【作者】 苏营营；

【导师】 朱校斌；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 环境科学， 2009， 博士

【摘要】 工业的高速发展使地球上有限的水资源受到日益严重的污染,去除水中的有毒、有害化学物质已成为环保领域的一项重要工作。纳米材料与技术的开发应用为实现高效、低成本的水处理开辟了新的途径。本课题组开发的纳米-亚纳米功能新材料(生态宝)可用作养殖生态环境改良剂,它对“三氮”、硫化物、CODCr、BOD5、重金属等有害物质具有很好的去除能力。生态宝用于养殖幼参,有显著的促生长、增加成活率的作用。生态宝用于养殖对虾,对虾体内重金属含量有明显降低。以粉末状P25型纳米TiO2为光催化剂,系统的研究了它对染料AB80的光催化降解。在紫外光照射下,光催化反应75min,染料AB80溶液完全脱色,光催化反应135min,染料溶液完全矿化;AB80的光催化脱色反应遵从准一级反应动力学;催化剂的最佳剂量为1.0g/L。AB80在TiO2颗粒表面的吸附符合Langmuir方程式,随着pH值的增加吸附量迅速减少;pH值在反应中起着重要的作用,碱性溶液中的反应速度比酸性溶液的大,pH=10.0初始反应速度最大;电子捕获剂(H2O2)的加入能够显著的提高反应速率,H2O2浓度为5mmol/L时,反应速度变为原来的2.78倍。以硅藻土为载体,采用溶胶-凝胶法制备了负载型的纳米TiO2,SEM分析结果表明,TiO2的包覆量对负载光催化剂的形貌有很大影响,TiO2包覆量较低(14.5%)的复合物无团聚现象发生。XRD分析结果表明,所制备的TiO2为锐钛矿和金红石混晶型,平均粒径11nm。FT-IR分析结果表明,TiO2和硅藻土之间没有生成化学键。以染料AB80和B-2BF为模型污染物,利用制备的光催化剂复合物进行了吸附-光催化试验,结果表明,TiO2包覆量为14.5%的复合物具有较高的吸附-光催化活性,对模型污染物的降解效果好于德国Degussa公司的商品纳米P25-TiO2。溶液pH对TiO2/硅藻土复合物光催化活性影响很大,弱酸性条件有利于反应的进行。TiO2/硅藻土对实际印染废水有较好的降解效果,试验条件下,废水光催化反应3.5h,色度去除率为100%。研究了液固多相光催化反应的催化剂失活原因及再生手段,提出TiO2/硅藻土复合物再生的方法为酸洗和高温烧结。对于模拟印染废水来说,光催化剂重复使用对光催化活性几乎没有影响,重复使用15次后,催化活性仅降低了12%。而对实际印染废水来说,重复使用对光催化活性有影响,光催化剂复合物重复使用7次后,催化活性降低了41%。TiO2/硅藻土复合光催化剂成本低,简便易行,光催化效果好,有望在环境污染物治理中得到广泛的应用。采用CuCl水解法制得了硅藻土负载的纳米Cu2O,并利用XRD、SEM等手段对其进行表征。研究了负载的纳米Cu2O对B-2BF和AB80染料废水的光催化降解,发现纳米Cu2O经过负载后,团聚减少,分散性好,对染料废水的光催化降解效率成倍增长。纳米Cu2O包覆量为31.3%的光催化剂复合物光催化活性最好,其光催化效率是纯的Cu2O的6倍。负载的纳米Cu2O可以有效的利用太阳光进行光催化反应,而且太阳光下纳米Cu2O的光催化活性比纳米TiO2的强。太阳能是取之不尽、用之不竭的清洁能源,利用太阳能来处理染料废水成本低、无污染,是一种非常有发展前景的环境治理新技术。pH 5-pH 7是负载纳米Cu2O光催化降解B-2BF的最佳反应范围。负载的纳米Cu2O光催化剂有较好的稳定性,重复使用8次以后,其脱色率仍能达到75%以上。更多还原

【Abstract】 With the development of industry, the finite water resources suffers increasingly serious pollution. Eliminate the toxic and hazardous substances in water become an important task for environmental protection. The exploitation and application of nanomaterials and nanotechnology supply new way for high efficiency and low cost water treatment.The new nano-subnano function material (Ecosystem Improved Agent) developed by our team can get rid of“three-nitrogen”, sulfuret, CODCr, BOD5 and heavy metal in water. The Ecosystem Improved Agent can also promote the sea cucumber growth, increase the survival percentage of sea cucumber and decrease the heavy metal content of prawn.The photocatalytic degradation of dye AB80 was investigated in aqueous with pulverous P25-TiO2. The dye was decolorized in 75 min and mineralized completely in 135 min under UV-light. The decoloration reaction of the AB80 followed pseudo-first order kinetics and the catalyst loading of 1.0 g/L was used as the optimal dosage. The adsorption of AB80 onto TiO2 was found to be well expressed by the Langmuir equation. With the increased of pH, the adsorptive capacity decreased quickly. It was found that the degradation rate of AB80 was affected intensively by the pH of the solution. High pH value was beneficial to the photocatalytic degradation reaction. The initial rate was biggest when the pH=10.0. Proper dosage of the electron accepters H2O2 could enhance the reaction rate; the reaction rate was 2.78 times quicker than control when the concentration of H2O2was 5mmol/L.Diatomite supported nano-TiO2 composite was prepared by sol-gel method. SEM analysis indicated that the coated TiO2 amount affected the pattern of photocatalyst composites. The low TiO2 content (14.5%) had not reunion. XRD analysis indicated that the TiO2 coated on the surface of diatomite was the mixed crystal of anatase and rutile, the average particle size is 11 nm. FT-IR analysis indicated that no chemical bond generated between TiO2 and diatomite, the binding force was van der waals force. The adsorptive-photocatalytic activity of composite was studied using dye AB80 and B-2BF as model pollutant. The results indicated that composite coated 14.5% TiO2 expressed the best adsorptive-photocatalytic activity, and its decolorizing rate for model pollutant was larger than that of the Degussa P25-TiO2. The photocatalytic activity of TiO2/diatomite was affected intensively by the pH of the solution. Weakly acidic condition was beneficial for the reaction. The actual dye wastewater can be well degraded by TiO2/diatomite, and the decolorization ratio was 100% after irradiation of 3.5h under the experiment condition. The photocatalyst inactivated reason and regenerated methods were studied. Regenerative method for the TiO2/diatomite was acid washing and high temperature burning. The repetitive-use of photocatalyst almost didn’t affect the activity for the model dye wastewater, the photocatalytic activity reduced only 12% after repetitive-use the catalyst for 15 times. But for the actual dye wastewater, the repetitive-use of photocatalyst affected the activity, the photocatalytic activity reduced 41% after repetitive-use the catalyst for 7 times. For the TiO2/diatomite composite, the cost was low, synthesis method was simple and photocatalytic effect was good. It is expect that the composite would be widely used in environmental pollution control.Copper oxide nano-particles immobilized on diatomite were prepared by hydrolyzation of CuCl. The obtained products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The visible light photocatalytic degradation of dye AB80 and B-2BF with immobilized Cu2O was studied. The reunion of Cu2O decreased after immobilization, and the photocatalytic activity increased greatly. The optimal Cu2O content was 31.3% for the photocatalyst composite whose photocatalytic activity was 6 times as great as pure Cu2O. The nano-sized Cu2O can make good use of sunlight for photocatalytic reaction, furthermore, the photocatalytic activity of Cu2O was better than TiO2 under sunlight. Solar energy was free, and its supplies were unlimited. The cost of sunlight photocatalitic dye wasterwater was low and the process hadn’t any contamination, so sunlight photocatalisis would be a promising technique for environmental management. The range of pH 5-pH 7 was optimum for the photocatalysis of B-2BF. The stability of catalyst was good, after repetitive-use the catalyst for 8 times, the photocatalytic degradation rate could remain above 75%.更多还原