改性纳米TiO_(2)的制备及光催化降解重金属废水的研究

Preparation of modified nano-TiO_(2)and photocatalyticdegradation of heavy metal wastewater

以钛酸丁酯为钛源,硝酸铈为改性剂,通过溶胶-凝胶法制备了不同稀土Ce掺杂量(0,0.3%,0.6%和0.9%(摩尔分数))的改性纳米TiO2粒子。采用XRD、SEM、UV-Vis、PL和光催化测试等,研究了不同稀土Ce掺杂量对纳米TiO2粒子物相结构、微观形貌、光谱性能和光催化性能的影响。结果表明,制备出的纳米TiO_(2)粒子均为锐钛矿相,且结晶度较高;掺入稀土Ce后,纳米TiO_(2)粒子的形貌逐步变为规则的球形,晶粒得到了细化,当稀土Ce的掺杂量为0.6%(摩尔分数)时,TiO_(2)粒子的晶粒尺寸最为规则,分布最为均匀;稀土Ce掺杂的纳米TiO_(2)粒子的吸收边带发生了红移,吸收边带增大,稀土Ce的掺杂有效抑制了电子-空穴对的复合;稀土Ce改性纳米TiO_(2)粒子对重金属废水中Cr(Ⅵ)的降解效率得到了明显提高,当稀土Ce的掺杂量为0.6%(摩尔分数)时,纳米TiO_(2)在180 min时的降解效率最高为92.7%,相比纯纳米TiO_(2)的降解效率,提高了166.4%。综合分析可知,稀土Ce的最佳掺杂比例为0.6%(摩尔分数)。

Using butyl titanate as titanium source and cerium nitrate as modifier,modified nano-TiO_(2) particles with different Ce doping contents(0%,0.3 mol%,0.6 mol%,0.9 mol%)were prepared by sol-gel method.The effects of different rare earth Ce doping on the phase structure,micro morphology,spectral properties and photocatalytic properties of nano-TiO_(2) particles were studied by XRD,SEM,UV-Vis,PL and photocatalytic tests.The results showed that the prepared nano-TiO_(2) particles were anatase phase with high crystallinity.After adding rare earth Ce,the morphology of nano-TiO_(2) particles gradually became regular spherical,and the grains were refined.When the doping amount of rare earth Ce was 0.6 mol%,the grain size of TiO_(2) particles was the most regular and the distribution was the most uniform.The absorption sideband of rare earth Ce doped nano-TiO_(2) particles had a red shift and the absorption sideband increased,and the doping of rare earth Ce effectively inhibited the recombination of electron hole pairs.The degradation efficiency of Cr(Ⅵ)in heavy metal wastewater had been significantly improved by rare earth Ce modified nano-TiO_(2) particles,and when the doping amount of rare earth Ce was 0.6 mol%,the highest degradation efficiency of nano-TiO_(2) at 180 min was 92.7%,which was 166.4%higher than that of pure nano-TiO_(2).Comprehensive analysis showed that the optimum doping ratio of rare earth Ce was 0.6 mol%.