Ag_2O-Bi_2MoO_6:制备及光催化降解富里酸

Ag_2O Doped Bi_2MoO_6: Preparation and Photocatalytic Activity for Fulvic Acid Degradation

以钼酸铵、硝酸铋和硝酸银为原料,以十六烷基三甲基溴化铵(CTAB)为辅助活性剂,采用水热法合成了Ag2O-Bi2MoO6光催化剂。用X射线粉末衍射、扫描电镜及紫外-可见吸收光谱等进行表征,并对水中天然有机物富里酸进行了光催化氧化研究。结果表明:未掺杂钼酸铋表面平滑,Ag2O-Bi2MoO6表面有明显的小块颗粒存在,分布集中,且其XRD图出现Ag2O的衍射峰。与未掺杂样品相比,掺杂Ag2O后Bi2MoO6的可见光催化活性提高,当掺银量为1.5%时活性最高。实验最佳催化剂浓度为0.6 g·L-1,在溶液pH值减小、富里酸初始浓度减小时有助于富里酸的去除。富里酸降解过程符合一级反应动力学方程,拟合方程为y=-0.019 5x。对富里酸降解产物进行发光菌生物毒性测试,发现光催化2 h后降解产物比处理前毒性降低约90%。

We use ammonium molybdate, bismuth nitrate and silver nitrate as raw materials, hexadecyl trimethyl ammonium bromide（CTAB） as auxiliary surfactant to synthesize photocatalyst Ag2O-Bi2MoO6 via hydrothermal method. The photocatalyst was characterized by XRD, SEM and UV-Vis spectroscopy. The photocatalytic oxidation of fulvic acid in water was performed over the catalyst. The results show that the surface of pure bismuth molybdate is smooth while on the surface of Ag2O-Bi2MoO6 there are some well-distributed small grains.The XRD pattern of Ag2O-Bi2MoO6 shows diffraction peaks of Ag2 O. Compared with the pure sample, Ag2OBi2MoO6 has much higher photocatalytic activity under visible light, and when its doping level is 1.5%, it shows the highest activity. The best catalyst concentration is 0.6 g·L^-1. The decrease in pH value of the solvent and initial concentration of fulvic acid will promote the removal of fulvic acid. The degradation process of fulvic acid conforms the first order kinetics, and the fitting equation is y=-0.019 5x. A Photobacterium phosphoreum toxicity test results show that the toxicity of the 2 h photocatalytic degradation product is reduced by about 90% compared to the un-degraded fulvic acid.