非均相类Fenton催化剂的制备及其降解橙黄Ⅱ性能研究

发布时间：2018-03-16 08:54

  本文选题：非均相类Fenton　切入点：CuFe_2O_4　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：染料废水成分复杂、色度高、有机物含量高、可生化性差,属于典型的难降解有机废水,对环境的危害极大,因而寻求一种经济有效的处理方法是水污染处理的一个难题。高级氧化技术中的Fenton反应具有氧化性强、反应速度快等优点,因而广泛用于染料废水处理中。但传统Fenton反应需在较强酸性条件下进行,且H202利用率不高,反应后会产生大量铁泥,出水颜色发黄,从而引发二次污染等问题。研究发现,非均相Fenton反应在一定程度上可解决传统均相Fenton反应存在的问题,同时可实现催化剂回收利用,具有良好的应用前景。基于SO4·-的过硫酸盐活化是近年发展起来的一种类Fenton反应体系,具有反应条件温和、操作简单、自由基利用率较高等优点,可进一步解决传统Fenton反应存在的问题,因而成为类Fenton体系研究的又一热点。本文采用柠檬酸辅助溶胶-凝胶法制备了CuFe2O4、CuO和Fe203三种非均相催化剂,在常温常压条件下催化K2S208氧化降解橙黄Ⅱ。优化催化剂制备条件,并对所制备催化剂进行表征。实验考察了反应影响因素对催化降解性能的影响,对催化剂稳定性进行分析,初步探讨了催化剂催化机理,以期对染料废水的有效处理提供一种新的理论依据和技术支持。考察焙烧温度和焙烧时间对CuFe2O4催化活性的影响,确定其焙烧温度400℃,焙烧时间2h,在此温度下得到CuO和Fe203的最佳焙烧时间为2h. XRD和EDS结果表明,所制备催化剂确为CuFe2O4、CuO和Fe2O3、SEM和BET分析可知,实验制备CuFe2O4、CuO和Fe203平均粒径较小,依次分别为52nm、67nm、139nm。实验得到溶液初始pH值、K2S208投加量和橙黄Ⅱ初始浓度是影响催化降解效果的重要因素。其中,CuFe2O4的催化降解效果最好,CuO次之,Fe203最差。当橙黄Ⅱ初始浓度20mg/L,催化剂浓度均1g/L, K2S2O8浓度均0.5g/L,初始pH均5.3,反应180min后,三个反应体系对橙黄Ⅱ的色度去除率和TOC去除率依次分别为98%和62%、97%和50%、24%和21%。对CuO/K2S2O8和CuFe2O4/K2S2O8反应体系的催化降解机理进行研究,得出反应体系中起催化作用的主要是Cu。CuO用作催化剂,酸性条件下以Cu2+的均相催化为主,辅以非均相催化,增大pH至弱酸性或碱性时,以非均相催化为主；CuFe2O4用作催化剂,在各pH范围内以非均相催化为主,增大反应pH时,催化效果更好。自由基捕获实验得出反应体系中主要活性中间体为SO4·-和HO·,酸性条件以S04.-为主,碱性条件以HO·为主。催化剂稳定性分析可知,实验制备催化剂用到K2S2O8反应体系时,CuFe2O4的催化活性和稳定性最好,CuO次之,Fe2O3最差,表明实验制备CuFe2O4是一种很有潜能的非均相类Fenton催化剂。
[Abstract]:Dye wastewater is a typical refractory organic wastewater with complex composition, high chromaticity, high organic content and poor biodegradability, which is harmful to the environment. Therefore, it is a difficult problem for water pollution treatment to seek an economical and effective treatment method. The Fenton reaction in advanced oxidation technology has the advantages of strong oxidation, fast reaction speed, and so on. So it is widely used in dye wastewater treatment, but the traditional Fenton reaction needs to be carried out under the condition of strong acidity, and the utilization ratio of H202 is not high. After the reaction, a large amount of iron sludge will be produced and the effluent color will turn yellow, thus causing secondary pollution and so on. The heterogeneous Fenton reaction can solve the problem of traditional homogeneous Fenton reaction to some extent, and can realize the recovery of catalyst at the same time. Persulfate activation based on SO4 路- is a kind of Fenton reaction system developed in recent years. It has the advantages of mild reaction conditions, simple operation, high free radical utilization rate and so on. It can further solve the problem of traditional Fenton reaction and become another hotspot in the study of Fenton like system. In this paper, three kinds of heterogeneous catalysts, CuFe2O4CuO and Fe203, were prepared by citric acid assisted sol-gel method. The oxidation degradation of orange by K2S208 was studied under normal temperature and atmospheric pressure. The preparation conditions of the catalyst were optimized, and the catalyst was characterized. The influence of reaction factors on the catalytic degradation performance was investigated experimentally, and the stability of the catalyst was analyzed. The catalytic mechanism of catalyst was preliminarily discussed in order to provide a new theoretical basis and technical support for the effective treatment of dye wastewater. The effects of calcination temperature and time on the catalytic activity of CuFe2O4 were investigated, and the calcination temperature was determined at 400 鈩，

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