Arsenic Removal Research Articles

High-efficiency removal of As(iii) from groundwater using siderite as the iron source in the electrocoagulation process.

Electrocoagulation technology, due to its simplicity and ease of operation, is often considered for treating arsenic-contaminated groundwater. However, challenges such as anode wear have hindered its development and application. This study aims to develop a siderite-filled anode electrocoagulation system for efficient removal of As(iii) and investigate its effectiveness. The impact of operational parameters on the removal rate of As(iii) was analyzed through single-factor tests, and the stability and superiority of the device were evaluated. The response surface methodology was employed to analyze the interactions between various factors and determine the optimal operational parameters by integrating data from these tests. Under conditions where the removal rate of As reached 99.3 ± 0.37%, with an initial concentration of As(iii) at 400 μg L-1, current intensity at 30 mA, initial solution pH value at 7, and Na2SO4 concentration at 10 mM. The flocculant used was subjected to characterization analysis to examine its structure, morphology, and elemental composition under these optimal operational parameters. The oxidation pathway for As(iii) within this system relies on integrated results from direct electrolysis as well as ˙O2 -, ˙OH, and Fe(iv) mediated oxidation processes. The elimination of arsenic encompasses two fundamental mechanisms: firstly, the direct adsorption of As(iii) by highly adsorbent flocculants like γ-FeOOH and magnetite (Fe3O4); secondly, the oxidation of As(iii) into As(v), followed by its reaction with siderite or other compounds to generate a dual coordination complex or iron arsenate, thus expediting its eradication. The anodic electrocoagulation system employing siderite as a filler exhibits remarkable efficiency and cost-effectiveness, while ensuring exceptional stability, thereby providing robust theoretical underpinnings for the application of electrocoagulation technology in arsenic removal.

Ferrocene-based metal-organic frameworks with dual synergistic active sites for selectively electrochemical removal of arsenic from contaminated water

The effective removal of trace levels of the highly toxic arsenite (As(Ⅲ)) from groundwater is crucial to address the threat to drinking water supply. Herein, we developed an electrochemical separation system utilizing redox-active ferrocene-based metal-organic frameworks (termed Fe-DFc) for selective removal of As(III). This system leveraged 1,1′-ferrocenedicarboxylic acid as a ligand coordinated with iron, enabling the highly selective capture and conversion of As(III) from groundwater. The Fe-DFc electrode-based electrochemical system not only effectively removed As(III) even in the presence of a 1250-fold excess of competing electrolytes, but also converted about 96 % of the adsorbed As(III) into the less toxic As(V), surpassing the results of those documented in the current literature. X-ray absorption fine structure analysis and density functional theory calculations demonstrated that the high selectivity of Fe-O6 moiety and the exceptional redox activity of Fc synergistically contributed to the efficient removal of As(III). Moreover, the electrochemical separation system enabled the remediation of arsenic-contaminated groundwater at a low energy cost of 0.033 kWh m−3 during long-term operation, highlighting the application potential of the electrochemical technology for arsenic removal from contaminated water.

Investigation of the use of Botswana coal fly ash as a material for the adsorption of arsenic from fortified water

<p>The main objective of the study was to characterize raw (RFA), water-washed (WFA) and iron-modified (Fe-WFA) Botswana coal fly ash to determine the physical and chemical properties as well as investigate its potential use as adsorbents for the removal of arsenic(III) ((As(III)) from fortified water. Scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS) showed particles with irregular size and shape for all the materials and porous iron oxide flakes for Fe-WFA. The SEM-EDS, X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) showed the main constituents of RFA, WFA and Fe-WFA to be SiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub> and CaO. The XPS further showed the surface composition of Fe-WFA with higher Fe content at 19.7% compared to 0.8% and 1.2% for RFA and WFA respectively. The XRF and XRD results confirmed the successful modification of WFA with iron by showing the Fe<sub>2</sub>O<sub>3</sub> composition increasing from 12.6% of WFA to 25.5% for Fe-WFA. The inductively coupled plasma-mass spectrometry (ICP-MS) results showed continuous reduction of metal concentrations for WFA and Fe-WFA from the first to the sixth wash. The adsorption of As(III) on the adsorbents followed the Freundlich adsorption model. The maximum adsorption capacities of 0.85, 0.02 and 2.26 mgg<sup>−1</sup> were obtained for RFA, WFA and Fe-WFA respectively.<strong></strong></p>

3D-printing of Fe–Ni bimetallic particles and their application in removal of arsenic from water

Arsenic is a hazardous element found in water sources, and removing it is crucial for ensuring a safe environment and water quality. Iron-based metal oxides efficiently remove arsenic; however, their small particle sizes make separation from water difficult after arsenic removal. Furthermore, the growing global issue of polymer waste further complicates environmental concerns. Combining three-dimensional (3D) printing and adsorption technology by incorporating nanosized functional materials into supporting polymers offers a potential solution to address both challenges. In this study, we developed a 3D-printed adsorption material through the incorporation of synthesized Fe–Ni bimetallic particles into a supporting polymer using selective laser sintering (SLS) technology. This adsorbent's properties were examined through scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and zeta potential. Furthermore, its performance in removing As(III) and As(V), even at trace levels, was assessed under varied conditions. The 3D-printed adsorbent demonstrated excellent removal of As(III) at pH 6, and As(V) at pH 4, lowering their concentration below 10 μg/L, thereby adhering to the limit established by the World Health Organization (WHO). Both As(III) and As(V) fitted the Freundlich isotherm and pseudo-second-order model, suggesting potential heterogeneous and chemisorption processes. FT-IR indicated that the exchange of the –OH group of Fe–OH with oxyanions of As(III) and As(V) could be the adsorption mechanism. Additionally, thermodynamic evaluation unveiled an endothermic and non-spontaneous adsorption reaction. The 3D-printed adsorbent exhibited excellent reusability across recurring adsorption cycles. The combination of SLS 3D printing with Fe–Ni bimetallic particles produces structures that retain their functionality in removing both arsenic species present in water. This indicates the potential of the 3D-printed adsorbent for effective treatment of arsenic-contaminated water, offering remedies to challenges like handling small particle sizes, mitigating polymer waste, and addressing environmental concerns.

Disposable Waste Aluminium Pan Derived Pseudoboehmite Nanoparticles for Concurrent Removal of Fluoride and Arsenate from Aqueous Medium

AbstractThe co‐occurrence of fluoride and arsenate in groundwater is a growing global concern owing to their synergistic adverse effect on human health. Thus, development of materials capable of capturing fluoride and arsenate simultaneously from aqueous medium is of much need. Moreover, it is a matter of great research importance to develop sustainable adsorbents by recycling solid wastes. Keeping this in mind, herein a novel pseudoboehmite nanoparticles (PBN) were synthesized by chemical valorization of disposable waste aluminium pan for simultaneous removal of fluoride and arsenate in aqueous medium. The physicochemical properties of the material were confirmed using analytical techniques such as XRD, BET, FT‐IR, FESEM etc. Batch study confirms the maximum monolayer adsorption of 90.10 mg g−1 and 94.84 mg g−1 of fluoride and arsenate respectively, which shows comparable affinity of the material for both contaminants. The selectivity of the adsorbent towards fluoride and arsenate was further evaluated by set of kinetic experiments in both single‐ion and mixture‐ion environment. The synthesis of pseudoboehmite nanomaterial using disposal waste Al pan and its high efficacy for removal of fluoride and arsenic even in presence of competing anionic environments provide a new direction of waste management for sustainable remediation of groundwater contaminants.

Enhanced arsenic removal using biochar immobilized bacteria encapsulated in polyvinyl alcohol-sodium alginate beads: Fabrication, optimization and performance evaluation

Arsenic ranks first on the Substance Priority List of the Agency for Toxic Substances and Disease Registry and causes a wide range of health problems, including cancer and even death. The present work was focused on the removal of arsenic using bacteria, Proteus alimentorum strain TY6 and Pseudomonas aeruginosa strain K7Pb, immobilized on peanut shell biochar [0.05 % (w/v)] and encapsulated in polyvinyl alcohol (PVA) – sodium alginate (SA) beads crosslinked with calcium chloride (CaCl2). The maximum removal efficiency obtained was 92.29 ± 0.51 % and 93.63 ± 0.09 % for As(V), using beads of K7Pb and K7Pb + TY6 respectively, whereas for As(III), it was 91.71 ± 0.51 % with TY6 and 93.35 ± 0.05 % for KP7b + TY6, at pH 7 at 30 °C. Surface morphology was characterized by scanning electron microscopy and energy-dispersive x-ray analysis. This study revealed that the encapsulated bacteria immobilized on biochar were more effective than the free-cell and bacteria immobilized on biochar. It was also found that the beads could be reused effectively for five cycles (for K7Pb and TY6) and eight cycles (for K7Pb + TY6) before their removal efficiency reduced to below 80 %.

An Arsenic Removal Technology and Its Application in Arsenic-Containing Copper

The usage of copper (Cu) ores containing low or no arsenic (As) has reduced, and Cu ores containing high levels of As have emerged as vital mineral resources for Cu extraction and processing. The quality of the Cu ores has decreased from 1.6% to approximately 1.0%. The proportion of As to Cu in 15% of Cu resources currently reaches 1:5. However, during the extraction and processing of Cu ores, As presents significant environmental harm. Hence, safely and effectively removing As is paramount in Cu smelting and processing, holding substantial importance in fostering environmentally sustainable practices within the Cu extraction and processing industry. This article consolidates the resource distribution of As-containing Cu (ACC) ores, comprehensively and systematically evaluates the present advancements in extracting techniques for these minerals, and identifies the challenges inherent in pyrometallurgical and wet processes for treating ACC deposits. Pyrometallurgy is a simple primary roasting technique and has widespread applicability in the treatment of various ACC minerals. Its disadvantages are the emission of exhaust gas and the high treatment costs associated with it. The wet arsenic removal method boasts advantages including minimal air pollution and a high resource recovery rate, significantly aiding in Cu concentrate recovery; its major drawback is the production of As-containing wastewater. The hydrometallurgical removal of As from ACC mines involves extracting As through leaching. Recently, biometallurgy has presented innovative solutions using specialized microorganisms to bioleach or bioabsorb As, but large-scale industrial applications still lack specific practical implementation. This review explores the underlying causes of the challenges encountered in processing ACC minerals. Additionally, it highlights pyrometallurgical roasting coupled with high-temperature filtration as a pivotal advancement in the extraction and processing of ACC ores.

Humic Substances from Sludge Compost with Biochar Addition: An Effective Washing Agent for Arsenic Removal from Contaminated Soil

Humic Substances from Sludge Compost with Biochar Addition: An Effective Washing Agent for Arsenic Removal from Contaminated Soil

Deep removal of arsenic from arsenic-bearing gypsum using a seed-induced crystal control technique and its mechanisms

Arsenic-bearing gypsum (ABG), a byproduct from the lime/ferric sulfate process in the waste acid treatment of the heavy non-ferrous industry, represents a substantial hazardous arsenic (As) waste issue in China. Due to the potential arsenic leakage, the disposal of ABG poses an urgent challenge to the surrounding environment. The elevated As content and the low-value-added recycling products are the primary hurdles hindering ABG recycling. In this study, precise control over the gypsum crystal and As species in Na2SO4-H2SO4 solutions under mild conditions facilitated the deep removal of As (with a leaching efficiency of 92.45 % and a final product As concentration of 80.32 ppm) and simultaneous preparation of high-strength α-bassanite (with a compressive strength of 35.38 MPa) from the pre-treated ABG. This process occurred during the recrystallization from dihydrate gypsum (CaSO4·2H2O, DH) to α-bassanite (α-CaSO4·0.5H2O, α-HH), involving DH dissolution followed by α-HH crystallization. The encapsulated As was fully released during the dissolution process, crucial for the efficient elimination of As impurities. H2SO4 dissolved the released As, transforming it into the protonated species (H3AsO4) with a distinct structure and a less negative binding energy (ΔEB) to SO42-. This transformation prevented the chemical incorporation of the released As during the α-HH crystallization process. Additionally, the morphology and size of α-HH were controlled by seeding in the mixed solutions. The formation of large short-columnar α-HH crystals with a low specific surface area significantly reduced the surface adsorption of As, further enhancing As leaching efficiency. Importantly, the large short-columnar α-HH was identified as high-strength gypsum with high added value. This study provided innovative guidance for efficiently removing impurities from gypsum and pioneered a cost-effective approach for the clean and high-value utilization of industrial gypsum residues.

Sustainable and green removal of arsenic from crude tin via vacuum gasification–directional condensation

In the realm of high–tech industries, Sn has emerged as an indispensable strategic metal. However, the pyrometallurgical refining process of crude Sn is marred by the production of a substantial amount of hazardous solid waste, notably As–Al slag, posing a direct threat to the ecological safety of the production areas. This study delineates a novel process for the removal of As from crude Sn, employing vacuum gasification–directional condensation, corroborated by theoretical calculations and laboratory experimental research. Theoretically, at a system pressure ranging from 1–10 Pa, the initial volatilization temperatures of Sn and As exhibit significant variance. However, the formation of intermetallic compounds can induce Sn volatilization. Experimentally, the condensation temperature for As was predominantly within 331.7–484.7 K. During the vacuum gasification–directional condensation process, the presence of Sn4As3 intermetallic compounds impeded As volatilization. And under optimal conditions, the As content in the Sn product was recorded at 0.0053 %. Inspired from the calculations, a multistage vacuum distillation method was successfully proposed and achieved to remove As from crude tin. Typically, the total material recovery rate is 99.96 %, and the direct rate of Sn is 93.02 %. The total power consumption and emission of this process are better than the corresponding parameters of other treatment processes, which is a promising solution for the cleaning and effective removal of As.

Removal of arsenic and recovery of tin from arsenic-containing multi-metallic materials by vacuum reduction roasting

Arsenic-containing multi-metallic materials, are typical hazardous wastes generated in the process of tin recovery from zinc smelting leach slag, exhibit low resource utilization and pose a significant risk of environmental pollution. This research proposed a vacuum reduction roasting technique utilizing anthracite as the reducing agent to remove arsenic and reclaim tin from such materials, characterized by high arsenic levels (8∼wt%) and the presence of several valuable metals. The results indicated that the arsenate in these materials was transformed into As2O3, which has better volatility, while SnO2 was converted to SnO and Sn. Moreover, under the optimal conditions of a roasting temperature of 750 °C, 10 % anthracite, and a roasting duration of 3 h, the arsenic removal efficiency reached 96.97 %, and the tin recovery rate was 84.48 %. Consequently, the arsenic concentration decreased to 0.53 %, and the tin concentration in the roasted product increased from 17.70 % to 31.41 %. The final product contained phases of arsenic and tin, including Sn, SnO2, and FeAs. Meanwhile, this study provides a promising solution for the green and efficient separation of tin and arsenic in typical arsenic-containing multi-metallic materials.

Remediation of arsenic and fluoride from groundwater: a critical review on bioadsorption, mechanism, future application, and challenges for water purification.

In the past few decades, the excessive and inadequate use of technological advances has led to groundwater contamination, mainly caused by organic and inorganic pollutants, which are highly harmful to human health, agriculture, water bodies, and aquaculture. Among all toxic pollutants, As and F- play a significant role in groundwater contamination due to their excellent reactivity with other elements. To mitigate the prevalence of arsenic and fluoride within the water system, the use of biochar gives an attractive strategy for removing them mainly because of the substantial surface area, pore size, pH, aromatic structure, and functional groups inherent in biochar, which are primarily dependent upon its raw material and pyrolysis temperature. Researcher develops different methods like physiochemical and electrochemical for treating arsenic and fluoride contamination. Among all removal methods, bioadsorption using agricultural waste residues shows effective/feasible removal of As and F- due to its low cost, ecofriendly nature, readily available, and efficient reuse compared with several other harmful synthetic materials that demand costly design specifications. This study discusses current developments in bioadsorption methods for As and F- that use agricultural-based biomaterials and describes the prevailing state of arsenic and fluoride removal strategies that use biomaterials precisely.

Potential of biochar and humic substances for phytoremediation of trace metals in oil sands process affected water

Oil sands process affected water (OSPW) is produced during bitumen extraction and typically contains high concentrations of trace metals. Constructed wetlands have emerged as a cost effective and green technology for the treatment of metals in wastewaters. Whether the addition of amendments to constructed wetlands can improve metal removal efficiency is unknown. We investigated the synergistic effects of carbon based amendments and wetland plant species in removal of arsenic, cadmium, cobalt, chromium, copper, nickel, and selenium from OSPW. Three native wetland species (Carex aquatilis, Juncus balticus, Scirpus validus) and two amendments (canola straw biochar, nano humus) were investigated in constructed wetland mesocosms over 60 days. Amendment effect on metal removal efficiency was not significant, while plant species effect was. Phytoremediation resulted in removal efficiencies of 78.61–96.31 % for arsenic, cadmium, and cobalt. Carex aquatilis had the highest removal efficiencies for all metals. Amendments alone performed well in removing some metals and were comparable to phytoremediation for cadmium, cobalt, copper, and nickel. Metals were primarily distributed in roots with negligible translocation to shoots. Our work provides insights into the role of plants and amendments during metal remediation and their complex interactions in constructed treatment wetlands.

Preparation and Characterization of Ferrihydrite: Application in Arsenic Removal from Aqueous Solutions

Arsenic pollution is a public health hazard in Burkina Faso due to its impact on human health and water resources. To mitigate this pollution, ferrihydrite material has been synthesized and characterized to be used as adsorbent for arsenic removal in aqueous solutions. This study aimed to contribute to improve of access to clean drinking water by removing arsenic from water using ferrihydrite. Arsenic species such as As(III) and As(V) were removed through batch adsorption. Experiments were carried out in batch mode using arsenic aqueous solutions. The characterization of ferrihydrite using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDX), X-ray Diffraction (XRD), Infrared (IR), and Brunauer Emmett Teller (BET) showed that an amorphous and microporous 2-line ferrihydrite. The total specific surface area and pH at point of zero charge (pHpzc) were 184.518 m²/g and 9.41, respectively. The optimal adsorbent doses were 4 g/L for As (V) and 8 g/L for As (III). The optimum pH range for the adsorption of As (V) and As (III) was between 2 and 10, The maximum adsorption capacity was 15.07 mg/g for As(V) and 13.01 mg/g for As(III) with increasing concentration between 2 and 16 mg/L. Equilibrium time for As (V) and As (III) on ferrihydrite was found to be 720 min and 960 min, respectively. The adsorption of As(V) and As(III) was consistent with the Langmuir monolayer model on ferrihydrite. Arsenic adsorption was occurred according to spontaneous chemical reaction. Arsenic removal was occurred on a monolayer following the pseudo-second order kinetic.

Template-free synthesis of urchin-like iron-cerium oxides for highly efficient arsenate removal from water

The realization of adsorbents for highly efficient arsenic (As) removal from water is of very importance but challenging in the water treatment. Herein, we synthesized urchin-like iron-cerium oxides (UICO) via a simple and green one-pot method without template. The arsenate (As(V)) adsorption kinetics and isotherm reveal that UICO can effectively remove the 92 % of As(V) within 30 min under the As(V) initial concentration of 10 mg/L, and exhibits a high maximum As(V) adsorption capacity of 158.35 mg/g, which is superior to that of most reported Fe/Ce-based inorganic adsorbents. Moreover, As(V) adsorption mechanism study reveals that the As(V) adsorption involves ion-exchange between As(V) in water and the hydroxyl groups of UICO. The UICO has good potential as an environmental functional material to efficiently remove As(V) from water in practical applications.

Customizable Zr-MOF nanoantidote-based multieffective arsenic detoxification and its extended low-toxic therapy

Arsenic (As) poisoning has become a global public problem threatening human health. Chelation therapy (CT) is the preferred treatment for arsenic poisoning. Nevertheless, efficient and safe arsenic removal in vivo remains a daunting challenge due to the limitations of chelators, including weak affinity, poor cell membrane penetration, and short half-life. Herein, a mercapto-functionalized and size-tunable hierarchical porous Zr-MOF (UiO-66-TC-SH) is developed, which possesses abundant arsenic chemisorption sites, effective cell uptake ability, and long half-life, thereby efficiently removing toxic arsenic in vivo. Moreover, the strong binding affinity of UiO-66-TC-SH for arsenic reduces systemic toxicity caused by off-target effects. In animal trials, UiO-66-TC-SH decreases the blood arsenic levels of acute arsenic poisoning mice to a normal value within 48 h, and the efficacy is superior to clinical drugs 2,3-dimercaptopropanesulfonic acid sodium salt (DMPS). Meanwhile, UiO-66-TC-SH also significantly mitigates the arsenic accumulation in the metabolic organs of chronic arsenic poisoning mice. Surprisingly, UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates the side effects of arsenic drugs antitumor therapy. Statement of significanceArsenic (As) contamination has become a global problem threatening public health. The present clinical chelation therapy (CT) still has some limitations, including the weak affinity, poor cell membrane permeability and short half-life of hydrophilic chelators. Herein, a metal−organic framework (MOF)-based multieffective arsenic removal strategy in vivo is proposed for the first time. Mercapto-functionalized and size-tunable hierarchical porous Zr-MOF nanoantidote (denoted as UiO-66-TC-SH) is accordingly designed and synthesized. After injection, UiO-66-TC-SH can form Zr−O−As bonds and As−S bonds with arsenic, thus enhancing arsenic adsorption capacity, cycling stability and systemic safety simultaneously. The acute arsenic poisoning model results indicate that UiO-66-TC-SH shows superior efficacy to the clinical drug sodium dimercaptopropanesulfonate (DMPS). More meaningfully, we find that UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates side effects of arsenic drugs anti-tumor therapy.

Effects of calcined oyster shell powder composited with iron salt on the simultaneous removal of phosphorus and arsenic during algal bloom control process

Calcined oyster shell powder (COS) has the potential to serve as an efficient coagulant aid in water treatment for iron salt (IS) due to its potentially high aid capacity in alkalinity recovery and the simultaneous removal effects on algae, arsenic, phosphorus, and organic substances. However, little information is available on the specific effects and environmental impacts of COS composited with IS in coagulation for algal bloom removal. Hence, the COS was used as a coagulant aid to investigate the simultaneous removal effects on phosphorus and arsenic as well as the water environment changes during the bloom control of Microcystis aeruginosa using ferric chloride as a coagulant impacted by different hydraulic disturbances. Results showed that compared to the single IS coagulation with a pH value of about 3.1, the pH value significantly increased and stabilized at 7.5 from the 3rd day with the COS as the coagulant aid condition. Meanwhile, the removal rates of arsenic and phosphorus also improved by 14.4 % and 50.6 %, respectively, within 12 h, achieving near complete removal with little re-release risk, demonstrating excellent alkalinity adjustment and persistently simultaneous removal effects on phosphorus and arsenic. Furthermore, the coagulation aid of COS effectively inhibited the release of fulvic acid-like substances from algal cells on the 7th day. Meanwhile, it promoted the secretion of humic acid-like substances and microcystins production, as well as the release of fluorescent substances under hydraulic disturbance conditions. From the structural information presented by X-ray photoelectron spectroscopy (XPS), the precipitates mainly consisted of proteins and lipids derived from algal cells, calcium carbonate, ferric hydroxide, and trace amounts of arsenite, further confirming their precipitated mechanism of algal cell combined through COS and IS. The results provide scientific support for the practical application of COS in algal blooms and its subsequent environmental risk control.

Evaluation of the applicability of carbon-based materials for arsenic removal from flue gases

Arsenic is an highly toxic element which may be released into the atmosphere during the combustion of solid fuels. This paper verifies the possibility of using char from tires CT and lignite dust LD as materials for the adsorption of gaseous forms of As. The source of the gaseous forms of arsenic was coal combustion under laboratory conditions. Adsorption tests included both different sorbent bed temperatures (120–180°C) and various flue gas compositions (resulting from the combustion of bituminous and lignite coals). It was shown that sorption temperature did not affect the arsenic removal efficiency for both analysed sorbents. The average As removal efficiency for tire char and lignite dust was 88 and 92%, respectively. The composition of the burned coal, and thus the composition of the flue gas, significantly influences the efficiency of Asgas adsorption. While for LD the level of As removal was still high (more the 90%), the sorption of Asgas by tire char from the flue gas when lignite was burned was less effective (the efficiency was below 80%). It was additionally indicated via a leachability test that "used" CT could be safely disposed of while LD would require appropriate management. Based on the comparison of the performance of CT and LD with commercial AC activated carbon and the differences in their market price, it can be concluded that the studied alternative sorbents are competitive with AC.

Assessing the Long-Term Effectiveness of Sustainable Rural Water Treatment Technologies in Mitigating Arsenic Contamination of Groundwater in Afghanistan

Arsenic contamination in groundwater is a pressing global concern, impacting more than fifty million individuals across seventy-plus countries. Various sources contribute to this contamination, including human activities, geological processes, and natural biological factors. Afghanistan, where groundwater serves as the primary drinking water source, faces a critical need for sustainable arsenic removal solutions. Currently, 78% of the population relies on household tub wells for safe drinking water, highlighting the urgency of addressing arsenic contamination. Recent studies have revealed alarming arsenic levels, with approximately 61% of water samples exceeding World Health Organization standards.This study aims to assess and compare existing arsenic removal technologies to determine their suitability for Afghan households. Three commonly used methods—Sono Sand Filter, Kanchan Arsenic Removal, and Arsenic Bio Sand Filter—will be evaluated based on their efficacy and practicality. Preliminary findings indicate that the Arsenic Bio Sand Filter exhibits the highest efficiency, achieving a removal rate of 95%. Furthermore, this method offers additional benefits such as reducing pathogens, bacteria, iron, and turbidity levels. The ultimate goal of this research is to provide insights to policymakers and stakeholders, enabling them to develop effective mitigation strategies. By addressing arsenic-related health risks, these strategies can contribute to improving public health outcomes in Afghanistan

Outstanding performance of magnetic La2O2CO3/Fe3O4 nanosheets for simultaneous removal of phosphate and arsenate from wastewater

The chemical similarities and co-occurrence of phosphate and arsenate contamination have heightened the focus on their efficient simultaneous removal. In this study, magnetically recoverable La2O2CO3/Fe3O4 nanosheets were synthesized through the calcination of La-Fe binary metal glycolate. Based on magnetic and adsorption properties, La2O2CO3/Fe3O4 nanosheets with a La to Fe molar ratio of 1:1 (La2O2CO3/Fe3O4-1) were selected for further exploration. Electron microscopy characterization revealed that the nanocomposites consist of stacked La2O2CO3 and Fe3O4 nanosheets. The La2O2CO3/Fe3O4-1 nanocomposites exhibited exceptional adsorption capacities of 114.6 mg P/g and 230.2 mg As/g. Additionally, the material exhibited rapid adsorption kinetics and maintained excellent adsorption performance within a pH range of 3.0 to 9.0, showing significant selectivity for phosphate and arsenate even in the presence of various coexisting ions. Adsorption-desorption cycling tests indicated good potential for recycling. When applied to the spring water of Yangzonghai Lake, the material efficiently reduced the concentrations of phosphate and arsenate from 0.725 mg P/L and 1.380 mg As/L to below 0.020 mg P/L and 0.010 mg As/L, respectively. Mechanistic studies suggest that La2O2CO3 facilitates the removal of phosphate and arsenate primarily through electrostatic attraction and ligand exchange. These findings indicate that La2O2CO3/Fe3O4 holds significant promise for the co-removal of phosphate and arsenate, even at low concentrations.