木素类模型物紫丁香醇TiO_2光催化降解

Photocatalytic Degradation of Syringol Lignin Model by Titanium Dioxide

在光催化反应器中,以紫外光(功率11 W,波长253.7 nm)作光源,在TiO2悬浮体系中,对含有木素类模型物紫丁香醇的有机废水进行了光催化降解实验,并研究了其反应特性。实验结果表明,暗反应60 min后,紫丁香醇在TiO2催化剂表面达到吸附解吸平衡,吸附总量百分比基本相同,TiO2表面饱和吸附量是初始溶液中紫丁香醇质量的16.3%;当TiO2用量为0.4 g/L,溶液pH值为3以及连续曝气和搅拌条件下,由降解吸光度曲线可知,经该紫外光照射12 h,初始浓度40.5 mg/L的溶液去除率达52%,继续照射4 h,最终可达到完全降解。由降解吸光度曲线和化学特征功能团显色实验可初步推断,在一定的紫外光照射下,紫丁香醇支链上的一个甲氧基先与苯环发生断裂,生成了具有单甲氧基结构的中间体-愈创木酚。通过联立方程定量分析了降解过程中紫丁香醇和愈创木酚的浓度。??

In the cylindrical photocatalytic reactor, the degradation characteristics of the syringol lignin （SL） obtained from organic wastewater was investigated in the TiO2 suspension system using ultraviolet （UV） irradiation （power 11 W, wave lenght 253.7 nm）. The results showed that the SL adsorption on the surface of TiO2 reached equilibrium in 60 minutes in the dark reaction. The adsorption proportion of SL was similar, it was 16.3 % mass fraction of SL initial mass inthe solution. The absorbance curve of the degradation solution indicated that the degradation ratio of SL was 52% in 12 hours UV radiation for the 0.4 g/L TiO2 concentration （pH 3） and the 40.5 mg/L SL initial concentration in the case of continuous aeration and stirring, syringol lignin could be almost mineralized if UV irradiation was continued again for 4 houres. Based on the ABS curve and the color experiment of functional groups, it could be estimated that the double methoxyl of syringol lignin partly broke and became single methoxyl structure as guaiacol lignin under UV irradiation. The concentrations of syringol lignin and guaiacol lignin were quantitatively analyzed with simultaneous equations.