混合法制备天然沸石基臭氧催化剂的性能与表征

Performance and characteristics of natural zeolite-based ozone catalysts prepared by the mixing method

  • 摘要: 臭氧催化剂生产成本高,目前已成为限制臭氧催化氧化技术工程应用的重要因素之一。采用廉价易得的天然沸石粉作为催化剂载体原材料,以Cu为活性组分,通过混合法制备催化剂并测定其性能,探究天然沸石基臭氧催化剂的最佳制备条件,并对催化剂进行了形貌结构表征。结果表明:使用快脱粉作为黏结剂,添加量为10%(质量浓度)并在600 ℃焙烧制备的天然沸石基臭氧催化剂综合性能最佳,当反应30 min时,其对石化废水COD吸附去除率为37.27%;利用吸附饱和的催化剂对石化废水进行臭氧催化氧化,反应30 min时,COD去除率为43.48%,三维荧光图谱中区域Ⅰ~Ⅴ荧光类物质去除率分别达76.68%、82.52%、86.83%、80.16%及79.38%。表征结果表明,最佳天然沸石基臭氧催化剂形貌结构与沸石本身差异不大,比表面积仅增加1.75%,但孔容与平均孔径较天然沸石分别增大23.40%与21.48%,有利于提高污染物吸附和臭氧催化氧化去除效果;SEM-EDS结果表明,催化剂活性组分Cu在沸石载体中负载均匀,不仅提高了其催化活性,也有利于维持催化剂的稳定性。从生产成本上来看,沸石催化剂较氧化铝催化剂低3 000元/t,经济效益显著。通过混合法制备的天然沸石基臭氧催化剂具有优异的催化活性,能够高效处理石化二级出水,且可以大幅降低催化剂生产成本,在催化剂制备、工业废水深度处理和工程化推广等方面具有一定的潜力。

     

    Abstract: The high production cost of ozone catalysts has now become one of the important factors limiting the engineering application of ozone catalytic oxidation technology. The catalyst was prepared by mixing method using cheap and easily available natural zeolite powder as the raw material of catalyst carrier and Cu as the active component. Its performance was measured to investigate the optimal conditions for preparing natural zeolite-based ozone catalysts, and the catalysts were characterized in terms of morphology and structure. The results showed that the natural zeolite-based ozone catalysts prepared by using quick release powder as binder, adding 10% (mass fraction) and roasting at 600 ℃ had the best overall performance, and the adsorption and removal rate of COD from petrochemical wastewater was 37.27% when the reaction was for 30 min. The ozone catalytic oxidation of petrochemical wastewater was carried out by using adsorption-saturated catalysts, the removal rate of COD was 43.48% when the reaction was for 30 min, and the removal rates of fluorescent substances in the three-dimensional fluorescence spectra from region Ⅰ to Ⅴ reached 76.68%, 82.52%, 86.83%, 80.16% and 79.38%, respectively. The characterization results showed that the best natural zeolite-based ozone catalyst had little difference in morphology and structure with the zeolite itself, and the specific surface area only increased by 1.75%. However, the pore volume and the average pore size increased by 23.40% and 21.48%, respectively, compared with that of the natural zeolite, which was conducive to the enhancement of the pollutant adsorption and ozone catalytic oxidation and removal effect. The SEM-EDS results showed that the active component of the catalyst, Cu, was uniformly loaded in the zeolite carriers, which not only improved the catalytic activity, but also helped maintain the stability of the catalyst. In terms of production cost, the zeolite catalyst was 3 000 yuan/t lower than the alumina catalyst, with significant economic benefits. The results show that the natural zeolite-based ozone catalysts prepared by the hybrid method have excellent catalytic activity, are capable of efficiently treating petrochemical secondary effluent, and can significantly reduce the production cost of the catalysts, which has certain potentials in the preparation of catalysts, the deep treatment of industrial wastewater, and the engineering promotion.

     

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