The Effects of Solution Concentration, Drying, Aging Time, and Mixture of Goethite with As(V)-Fe(OH)(3) on the Chemical Extraction of Arsenate Associated with Iron (Hydr)oxides
The Effects of Solution Concentration, Drying, Aging Time, and Mixture of Goethite with As(V)-Fe(OH)(3) on the Chemical Extraction of Arsenate Associated with Iron (Hydr)oxides
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溶液浓度、干燥、陈化时间以及针铁矿与As(V)-Fe(OH)(3)混合对化学萃取伴生铁(氢氧化物)砷酸盐的影响
DOI：
10.1089/ees.2016.0217
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发表时间：
2017
影响因子：
1.8
通讯作者：
Jia Yongfeng
中科院分区：
文献类型：
--
作者：
Yuan Zidan;Wang Shaofeng;Wang Shuying;Chen Yiping;He Xinyu;Jia Yongfeng
研究了用磷酸盐缓冲液、氢氧化钠（NaOH）、盐酸（HCl）和草酸盐缓冲液从吸附态（ad）和共沉淀态（cpt）As-Fe（OH）3、As-Fe_3 O_4中萃取砷（As）的方法。研究了溶液浓度、样品干燥、陈化时间、针铁矿与新鲜As-Fe（OH）3（cpt）混合物对砷萃取率的影响。对于新鲜的As-Fe（OH）3（ad）和As-Fe（OH）3（cpt），100%的As被1 mol/L（M）磷酸盐（pH 5.0）或0.5 M NaOH萃取。较低浓度的磷酸盐（pH 5.0、0.05和0.1 M）和NaOH（0.1 M）可降低As-Fe（OH）3缔合物中As的回收率。干燥和老化的As-Fe（氢）氧化物协会显着抑制的提取率和速率的吸附和共沉淀作为相对于新鲜样品。磷酸盐和砷酸盐在聚集态或结晶态含砷氧化铁颗粒中的缓慢扩散可能是主要原因。由于As在针铁矿上的再吸附，针铁矿与新鲜As-Fe（OH）3（cpt）的共存导致As在1 M HCl或0.2M草酸盐（pH 3.25）下的不完全释放（约70%）。然而，当使用0.1 M磷酸盐和1 M HCl的混合物时，100%的As被回收，表明向HCl或草酸盐溶液中添加少量磷酸盐有助于完全提取与无定形Fe（hydr）氧化物共沉淀的所有As。
Extraction of arsenic (As) from adsorbed (ad) and coprecipitated (cpt) As-Fe(OH)3, As-Fe3O4using phosphate buffer, sodium hydroxide (NaOH), hydrochloric acid (HCl), and oxalate buffer was studied. In addition, the effects of the solution concentrations, sample drying, aging time, and goethite and fresh As-Fe(OH)3(cpt) mixture on the extraction efficiencies of As were investigated. For fresh As-Fe(OH)3(ad) and As-Fe(OH)3(cpt), 100% of the As was extracted by either 1 mol/L (M) phosphate (pH 5.0) or 0.5 M NaOH. Lower As recoveries from As-Fe(OH)3associations were obtained by lower concentrations of phosphate (pH 5.0, 0.05 and 0.1 M) and NaOH (0.1 M). Drying and aging of the As-Fe (hydr)oxide associations significantly inhibited the extraction ratio and rate of adsorbed and coprecipitated As relative to fresh samples. The slow intraparticle diffusion of phosphate and arsenate in aggregated or crystalized As-bearing Fe (hydr)oxide particles is possibly the dominant cause. Due to readsorption of As onto goethite, the coexistence of goethite with fresh As-Fe(OH)3(cpt) resulted in an incomplete release of As (∼70%) with either 1 M HCl or 0.2 M oxalate (pH 3.25). However, when a mixture of 0.1 M phosphate and 1 M HCl was used, 100% of the As was recovered, indicating that the addition of a small amount of phosphate into the HCl or oxalate solutions is helpful to completely extract all of the As coprecipitated with amorphous Fe (hydr)oxides.