SiW_(12)/NaY固体杂多酸催化剂的微波合成及LAS降解性能研究

Studies on Synthesis of Silicotungstic Acid Supported on NaY Zeolite Catalysts by Microwave Radiation and Their Degradation Properties for Linear Alkylbenzene Sulfonates

以微波辐射方法合成了NaY分子筛、二氧化锆和二氧化钛不同载体负载磷钨酸、磷钼酸、硅钨酸不同杂多酸的固体酸催化剂,用Hammett指示剂与紫外光谱相结合的方法测定固体杂多酸催化剂的酸度,发现SiW12/NaY酸性最强。单因子实验研究了制备条件对SiW12/NaY固体酸催化剂酸活性的影响,正交试验探讨了影响SiW12/NaY固载杂多酸活性四个因素的大小顺序为:烧结时间>烧结功率>浸泡浓度>浸泡时间,催化剂制备的优化条件为:硅钨酸水溶液浓度0.10 mol/L,浸泡时间30 h,微波功率750 W,烧结时间40 min,制得的催化剂酸度最高。应用0.050 g SiW12/NaY固载硅钨酸催化剂降解150 mg/L,pH值为3的十二烷基苯磺酸钠(LAS)溶液60 min,LAS降解率由76%提高到94.5%。固载硅钨酸催化剂对LAS的降解率明显提高。

Solid acid catalysts, such as H3PW12O40, H3 PMo12 O40 and H3PW12O40 supported on NaY zeolite, zirconium dioxde and titanium dioxed, were synthesized by microwave radiation. The acid strength of the catalysts was determined by Hammett indication method and UV spectroscopy. The acid strength of H3PW12O40/NaY zeoltite is the highest. The effect of preparation conditions on the acid strength of SiW12/NaY was investigated. It was found that the effect of the four main factors was in the order of agglomeration time 〉 agglomeration power 〉 immersing concentration 〉 immersing time, and the highest acid streugth was obtained when the aqueous solution concentration of H3SiW12O40 was 0.10 mol/L, the immersing time was 30 h, the microwave agglomeration power was 750 w, and the agglomeration time was 40 min. The catalytic degradation activity for linear alkylbenzene sulfonates （LAS） was measured and the degradation rate of LAS increased from 76% to 94.5% when SiWn/NaY was 0.050 g, the concentration of LAS was 150 mg/L, the pH was 3, and the degradation time was 60 min. The supported acid catalyst was more active than pure NaY zeolite.