亚硫酸盐强化UV/PS去除水中有机物同步控制溴酸盐生成研究

In recent years, sulfate radical-based advanced oxidation processes have been developed as a novel and efficient technology for removal of pollutants. However, the residual oxidant becomes a common issue and bromate, a potential human carcinogen, would be produced in the presence of bromide, which impair the water quality. Sulfite has recently been considered to be an alternative resource of sulfate radical with advantages of low cost and no secondary pollution. When combining sulfite to activated persulfate process, the generation of sulfate radical would be promoted with the decrease of residual oxidants. Moreover, bromate formation would be controlled as well, which could be attributed to the reduction of intermediates such as hypobromous acid by sulfite. This study aims to investigate the removal of organics and oxidation of bromide ions by the combined sulfite and UV/persulfate process. The kinetic model for the combined system will be set up, as well as the synchronous mechanism will be disclosed. Additionally, the promotion of organic pollutants degradation in UV/persulfate process by combing sulfite and the synchronous bromate control will be also evaluated. This project is expected to provide basis for the application of this technology in water supply, especially for bromide-containing water treatment, which is meaningful for the protection of drinking water safety.

基于硫酸根自由基（SO4•−）的高级氧化工艺作为一种新型且高效的氧化技术，近年来被广泛用于降解各类有机污染物，但是往往存在氧化剂残留问题，而且当水中含有溴离子时，容易生成具有致癌性的溴酸盐，威胁水质安全。亚硫酸盐作为近几年提出的SO4•−的替代来源，具有成本低廉、无二次污染等优点。若将亚硫酸盐与过硫酸盐（PS）活化技术联用，不仅理论上可以促进SO4•−的产生，减少氧化剂残留，而且亚硫酸盐能够还原次溴酸等中间产物从而抑制溴酸盐生成。本项目将针对上述推测考察亚硫酸盐与UV/PS联用体系对水中有机物的去除过程和对溴离子的氧化规律，构建动力学模型，揭示该体系的作用机理，探讨亚硫酸盐强化UV/PS降解有机物并同步控制溴酸盐生成的可行性。本项目研究将为该技术在给水领域特别是含溴水体处理中的应用提供基础，对于保障饮用水安全具有重要意义。

紫外/过硫酸盐（UV/PS）高级氧化技术是近年来水处理领域的研究热点之一，但是当水中含有溴离子时，容易生成具有致癌性的溴酸盐，威胁水质安全。考虑到亚硫酸盐（S(IV)）常被看作PS的替代品而且具有还原性，有望抑制溴酸盐产生，因此将S(IV)与UV/PS联用成为了解决上述问题的一种新思路。本项目系统研究了UV/PS/S(IV)体系对水中有机物的去除过程和对溴离子的氧化规律，研究结果表明：1）S(IV)能够显著强化UV/PS体系对橙黄II等多种典型染料的脱色效果，但是强化效果具有明显的选择性，推测主要与UV对S(IV)的活化作用有关，提升了自由基产率；2）经过实验证实UV/S(IV)在有氧条件下具有氧化能力，能够有效降解以药品为代表的多种有机物，并探讨了不同因素的影响，反应机理主要涉及在溶解氧作用下硫氧自由基和活性氧物种的相互转化；3）在氧化溴离子过程中S(IV)可以明显抑制UV/PS体系中溴酸盐的生成，推测主要作用途径是S(IV)快速将溴原子还原回溴离子从而避免了中间产物次溴酸的积累。本项目的科学意义在于提出了一种强化UV/PS去除有机物的新技术，并且揭示该技术对于溴酸盐的同步控制过程与机理，研究结果将为该技术在给水领域特别是含溴水体处理中的应用提供基础。