【作者】 李瑞；

【导师】 陈冠益； 李宁；

【作者基本信息】 天津大学 ， 环境工程， 2021， 硕士

【摘要】 污泥年产量大且富含有机质,经高温处理后可制备表面基团丰富、孔隙度高且比表面积大的碳材料,实现其资源化利用。近年来,非均相催化过一硫酸盐（PMS）技术具有无额外能量摄入、反应条件温和和氧化能力强等优势,已广泛用于水污染治理研究。污泥生物炭活化PMS,催化活性强,体系中同时产生多种活性物质,实现水中污染物的高效去除。但目前热解参数对污泥炭表面活性位点生成规律、活性物种释放及催化效果的影响仍不明晰。本课题以探究催化剂表面活性位点对氧化体系中活性物种的释放规律为目的,采用污泥生物炭活化PMS,探究不同制备条件对污泥炭理化特性的影响,以环丙沙星（CIP）为模型污染物,分析其在污泥炭活化PMS体系中的降解效果,探析催化剂表面活性位点对氧化体系中活性物种的贡献,并分析CIP降解作用位点、反应路径及毒性变化。结果表明,适当提高热解温度、升温速率和热解时间后,不稳定的氮位点（吡咯氮和吡啶氮）及与C相连的-OH分别更易于向石墨氮和C=O转化,并提高污泥炭表面石墨化程度。非均相催化剂表面活性位点是PMS氧化体系产生活性物种的关键因素。在N₂气氛下以20°C/min升温至700°C停留120 min制备的污泥炭活性最高,经120 min活化PMS反应对CIP氧化去除率达94.2%。在设计搭建的PMS连续流装置中,三次循环实验中CIP去除率可稳定在96%以上。随着氧化反应进程的推进,与CIP的毒性相比,CIP降解产物的急性毒性、发育毒性和致突变性整体下降。催化剂表面活性位点与氧化体系中活性物种相关性分析结果指出,C=O、石墨氮、吡啶氮、晶格氧位点和较高的石墨化水平有助于¹O₂形成。Fe位点和石墨氮促进^·OH的释放,Fe位点、晶格氧和吡啶氮也可促进SO₄^·-的形成。在CIP降解过程中,¹O₂为主要活性物种,而^·OH和SO₄^·-起辅助作用。该研究为高活性生物炭基催化剂的设计提供理论基础,对PMS体系中活性物种的生成机制提供新的见解,有利于促进污泥的资源化利用和污染水体的高效处理。更多还原

【Abstract】 Sewage sludge（SS）is rich in organic matter with large annual output.Carbon materials are obtained with rich surficial active sites,high porosity and large specific surface area after the high temperature treatment of SS,and realize the resource utilization of SS.In recent years,heterogeneous catalyst activated peroxymonosulfate（PMS）technology has been widely used in wastewater purification due to its advantages such as no additional energy intake,mild reaction conditions,and strong oxidizing ability.Besides,endowing the properties of strong catalytic activity,sewage sludge-derived biochar（SSB）is used to activate PMS,achieving the removal of water pollutants with high efficiency.However,the effects of pyrolysis parameters on the generation of active sites on SSB surface,the release of reactive oxygen species（ROSs）and the catalytic effect are still unclear.This study was aimed to explore the regulation about the release of ROSs on the surface of catalysts during PMS activation.SSB acted as the catalyst to activate PMS.Ciprofloxacin（CIP）was used as a model pollutant to analyze the oxidation effect in SSB/PMS systems.The influence of active sites on SSB surface on the release of active species was investigated in PMS systems.The action sites on CIP molecular,the degradation pathway and the toxicity changes were also analyzed.The research results showed that the appropriate increase of pyrolysis temperature,heating rate and pyrolysis time was beneficial to the conversion from pyridinic N and pyrrolic N to graphitic N,the formation of C=O sites,and the improvement of graphitization level.The active sites on the surface of heterogeneous catalysts were the key to produce active species in PMS systems.Superior activity of SSB for CIP oxidation was observed at heating rate of 20°C/min,porolysis temperature of 700°C and porolysis time of 120 min under N₂ atmosphere.After CIP adsorption reached equilibrium,the removal rate of CIP was 94.2%after 120 min of oxidation in SSB-700-20-120/PMS system.In addition,a packed column reactor for continuous flow degradation of CIP with SSB catalyst/PMS was designed.The packed column reactor realized continuous and stable treatment of antibiotic wastewater with high efficiency,which maintained the CIP removal rate at over 96.0%after three cycles of utilization.On the whole,the acute toxicity,developmental toxicity and mutagenicity of CIP degradation products decreased in comparison with those of CIP.C=O,graphitic N,pyridinic N,lattice O sites and higher graphitization level contributed to the formation of ¹O₂ according to the results of correlation analysis between active sites on the catalyst surface and ROSs in PMS systems.Fe sites and graphitic N promoted the release of^·OH.Besides,Fe sites,lattice O and pyridinic N also facilitated SO₄^·-generation.¹O₂ was dominant while^·OH and SO₄^·-played a minor role in CIP degradation.This research provided a new insight into the improvement of SSB catalytic performance,and the generation mechanism of reactive oxygen species in PMS system.The obtained results were beneficial to sewage sludge utilization as heterogeneous catalysts for wastewater remediation.更多还原