掺硫活性炭活化过硫酸盐机理及其处理煤气化废水中难降解有机物的研究

The biologically pretreated coal gasification wastewater which contains a great deal of refractory organics has brought tremendous pressure on the environment. Persulfate activation is an emerging advanced oxidation technology for wastewater treatment in recent years. Persulfate activation by activated carbon process (AC/PS) can avoid secondary pollution by transition metal activation. However, the low activation rate of PS by AC limits the widely using of AC/PS. Sulfur doping on AC can significantly improve the activation rate of peroxide by AC. But it is difficult to improve PS activation rate through targeted sulfur doping of AC due to the lack of theoretical cognition of PS activation mechanism by sulfur functional groups on AC. The theoretical cognition lacking is a serious constraint on the development and application of PS activation by sulfur doped activated carbon (SDAC/PS).This study will investigate following area : mastering the targeted AC sulfur doping modification through the sulfur doping modification of AC and analysis of surface functional groups; basing on the radical detection technology, systematic investigation on the effects of SDAC surface chemical characteristics on PS activation kinetics and mechanism; investigation of the degradation of p-chlorophenol (the highly toxic pollutant in coal gasification wastewater) by SDAC/PS, clarifying the mechanism of radicals formation and pollutants degradation in coal gasification wastewater oxidation process by SDAC/PS through the research of adsorption, degradation kinetic, radical and byproducts analysis. This work will provide the experimental and theoretical evidences for the improvement of SDAC/PS.

煤气化废水经生化处理后仍含有大量难降解有机物，对环境带来巨大压力。活化过硫酸盐（PS）技术是近年新兴的高级氧化污水处理技术，采用活性炭（AC）活化过硫酸盐可避免过渡金属活化造成的二次污染，但其应用仍受制于AC较低的PS活化速率。对AC进行硫掺杂改性能显著提高AC活化过氧化物速率，但目前对于AC含硫官能团活化PS机制还缺乏理论认识，无法采用针对性的S掺杂方法提高活化PS效能，严重制约着掺硫活性炭活化PS工艺（SDAC/PS）的开发应用。本课题通过对AC进行掺硫改性，结合官能团表征技术，掌握SDAC的可控掺硫工艺；结合自由基检测技术系统研究SDAC含硫官能团对PS活化影响的内在机制；以煤气化废水残留高毒污染物对氯苯酚为目标污染物，通过对SDAC活化PS降解对氯苯酚动力学研究及自由基、反应产物分析，阐明SDAC活化PS机制及其降解氯苯酚机理，为改进SDAC/PS氧化工艺提供理论指导和实验依据。

二级出水中的难降解有机物的处理一直是环境领域研究的难点。活性炭活化过硫酸盐可以有效处理难降解有机物，但常规活性炭较低的活化性能仍然是其最大的问题。本课题通过SO2表面掺杂、聚噻吩等含硫有机物作为前驱体的原位体相掺杂等方式制备了一系列掺硫活性炭（SDAC）。系统考察了前驱体性质、制备条件等对SDAC表面含硫、含氧官能团的影响规律。同时，采用制备的一系列SDAC对过硫酸盐（PS）进行了有效活化，系统研究了不同表面化学性质的SDAC活化PS降解对氯苯酚污染物的性能。明确了含C-S-C键的还原性含硫官能团是SDAC活化PS的关键杂原子官能团。采用自由基清除实验探究了SDAC活化PS过程的内在反应机制，证实和阐述了PS在SDAC表面通过自由基机理间接氧化和非自由基机理直接氧化对污染物进行氧化降解。