کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4485882 | 1316968 | 2006 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: 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 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](/preview/png/4485882.png)
Stripping voltammetry capable of detecting 0.3 μg/L arsenate and arsenite was applied for speciation analysis of arsenic sorbed onto synthetic ferrihydrite, goethite at As/Fe ratio of ∼1.5 mg/g with or without birnessite after sequential extraction using 1 M phosphate (24 and 16 h) and 1.2 M HCl (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–birnessite and 57–94% for goethite–birnessite systems with Fe/Mn ratios of 7, 70, 140 and 280 g/g.
Journal: Water Research - Volume 40, Issue 11, June 2006, Pages 2168–2180