Reductive removal of arsenic from waste acid containing high-acidity and arsenic levels through iodide and copper powder synergy

Wang, An; Zhou, Kanggen; Zhang, Xuekai; Zhou, Dingcan; Peng, Changhong; Chen, Wei

doi:10.1016/j.cej.2019.05.018

Cited by 31 publications

(8 citation statements)

References 42 publications

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“…XPS analysis was performed to identify the valence state of arsenic in the precipitates (Figure c,d). Two peaks located at 44.5 and 41.7 eV, which can be assigned to As(0) and As(III) within As 2 O 3 , ,, were obtained from the As 3d spectra of the precipitates. The presence of a small amount of As 2 O 3 in the precipitates is due to the partial oxidation of As(0) during the preparation and characterization of the samples (eq 48 in Table ).…”

Section: Resultsmentioning

confidence: 99%

“…12 Thus, the removal of arsenic from strongly acidic wastewater in the form of solid As(0) is of great interest since arsenic can be recovered and the treated arsenic-free wastewater can be recycled. Previous studies innovatively found that As(V) and As(III) can be efficiently reduced to As(0) by UV/TiO 2 /methanol, 13 Cu(0)/iodide, 14 and Cu(0)/chloride 15 processes. However, these reduction processes occur under heterogeneous conditions, in which the formed As(0) is mixed with solid reagents that are difficult to separate from each other, resulting in the difficulty of As(0) recovery.…”

Section: ■ Introductionmentioning

confidence: 99%

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Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Kong

Zhao

et al. 2022

Environ. Sci. Technol.

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The removal of arsenic (As(V) and As(III)) from strongly acidic wastewater using traditional neutralization or sulfuration precipitation methods produces a large amount of arsenic-containing hazardous wastes, which poses a potential threat to the environment. In this study, an ultraviolet/formic acid (UV/HCOOH) process was proposed to reductively remove and recover arsenic from strongly acidic wastewater in the form of valuable elemental arsenic (As(0)) products to avoid the generation of hazardous wastes. We found that more than 99% of As(V) and As(III) in wastewater was reduced to highly pure solid As(0) (>99.5 wt %) by HCOOH under UV irradiation. As(V) can be efficiently reduced to As(IV) (H2AsO3 or H4AsO4) by hydrogen radicals (H•) generated from the photolysis of HCOOH through dehydroxylation or hydrogenation. Then, As(IV) is reduced to As(III) by H• or through its disproportionation. The reduction of As(V) to H4AsO4 by H• and the disproportionation of H4AsO4 are the main reaction processes. Subsequently, As(III) is reduced to As(0) not only by H• through stepwise dehydroxylation but also through the disproportionation of intermediate arsenic species As(II) and As(I). With additional density functional theory calculations, this study provides a theoretical foundation for the reductive removal of arsenic from acidic wastewater.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Kong

Zhao

et al. 2022

Environ. Sci. Technol.

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“…Coagulants such as iron sulfate and aluminum sulfate are added to improve the filtration of precipitates [12]. Other techniques proposed to control impurities are solvent extraction and electrochemical processes such as electro-dialysis, electrochemical ion exchange, and electrocoagulation [23,24].…”

Section: Weak Acid Treatmentmentioning

confidence: 99%

Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters

Araya

Toro

Castillo

et al. 2020

Metals

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In this study, weak acid in the curing and leaching stages of copper ore was incorporated, and we analyzed its effect on the dissolution of copper and final impurities. The weak acid corresponds to a wastewater effluent from sulfuric acid plants produced in the gas treatment of copper smelting processes. This effluent is basically water with high acidity (pH-value low at 1), which contains several toxic elements and some valuable metals. The results indicated that there is no positive or negative effect on the incorporation of the weak acid in the curing stage, while the case of the leaching stage is favored. Toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) toxicity tests were performed on the solid leaching residues, determining that they accomplish the stability ranges of the impurities (Pb, Cd, Hg, Cr, Ba, Se, As, and Ag).

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“…Sulfidation is an efficient method for the removal of HMs from acid-scrubbing effluents. − However, the addition of metal sulfide reagents (Na 2 S, NaHS, or FeS) to the acid effluents would not only introduce unexpected metal cations, but also lower acid recovery efficiency. , Adding gaseous H 2 S as the reagent in the liquid-phase can remove HMs by direct sulfidation process (DSP), which can successfully overcome the above problems. − The concentration of HMs is relatively high (up to 10 000 mg/L) while the emission limit of most HMs in these industries is relatively low (0.5 mg/L). , Increasing the H 2 S concentration can shorten HMs removal time and increase removal efficiency. , However, the transportation and storage of high concentrations of H 2 S (HC-H 2 S) are not allowed in many districts because of its high toxicity once released to the environment . In practical applications, there are some interim HC-H 2 S production processes.…”

Section: Introductionmentioning

confidence: 99%

“…12−15 The concentration of HMs is relatively high (up to 10 000 mg/L) while the emission limit of most HMs in these industries is relatively low (0.5 mg/ L). 16,17 Increasing the H 2 S concentration can shorten HMs removal time and increase removal efficiency. 18,19 However, the transportation and storage of high concentrations of H 2 S (HC-H 2 S) are not allowed in many districts because of its high toxicity once released to the environment.…”

Section: Introductionmentioning

confidence: 99%

Production of H₂S with a Novel Short-Process for the Removal of Heavy Metals in Acidic Effluents from Smelting Flue-Gas Scrubbing Systems

Sun

Huang

et al. 2021

Environ. Sci. Technol.

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Direct sulfidation using a high concentration of H2S (HC-H2S) has shown potential for heavy metals removal in various acidic effluents. However, the lack of a smooth method for producing HC-H2S is a critical challenge. Herein, a novel short-process hydrolysis method was developed for the on-site production of HC-H2S. Near-perfect 100% efficiency and selectivity were obtained via CS2 hydrolysis over the ZrO2-based catalyst. Meanwhile, no apparent residual sulfur/sulfate poisoning was detected, which guaranteed long-term operation. The coexistence of CO2 in the products had a negligible effect on the complete hydrolysis of CS2. H2S production followed a sequential hydrolysis pathway, with the reactions for CS2 adsorption and dissociation being the rate-determining steps. The energy balance indicated that HC-H2S production was a mildly exothermic reaction, and the heat energy could be maintained at self-balance with approximately 80% heat recovery. The batch sulfidation efficiencies for As(III), Hg(II), Pb(II), and Cd(II) removal were over 99.9%, following the solubilities (K sp) of the corresponding metal sulfides. CO2 in the mixed gas produced by CS2 hydrolysis did not affect heavy metals sulfidation due to the presence of abundant H+. Finally, a pilot-scale experiment successfully demonstrated the practical effects. Therefore, this novel on-site HC-H2S production method adequately achieved heavy metals removal requirements in acidic effluents.

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Reductive removal of arsenic from waste acid containing high-acidity and arsenic levels through iodide and copper powder synergy

Cited by 31 publications

References 42 publications

Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters

Production of H₂S with a Novel Short-Process for the Removal of Heavy Metals in Acidic Effluents from Smelting Flue-Gas Scrubbing Systems

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Reductive removal of arsenic from waste acid containing high-acidity and arsenic levels through iodide and copper powder synergy

Cited by 31 publications

References 42 publications

Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Reductive Removal and Recovery of As(V) and As(III) from Strongly Acidic Wastewater by a UV/Formic Acid Process

Leaching of Oxide Copper Ores by Addition of Weak Acid from Copper Smelters

Production of H2S with a Novel Short-Process for the Removal of Heavy Metals in Acidic Effluents from Smelting Flue-Gas Scrubbing Systems

Contact Info

Product

Resources

About

Production of H₂S with a Novel Short-Process for the Removal of Heavy Metals in Acidic Effluents from Smelting Flue-Gas Scrubbing Systems