Sulfate radical-based removal of chloride ion from strongly acidic wastewater: Kinetics and mechanism
Sulfate radical-based removal of chloride ion from strongly acidic wastewater: Kinetics and mechanism
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DOI：
10.1016/j.jhazmat.2020.124540
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发表时间：
2021-03-26
影响因子：
13.6
通讯作者：
Peng, Xianjia
中科院分区：
文献类型：
--
作者：
Hu, Xingyun;Zhu, Feng;Peng, Xianjia
针对强酸性废水，传统的石灰中和法产生大量的危险废物，存在严重的环境风险。因此，提出了在去除所含污染物后回收净化废水的方法。然而，在这些污染物中，氯离子（Cl（-I））相当难以去除。提出了一种利用热活化过硫酸盐（PS）去除Cl（-I）的新方法。在优化条件下，实际废水中初始Cl（-I）的去除率达到96%以上，残余Cl（-I）浓度低于158 mg/L，满足废水回用对Cl（-I）浓度的要求。并对其机理进行了探讨。在强酸性废水中，高浓度的H+通过两条途径促进PS的热活化过程。(1)H+促使S2 O 82-转化为HSO 4-和SO 4-，然后转化为HSO 5-，最后转化为？哦，然后呢？SO4？70多岁的时候C. (2)H+促使生产的？#21518;，通过转型？SO4？变成什么HSO 4和卵裂？HSO 4。Cl（-I）去除的关键步骤被确定为形成？Cl还是？氯气？从Cl（-I）的氧化？SO4？然后呢？OH的贡献率分别为67.4%和32.6%。
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 S2O82- into HSO4 - and SO4, and then into HSO5 - that was finally transformed into ?OH and ?SO4? at above 70 ?C. (2) H+ prompted the production of ?OH through the transformation of ?SO4? into ?HSO4 and the cleavage of ?HSO4. The key step for Cl(-I) removal was identified as the formation of ?Cl or ?Cl2? from the oxidation of Cl(-I) by ?SO4? and ?OH, and their contribution ratios were estimated to be 67.4% and 32.6%, respectively.