紫外光强化氧化铋去除污酸废水中氯离子的效能与机理

我国有色金属冶炼过程污酸废水年产生量达到数亿立方米，是有色冶金行业的重大难题，污酸废水处理回用的技术瓶颈是氟、氯在强酸性条件下的选择性去除。我们在已初步解决氟选择性沉淀去除问题基础上，在本项目中进一步针对氯离子去除难题，提出紫外光强化氧化铋选择性脱氯的技术思路。项目拟开展紫外光强化氧化铋去除污酸废水中氯离子的效能与影响因素研究，解析强酸性条件下氧化铋光促溶解作用以及氧化铋/氯氧化铋异质节光促转化过程，深入探讨强化脱氯作用机理，并开展脱氯剂再生与废水脱氯扩大试验。拟实现氯离子去除效率达到98%以上、氯离子残留浓度低于100ppm的技术指标，以期解决当前氧化铋沉淀法受化学平衡常数和化学反应动力学限制而脱氯效率低、氧化铋投加量大、难以适用于硫酸浓度较低污酸废水的瓶颈问题；同时阐明强化过程的作用机理，为解决污酸废水高效脱氯的技术难题提供新的理论依据。

Annualy, hundreds of millions of dirty acid wastewater were produced in China from nonferrous metal industries. This has became a major difficulty in nonferrous metal industries. The technical bottleneck in dirty acid wastewatertreatment is the selective romoval of fluoride and chloride under strongly acidic conditions. We have preliminariely solved the problem of selective removal of fluoride and based on this, the present project further focus on the issue of selective removal of chloride from dirty acid wastewater. UV light enhanced chloride removal employing bismuth oxide as precipitant was proposed in this project and the following research work was planned to be carried out: the efficiency optimization and effecting factors; the photo-promoted dissolution process of bismuth oxide; the photo-transformation process of bismuth oxide/bismuth oxychloride heterojunction; the mechanism for UV light enhancement; the regenetation of chloride removal reagent and bench-scale investigation. This project is aimed to achieve a chloride removal efficiency of above 98% and residual chloride concentration of below 100ppm, so as to overcome bottleneck problems of the low chloride removal efficiency, high bismuth oxide dosage, poor applicability under low sulphate acid concentration, which result from the limitation of equilibrium constant and reaction dynamics. At the same time, the mechanism will be elucidated, which will provide theoretical foundation for the solution of the difficult problems existing in chloride removal from dirty acid wastewater.