TiO2/锂硅粉-H2O2体系光催化降解邻苯二甲酸二甲酯机理分析

Analysis on mechanism of photocatalytic degradation of dimethyl phthalate over TiO2/lithium silicate powder-H2O2 system

利用自制的TiO2/锂硅粉催化剂与H2O2联用进行光催化降解邻苯二甲酸二甲酯(DMP)废水研究。实验结果表明,TiO2/锂硅粉与H2O2联用是降解DMP的有效方法,当TiO2/锂硅粉投加量为1.2 g/L、H2O2体积分数为2.0 m L/L、初始pH=8.0时,反应10 h的DMP降解率最大,为89.18%。通过LC/MS分析反应过程中DMP的降解产物,主要包括侧链缩合成环生成的水杨酸、羟基化产物邻苯二酚和苯环开环生成的2-羟基异丁酸。初步推测TiO2/锂硅粉-H2O2体系下DMP的碳链断裂从侧链开始。

Photocatalytic degradation of dimethyl phthalate(DMP)wastewater is performed through combining use of self-made TiO2/lithium silicon powder catalyst and H2O2.Experimental results show that the TiO2/lithium silicon powder-H2O2 technology is an effective method for degrading DMP.The degradation rate of DMP reaches the biggest,89.18%when the dosage of TiO2/lithium silicon powder is 1.2 g·L-1,the dosage of H2O2 is 2.0 ml·L-1,the initial pH=8.0 and reaction lasts for 10 h.It is found by LC/MS analysis that the degradation products of DMP during the reaction mainly include salicylic acid that is formed through side chain condensing into ring,catechol that is a hydroxylated product and 2-hydroxyisobutyric acid that is formed by ring opening of benzene.It is presumed that the carbon chain cleavage of DMP starts from the side chain under TiO2/Lithium silicon powder-H2O2 system.