g-C_(3)N_(4)-Bi_(2)WO_(6)/沸石复合光催化材料的制备及氨氮降解研究

Study on Preparation of g-C_(3)N_(4)-Bi_(2)WO_(6)/Zeolite Composite Photocatalytic Materialand Its for Ammonia Nitrogen Degradation

利用高温法制备g-C3N4,通过水热法分别制备g-C_(3)N_(4)-Bi_(2)WO_(6)光催化剂及沸石分子筛,以沸石分子筛为载体,利用简单研磨共混煅烧法制备g-C_(3)N_(4)-Bi_(2)WO_(6)/沸石复合光催化剂。通过SEM、XRD、BET对复合光催化剂的结构性质及物相组成进行表征,同时以40mg/L氨氮为目标污染物,研究了复合催化剂吸附、光催化及循环稳定等性能并确定了使用的最佳投料比,最后对作用的活性物质进行分析。结果表明,对Bi_(2)WO_(6)进行掺杂及负载化改性后,比表面积及总孔容分别提高了217.1m^(2)/g、0.497cm^(2)/g,对氨氮吸附能力明显增强,达到7.92mg/g;以千分之一投料,光照10h,光催化可降解52.2%的氨氮,较改性前提高了35.8%,且在循环使用七次后,降解率仍为44%,具有良好的稳定性;降解中主要的活性物质为电子空穴(h^(+))与超氧自由基(·O2^(-))。

g-C3N4 was prepared by high temperature method,g-C_(3)N_(4)-Bi_(2)WO_(6) photocatalyst and zeolite molecular sieve were prepared by hydrothermal method,g-C_(3)N_(4)-Bi_(2)WO_(6)/zeolite composite photocatalyst was prepared by simple grinding blending and calcination method using zeolite molecular sieve as carrier.The structural properties and phase composition of the composite photocatalyst were characterized by SEM,XRD and BET.At the same time,taking 40 mg/L ammonia nitrogen as the target pollutant,the adsorption,photocatalysis and cycle stability of the composite catalyst were studied,and the optimal feed ratio was determined.Finally,the active materials were analyzed.The results showed that,after doping and loading modification of Bi_(2)WO_(6),the specific surface area and total pore volume increased by 217.1 m^(2)/g and 0.497 cm^(2)/g,respectively,and the adsorption capacity of ammonia nitrogen was significantly enhanced,reaching 7.92 mg/g.Feeding at one in a thousandth,under the light of 10 h,it could degrade 52.2% of ammonia nitrogen,which was 35.8% higher than before modification,and after seven times of recycling,the degradation rate was still 44%,which had good stability.The main active materials in the degradation process were electron holes(h^(+))and superoxide radicals(·O2-).