CdS/TiO2光催化去除水体中氨氮的研究

利用溶胶-凝胶法制备了不同比率的CdS掺杂TiO₂复合纳米颗粒催化剂,并用其进行了紫外光、日光灯和太阳光全波长光催化去除水中氨氮和其它形式无机氮的对比实验研究.考察了添加催化剂的量、CdS复合比率、有氧化态氮亚硝酸根或硝酸根与氨氮共存时光催化脱氮的耦合效果、外加光源等对脱除氨氮效率的影响,并研究了后3个因素对CdS光腐蚀程度的影响.对于氨氮初始质量浓度为50mg/L的模拟废水,在通空气搅拌条件下,n(CdS):n(TiO₂)=0.17的CdS/TiO₂催化剂脱氮效果最佳,此时经紫外光照2h后脱除氨氮效率达41.5%.实验结果表明:复合催化剂中CdS的含量是影响光催化活性和光腐蚀程度的重要因素.

Removing Ammonia Nitrogen from Water Using CdS/TiO2 Photocatalyst

CdS/TiO2 composite photocatalysts were prepared by using a sol-gel method.The catalysts were tested in removing ammonia pollutant in water by photocatalysis under the illumination of different light sources (UV,solar light,fluorescent lamp,indoor natural light).The effects of the CdS to TiO2 ratio,catalyst concentration,addition of nitrite/nitrate on ammonium removal were also investigated.The test results showed that the optimum ratio of n(CdS)to n(TiO2) is 0.17∶1,with 50 mg/L ammonium in water,the removal of NH4-N reaches 41.5% after 2 hours of irradiation.When purged with nitrogen gas,both ammonium nitrogen and nitrate/nitrite can be simultaneously removed.It is concluded that the ratio of n(CdS)∶n(TiO2) is important for the synergetic photocatalytic activity and the extent of photo-corrosion of CdS was reduced in the mixed composite catalyst CdS/TiO2.