State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; National Engineering Laboratory for Industrial Wastewater Treatment, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2021 May 15;410:124540. doi: 10.1016/j.jhazmat.2020.124540. Epub 2020 Nov 11.
Specific to strongly acidic wastewater, the traditional lime neutralization produces massive hazardous waste and present serious environmental risks. Thus, the recycling of purified wastewater after the contained contaminants being removed has been proposed. However, among these contaminants, chloride ion (Cl(-I)) is rather difficult to remove. This study proposes a new method to remove Cl(-I) using thermal activated persulfate (PS). Under optimized conditions, above 96% of initial Cl(-I) was removed from the actual wastewater, and the residual Cl(-I) was below 158 mg/L, which satisfies the requirement of Cl(-I) concentration for wastewater recycling. Furthermore, the mechanism was investigated. In the strongly acidic wastewater, the high concentration of H prompted the thermal activation process of PS through two pathways. (1) H prompted the transformation of SO into HSO and SO, and then into HSO that was finally transformed into ·OH and ·SO at above 70 ℃. (2) H prompted the production of ·OH through the transformation of ·SO into ·HSO and the cleavage of ·HSO. The key step for Cl(-I) removal was identified as the formation of ·Cl or ·Cl from the oxidation of Cl(-I) by ·SO and ·OH, and their contribution ratios were estimated to be 67.4% and 32.6%, respectively.
针对强酸废水，传统的石灰中和会产生大量危险废物，并带来严重的环境风险。因此，提出了去除所含污染物后对净化废水进行回收利用的方法。然而，在这些污染物中，氯离子 (Cl(-I)) 很难去除。本研究提出了一种使用热激活过硫酸盐 (PS) 去除 Cl(-I) 的新方法。在优化条件下，实际废水中超过 96%的初始 Cl(-I)被去除，残留的 Cl(-I)低于 158 mg/L，满足废水回收的 Cl(-I)浓度要求。此外，还研究了其去除机制。在强酸性废水中，高浓度的 H 通过两种途径促进 PS 的热激活过程。(1)H 促使 SO 转化为 HSO 和 SO，然后转化为 HSO，在 70℃以上最终转化为·OH 和·SO。(2)H 通过·SO 转化为·HSO 和·HSO 的裂解，产生·OH。Cl(-I)去除的关键步骤是 Cl(-I)被·SO 和·OH 氧化生成·Cl 或·Cl，其贡献比例分别估计为 67.4%和 32.6%。
