秸秆对染料废水中甲基橙的吸附动力学和热力学研究

Research on Adsorption Kinetics and Thermodynamics of Methyl Orange from Dye Wastewater by Straw

实验选用玉米秸秆作为吸附剂,对染料废水中的甲基橙进行吸附,考察甲基橙初始浓度、吸附剂用量、溶液pH、吸附温度和吸附时间对甲基橙吸附的影响情况,从而确定实验最佳的吸附条件,并对吸附性能进行热力学和动力学研究.实验结果表明,最佳吸附条件为:吸附温度为50℃、溶液pH=7、吸附剂的用量为0.25 g、吸附时间为3 h、甲基橙的初始浓度150 mg·L^(-1),秸秆对甲基橙的吸附率达到了82%以上;热力学分析实验数据符合Langmuir吸附等温模型;热力学参数吉布斯自由能变△G<0,热力学焓变△H>0,熵变△S>0,说明此吸附是自发的吸热过程;动力学分析实验数据符合准二级动力学方程.

Corn straw was selected as the adsorbent to absorb methyl orange in dye wastewater in the experimen, initial concentration of methyl orange, adsorbent dose, solution pH, adsorption temperature, adsorption time on the absorption of methyl orange, to determine the optimum adsorption conditions, The thermodynamics and kinetics of the adsorption properties were also studied. The results showed that the optimum adsorption conditions were as follows: the adsorption temperature was 50 ℃, pH=7, the amount of adsorbent was 0.25 g, the adsorption time was 3 h, and the initial concentration of methyl orange was150 mg/L. The adsorption rate of methyl orange on straw was above 82%.The experimental data of thermodynamic analysis accord with Langmuir adsorption isotherm model. Thermodynamic parameter Gibbs free energy variation ?G<0, thermodynamic enthalpy change?H>0, entropy change delta ?S>0, indicating that the adsorption is a spontaneous endothermic process;The experimental data of dynamic analysis accord with the quasi-second-order dynamic equation.