【作者】 王涛；

【导师】 郑兴； 张耀中；

【作者基本信息】 西安理工大学 ， 环境工程， 2020， 硕士

【摘要】 膜法水处理技术因其分离效率高、出水水质好、设备操作简单等优势,在水处理领域得到广泛研究和应用。但是运行过程出现的严重膜污染问题制约着膜技术的发展,成为膜技术的瓶颈。膜污染后常采用的化学离线清洗,不仅操作繁琐,对膜表面能造成不可逆损伤,而且会导致二次污染;另外现有膜技术对物质进行分离,其功能单一,对一些资源性物质很难做到有效回收。本研究分别利用聚吡咯与聚苯胺改性不锈钢网基底制备复合导电滤膜,实现导电滤膜在线通电反洗控制膜污染及利用其电化学性能实现资源物质回收的目的,主要研究内容如下:(1)利用电化学聚合法,分别在规定浓度的吡咯和苯胺单体溶液中将过滤精度为4μm的不锈钢网基底进行电化学循环伏安法扫描,制备聚吡咯和聚苯胺/不锈钢网复合导电滤膜,通过调整循环伏安扫描圈数,控制两种复合滤膜通量范围在600-2000 L/(m2·h·bar),实现复合滤膜的优异过滤功能。制备的复合滤膜具有良好导电能力、过滤性能、结构稳定性及电化学稳定性。(2)为研究复合导电滤膜对污染物截留及通电反洗膜污染控制效果,分别采用标准模拟污染物(海藻酸钠、牛血清蛋白和腐殖酸)溶液以及实际二级出水进行过滤及反冲洗循环实验,结果表明复合导电滤膜对有机物的截留效果较好,膜污染控制得到强化。以复合导电滤膜为阴极、石墨棒为阳极,0.1mol/L的氯化钠为反清洗液,施加2V电压时,膜通量恢复率显著优于对照组。研究表明,复合滤膜通电后的材料表面膨胀、亲水性提高、生成气泡以及形成电场极化作用都显著提高了膜污染控制的效果。(3)为进一步研究聚苯胺复合滤膜对资源性物质磷的吸附回收,采用磷标准液及实际二级出水进行磷吸附解吸附研究。不通电吸附时吸附容量为0.0457mg/cm2;电压为5V时,解吸附效果达到98%以上,重复5次吸附解吸附,聚苯胺复合滤膜仍具有良好的吸附解吸附能力。以上研究表明,基于不锈钢网电化学聚合高分子制备复合滤膜为滤膜开发与制备提供了一种新颖思路;通过不锈钢网阴极膜外加电场可以有效提高膜污染控制效果,操作简便,具有明显的经济和环境效益;利用聚苯胺导电滤膜吸附解吸附资源物质磷(P)并进行回收浓缩的过程为分离膜的功能化开发提供技术指导意义。更多还原

【Abstract】 Water treatment technology based on membrane has been widely researched and applied in the field of water treatment due to its advantages such as high separation efficiency,good effluent quality,and simple equipment operation.However,the serious membrane fouling problem in the operation process restricts the development of membrane technology and becomes the bottleneck of membrane technology.The chemical off-line cleaning often used after membrane fouling is not only cumbersome,can cause irreversible damage to the membrane surface,but also leads to secondary pollution;in addition,the existing membrane technology separates the substances,and its function is single,which is difficult to effectively recycle some resource materials.In this study,polypyrrole and polyaniline were used to modify the stainless steel mesh substrate to prepare a composite conductive filter membrane.The conductive filter membrane was used to control membrane fouling by backwashing during power on.Using its electrochemical properties to achieve the purpose of resource material recovery,the main research contents are as follows:(1)Using electrochemical polymerization method,the stainless steel mesh substrate with a filtration accuracy of 4μm was prepared by electrochemical cyclic voltammetry in the pyrrole and aniline monomer solutions of the specified concentration to prepare polypyrrole and polyaniline/stainless steel mesh composite conductive filter membrane,by adjusting the number of cyclic voltammetry scans,the flux range of the two composite filter membranes is controlled at 600-2000L/(m2·h·bar),and the excellent filtration function of the composite filter membrane is realized.The prepared composite filter membrane has good electrical conductivity,filtration performance,structural stability and electrochemical stability.(2)In order to study the effect of composite conductive filter membrane on the interception of pollutants and the control of backwash membrane fouling during power on.The standard simulated pollutant(sodium alginate,bovine serum protein and humic acid)solution and the actual secondary effluent were used for filtration and backwash cycle experiments respectively.The results show that the composite conductive filter membrane has a good effect of intercepting organic matter,and the control of membrane fouling is strengthened.The composite conductive filter membrane was used as the cathode,the graphite rod was used as the anode,and 0.1mol/L sodium chloride was used as the backwashing solution.When the voltage of 2V was applied,the membrane flux recovery rate was significantly better than that of the control group.Studies have shown that expansion of the surface of the composite filter membrane after power on,the increase in hydrophilicity,the generation of bubbles,and the formation of electric field polarization all significantly improve the control effect of membrane fouling.(3)In order to study the adsorption and recovery of the phosphorus resource by the polyaniline composite filter membrane,phosphorus adsorption and desorption studies were carried out using phosphorus standard solution and actual secondary effluent.The adsorption capacity is 0.0457mg/cm2 when it is not power on;when the voltage is 5V,the desorption effect reaches more than 98%,and the adsorption and desorption are repeated 5 times,and the polyaniline composite filter membrane still has good adsorption and desorption capabilities.The above research shows that the preparation of composite filter membrane by electrochemical polymer based on stainless steel mesh provides a novel idea for filter membrane development and preparation;the application of electric field by the stainless steel mesh cathode membrane can effectively improve the membrane pollution control effect,and the operation is simple and have obvious economic and environmental benefits.The process of using polyaniline conductive filter membrane to adsorb and desorb the resource substance phosphorus(P)and carry out recovery and concentration provides technical guidance significance for the functional development of separation membrane.更多还原