorporated into the CA matrix. The mechanical, hydrophilicity and adsorption characteristics of fabricated MMMs were investigated. The crystallinity of MMM enhanced after the addition of GG-BM MOFs. In addition, the mechanical characteristics of MMMs were improved with the incorporation of GG-BM MOFs inside the polymer matrix. Maximum stress and strain was obtained for 2 wt% MMM (36.4 N/mm and 11% respectively). The CO adsorption performance was evaluated at 10 bar and 45 °C. The FTIR results represent insignificant bond shifting with the addition GG-BM MOFs at these conditions. The overall results showed that MMMs containing 2 wt% GG-BM MOFs have good adsorption properties for CO i.e 3.15 wt% of CO. The MMMs have shown a decrease in the mechanical properties and CO adsorption at the higher GG-BM MOFs loading due to the presence of agglomeration which was confirmed through SEM. Thus, the addition of GG-BM MOFs in the CA matrix positively altered the physicochemical characteristics of the resulting MMMs, which could assist them in achieving remarkable CO adsorption at 2 wt%.
Topics: Carbon Dioxide; Graphite; Adsorption; Gases; Polymers
PubMed: 37541443
DOI: 10.1016/j.chemosphere.2023.139721 -
Environmental Pollution (Barking, Essex... Jul 2023The remediation of acid mine drainage (AMD) is particularly challenging because it contains a large amount of Fe and a high concentration of SO. To reduce the pollution...
The remediation of acid mine drainage (AMD) is particularly challenging because it contains a large amount of Fe and a high concentration of SO. To reduce the pollution caused by SO and Fe in AMD and realize the recycling of solid waste, this study used distillers grains as raw materials to prepare biochar at different pyrolysis temperatures. Calcium alginate-biochar composite (CA-MB) was further synthesized via the entrapment method and used to simultaneously remove SO and Fe from AMD. The effects of different influencing factors on the sorption process of SO and Fe were studied through batch adsorption experiments. The adsorption behaviors and mechanisms of SO and Fe were investigated with different adsorption models and characterizations. The results showed that the adsorption process of CA-MDB600 on SO and Fe could be well described by Elovich and Langmuir-Freundlich models. It was further proved by the site energy analysis that the adsorption mechanisms of SO onto CA-MDB600 were mainly surface precipitation and electrostatic attraction, while that of Fe removal was attributed to ion exchange, precipitation, and complexation. The applications of CA-MDB600 in actual AMD proved its good application potential. This study indicates that CA-MDB600 could be applied as a promising eco-friendly adsorbent for the remediation of AMD.
Topics: Adsorption; Alginates; Water Pollutants, Chemical; Charcoal; Kinetics
PubMed: 37094733
DOI: 10.1016/j.envpol.2023.121702