不同pH条件下As还原对砷释放的影响实验研究  

Experimental Study on Effect of Reduction of Arsenic on Arsenic Release under Different pH Conditions

作　　者：熊鹏[1] 李义连[1] 

机构地区：[1]中国地质大学(武汉)环境学院,湖北武汉430074

出　　处：《环境科学与技术》2013年第1期16-19,共4页Environmental Science & Technology

基　　金：国家863项目(2007AA06Z333)

摘　　要：通过考察不同pH条件下Fe（Ⅲ）-A（sⅤ）体系和Fe（Ⅲ）-As（Ⅲ）体系各Fe形态、As形态、以及体系ORP的变化,考察不同pH条件下As还原对砷释放的影响。实验结果表明：在pH为3~5左右范围内,Fe（Ⅲ）-A（sⅤ）体系和Fe（Ⅲ）-A（sⅢ）体系中的Fe（Ⅲ）均发生部分絮凝沉淀,在水样pH为6~10范围内,Fe（Ⅲ）-As（Ⅲ）体系中Fe（Ⅲ）的絮凝沉淀较Fe（Ⅲ）-As（Ⅴ）体系明显。Fe（Ⅲ）-As（Ⅴ）体系与Fe（Ⅲ）-A（sⅢ）体系中As总随pH的变化趋势基本一致,但是Fe（Ⅲ）-A（sⅢ）体系As总的浓度水平要比Fe（Ⅲ）-A（sⅤ）体系的浓度水平要高。结果表明：同等pH环境条件下,如果A（sⅤ）被还原成A（sⅢ）,则Fe（Ⅲ）-As体系中就会出现As的释放,且不同pH条件下对应的As总的差值即可反映出当A（sⅤ）还原成A（sⅢ）时Fe（Ⅲ）-As体系中所释放的砷的量。Through investigating the change with time of each iron speciation,arsenic speciation and ORP of system under different pH conditions between Fe（Ⅲ）-As（Ⅴ）system and Fe（Ⅲ）-As（Ⅲ）system,the effect of the reduction of arsenic on arsenic release under different pH conditions was studied.Results indicated that within pH range of about 3~5,Fe（Ⅲ）in Fe（Ⅲ）-As（Ⅴ）system and Fe（Ⅲ）-As（Ⅲ）system both hydrolyzed partially,while within pH range of 6~10,flocculation and precipitation degree of Fe（Ⅲ）of Fe（Ⅲ）-As（Ⅲ）system was more obvious than Fe（Ⅲ）-As（Ⅴ）system.The change trend with pH of total arsenic concentration of Fe（Ⅲ）-As（Ⅲ）system was basically consistent with Fe（Ⅲ）-As（Ⅴ）system,but whole concentration level of total arsenic concentration of Fe（Ⅲ）-A（s Ⅲ）system was higher than Fe（Ⅲ）-A（s Ⅴ）system.Arsenic release would appear in Fe（Ⅲ）-As system if A（s Ⅴ）was reduced to A（s Ⅲ）under equal pH condition and corresponding difference value of total arsenic concentration between Fe（Ⅲ）-A（s Ⅴ）system and Fe（Ⅲ）-A（s Ⅲ）system under different pH condition could show the quality of arsenic released from Fe（Ⅲ）-As system when A（s Ⅴ）was reduced to As（Ⅲ）.

关 键 词：AS 还原 释放 PH 

分 类 号：X131[环境科学与工程—环境科学]