硫酸根自由基高级氧化过程中硝基副产物的生成机制

Sulfate radical (SO4•-)-based advanced oxidation processes (SR-AOPs) are widely applied for remediation of soil and groundwater contaminated by organic pollutants due to their cost-effectiveness, easy operation and environmentally friendly property. The formation of potential hazardous and toxic byproducts during SR-AOPs application, however, receives little attention up to date. Because of its high oxidizing potential, SO4•- is capable of degrading pollutants as well as activating nitro substituent in reaction matrix. The activated nitro species further react with organic compounds present in soil and water, leading to the formation of highly carcinogenic and mutagenic nitro byproducts. The purpose of this project is to investigate the transformation mechanism and rule of nitro substituent of organic compounds and inorganic nitrate and nitrite in typical SR-AOPs system. Based on these results, the formation mechanism and kinetics of nitro byproducts will be elucidated. The critical factors influencing the formation of nitro byproducts will be determined. Operational parameters or additional pretreatment technologies will also be investigated to eliminate nitro byproducts formed in SR-AOPs system and to reduce ecotoxicological risk. The development of this project is favorable for determining the target pollutants suitable for SR-AOPs treatment and its applicable scope, and will provide scientific evidence for fully assessment of the safety and applicability of SR-AOPs.

硫酸根自由基（SO4•-）高级氧化技术（SR-AOPs）由于廉价高效、易于操作、环境友好而被广泛用于土壤和地下水有机污染修复。然而SR-AOPs使用过程中可能产生的有毒有害副产物尚未引起学术界足够的重视。由于硫酸根自由基的强氧化性，在降解污染物的同时，也可能将反应介质中的硝基活化，进而和土壤或水中的有机物发生反应，生成强致癌、致突变的硝基副产物。本项目拟分别探究有机物中的硝基和无机硝酸根、亚硝酸根离子在典型SR-AOPs体系中的转化机制和规律，在此基础上剖析硝基副产物的生成机制和动力学规律，明确影响硝基副产物生成的关键因素，探讨如何调控工艺条件或增加预处理技术，以期削减SR-AOPs过程中硝基副产物的生成，降低其生态风险。本项目有助于确定SR-AOPs治理的污染对象及适用范围，为全面评价SR-AOPs的安全性、可行性提供科学依据。

硫酸根自由基（SO4•-）高级氧化技术（SR-AOPs）因其具有廉价高效、环境友好的优点而被广泛用于土壤和地下水有机污染修复。然而SR-AOPs使用过程中可能产生的有毒有害副产物尚未引起学术界足够的重视。本项目研究表明，SO4•-的强氧化性使其在降解污染物的同时亦可与有机污染物分子中的硝基（-NO2）、水质中的亚硝酸根离子（NO2-）反应，从而生成活性硝化剂二氧化氮自由基（NO2•），进而与母体或水体中其它有机物反应，产生强致癌、致突变的硝基副产物。本项目探究了硝基和NO2-在典型SR-AOPs体系中的转化机制和规律，在此基础上鉴定了硝基副产物的种类、浓度、生成机制和动力学规律，评估了硝基副产物的生态毒性和环境风险，明确了影响硝基副产物生成的关键因素，并探讨了如何调控工艺条件或增加预处理技术，以期削减SR-AOPs过程中硝基副产物的生成，降低其生态风险。本项目研究结果有助于确定SR-AOPs治理的污染对象及适用范围，为全面评价SR-AOPs的安全性、可行性提供科学依据。