【作者】 何斌；

【导师】 韩卫清；

【作者基本信息】 南京理工大学 ， 环境工程， 2020， 硕士

【摘要】 随着化学工业的迅猛发展,高浓度有机废水对全球水资源安全造成了严重的威胁,尤其是难生物降解的有机污染物,常规生物法降解此类废水存在效率低、出水有残留等问题。电化学-芬顿催化技术是一种经济、高效的高级氧化技术。目前,电化学-芬顿催化技术的理论研究已趋于成熟,但在实际应用中,还仍然存在难以持续高效、规模化运行,处理成本高等难点。因此,构建新型电化学-芬顿催化技术系统,并探究其在难降解化工废水的应用研究具有十分重要的意义。本论文首先构建了序批式电催化芬顿-电化学氧化体系,以四甲基哌啶酮为特征污染物,详述了体系的反应器设计、组装和工作流程,探究和验证了该系统中的阳极氧化产Fe²⁺、阴极催化产H₂O₂、Fenton过程及其氧化机制,并研究了该系统中操作参数,包括电流密度、p H对H₂O₂产量以及COD_cr的去除效果的影响,确定了该系统最优操作参数（p H=3,电流密度为20 m A/cm²）。在最优参数条件下,该系统对四甲基哌啶酮模拟废水和某厂实际废水处理效果优秀,120 min内对模拟废水的TOC去除率达到46.4%,对实际废水的COD去除率可达82.8%。为进一步提高体系的氧化反应效率,设计了以气体扩散电极为阴极的连续流电催化芬顿氧化体系。研究该系统中不同电流密度、不同流量和电解质变化对H₂O₂产率的影响,确定产H₂O₂最优条件是是2 L/h的流量和20 m A/cm²的电流密度。以苯并三唑（BTR）为特征污染物,根据该体系连续处理BTR模拟废水过程中BTR和TOC随时间变化,得到该系统的最佳操作参数为:电流密度为20 m A/cm²,p H=3,流量为2 L/h,Fe²⁺为0.1 m M。最优条件下,BTR在40 min内可完全降解,去除率基本达100%,TOC去除率最高达58.3%,废水毒性明显降低。最后在比较了该系统处理BTR在城镇二级污水处理厂出水的降解变化,得到在最优条件下,该污染物BTR在40 min内完全降解,BTR废水的TOC去除率达40.8%,处理效果优秀。本研究构建的新型电催化芬顿氧化体系处理高效,极具规模化应用前景等优势,为电催化芬顿系统在化工废水处理的工程应用提供理论支撑和借鉴。更多还原

【Abstract】 With rapid development of the chemical industry,the wastewater contains high-concentration organic pollutants poses a serious threat to global water security,especially the recalcitrant organic matters.Whereas,these refractory organic contaminants can be hardly treated by conventional biological methods.Electrochemical-Fenton catalytic process is an advanced oxidation technology which is economical and efficient.At present,the theoretical research of electrochemical-Fenton catalytic process has matured.However,the disadvantages such as unsustainable efficiency,difficult to run in scale operation,high cost and poor stability are still exist in the practical applications.Therefore,it is significant to build a new system of electrochemical-Fenton catalytic process and explore its application in refractory chemical wastewater treatment.In this research,a sequential batch electrocatalytic Fenton-electrochemical oxidation system was first investigated,and tetramethyl piperidone as the target pollutant.The reactor design,assembly,and experimental procedure of the system were described step by step.Furthermore,the process of anodic oxidation of Fe²⁺generation,cathodic catalytic of H₂O₂generation and mechanism of Fenton and its oxidation were studied and verified.The operating parameters of the system were also investigated,including the influence of current density and p H on the H₂O₂production and COD_crremoval.The optimal operation parameters of the system were determined（p H=3,current density 20 m A/cm²）.Under this optimal operating condition,the maximum TOC removal rate of the tetramethyl piperidone simulated wastewater was 46.4%with 120 min reaction time,and the COD removal rate of actual wastewater reached 82.8%.Then,in order to achieve further improvement in oxidation efficiency of sequential batch system,a continuous flow electrocatalytic Fenton oxidation system with a gas diffusion electrode as a cathode was designed.The influence of the different current density,different flow rates and electrolyte changes on the yield of H₂O₂in this system were investigated.Using Benzotriazole（BTR）as the targeted pollutant,Benzotriazole and TOC of the simulated wastewater are continuously changed with time.The optimal operation parameters of the system were determined:current density was 20 m A/cm²,p H=3,flow rate was 2 L/h,Fe²⁺was 0.1 m M.Under this optimal operation condition,Benzotriazole can be completely removed in 40minutes,TOC removal rate was 58.3%and the toxicity of wastewater was also significantly reduced.Finally,the degradation of Benzotriazole in the secondary wastewater treatment plant was compared.Under this optimal condition,Benzotriazole was completely degraded within 40 min,and the TOC removal rate of Benzotriazole wastewater reached 40.8%.The novelty electrocatalytic Fenton oxidation system was based on this research,which exhibited advantages of higher efficiency and broad prospects in large-scale application.Furthermore,this study can also provide the reference and theoretical support in the future engineering applications of disposing chemical wastewater by using electrocatalytic Fenton oxidation processes.更多还原