【作者】 张峰；

【导师】 冯传平；

【作者基本信息】 中国地质大学（北京） ， 环境科学与工程， 2011， 博士

【摘要】 光催化技术因其鲜明的特点被认为是最具发展潜力的水处理技术之一。现阶段,制约光催化实际应用的瓶颈问题未得到根本性解决,针对目标水体特性选择光催化与其它工艺组成联合工艺,通过两者优势互补获得更好处理效果,则更具实际意义。本文针对光催化技术处理难降解有机废水、印染废水以及硝酸盐污染地下水时存在的缺陷,分别组建联合工艺,进行了光电联合催化处理苯酚废水、电化学-光催化组合工艺处理酸性橙Ⅱ废水以及生物慢滤-光催化组合技术处理硝酸盐微污染地下水的研究。主要结论如下：(1)采用光电联合催化工艺处理苯酚废水,在发挥光催化、电化学各自降解功效的同时产生了协同作用,溶液中氯离子的存在可以显著地提高协同增强的效应。在光催化和电化学工艺间的交互影响下氧化物质产率的提高是联合体系中协同增强作用出现的原因。光电联合工艺可明显缩短苯酚降解以及矿化的时间,提升单位电耗的矿化效率。在电流密度30mA/cm2、NaCl投加量0.3g/L、pH为6左右的反应条件下,初始浓度50mg/L苯酚在2.5小时内被完全去除,降解6小时后,TOC去除率达到75%；(2)采用电化学-光催化组合工艺处理酸性橙Ⅱ废水,电化学氧化前处理使溶液迅速褪色的同时也使大分子有机物发生了分解,有效的提高了后续光催化氧化工艺的TOC降解速率；而后续的光催化氧化工艺可无选择的氧化有机物,避免降解过程中出现中间产物的累积。3L初始浓度50mg/L的酸性橙Ⅱ溶液经1h电解加上6h光催化氧化降解,TOC的去除率达到了81%,矿化所需时间大大缩短。组合工艺完成50%矿化率时的耗电量仅是电化学工艺完成相同矿化率耗电量的71%；(3)采用生物慢滤-光催化组合工艺处理硝酸盐氮微污染地下水,组合工艺中前置的生物慢滤工艺可有效地脱除水中的硝酸盐,后置的光催化氧化工艺则对慢滤出水中残余的有机物、氨氮以及细菌总数起到削减作用。当原水硝氮含量在27.8-43.7mg/L,滤速0.35m/h,以碳氮比2：1外加碳源时,组合工艺出水硝氮含量低于《生活饮用水卫生标准》中的规定,经过后续光催化处理后CODMn和细菌总数也达到饮用水的要求。更多还原

【Abstract】 Because of its notable advantages, photocatalytic oxidation is considered as one of the most potential water treatment techniques. At present, the bottlenecks which restrict the application of photocatalytic technique have not been solved. Therefore, it is practical to develop the combined process of photocatalysis and other technique according to the feature of target pollutant. In combined process, the advantages of both single processes could be utilized, and the more efficient or economical removal could be achieved. In this study, a combined independent photocatalytic and electrochemical process (CPE) was investigated for phenol degradation, a coupled electrochemical and photocatalytic process (CEP) for Acid Orange II (AOII) mineralization and a coupled biology slow filtration and photocatalytic process (CFP) for nitrate removal form solution. The main results were as follows:(1) The CPE process exploited both single processes to produce a synergistic enhancement effect, and this effect was enhanced by adding NaCl into solution. The higher productivity of oxidizing substances resulting from the interaction between photocatalysis and electrolysis is probably the main reason for this synergy. In CPE process, the required time for mineralization was shorter and the energy efficiency was higher than that in both single processes. In this process,100% of phenol and 75% of total organic carbon were removed within 6 hours in the presence of 0.3 g/L NaCl electrolyte at a current density of 30 mA/cm2 and initial pH 6.10;(2) During the degradation of AOII with the CEP process, the electrochemical pretreatment made the solution faded rapidly and the dye molecular decomposed. Thus, the removal rate of TOC with the posterior photocatalysis increased significantly. Moreover, the accumulation of intermediates which appeared during the anterior electrolysis was eliminated efficiently by the posterior photocatalysis. After one hour of electrolysis followed with six hours of photocatalysis,81% of TOC was removed from the solution. The time consumed for mineralization with CEP process was much shorter than that with photocatalysis. The power consumption for 50% of TOC removal by CEP process was just 71% of that for the same TOC removal by electrolysis;(3) In the CFP process, the nitrate in the polluted groundwater was removed efficiently by the anterior biological slow filtration, and the residual organics, ammonia and total ba(?)terial count was reduced partially in the subsequent photocatalytic treatment. Under the running conditions of influent NO3--N=27.8-43.7mg/L, dosage of glucose as C/N=2:1 and filtering velocity=0.35 m/h, the effluent NO3--N was always below normative limit of drinking water in china, and the CODMn and tatal bacterial count also met the drinking water requirement after photocatalytic treatment.更多还原