Effect of initial pH on the extraction of vanadium, tungsten, and arsenic. Consideration of the extraction efficiencies for V and W, as well as the acid consumption necessary for pH adjustment, an initial pH of 9.0 was identified as the most optimal condition. Under this pH setting, the extraction rates for V and W were achieved at 83.42 % and ...
The sequential extraction results showed that the arsenic in the TRW mainly existed in the form of ionically bound As, strongly adsorbed As, As coprecipitated with Mn(Ⅱ) oxides, Amorphous ferric (Ⅲ) arsenates (AFA), and As coprecipitated with pyrite, and the proportions of them in the total arsenic were 5.91%, 6.75%, 18.16%, 5.66%, …
The arsenic extraction was found to follow a first-order reaction, which can be expressed as log (C t /C 0)=−(k/2.303)t, where C t is the residual arsenic in soil (mmol kg −1) at time t; C 0 is the initial arsenic in soil (mmol kg −1); k is the rate constant (min −1); t is the time (min).
Our predictions show that the average concentration of arsenic in Chinese soils has increased from 11.9 mg kg −1 in 2000 to 12.6 mg kg −1 in 2020, which represents a rise of 0.7 mg kg −1 ...
Based on the improvement of the BCR extraction method, the occurrence rule of arsenic element was analyzed in the extraction experiment, and the risk assessment codes (RACs) of each discharge residue was calculated with reference to the literature (Zhou et al., 2021a). At the same time, the toxicity characteristic leaching …
Among various potassium and sodium salts, potassium phosphate was most effective in extracting arsenic, attaining more than 40% extraction in the pH range of 6–8 with minimum damage to the soil properties. Exchange mechanism is proposed for the extraction of arsenic from soil by phosphate. Sequential extraction shows that …
With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500 mg of freeze-dried vegetable sample, extracted by closed vessel microwave-assisted extraction using 10 mL of 2% v/v HNO 3 at 90°C for 17 min. Application of the method in the analysis of 24 market ...
Arsenic extraction efficiency for chicken in the first extract ranged from 42 to 60% of total arsenic present in the raw material, and in the three consecutive extracts from 70 to 75% [18]. The 1:1 methanol:water mixture was chosen since the 9:1 and 1:1–9:1 methanol:water mixtures provide similar recoveries, although no solid residues were ...
We found that As extraction was most effective using NaOH, with the As extraction efficiency increasing up to >99% with increasing NaOH concentrations (0.01, 0.1, and 1 M). Extraction with Na 2 CO 3 and Ca(OH) 2 was ineffective (<5%). Extraction time (hour, day, week) played a secondary role in As release but tended to be important …
It is the arsenic in these fractions which is more bioavailable and therefore of greater importance for risk assessment and management. Phosphate solutions have been widely used as an extraction medium for soil arsenic (Loeppert et al., 2002; Manning and Martens, 1997). Extraction of arsenic with phosphate is through ligand exchange that ...
The extraction of the arsenic species As(III), As(V), MMA and DMA was investigated and optimized using HCl and H 3 PO 4 in a wide concentration range from 0.1 to 9.5 M. The detection of the individual arsenic species was carried out using hydride generation inductively coupled plasma-optical emission spectrometry (HG-ICP-OES).
This study shows that nanocrystalline iowaite is a promising, low-cost material for arsenic removal from natural arsenic-rich waters or contaminated high …
A membrane inspired by the arsenic–protein interactions in biological systems allows the efficient removal of various arsenic species from contaminated water.
Notre méthode d'extraction des espèces d'arsenic d'origine toxique [As(III), As(V), DMA et MM A] à partir des urines a été adaptée d'une très vieille publi cation de Chariot (7) : As(III) est extrait par le benzène à partir d'un milieu chlorhydrique concentré ; As(V) est extrait après addition dans le milieu chlorhydrique
3.3.1. Arsenic Extraction. In previous studies, many authors obtained a significant amount of arsenic and iron extraction using ascorbic acid in a range from 0.01 to 0.1 M [47,48,49]. In this present study, 0.1 M ascorbic acid was adopted to combine with 0.2 M oxalic acid and 0.2 M citric acid to obtain the mixture solutions that were used in ...
We compared four methods to extract arsenic (As) from three different plants containing different As levels for As speciation with the goal of developing a more …
It is also can be observed in Fig. 5 (d) that the time has different influences on the extraction of arsenic and antimony. As the leaching time going, the arsenic extraction gradually increases to more than 96%, and almost keeps stable after 3 h. In comparison, the antimony extraction decreases from 0.8% to 0.2% in 3 h.
PV plants after growing in soil containing 200 mg kg − 1 AsV were used to compare As extraction and speciation of four extraction methods. Total As concentrations in the roots and fronds were 586 and 7714 mg kg − 1 (Table 1).Arsenic in PV consisted of primarily inorganic species, with 82% of As in the roots as AsV, and 89% as AsIII in the …
We developed and tested a sequential extraction procedure (SEP) for As by choosing extraction reagents commonly used for sequential extraction of metals, ... Arsenic was analyzed using an Atomic Absorption Spectrometer (AAS) coupled with a FIAS-400-hydride system (Perkin-Elmer 2100). Al, Fe, Mn, Ca, Mg, Na and Si were …
The maximum percentage of arsenic extraction obtained in the study of TLL influence (%E = 99.35%) was reached in the second TL (TLL = 41.83% w/w). However, in the first TL (TLL = 33.55% w/w), in the same proportion of APDC, the percentage of arsenic extraction was 98.33%, which was not significantly different from the observed maximum.
Experiments by adding arsenic filter cake furtherly confirmed the reducibility of As 2 S 3 and realized simultaneous extraction of arsenic in arsenic cake and acid leaching solution. Eventually, arsenic was recovered as As 2 O 3 with a high purity of 98.56 % and the total extraction extent of indium is 93.76 %.
Abstract. Several extraction and chromatographic methods were evaluated to identify optimum conditions for arsenic speciation analysis in seafood and seaweed. The extraction systems, which include aqueous, aqueous-organic, acidic, basic, and enzymatic solutions, were examined for their efficiency in extracting arsenic from finfish, …
We have developed a novel microwave-assisted extraction method for determining the arsenic (As) speciation in soils that is based on extraction with phosphate solutions, including orthophosphoric acid, ammonium dihydrogen orthophosphate, and ammonium hydrogen orthophosphate. The highest extracting efficiency was obtained …
Arsenic is ranked as the first compound in the Substance Priority List 2023 by the Agency for Toxic Substances and Disease Registry (ATSDR). The most prominent entrance to the human body is through drinking water wherein the predominant species are arsenite and arsenate. ... Among them, solid-phase extraction (SPE) is the most …
Abstract. Depending on the physical, chemical and biogeochemical processes and condition of the environment, various arsenic species can be present in water. Water soluble arsenic species …
Arsenic Standards and Reagents. The following arsenicals were used for preparation of stock standard solutions at concentrations of 100 μg L −1 by serial dilution in deionized water (DIW). Disodium hydrogen arsenate (Na 2 HAsO 4) (99% pure) was purchased from Sigma-Aldrich (St. Louis, MO).Methylarsonic acid, disodium salt (CH 3 …
They found that when the minerals are enriched with arsenic, gold can enter mineral structural sites by directly binding to arsenic, forming, chemically speaking, Au (2+) and As (1-) bonds. This ...
Arsenic mobility and transport into groundwater is highly dependent on its chemical distribution in sediments. In this study, a combination of sequential extraction and mineralogical investigation by X-ray diffraction on a sample collected from the hydrogeological experiment site of Poitiers (France) was tested to evaluate and predict …
The arsenic extraction from the arsenic-containing cobalt and nickel slag, which came from the purification process of zinc sulfate solution in a zinc smelting factory, was investigated. The alkaline leaching method was proposed according to the mode of occurrence of arsenic in the slag and its amphoteric characteristic.
Introduction. Arsenic is the 20th-highest natural metalloid found in the earth's crust, is well known for its adverse effects on both humans and marine life.
A novel sequential extraction method for the speciation of AsIII and AsV in oxic and anoxic mineral soils was developed and tested. The procedure consists of seven extraction steps targeting various As pools ranging from weakly adsorbed to well-crystalline species. Each step was specifically designed to preserve the AsIII and AsV …
1. Introduction. High arsenic (As) groundwater has been found worldwide (Smedley and Kinniburgh, 2002, Harvey et al., 2002, Fendorf et al., 2010, Guo et al., 2014).Arsenic desorption and reductive dissolution of its host minerals (such as Fe oxides) have emerged as the leading mechanisms for the release of As into groundwater (Islam …
Hence, the extraction of arsenic species in rice flour with 1% HNO 3 under 100 °C is recommended instead of 90 °C for 2.5 h. 3.3.2. Enzymatic Extraction by Shaking. As reported in the literature, α-amylase hydrolyses the α-1,4-linkage of starch, which is the major component in rice of up to 78% . This process could increase the solubility ...
Under optimal conditions; a mixture of 1 mol/L HCl and 0.02 mol/L thiourea with an organic/aqueous ratio of 1:4 at 323.15 K for 60 min, the extraction of arsenic reached 78.2 %. Further, batch simulation via two-stage counter-current extraction, and estimation by McCabe-Thiele diagram proved to be enhanced arsenic extraction to …
Generally microwave extraction is used to determine inorganic arsenic in food and provided good arsenic speciation extraction efficiencies (generally >90%) for samples of rice and wheat . The method is based on extracting samples with trifluoroacetic acid/H 2 O 2 and measuring arsenate by anion exchange HPLC-ICP-MS using aqueous …
Arsenic extraction by dithionite was low due to the re-adsorption of arsenic to the newly formed iron oxide phase (magnetite) in the soil. Therefore, commonly used chelating agents, including oxalate, citrate, and EDTA, were added to reducing agents in order to enhance the reductive extraction of arsenic from soils.
During the gold production process, the coexistence of arsenic and antimony will increase the consumption of CN −, OH − and O 2, and produce precipitates coated on the surfaces of gold particles so as to decrease the efficiency of gold extraction (Eisler, 2004; Yang et al., 2017). It is necessary to remove arsenic and antimony from gold ...
