砷酸复盐矿化沉淀高效除砷行为及机理  

Behavior and mechanism of efficient arsenic removal by arsenate double salt mineralization precipitation

作　　者：房金梅 孙伟[2] 韩海生[2] 徐龙华[1] 岳彤[2] 胡文吉豪 王宇峰 薛凯 田佳[1,2] FANG Jinmei;SUN Wei;HAN Haisheng;XU Longhua;YUE Tong;HU Wenjihao;WANG Yufeng;XUE Kai;TIAN Jia(School of Environment and Resources,Southwest University of Science and Technology,Mianyang 621000,China;School of Minerals processing and Bioengineering,Central South University,Changsha 410083,China)

机构地区：[1]西南科技大学环境与资源学院,绵阳621000 [2]中南大学资源加工与生物工程学院,长沙410083

出　　处：《中国有色金属学报》2024年第10期3490-3501,共12页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(52304315);湖南省重大科技攻关“揭榜挂帅”制项目(2023ZJ1100)。

摘　　要：针对常规化学沉淀法处理碱性含砷废水无法高效选择性除砷的问题,提出采用砷酸复盐矿化沉淀法处理含砷废水。对25℃的Mg^(2+)-NH^(+)_(4)-AsO^(3-)_(4)-OH^(-)-H_(2)O体系进行了热力学计算,研究了工艺参数对除砷率的影响,为砷酸复盐矿化沉淀过程建立了动力学调控机制,探索了杂质离子对除砷效果的影响。结果表明:pH对除砷率和砷渣品位的影响显著;增大镁盐和氨盐用量能在一定程度上提高除砷率,但镁盐过量时砷渣品位会随镁盐用量的增加而减小;增加镁盐用量有利于缩短达到平衡所需的时间;升温会明显降低除砷率和砷渣品位。杂质离子Ca^(2+)、Fe^(3+)和SiO^(2-)_(3)的加入会形成新的化合物并与砷共沉淀,对除砷具有促进作用,而加入PO^(3-)_(4)形成磷酸复盐与砷酸复盐的形成存在竞争关系,会抑制砷酸复盐矿化除砷。In response to the challenge of inefficiency in selectively removing arsenic from alkaline arsenic containing wastewater using conventional chemical precipitation methods,a proposal was set forth to employ arsenate double salt mineralization precipitation for wastewater treatment.Thermodynamic calculations were conducted on the Mg^(2+)-NH^(+)_(4)-AsO^(3-)_(4)-OH^(-)-H_(2)O system at 25℃,investigating the influences of process parameters on arsenic removal effect.The study established a kinetic control mechanism for the arsenate double salt mineralization precipitation process,while exploring the impact of impurity ions on arsenic removal efficacy.The results indicate that pH significantly affects both arsenic removal effect and arsenic residue quality.Increasing the dosages of magnesium and ammonia salts can enhance arsenic removal to a certain extent,yet excessive magnesium salt usage diminishes arsenic grade of arsenic residue with escalating dosage.Augmenting magnesium salt dosage facilitates a reduction in the time required to reach equilibrium.The addition of impurity ions Ca^(2+),Fe^(3+),and SiO^(2-)_(3) fosters the creation of novel compounds,which subsequently co-precipitate with arsenic,thereby enhancing the process of arsenic removal.However,the addition of PO^(3-)_(4)establishes a competitive relationship between the formation of phosphate double salt and arsenate double salt,consequently inhibiting arsenic removal by arsenate double salt mineralization.

关 键 词：含砷废水 热力学 动力学 砷酸复盐 选择性除砷 

分 类 号：X505[环境科学与工程—环境工程]