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改性TiO2协同H2O2光催化降解间硝基苯磺酸钠的研究

Photocatalytic Degradation of Nitrobenzene Sulfonate by Modified Titanium Dioxide and Hydrogen Peroxide

【作者】 李梅

【导师】 李继;

【作者基本信息】 哈尔滨工业大学 , 环境科学与工程, 2011, 硕士

【摘要】 间硝基苯磺酸钠(3NBSAS)使用广泛、结构稳定、毒性较大,对水体污染大。利用TiO2光催化降解有机物,具有催化材料来源方便、无毒无害、光电性能优良等特点。本文旨在通过对TiO2进行负载、掺杂,在H2O2协同下,可见光催化降解以3NBSAS为代表的生物难降解有机物质,同时保证催化剂具有良好的稳定性能和可回收性能。采用溶胶-凝胶法制备了以铁掺杂的TiO2光催化剂,通过正交实验,考察影响催化剂性能的主要参数。结果发现:当钛酸丁酯:无水乙醇:去离子水:硝酸的体积比为20: 120: 12: 1、铁的掺杂比为1.25wt%、煅烧温度为500℃时,催化剂性能最好,反应2h,对3NBSAS的去除率为67.2%;浓度范围为0100mg/L时,催化去除效果较好,当3NBSAS浓度为25mg/L时,pH为6,H2O2量为0.8mL/L,催化剂量为1.2g/L,反应2h,去除率为69.3%。将溶胶-凝胶法制备Fe/TiO2光催化剂负载于活性炭上,结果表明:负载后催化剂活性得到提高,当TiO2与活性炭的配比为0.52时,负载催化剂活性最高,反应2h,此时3NBSAS的去除率达到81.4%。循环使用五次后,该负载催化剂可回收率均高于97%,3NBSAS的去除率均高于80%。为实现催化剂在可见光下的活性,对负载催化剂进行S、Ce掺杂,掺Ce的载体催化剂对可见光没有响应,而掺S的载体催化剂对可见光有响应,当S的配比为1.5%时,反应4h,催化剂在可见光下对3NBSAS(25mg/L)的去除率可达到45.5%。

【Abstract】 3-nitro-benzenesulfonic aci sodium (3NBSAS) is a widely used chemical intermediate. Due to its stability、toxicity and severe environmental pollution to the water body, the removal of 3NBSAS has become an increasingly hot topic. Photocatalytic methods using TiO2 is favovered in the degradation of organic matter for its poisonlessness, harmlessness, excellent photoelectricity properties and high avalability of catalytic mateiral. This paper aims to remove 3NBSAS using the doped and loaded TiO2 under visible light while ensuring the stability and recyclablity of the catalyst.In this paper, Fe/TiO2 photocatalyst is prepared with sol-gel method. The influence of ethanol, deionized water, nitric acid, iron doping and calcination temperature on catalyst performance was examined by gorthogonal experiments. It was found that the catalyst had the best performance when the volume ratio of butyl titanate: ethanol: deionized water: nitric acid was 20:120:12:1.0, iron doped ratio was 1.25wt%, and calcination temperature was 500℃. The substrate removal rate was 67.2% under above conditions. The effect of reaction conditions, including solution pH, H2O2 volume ,amount of catalyst, substrate concentration, reaction time on catalyst performance was also considered. The results showed that the substrate concentration was the key factor. The catalyst removal efficiency was satisfactory when substrate concentration was less than 100mg/L. The substrate removal rate was 69.3%, when the substrate concentration was 25mg/L, pH was 6, H2O2 was 0.8mL/L, and catalyst amount was 1.2mg/L.Fe/TiO2 was loaded on the activated carbon with sol-gel method. The results showed: the photocatalytic activity had been increased after loading. The removal rate of 3NBSAS is 81.4%, with a 14.2% increacement, when the proportion of TiO2 and activated carbon is 0.52. After 5 times catalyst recycle, the recyclable rates of catalyst were higher than 97% and the substrate removal rates were all higher than 80%.Then the loaded catalyst was doped with S, Ce, for higher catalytic activity under visible light. The one doped with S responsed to the visible light, but the Ce-doped catalyst did not. The removal rate of 3NBSAS (25mg/L) was about 45.5% with 1.5wt% S.

【关键词】 TiO2H2O23NBSAS活性炭可见光
【Key words】 TiO2H2O23-nitro-benzenesulfonic aci sodiumActivated carbonVisible light
  • 【分类号】X703.1
  • 【下载频次】99
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