Enhanced recovery of arsenite sorbed onto synthetic oxides by L-ascorbic acid addition to phosphate solution: calibrating a sequential leaching method for the speciation analysis of arsenic in natural samples

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LDEO Publication: 
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Year of Publication: 
2006
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Journal Title: 
Water Research
Journal Date: 
Jun
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Tertiary Title: 
Volume: 
40
Issue: 
11
Pages: 
2168-2180
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Publisher: 
ISBN Number: 
0043-1354
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Accession Number: 
ISI:000238788000008
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Abstract: 

Stripping voltammetry capable of detecting 0.3 mu g/L arsenate and arsenite was applied for speciation analysis of arsenic sorbed onto synthetic ferrihydrite, goethite at As/Fe ratio of similar to 1.5 mg/g with or without birnessite after sequential extraction using 1 M phosphate (24 and 16 h) and 1.2 M HCI (1 h). Precautions to avoid oxygen were undertaken by extracting under anaerobic conditions and by adding 0.1 M L-ascorbic acid to 1 M NaH2PO4 (pH 5). Addition Of L-ascorbic acid did not reduce As(V) to As(III). The recovery rate for As(III) using L-ascorbic acid for extraction (pH 5) but not for adsorption was 81% and 74% of total sorbed As, and was 99% and 97% of extracted As for ferrihydrite and goethite, respectively. Birnessite oxidized most As(III) during the adsorption procedure. L-ascorbic acid used both in adsorption and extraction procedures improved the recovery of As(III) to 79-94% for ferrihydrite-bimessite and 57-94% for goethite-birnessite systems with Fe/Mn ratios of 7, 70, 140 and 280 g/g. (c) 2006 Elsevier Ltd. All rights reserved.

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060FNTimes Cited:2Cited References Count:33

DOI: 
DOI 10.1016/j.watres.2006.03.032