TiO_2@酵母菌复合催化剂对刚果红的吸附特性研究

Adsorption properties of Congo red dye wastewater by the composite catalysts of TiO_2@ yeasts

研究了TiO2@酵母复合型催化剂对阴离子染料刚果红的吸附性能,考察了pH、催化剂投加量、刚果红初始浓度、温度等因素对吸附效率的影响,并对吸附过程进行了动力学、等温模型和热力学分析.结果表明pH对吸附效率影响较大,最佳pH值为3;当刚果红浓度在10~50mg·L-1时,吸附量随着浓度的增加而增加;催化剂投加量为0.5 g·L-1,吸附效率较高;温度对吸附过程影响较小.TiO2@酵母复合催化剂吸附刚果红的过程符合准二级动力学模型;化学吸附为主要控制步骤;吸附过程符合Langmuir等温吸附方程,为单分子层吸附;ΔG为负值且ΔH为正值表明吸附是自发吸热过程.

In this study,TiO2@ yeasts composite catalysts were used to treat the anionic Congo red aqueous solutions. Factors affecting the adsorption process,such as pH,dye concentration,dosage of composite catalysts and temperature were investigated,respectively. The results show that pH has a significant impact on the efficiency of adsorption and the optimal pH value is about 3. When the dose of catalysts is 0. 5 g·L-1,the optimum absorption of Congo red by the composite catalysts is achieved. The adsorption capacity is enhanced with increasing initial concentration. The temperature has slight effect on the adsorption processes. The pseudo-second-order kinetic equation is suitable for simulation of the adsorption processes,indicating the processes is dominated by chemical absorption. The Langmuir model was found to be in better correlation with the experimental data,indicating the absorption belongs to monolayer molecular adsorption. The spontaneous and endothermic nature of the absorption process can be verified by the negative values of the standard free energy change ΔG and the positive values of ΔH.