催化臭氧响应膜制备及应用研究

发布时间：2018-06-13 13:44

  本文选题：腐植酸 + 催化臭氧化　； 参考：《东北电力大学》2017年硕士论文

【摘要】：腐植酸(Humic Acids,HA)广泛地分布在地表水中,因使水变成褐色,与金属或有机物反应生成复杂物质,与活性氯反应生成消毒副产物而得到广泛关注,如何有效去除水中HA具有重要意义。膜分离技术在HA处理过程中的得到广泛关注,然而膜污染问题是制约该技术发展的瓶颈。催化臭氧化技术可有效降解水中有机物,但催化降解过程中存在着催化剂流失和回收等问题。通过将具有催化臭氧能力强的催化剂负载到膜上,制备出催化臭氧化响应膜,依靠膜分离与催化臭氧化技术耦合来提高膜分离效率,并解决催化剂流失、回收以及膜污染的问题。本研究开发了一种具有高催化活性的催化臭氧响应膜,并将其与催化臭氧化技术耦合来处理HA,研究内容和结果如下:(1)采用溶胶-凝胶法制备纳米TiO_2,用响应面法优化纳米TiO_2催化臭氧降解HA的最佳实验条件,得到的最佳实验条件为:煅烧温度为565℃,TiO_2投加量为0.31 g/L,臭氧浓度为16.75 mg/L,溶液pH为6.91;此条件下HA的去除率为87.15%。(2)采用溶胶-凝胶法制备出不同Ti-Ce复合物(掺杂Ti/Ce摩尔比为0.2-1.0)。在最佳实验条件下,通过考察催化臭氧氧化HA的活性,筛选出最佳的Ti/Ce掺杂比为1/0.8;通过比较单独臭氧氧化、TiO_2催化臭氧化、Ti-Ce(1/0.8)复合物催化臭氧化中臭氧利用率、表观分子量分布,发现Ti-Ce(1/0.8)复合物催化臭氧化中臭氧的利用率最高,达到62%,并且其催化降解HA和中间产物的效果最好,表明Ti-Ce(1/0.8)复合物具有高的催化活性;在催化臭氧降解HA过程中,通过研究均相和异相反应的动力学表明:均相和异相反应的速率分别为0.054 min-1及0.066 g·L-1·min-1;此外,异相反应对污染物去除贡献率在所有pH下均小于50%,说明催化降解HA的反应主要发生在本体溶液中。(3)采用共混法制备了不同含量Ti-Ce(1/0.8)复合物的催化膜,通过SEM表明Ti-Ce复合物成功共混于催化膜,Ti-Ce(1/0.8)复合物添加量为2%时,催化膜的孔隙率和平均孔径均增大;Ti-Ce(1/0.8)复合物的添加影响着膜的亲疏水性、纯水通量、截留率、平均孔径及孔隙率;通过接触角测定表明:Ti-Ce复合物添加量为2%时,催化臭氧化膜的接触角降低的最为明显,继续增加复合物添加量没有引起接触角显著降低;通过与PVDF纯膜、1%Ti-Ce(1/0.8)/PVDF膜和3%Ti-Ce(1/0.8)/PVDF膜相比,2%Ti-Ce(1/0.8)/PVDF膜的纯水通量增加最明显,达到32.61 L·m-2·h-1,但其截留率有所降低。(4)对催化臭氧响应膜处理HA的研究表明:催化臭氧化响应膜对HA和溶液TOC的去除率大小顺序为:2%Ti-Ce(1/0.8)/PVDF膜+O33%Ti-Ce(1/0.8)/PVDF膜+O_31%Ti-Ce(1/0.8)/PVDF膜+O3PVDF膜+O_3。PVDF膜的通量衰减最严重,为初始值的31%,2%Ti-Ce(1/0.8)/PVDF膜的通量明显提高,衰减量仅为初始量的23%。进一步研究表明,与纯膜相比,2%Ti-Ce(1/0.8)/PVDF膜的可逆污染阻力和不可逆污染阻力分别降低了37%和58%,表明2%Ti-Ce(1/0.8)复合物强化了膜孔中的催化臭氧化反应,具有自清洁膜的特征。
[Abstract]:Humic acid (humic acid) is widely distributed in surface water. It is widely concerned about how to effectively remove HA from water because it becomes brown, reacts with metal or organic compounds to form complex substances and reacts with active chlorine to form disinfection by-products. Membrane separation technology has been widely concerned in the process of HA treatment. However, membrane fouling is the bottleneck to the development of this technology. Catalytic ozonation can effectively degrade organic matter in water, but there are some problems such as catalyst loss and recovery in the process of catalytic degradation. The catalytic ozonation response membrane was prepared by loading the catalyst with strong catalytic ozone ability onto the membrane. The membrane separation efficiency was improved by the coupling of membrane separation and catalytic ozonation technology, and the loss of catalyst was solved. Recovery and membrane fouling. In this study, a catalytic ozone responsive membrane with high catalytic activity was developed. The results are as follows: (1) Nano-TiO-2 was prepared by sol-gel method, and the optimum experimental conditions for the catalytic ozonation of HA were optimized by response surface method. The optimum experimental conditions are as follows: calcination temperature is 565 鈩，

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