UiO-66对废水中二氯苯氧乙酸的吸附特性

Adsorption Characteristics of 2,4-D on UiO-66 from Wastewater

以Ui O-66型金属有机框架为吸附剂,研究了时间、p H值和温度对自制金属有机框架Ui O-66吸附2,4-D性能的影响.结果表明,Ui O-66的吸附平衡时间为24 h;初始溶液最佳p H值为4.0;Ui O-66上的平衡吸附量随温度的升高而增加,实验最佳温度应控制在30℃.Ui O-66对2,4-D的吸附符合Langmuir吸附模型;吸附动力学符合拟二级模型;颗粒内扩散过程是吸附速率控制步骤;热力学计算结果显示ΔG<0、ΔH>0、ΔS>0,由此判断吸附是自发、吸热、熵增加的化学过程.本实验表明,Ui O-66在去除农业废水中2,4-D领域有实际应用的潜力.

With UiO-66 metal organic framework as the adsorbent, the influences of factors such as time, pH value, temperature on the adsorption were studied. The results showed that the adsorption effect was best at pH = 4. 0 for the adsorption system and the adsorption equilibrium time was 24 h. The equilibrium adsorption capacity increased with the increasing temperature and the optimal temperature should be controlled at 30℃ . The adsorption of 2,4-D on UiO-66 followed Langmuir isotherm model and the adsorption kinetics could be better described by pseudo-second-order model. The intraparticle diffusion process was the rate-controlling step for adsorption processes. The results of thermodynamic calculations showed that △G 〈 0, △H ﹥ 0, △S ﹥ 0. So the adsorption was a spontaneous, endothermic chemical process with increased randomness. The main interaction forces of adsorption were chemical bonding force and electrostatic interactions force. Results of the study suggested that UiO-66 had the potential ability for 2,4-D removal from wastewater.