Extraction Of Arsenic Research Articles

Arsenic removal strategy in the processing of an arsenopyritic refractory gold ore

In the gold mining industry, the exploitation of low-grade refractory deposits generates effluents with high arsenic concentrations. In this study, an additional stage in the processing of an arsenopyritic refractory gold ore was studied. Arsenic extraction in an alkaline pretreatment was evaluated to avoid metalloid release in the subsequent gold thiosulfate leaching stage, without affecting precious metal extraction. Experiments were conducted with different extracting agents (citric acid, sodium bicarbonate, oxalic acid, deionized water); contact time in the alkaline pretreatment stage (6 and 13 days) was also assessed; furthermore, the effect of arsenic extraction time (4 h, 6 days and 12 days), concentration of oxalic acid (0.02, 0.1, 0.5 M) and temperature (25, 70 °C), was studied. The results showed that it is possible to remove arsenic without altering the subsequent release of gold (80%). The best conditions were: 0.1 M oxalic acid for 1 h and at 70 °C. Finally, it was observed that the concentration of As released into the subsequent thiosulfate leach decreases by 97.7% (from 640 to 15 mg/l), thereby conserving its ability to eventually be recycled after gold recovery.

RECYCLING TECHNOLOGY OF ACTIVE MATERIALS OF THE ZINC-MANGANESE CURRENT SOURCES

It is being investigated whether it is possible to develop a low-cost method for processing used Zn-MnO2 primary chemical power sour­ces, which is focused on a closed cycle of ge­nerating zinc-manganese power sources from wasted batteries. It is proposed that chemical processing reagents be replaced with less dangerous ones for the environment and people, in accordance with «green chemi» principles. The existing hydrometallurgical method of processing of primary current sources with selective extraction of the spent part of the anode mass is modified and laboratory processed. The stage of additional extraction of arsenic is entered. The proposed technological scheme avoids heavy air loads in the form of carbon dioxide emissions by eliminating the stage of burning organic matter. The use of acetic acid allows to avoid sulfuric acid discharges and to obtain high-quality for secondary production of cathode mass of new chemical current sour­ces, as well as to obtain technical zinc powder and active zinc powder using hydrometallurgical technology for anode mass production of primary batteries. Also, the presence of stages of extraction of heavy metal ions (Hg2 +, Pb2 +, Cd2 +) and Arsenic to obtain products that can be further used in other technological processes makes this technology virtually waste-free, and in the stages of recovery of acetic acid and hypochlorite – closed. Thus, the use of the proposed technological schemes allows to make such production not only a little harmful to the environment, but also for workers, as well as to simplify the requirements for technological equipment.

Development of a green emulsion liquid membrane using waste cooking oil as diluent for the extraction of arsenic from aqueous solution – Screening, optimization, kinetics and thermodynamics studies

Environmental friendly treatment technology was adopted in the present work by employing green emulsion liquid membrane (GELM) for the extraction of arsenic from an aqueous solution. The GELM was composed of used waste cooking oil as a diluent, aliquat 366 as a carrier, span 80 as a surfactant and NaOH as a stripping agent. Waste cooking oil, a nontoxic organic solvent was used as a diluent. Initially, nine parameters, namely, surfactant concentration, carrier concentration, agitation time, agitation speed, pH of the external phase, treat ratio, internal phase concentration, arsenic concentration and volume ratio of organic to aqueous phase were selected and screened by Plackett-Burman design (PBD) for arsenic extraction. Then Box-Behnken design (BBD) was applied using the selected parameters to achieve the optimal condition for the arsenic extraction. The optimum conditions for the maximum removal of arsenic were: Surfactant concentration – 2.3 (v/v %), Carrier concentration – 5.6 (v/v%), Treat ratio – 12, internal phase concentration – 0.92 M, initial arsenic concentration – 100 ppm, O/A ratio – 1. The mechanism of arsenic extraction was also presented. The study on stripping and reuse of the GELM was discussed and recommended that membrane phase might be reused for 6 times. For the optimized factors the maximum extraction of arsenic was estimated as 99.0 %. Kinetic analysis shows that the arsenic extraction by GELM follows first-order reaction. In addition, thermodynamic analysis reveals that the extraction process was an endothermic, and spontaneous in nature.

Determination and uncertainty analysis of inorganic arsenic in rice by UHPLC-ICPMS

The present study arose from the need of to determine inorganic arsenic (iAs) at low levels in rice. Ultra-high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (UHPLC-ICPMS) using Kinetic Energy Discrimination (KED) mode to eliminate spectral interferences was used for analysis of iAs. Sample preparation involves extraction of inorganic arsenic (sum of As3+ and As5+) with water by heating at 90 °C for 5 min in water bath. Separation is accomplished with a reversed-phase ion pack column using a gradient chromatographic method followed by ICPMS analysis within 5 min. The method was validated in accordance with Commission Regulation (EU) No 836/2011 and performance characteristics were verified. Acceptable values were obtained for specificity, repeatability (HorRatr < 0.6), within-lab reproducibility (HorRatR < 0.3) with recovery 80-90%, limit of quantification (0.02 mg/kg), fitness-for-purpose and trueness (using CRM); thus, the method can be considered for official control purposes.

Effect of organic nutrients on bioleaching of low-grade copper concentrate at different temperatures

The goal of the present work was to study the effect of different organic nutrients (yeast extract and molasses) on the biooxidation of copper concentrate containing chalcopyrite, tennantite, sphalerite, and pyrite in batch experiments at different temperatures (of 40 to 55°C). For the experiments, representatives of microbial groups predominant in biohydrometallurgical processes, bacterium of the genus Sulfobacillus, Acidithiobacillus caldus, and archaea of the genus Acidiplasma, were used. It was shown that both temperature and addition of organic nutrients in the medium affected the activity of the bioleaching. In the same time, the effect of organic nutrients was significant only at high temperatures (50 and 55°C). In all experiments, biooxidation rate decreased at the highest temperature, 55°C. Since among the strains used in the study, only A. caldus MBC-1 is autotroph, which is able to provide the population with organic nutrients and is not active at 55°C, at this temperature it was not able to maintain activity of other strains. Therefore at 55°C, biooxidation activity strongly depended on the presence of organic nutrients. Despite temperature and presence of organic nutrient affected activity of concentrate biooxidation that was revealed by the differences in pH, Eh values and iron ions concentrations in the medium, copper, zinc and arsenic extraction rates depended on these factors to a lesser extent.

An effective separation of toxic arsenic from aquatic environment using electrochemical ion exchange process

The existence of arsenic in drinking water available for human consumption in multiple nations is among the major health issues globally. Intensified research efforts has made to eradicate arsenic contaminants from water in order to supply people who are living in multiple regions with safe drinking water. A novel process for the deletion of arsenic from aqueous solutions by the electrochemical ion exchange hybrid method were explored in this work. The paper aims to extract arsenic from aqueous solution and recycle it using an electrochemical ion exchange system for industrial purposes. A 3-compartment system was used to demonstrate this process: the center cell is separated from the anodized and cathodic chambers by means of double anionic exchange membrane, a middle cell packed with a strong anion exchange resin, and two rinse compartments, one at each electrode. Efforts are being made to illustrate the optimization of the operating parameters, including concentration, resin dose, pH, contact time, temperature for optimal arsenic removal in batch mode operation. The maximum removal of arsenic obtained is almost 100% and a minimum of 91% extraction at an initial intensity of 5–15 mg /L of arsenic with supply voltage in the 5–20 V range.

Study on Extraction Separation of Thioarsenite Acid in Alkaline Solution by -Type Tri-n-Octylmethyl-Ammonium Chloride.

To overcome the problem of arsenic separation and enrichment from an alkaline leaching solution in arsenic-containing dust, a -type tri-n-octylmethyl-ammonium chloride (TOMAC) method for extracting thioarsenite is proposed in this paper. Considering an alkaline leaching solution as the research object, after vulcanization pretreatment, TOMAC transformation and organic phase saturated extraction capacity were measured, and the extraction mechanism was preliminarily studied. First, Cl−-type quaternary ammonium salt was effectively transformed to -type by treating organic phase with saturated NaHCO3five times. TOMAC was effectively transformed from to type by alkaline washing with 1.0 mol/l NaOH solution; this washing was repeated thrice. Thereafter, the effects of organic phase composition, phase ratio, extraction time, and temperature on the extraction and separation of arsenic were investigated. The results show that under the conditions of 30% -type TOMAC + 15% sec-octanol + 55% sulfonated kerosene, VO/VA = 1/1, and 5 min extraction at room temperature, the single-stage extraction rate of AsIII is 85.2%. The AsIII concentration in raffinate can be reduced to less than 1.33 × 10−3 mol/l by four-stage countercurrent extraction, and the extraction rate of AsIII can exceed 98.4%.

Arsenic in Chemical and Metallurgical Conversions of Copper-zinc Concentrates


 
 
 Due to the deterioration of the quality of obtained sulfide-copper concentrates, arsenic circulates and accumulates in the intermediate products, which reduces the quality of the metal and associated product – sulfuric acid. A method of estimation the distribution of impurity elements can be created using the recycling of sulfide concentrates by various technologies (including autogenous smelting, matte conversion and flotation of slags). This technique is based on solving balance equations for iron, copper and arsenic with known compositions of the resulting products. The obtained data were used to assess of the extraction of arsenic into produce outputs (slag, matte, dust, etc.). In this study, the concentration of arsenic in the dust of metallurgical processes and sludge for cleaning acid solutions is confirmed. The increased temperature in the electrostatic precipitator of gas purification of autogenous processes lead to a partial transition of arsenic into the gas stream directed to the sulfuric acid production. It is possible to regulate the fraction of transition of arsenic to dust and sulfuric acid while changing the operating temperature in the electrostatic precipitator. To a lesser extent arsenic is concentrated in the tails of flotation of slag (11.7%) and metallic copper (2.9%). These data are useful for substantiating measures for the wastes recycling and improvement of the ecological environment in the enterprise operating districts.
 
 
 
 Keywords: arsenic, autogenous melting, matte conversion, slag flotation, purified gas treatment, distribution, dust, sludge
 
 
 
 
 

Studying the impact of alkaline sulfide leaching parameters upon the efficiency of arsenic recovery from copper skimmings of lead production

The article is concerned with the problem of arsenic circulation as copper skimmings of lead production — the product of the lead bullion decopperization process at a metallurgical complex, uniting copper and lead plants. A brief overview of the methods of processing arsenic-containing middling products for the purpose of arsenic removal is given; the main advantages and disadvantages are indicated. The possibility of processing copper skimmings by the method of alkaline sulfide leaching with separation into arseniccontaining solution and lead-copper precipitate is studied. The results of the researches into the influence of temperature, process duration, solids content in the pulp, particle size, and the ratio of sodium hydroxide to elemental sulfur in the alkaline sulfide reagent on the process of alkaline sulfide leaching of copper skimmings af lead production are provided. Within the studied range of varied factors, the highest indexes of arsenic extraction into solution (85.04%) were achieved under the following conditions: temperature — 85 °C, duration — 4 hours, solids content in the pulp — 350 g/dm3, fraction (–0.08 mm), NaOH/S ratio = 100 g/100 g in 1 dm3 of the solution. The proposed method for processing copper skimmings will allow one to selectively isolate arsenic into the dump waste product during subsequent precipitation and separate contaminant from lead-copper cake, into which precious metals also pass. Such an approach provides the reduction of arsenic circulation between the lead and copper manufacturing facilities.

Removal and reuse of arsenic from arsenic-bearing purified residue by alkaline pressure oxidative leaching and reduction of As (V)

Arsenic removal from arsenic-bearing purified residue by alkaline pressure oxidative leaching (APOL) and reduction of arsenate in solution to arsenite by sulfur dioxide gas was studied. The effects of different parameters including NaOH concentration, oxygen partial pressure, temperature, liquid/solid ratio, and leaching time for the extraction of arsenic were investigated based on thermodynamic calculation. The optimum leaching conditions have been established as: 2.5 mol/L of NaOH concentration, 0.5 MPa of oxygen partial pressure, 120 °C of temperature, 4 mL/g of liquid/solid ratio and 3.0 h of time. Under these conditions, the leaching rates of arsenic, zinc and nickel respectively reached 94.47%, 19.90% and 12.66%, while copper and cobalt were hardly leached out, achieving the selective removal of arsenic from the arsenic-bearing purified residue. The reduction of As(V) in solution was optimized by orthogonal experimental design method, and the effects of experimental parameters including initial pH, reduction temperature (T), flow rate of SO2 (F), and reduction time (t) on reduction of As(V) were investigated. The results show that the optimum reduction parameters were 4 of initial pH, 30 °C of temperature, 60 mL/min of SO2 flow rate and 2.5 h of time. Based on these conditions, the reduction rate of As(V) reached 92.95%.

Plant Nanobionic Sensors for Arsenic Detection.

Arsenic is a highly toxic heavy-metal pollutant which poses a significant health risk to humans and other ecosystems. In this work, the natural ability of wild-type plants to pre-concentrate and extract arsenic from the belowground environment is exploited to engineer plant nanobionic sensors for real-time arsenic detection. Near-infrared fluorescent nanosensors are specifically designed for sensitive and selective detection of arsenite. These optical nanosensors are embedded in plant tissues to non-destructively access and monitor the internal dynamics of arsenic taken up by the plants via the roots. The integration of optical nanosensors with living plants enables the conversion of plants into self-powered autosamplers of arsenic from their environment. Arsenite detection is demonstrated with three different plant species as nanobionic sensors. Based on an experimentally validated kinetic model, the nanobionic sensor could detect 0.6 and 0.2 ppb levels of arsenic after 7 and 14 days respectively by exploiting the natural ability of Pteris cretica ferns to hyperaccumulate and tolerate exceptionally high level of arsenic. The sensor readout could also be interfaced with portable electronics at a standoff distance, potentially enabling applications in environmental monitoring and agronomic research.

Use of aqueous two-phase systems formed by Triton X and choline chloride for extraction of organic and inorganic arsenic

The use of aqueous two-phase systems (ATPSs) for the extraction/speciation of arsenic has received attention in recent years. However, only ATPSs formed by polymer and salt have been used, hindering a global understanding of the mechanism of partitioning of the metalloid and limiting the development of strategies for arsenic speciation in these systems. Therefore, it is important to study the partitioning of different arsenic species in new and more environmentally friendly ATPSs, such as those formed by ionic liquids based on the choline cation. In this work, ATPSs formed by Triton X nonionic surfactant, choline chloride ionic liquid, and water were used to study the partitioning of three arsenic species (As(III), As(V), and dimethylarsinic acid (DMA)), in the absence and presence of the extracting agent ammonium pyrrolidine dithiocarbamate (APDC). Evaluation was made of the effects of the parameters extraction time, pH, tie-line length, extractant concentration, and nature of the surfactant on the distribution of the arsenic species in the ATPS. In the absence of the extracting agent, all the arsenic species were mainly transferred to the choline chloride-rich phase, with maximum extraction percentages of 69.02, 92.99, and 90.05% for As(III), As(V), and DMA, respectively. In the presence of APDC, the As(V) and DMA species mainly remained in the choline chloride-rich phase, while the As(III) was transferred to the surfactant-rich phase, with the best removal to this phase achieved using the ATPS formed by TX-165 + choline chloride + water, at pH 1.00 and with an APDC:arsenic molar ratio of 25. Compared to ATPSs formed by polymer and salt, the ATPSs formed by Triton X and choline chloride required up to nineteen times smaller amounts of APDC for quantitative extraction of As(III) to the phase low in electrolyte. Thus, the results demonstrated the excellent potential of the Triton X + choline chloride + water systems for the extraction, preconcentration, and speciation of arsenic, with the advantage that the components used to form the ATPSs make the technique more environmentally friendly.

A green strategy toward extraction of cadmium(II) during the transformation from arsenic-rich flue dust to scorodite

This paper presents an eco-friendly method for recovery of cadmium by solvent extraction and stabilization of arsenic through one-pool treatment on arsenic-rich flue dust. The morphology-controlled scorodite can be realized by adjusting reaction temperature. It is worth emphasizing that the arsenic-immobilized scorodite precipitates have superior crystallinity which exhibit excellent safety for long-term storage. In addition, the advantage brought about by taking hydrogen peroxide as leaching agent is that leachate is weakly acidic, which removes the need to add a large amount of neutralizing agent and facilitates the synthesis of scorodite. The results show that 97.3% of arsenic was leached from arsenic-rich flue dust and then 92.8% of the leached arsenic was transferred into scorodite with the recovery of 81.5% of cadmium under the optimal conditions. We hope that this work will provide a facile and environmentally friendly protocol for those interested in developing a new strategy for simultaneously recovering and stabilizing toxic heavy metal ions from industrial dust.

Electrodialytic treatment of secondary mining resources for raw materials extraction: Reactor design assessment

The sustainability of mining activities is compromised due to the high amounts of mining residues generated that have to be disposed of, often in open dams, that may cause environmental deterioration, e.g. release of toxic elements to water supplies. These residues are, however, secondary resources of raw materials. In the case of Panasqueira mine, they even are a source of tungsten, considered a critical raw material. The present work aims to assess the electrodialytic process efficiency for raw materials extraction from Panasqueira mine residues. Experiments were performed with 2 and 3-compartment electrodialytic reactors, applying current intensities between 50 and 100 mA, from 4 to 14 days, and sample suspensions enhanced with NaCl or effluent. Additionally, control experiments with no current application were carried out. The results showed that a 3-compartment reactor operating at 100 mA, with NaCl as supporting electrolyte, presented the highest extraction of copper (13%), tin (10%), tungsten (13%) and arsenic (63%).

Magnetic graphene oxide nanocomposite functionalized with glucamine for the trace extraction of arsenic (III) from aqueous media

The present investigation deals with the synthesis of newly designed glucamine-functionalized magnetic graphene oxide (MGO-GLu) nanocomposite for the magnetic solid-phase extraction of inorganic arsenic (III) from water and its determination by inductively coupled plasma mass spectrometry (ICP-MS). The synthesized nanocomposite was comprehensively characterized using scanning electron microscopy (SEM), Fourier transform Infrared (FTIR) and EDX. The extraction of arsenic was optimized by analyzing various parameters, and recovery efficiency of MGO-GLu was found to be maximum at 2 mL HNO3 (0.1 M) as desorption solvent, 20 mg sorbent, 40 mL sample volume, 5 min contact time, 2 min desorption time and pH 5. Subsequently, the proposed method was validated under the optimal conditions for its figures of merit comprising limits of detection (LOD), quantification (LOQ), precision and reproducibility that were estimated to be 0.05 ng mL−1, 0.18 ng mL−1, 3.23 and 6.7% (%RSD at 10 ng mL−1, for n = 3 and n = 12 intra- and inter-day), respectively. Finally, the proposed method was applied to real water samples obtained from different sources (river, tap and industrial wastewater) displaying a high recovery range of 83–104%. Thus, the designed nanocomposite sorbent offers ease of applicability, rapid analysis, ease of isolation and efficiency for the trace determination of inorganic arsenic in water environmental samples.

Comparison of different sequential extraction procedures to identify and estimate bioavailability of arsenic fractions in soil

For the sake of risk assessment for arsenic-contaminated sites, the purpose of this study is to estimate the bioavailable arsenic fractions in soil by using the three arsenic-specific sequential extraction procedures (SEPs) and distinguish which SEP can reliably identify and estimate the bioavailable arsenic, so as to screen the most suitable SEP for the risk assessment of arsenic-contaminated sites. The arsenic uptake by spinach and amaranth was used to evaluate bioavailability of arsenic fractions defined by the SEPs proposed by Shiowatana, Larios, and Wenzel, respectively, as well as the ability of these three SEPs to identify and estimate bioavailable arsenic. The results showed that besides the highly mobile arsenic fractions defined by each SEP, the less mobile HCl-extractable arsenic (mainly carbonate-bound arsenic) in Shiowatana SEP was also the source of bioavailable arsenic, and their contribution to bioavailable arsenic depended not only on their mobility but also on their content, suggesting that the independent extraction of carbonate-bound arsenic should be considered in the design of arsenic-specific SEPs. All three SEPs could provide approximate estimation of bioavailable arsenic fractions. Although Wenzel SEP performed slightly worse than Larios SEP and Shiowatana SEP, all three SEPs had acceptable accuracy and reproducibility in arsenic fractionation. However, the Shiowatana SEP performed more comprehensive in extracting potential bioavailable arsenic fractions and identifying the source of bioavailable arsenic, indicating that it might be more suitable for the risk assessment of arsenic-polluted sites based on arsenic fractionation.

The Arsenic Disposal from Cobalt Production Wastes

The study results of complex technology for arsenic extraction from dumps, which consist of such process steps as sludge soda roasting, water leaching and precipitation of arsenic sulfide from the solution are presented. The testing on unit of waste hydrochemical recycling is conducted. The technological cheme for recycling Tuvacobalt combine was proposed. The results showed that under optimal calcination and leaching conditions the arsenic content decreases from 3 wt.% in the starting material to 0.3 wt.% in the cake, and the degree of arsenic extraction into the solution rises to 92 %. According to the developed technology, products were obtained: arsenic sulfide, silicon dioxide and leaching cake.

Phytochemistry, Antioxidant Activity and Heavy Metal Content on Precooked and Raw of Celosia argentea L., Launaea taraxacifolia Wild. and Ocimum gratissimum L., Three Leafy Vegetables Eaten in Southern Benin

This study aimed to estimate and compare the antioxidant potential as well as the levels of heavy metal contamination of Celosia argentea (Amaranthaceae), Launaea taraxacifolia (Asteracea) and Ocimum gratissimum (Lamiaceae) collected in four municipalities of South-Benin by taking into accounts the treatment prior to consumption (precooked and raw). A low extraction yield was obtained during the extraction of leafy vegetables subjected to precooking. The phytochemical screening of Launaea taraxacifolia revealed the presence of triterpenes, steroids, flavonoids and tannins. The phytochemical analysis of Ocimum gratissimum revealed the presence of triterpenes, the steroids, tannins, anthraquinones, coumarins and alkaloids. The analysis of Celosia argentea revealed the presence of triterpenes, steroids, flavonoids, tannins, anthraquinones and alkaloids. The antioxidant activity of the various extracts was found to be dose-dependent. The extracts showed significant antioxidant activities with IC50 ranging from 4.03 to 11.42 µg/ml. Ocimum gratissimum had the strongest antioxidant power followed by Celosia argentea and Launaea taraxacifolia respectively. Pre-cooking of leafy vegetables would have an effect on antioxidant activity, which resulted in a slight increase in the DPPH inhibition power of pre-cooked vegetables compared to raw one. The analysis of heavy metals showed the presence of arsenic, mercury and manganese in the different plant extracts. The highest levels were observed in leafy vegetables collect at Cotonou (Houeyiho) followed by those from Sèmè-Podji but all below the thresholds defined by the World Health Organization. The precooking promoted a decrease of the quantity in heavy metals by leaching, causing low concentration in metals of vegetables precooked in contrast with raw ones.

Ultrasound enhanced solid-phase extraction of ultra-trace arsenic on Fe3O4@AuNPs magnetic particles

Using ultrasound (US) to reduce the agglomeration of magnetic materials has attracted many researchers’ attention in the field of magnetic solid phase extraction (MSPE). This paper showed that even the simple magnetic material (Fe3O4@AuNPs) can stimulate excellent arsenic (As) enrichment performance with the assistance of US. Compared with stirring dispersion, the extraction efficiencies of Fe3O4@AuNPs for 0.2 μg L−1 As(III) and As(V) improved by a factor of about 6.2- and 5.7-times with ultrasonic agitation, respectively. Importantly, when the ultrasonic frequency and power are varied within a certain range, the extraction efficiency was increased by about 50% and 130%, respectively. This effect of ultrasonic frequency and power on the enrichment of arsenic by magnetic materials has never been reported. The number, dispersion uniformity and energy released by the bursting of cavitation bubbles under different conditions are considered to be the main reasons for the above phenomena. Additionally, the As(III) or As(V) can be converted into a gaseous product by in-situ slurry chemical hydride generation (SCHG) technology, and the material adsorbed by the material can be effectively removed, thereby ensuring that the complex is repeated at least 5 times or more. Under the optimized conditions, the whole enrichment process can be shortened from ~1 h to several minutes in the presence of US. At the same time, the linear calibration range was 0.01–3.0 μg L−1 documenting that this US-assisted dispersive MSPE method coupled with a sensitive spectral detector (e.g. atomic fluorescence spectrometer, AFS) is suitable for analysis of inorganic As in natural water samples. The content of arsenic in five kinds of natural water samples ranged from 34 ng L−1 to 2.3 μg L−1.

Soil Microbial Communities Involved in Reductive Dissolution of Arsenic from Arsenate-Laden Minerals with Different Carbon Sources.

The natural microbial communities involved in arsenic (As) extraction under biostimulated conditions are still unclear. In this study, soil slurry was incubated with arsenate [As(V)]-laden Fe(III) or Al (hydr)oxides with lactate or acetate. After 40 d, dissolved As released from As(V)-laden Fe(III) accounted for 54% of the initial solid-phase As in lactate-amended slurries, while much less As was released from acetate-amended slurries. As was released more rapidly from As(V)-laden Al, but the total release was relatively low (45%). High-throughput Illumina sequencing of 16S rRNA genes revealed that dissimilatory metal(loid) reducers such as Desulfitobacterium became predominant in lactate-amended slurries. Moreover, anaerobic fermenters in the Sporomusaceae family were predominant. Interestingly, a Sporomusaceae bacterial strain isolated from the slurry was capable of releasing As from both As(V)-laden (hydr)oxides in the presence of lactate. The strain first released As as As(V) and subsequently reduced it to As(III) in the aqueous phase. These results suggest that lactate is a suitable carbon source for As extraction by natural microbial communities, and that both dissimilatory metal(loid) reducers and certain anaerobic fermenters play significant roles in As extraction. Microbial reductive dissolution of As may be expected to be a cost-effective restoration technique for As-contaminated soils.