【作者】 陈天翼；

【导师】 黄某霞；

【作者基本信息】 清华大学 ， 环境科学与工程， 2017， 硕士

【摘要】 工业废水通常污染物浓度高,如不妥善处理会对水环境造成巨大危害,因此为了保证工业废水达标排放或回用,需要在工业废水常规生化处理之后,增设深度处理单元。臭氧催化氧化利用催化剂促使臭氧分解产生羟基自由基（·OH）,具有氧化能力强、选择性弱、不产生二次污染等优势,是一种有效的深度处理技术。超细活性炭外表面积较大、表面含氧官能团较多,具有提升催化氧化效率的潜力。此外,陶瓷膜具有抗臭氧腐蚀的特点,可有效地分离细小的活性炭,并可利用臭氧的氧化作用,缓解陶瓷膜污染。本研究以研发新型高效臭氧催化氧化技术为目标,通过球磨制取了超细活性炭,考察了其催化臭氧氧化的效率,初步分析了超细活性炭催化臭氧氧化的机理;构建了一种超细活性炭-陶瓷膜臭氧催化氧化反应器,考察了其连续处理煤气化废水生化出水的效果及运行过程中臭氧对膜污染的控制情况。通过球磨制取了平均粒径为1.33μm的超细活性炭,其催化臭氧氧化较颗粒活性炭有明显的优势,当投加量为2.0 g/L时,反应10 min时反应达到平衡,总有机碳（Total Organic Carbon,TOC）去除率达90%。通过反应动力学分析,在超细活性炭的催化下,TOC降解反应速率常数是颗粒活性炭的64倍。活性炭催化臭氧氧化的效率与投加量和粒径均有密切的关系,通过进一步的分析,发现反应体系中的总表面积和几何比表面积是影响催化效率的关键因素。超细活性炭较颗粒活性炭具有更大的中孔和大孔结构,吸附阻力较低,从而其吸附速率较颗粒活性炭提升了15倍。同时,对超细活性炭,96%的催化反应发生在活性炭表面,认为其符合臭氧催化氧化的表面反应机理。超细活性炭的羟基自由基转化率是颗粒活性炭的330倍,与改性的碳纳米管接近。构建了超细活性炭-陶瓷膜臭氧催化氧化反应器,根据试验结果选取2.0 g/L超细活性炭、1-4 mg/L臭氧投加量作为深度处理煤气化废水生化出水的运行参数,此时色度和化学需氧量（Chemical Oxygen Demand,COD）去除率可达90%和75%,ΔCOD/ΔO₃为1.3。在水力停留时间为30 min、膜通量为50 L/（m²·h）的条件下连续运行时,出水色度和COD分别降低至10和50 mg/L。臭氧可将陶瓷膜的临界通量从35-40 L/（m²·h）提升至50-60 L/（m²·h）,运行过程中跨膜压差降低35%-40%并保持稳定,膜污染得到有效控制。超细活性炭-陶瓷膜臭氧催化氧化为煤气化废水的深度处理提供了一条可行的技术方案。更多还原

【Abstract】 Industrial wastewater contains high concentration of pollutants.It will greatly damage water environment if not well-treated.Therefore,advanced treatment should be implemented after common bio-chemical treatment of industrial wastewater,in order to guarantee the effluent can reach the discharge standards or be reused.As an effective advanced treatment process,catalytic ozonation uses catalysts to prompt the ozone decomposition into hydroxyl radicals（·OH）and it has high oxidation ability,less selectivity and is free of secondary pollution.Super-fine powdered activated carbon（SPAC）has potential to enhance the efficacy of catalytic ozonation,as it has higher external surface area and surface oxygen-containing groups.Besides,ceramic membrane can resist the oxidation of ozone and perform well in fine carbon separation.Meanwhile,the fouling of ceramic membrane can be alleviated,due to the oxidation of ozone.In this study,in order to develop a novel and effective catalytic ozonation technology,SPAC was synthesized by ball mill,its efficacy of catalytic ozonation was evaluated and the mechanism of SPAC catalytic ozonation was postulated.Furthermore,a SPAC combined with ceramic membrane catalytic ozonation reactor was established.Its performance in the continuous treatment of bio-chemical treatment effluent of coal gasification wastewater was evaluated.And the alleviation of ceramic membrane fouling by ozone was observed.SPAC with an average radius of 1.33μm was synthesized by ball mill and it outperformed granular activated carbon（GAC）significantly.When dosing 2.0 g/L,the reaction reached equilibrium within 10 min and 90%of total organic carbon（TOC）was removed.By kinetic analysis,the rate constant of TOC removal by SPAC catalytic ozonation was 64-fold than GAC.The efficacy of activated carbon（AC）catalytic ozonation was closely related to its dosage and particle size.Further,total surface area and geometric surface area of AC were recognized as key factors.SPAC had larger meso-and macro-pores,which brought less adsorption resistance and 15-fold increase in adsorption rate than GAC.Meanwhile,96%of catalytic reaction happened on the surface of SPAC and its mechanism was assumed to follow surface reaction mechanism.The conversion efficiency from ozone to hydroxyl radical of SPAC was 330-fold than GAC,which was even close to that of modified carbon nanotubes.A SPAC-ceramic membrane catalytic ozonation reactor was established.According to the results,2.0 g/L SPAC and 1-4 mg/L ozone dosage was chosen as running parameters for the treatment of the effluent of bio-chemical treatment of coal gasification wastewater.Under this condition,the removal rate of chroma and chemical oxygen demand（COD）reached 90%and 75%respectively andΔCOD/ΔO₃ reached 1.3.When hydraulic retention time was 30 min and membrane flux was 50 L/（m²·h）,the chroma and COD of the effluent of the reactor was 10 and 50 mg/L.Ozone can enhance the critical flux from 35-40 L/（m²·h）to 50-60 L/（m²·h）.The transmembrane pressure decreased35%-40%and was stable in the operation,which indicated that membrane fouling was controlled.SPAC-ceramic membrane catalytic ozonation reactor provided one of the feasible plans for the advanced treatment of coal gasification wastewater.更多还原