摘要
含砷尾矿在生物氧化作用下会产生大量含砷(As)酸性矿山废水,从而对周围生态环境造成严重危害,亟需系统性明晰含砷尾矿生物氧化过程中As的迁移转化规律.探究含砷尾矿生物氧化行为的影响因素有利于揭示As的迁移转化规律.以高砷尾矿(As含量>20%)为研究对象,考察了不同初始pH条件(1.2~2.8)和固体浓度(2.0~10.0 g·L^(-1))对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)生物氧化行为的影响.结果表明:As的生物氧化受初始pH值和固体浓度的显著影响.As的生物氧化效率随着初始pH或固体浓度的升高呈先升高后下降的趋势;在初始pH值2.0时,观察到As的浸出率(高达92.94%)比其他初始pH条件高.在固体浓度8.0 g·L^(-1)时具有最优的As浸出率(高达93.24%).在所有初始pH和固体浓度条件下可以发现生物浸出前期As的浸出效率快速上升,而生物氧化中期维持相对稳定并在生物氧化后期出现下降趋势,这与微生物活性变化和黄钾铁矾的形成有关.XRD和SEM分析结果显示在生物氧化过程中微生物氧化释放的Fe离子会逐渐形成黄钾铁矾沉淀,并覆盖矿物表面并形成钝化层,从而影响高砷尾矿中As的进一步浸出.本研究结果对明晰高砷尾矿生物氧化行为的影响因素和降低含砷尾矿的环境风险具有一定的理论指导意义.
Arsenic-bearing mine tailings will produce a large amount of arsenic(As)containing acid mine drainage under bio-oxidation,which will cause serious harm to the surrounding ecological environment.It is urgent to systematically understand the migration and transformation of As in the biooxidation process of arsenic-bearing tailings.Exploring the influencing factors of bio-oxidation behavior of arsenic-bearing tailings could be conducive to revealing the migration and transformation law of As.In this study,the effects of different initial pH conditions(1.2~2.8)and solid concentrations(2.0~10.0 g·L^(-1))on the bio-oxidation behavior of Acidithiobacillus ferrooxidans were investigated with high arsenic tailings(As>20%).The results showed that the As leaching efficiency was significantly affected by the initial pH and the solid concentration.The bioleaching efficiency of As showed a trend of first increasing and then decreasing with the increase of initial pH or solid concentration.With initial pH 2.0,the leaching efficiency of As(up to 92.94%)was observed to be higher than that of other initial pH conditions.Under the initial pH 1.2~2.8,the bioleaching efficiency of As showed a trend of first increasing and then decreasing with the increase of initial pH.The optimal As leaching efficiency(up to 93.24%)was obtained at 8.0 g·L^(-1) solid concentration.In all the initial pH and solid concentration,it was found that the leaching efficiency of As increased rapidly in the early stage,but remained relatively stable in the middle stage and decreased in the late stage of bioleaching,which was related to the changes of microbial activity and the formation of jarosite.The XRD and SEM analysis results showed that the jarosite precipitation would gradually form during bioleaching.The jarosite would cover the mineral surface and form a passivation layer that would affect the further As leaching in the tailings.The outcomes of this study will provide a theoretical significance for clarifying the influencing factors of bio-oxidation behavior and reducing the environmental risk of high-arsenic mine tailings.
作者
叶茂友
翟淑君
廖小健
孙水裕
梁嘉林
YE Maoyou;ZHAI Shujun;LIAO Xiaojian;SUN Shuiyu;LIANG Jialin(College of Resources and Environment,Zhongkai University of Agriculture and Engineering,Guangzhou 510225;School of Environmental Science and Engineering,Guangdong University of Technology,Guangzhou 510006)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第8期111-121,共11页
Acta Scientiae Circumstantiae
基金
广东省基础与应用基础研究基金联合基金-青年基金项目(No.2021A1515110662)
广东省普通高校特色创新类项目(No.2022KTSCX054)
广东省自然科学基金-重大基础研究培育(No.2015A030308008)。
关键词
生物氧化
砷黄铁矿
高砷尾矿
嗜酸性氧化亚铁硫杆菌
黄钾铁矾
bio-oxidization
arsenopyrite
high-arsenic mine tailings
Acidithiobacillus ferrooxidans
jarosite
