【作者】 于欣；

【导师】 吕东伟；

【作者基本信息】 哈尔滨工业大学 ， 土木水利（专业学位）， 2022， 硕士

【摘要】 陶瓷膜过滤是水体净化和回用的领先技术之一,但膜污染是陶瓷膜应用领域的关键限制因素。通过在陶瓷膜上修饰金属氧化物可以赋予陶瓷膜催化活性,有助于耦合原位氧化过程来强化膜滤抗污染性能。过氧乙酸具备氧化效率高和易于活化的特点,与陶瓷膜集成用于控制膜污染具有广阔的前景。本课题合成了Fe OCl改性陶瓷膜（Fe OCl-CM）并耦合过氧乙酸（PAA）氧化过程构建了PAA/Fe OCl-CM催化过滤体系,以牛血清蛋白（BSA）为模型蛋白质污染物测试过滤体系抗污染性能。深入分析了催化过滤机理及污染物的降解机制。首先,研究制备了具有催化活性的Fe OCl-CM。通过XRD、XPS、SEM/EDS、BET、AFM以及接触角测试表征分析了膜的形貌特征、元素组成等物化性质。综合表征结果可知,所制备的Fe OCl-CM表面和孔内均匀负载了Fe OCl纳米片催化材料,纯水接触角为37°,均方根粗糙度和平均粗糙度分别为36.8和28.8,纯水通量为30.71 L/（m²·h）,是具有高亲水性、低表面粗糙度的精细超滤陶瓷膜,有利于膜滤-高级氧化耦合工艺中对膜污染的缓解及强化过滤性能。其次,提出了实现高效缓解蛋白质污染的PAA/Fe OCl-CM催化过滤体系。与单一陶瓷膜过滤BSA相比,该体系能显著提高膜滤水平,归一化水通量由0.22提升至0.46,提高了近一倍。根据Hermia经典过滤堵塞模型拟合及SEM分析发现了膜污染缓解主要归因于过滤前端的膜孔堵塞和滤饼层污染的减轻,膜截面污染层明显变窄,膜表面团聚的BSA污垢被分解成小颗粒分散在膜上,提高了膜通量。最后,提出了PAA/Fe OCl-CM催化过滤体系抗污染机理及BSA的降解机理。催化过滤机理主要为原位生成的活性物种的氧化,其中^·OH和¹O₂是BSA降解的关键反应物种,而Fe OCl-CM、BSA、PAA三者之间的直接电子转移作用很小。BSA降解归因于催化氧化导致酰胺I和II带断裂以及芳香族氨基酸（如色氨酸、酪氨酸）的开环,大分子量的BSA被降解为小分子结构并且产物更加疏水,从而实现膜污染的有效控制。总之,本课题提出的PAA/Fe OCl-CM催化过滤策略可实现高效的膜污染控制,具有优异的发展潜力。更多还原

【Abstract】 Ceramic membrane filtration is one of the leading technologies for water purification and reuse,but membrane fouling is a key limiting factor in the application of ceramic membranes.The ceramic membrane can be endowed with catalytic activity by modifying metal oxides on the ceramic membrane,and the in-situ oxidation process can be coupled to enhance the pollution resistance of the membrane filtration.Peracetic acid（PAA）featured with high oxidation efficacy and easy activation,which integration with ceramic membranes has a broad prospect for the control of membrane fouling.In this study,a functionalized Fe OCl ceramic membrane（Fe OCl-CM）was synthesized and coupled with the oxidation process of peracetic acid（PAA）to construct a PAA/Fe OCl-CM catalytic filtration system.The anti-fouling performance was tested using bovine serum albumin（BSA）as the model protein foulant.The mechanism of catalytic filtration and the degradation mechanism of foulant were deeply analyzed.First,a Fe OCl-CM with catalytic activation was prepared.The morphology and elemental composition of the membranes were characterized by XRD,XPS,SEM/EDS,BET,AFM and contact angle measurements.According to the comprehensive characterization results,the Fe OCl-CM with uniform loading of Fe OCl nanosheets on the surface and in the pores was prepared,and which had water contact angle of 37°,the root mean square roughness and average roughness of 36.8 and 28.8,respectively,and the pure water flux of 30.7L m^-2h^-1.The Fe OCl-CM was a fine ultrafiltration with high hydrophilicity and low surface roughness,which was conducive to alleviating the membrane pollution in the membrane filtration-advanced oxidation coupling process and enhancing the filtration performance.Then,a PAA/Fe OCl-CM catalytic filtration system was proposed to achieve efficient mitigation of protein fouling.The membrane filtration level of the system was significantly improved,and the normalized water flux increased from 0.22 to0.46,which is nearly doubled compared with the membrane filtration of BSA with a single ceramic membrane.According to the fitting analysis of Hermia classical filtration fouling model and SEM,it was found that the mitigation of membrane fouling was mainly attributed to the reduction of membrane pore blocking at the filtration front end and the fouling of the cake layer.The fouling layer at the membrane cross-section was significantly narrowed,and the agglomerated BSA foulant on the membrane surface was decomposed into small particles which were dispersed on the membrane,thus improving the water flux.Finally,the anti-fouling mechanism of PAA/Fe OCl-CM catalytic filtration system and the degradation mechanism of BSA were proposed.The mechanism of catalytic filtration is mainly due to the oxidation of active species generated in situ,of which^·OH and ¹O₂are the key reaction species for BSA degradation,while the contribution of the direct electron transfer between Fe OCl-CM,BSA and PAA is very small.The degradation of BSA was attributed to the breakage of amide I and II bands and the ring opening of the aromatic amino acids（e.g.,tryptophan and tyrosine）.The large molecular weight BSA was degraded into a small molecular structure and the product was more hydrophobic,thus achieving effective control of membrane fouling.Overall,the PAA/Fe OCl-CM catalytic filtration strategy proposed in this study can achieve efficient membrane fouling control,and has an excellent development potential.更多还原