非均相催化臭氧氧化催化剂活性组分溶出问题研究

Heterogeneous catalytic ozonation, a novel alternative to traditional AOPs, has received wide interest as a promising technology for removing refractory organic pollutants in waters. It combines ozonation with the solid catalysts to mineralize refractory organic compounds in waters at an ambient temperature. But the leaching problem of active components in catalyst, which may result in the waters' secondary pollution, has become a key point affecting its industrial-scale application. So this project is planning to solve the leaching problem of active components in heterogeneous catalytic ozonation, its focus on: (1) the preparation of transitional metal (Fe or Co et al.) incorporated SBA-15 (Me-SBA-15) mesoporous molecular sieve with high catalytic activity and stability; (2) researching or discussing the leaching mechanism of active components in Me-SBA-15 mesoporous molecular sieve prepared by direct synthesis method and post-synthesis including grafting and impregnation method, and why Me leaching of Me-SBA-15 mesoporous molecular sieve prepared by direct synthesis method is greatly reduced compared with that of transitional metal loaded SBA-15 (Me/SBA-15); (3) the comparison of the active components' leaching mechanism, catalytic activity and stablity between Me-SBA-15 and Me-MCM-41 mesoporous molecular sieves; (4) the effects of active components' leaching in catalyst on the safety of water quality. This project will provide a kind of simple and feasible method for solving the leaching problem of active components in heterogeneous catalytic ozonation, and realizability for the application of both heterogeneous catalytic ozonation and SBA-15 mesoporous molecular sieve in water treatment.

非均相催化臭氧氧化技术用于修复水体污染已引起广泛关注，只需在成熟的臭氧氧化工艺中加入适量催化剂；但催化剂活性组分溶出及其引起的水体二次污染现象，已成为影响该技术应用的关键问题之一。因此本项目拟开展解决非均相催化臭氧氧化催化剂活性组分溶出问题研究。重点在于：（1）过渡金属Fe或Co等活性组分嵌入SBA-15介孔分子筛骨架的高效稳定性催化剂研制；（2）探明不同合成方法制备的过渡金属改性SBA-15介孔分子筛催化剂活性组分溶出机制及采用直接合成法较浸渍法制备催化剂活性组分溶出大为减少的原因；（3）过渡金属嵌入SBA-15和MCM-41两种介孔分子筛催化剂活性组分溶出机制、活性和稳定性比较研究；（4）催化剂活性组分溶出对催化臭氧氧化出水水质安全性的影响。本项目研究为解决非均相催化臭氧氧化催化剂活性组分溶出问题提供一种简便、易行的方法，有望为该技术及SBA-15介孔分子筛在水处理中应用提供可实现性。

本项目按照计划以九水硅酸钠为硅源（有机硅源）采用一步水热合成法制备出Fe嵌入SBA-15（Fe-SBA-15）分子筛骨架的改性催化剂以及Fe嵌入改性MCM-41（Fe-MCM-41）介孔分子筛催化剂等，优化了制备工艺； X射线粉末衍射（XRD）、等表征结果表明，通过一步合成法制备的Fe-MCM-41或Fe-SBA-15等改性催化剂具有较规则的六方孔道结构及较大的比表面积，且Fe成功进入了分子筛骨架。Fe的嵌入使MCM-41和SBA-15得比表面积均有一定程度减少，但仍然较比浸渍法制备的Fe负载催化剂大。与浸渍法制备的负载型催化剂相比，嵌入活性组分改性后的催化剂具有非常好的稳定性，在催化臭氧氧化过程中活性组分溶出大为减少，改善了出水水质，在催化剂重复使用2次后水体中几乎检测不出活性组分的溶出量；说明采用一步水热合成法制备出Fe嵌入SBA-15分子筛骨架的改性催化剂具有很好的稳定性，是一种有前景臭氧氧化催化剂。. 在该项目支持下，已在国外重要学术刊物上发表研究论文4篇（均为SCI刊源）；其中，2篇发表在Chemical Engineering Journal上（包括接受1篇）、1篇发表在Journal of Molecular Catalysis A: Chemical上、1篇发表在Separation and Purification Technology上；另外有会议论文1篇。该项目已经培养出2名全日制硕士研究生，他们已于2013年7月毕业。此外，项目主持人按计划与2名从事该项目的全日制硕士研究生一起2于2013年9月在贵阳参加了第七届全国环境化学大会。因此项目负责人认为课题组圆满完成了该项目的主要研究内容。