苯甲酸和磷酸共修饰TiO2降解罗丹明B的研究

Photodegradation of Rhodamine B with Titanium Dioxide Nanoparticles Modified by Benzoic Acid and Phosphoric Acid

通过简单化学吸附法,一步合成苯甲酸和磷酸表面共修饰TiO_2纳米粒子,其表面兼具亲水性、疏水性、亲氧性和负电性。在最佳修饰剂量条件下,氙灯照射2h,TiO_2纳米粒子对阳离子型染料罗丹明B的光降解率可由54.9%分别提高至71.5%、72.8%和91.2%。表面共修饰可实现磷酸基团的亲氧性与苯甲酸基团的疏水性协同作用,提升有机物向非均相光催化剂表面扩散速度和催化剂与水界面溶解O_2的交换速率,达到测定难降解有机污染物化学需氧量(COD)和总有机碳(TOC)的样品前处理要求。

Through an ester-like bond, titanium dioxide（TiO2） nanoparticles were modified with benzoic acid（or/and phosphoric acid） by one-step chemisorption. The surface characteristics of TiO2 were improved,with negatively charge, hydrophilicity, hydrophobicity, and oxygen affinity. After irradiation with Xenon lamp for 2 h, the photodegradation ratio of TiO2 for Rhodamine B（as cationic dyes） was improved from 54.9% to 71.5%,72.8%, 91.2% by the surface modification with the optimal dose of benzoic acid, phosphoric acid, benzoic acid and phosphoric acid, respectively. After surface co- modification,the synergistic effect from oxygen affinity of phosphate groups and hydrophobicity of phenyl group could be used to overcome the major obstacles of heterogeneous photocatalysis, including the poor surface coverage of the pollutants on the catalyst and the rapid consumption of oxygen on the TiO2 surface. The photodegradation ratio was enough for the requirement of sample pretreatment for the determination of COD and TOC.