CaF2(Tm3+)/TiO2光催化剂的制备及其对海水养殖废水中氨氮的降解研究

采用溶胶凝胶法制备了CaF2(Tm^3+)/TiO2光催化剂,并用扫描电子显微镜(SEM),X射线衍射(XRD)等手段对其晶型、粒径以及形貌进行了表征。对比分析了可见光下纯TiO2和CaF2(Tm^3+)/TiO2光催化剂对模拟海水养殖废水中氨氮的降解情况。结果表明,CaF2(Tm^3+)/TiO2光催化剂粒径基本在15~25nm,晶型为锐钛矿型;CaF2(Tm^3+)的掺杂提升了TiO2对可见光的利用率,使光催化效率大幅提升;CaF2(Tm^3+)/TiO2光催化剂对海水养殖废水中氨氮的适宜光催化降解条件为CaF2(Tm3+)掺杂比10%(摩尔分数)、CaF2(Tm^3+)/TiO2光催化剂投加量0.6g/L、氨氮初始质量浓度100mg/L、H2O2质量浓度0.3g/L、pH=10.0、反应时间2.0h,在此条件下,氨氮去除率可达近90%;光催化降解氨氮的最终降解产物为N2,处理比较彻底。

Preparation of CaF2(Tm3+)/TiO2 photocatalyst and its performance for treatment of ammonia nitrogen in marine cultured wastewater

The CaF2(Tm^3+)/TiO2 photocatalyst was prepared by sol-gel method.The crystal form,morphology and particle size of CaF2(Tm^3+)/TiO2 photocatalyst were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).The photocatalytic degradation of ammonia nitrogen by pure TiO2 and CaF2(Tm^3+)/TiO2 photocatalyst was compared in visible light.The results showed that the particle size of CaF2(Tm^3+)/TiO2 photocatalyst was ranged 15-25 nm,and its crystal form was anatase type.The doping of CaF2(Tm^3+)could enhance the utilization of visible light by TiO2,which greatly improved the photocatalytic efficiency.The suitable reaction conditions for photocatalytic degradation were as follows:the CaF2(Tm^3+)doping ratio was 10%(molar ratio),the dosage of CaF2(Tm^3+)/TiO2 photocatalyst was 0.6 g/L,the initial mass concentration of ammonia nitrogen was 100 mg/L,the mass concentration of H2O2 was 0.3 g/L,pH was 10.0,reaction time was 2.0 h.Under this condition,the ammonia nitrogen removal rate could reach nearly 90%.The final photocatalytic degradation product of ammonia nitrogen was N2,which indicated that the degtadation of ammonia nitrogen was complete.