pH对活化前后废弃铁铝泥吸附不同种磷动力学的影响

Effect of pH on adsorption kinetics of different phosphate species by raw and activated ferric-alum water treatment residuals

实验研究了300℃热活化前后的给水厂废弃铁铝泥(R-FARs和H300-FARs)对正磷酸盐、聚磷酸盐和有机磷酸盐的吸附动力学特性,并考察pH对不同磷吸附动力学的影响。结果表明,pH对不同磷吸附动力学过程的影响趋势相似,即低pH有利于吸附。准二级动力学模型能够更真实地反映不同磷在R-FARs和H300-FARs的吸附动力学行为,由拟合结果可知焦磷酸盐和六肌醇磷酸盐的初始吸附速率相对较大,而甘油磷酸盐最小;且活化作用明显提高了不同磷的初始吸附速率,并减弱了pH对初始吸附速率的影响。不同磷的吸附速率受到液膜扩散、颗粒内扩散和吸附反应三者共同控制,其中吸附反应是主要的控制步骤。

We investigated the effect of pH on the adsorption kinetics of different phosphate（P） species by the raw and 300℃ thermal activated ferric-alum water treatment residuals（R-FARs and H 300-FARs）.The results show that pH has a significant effect on the kinetics of different P species,and low pH is beneficial to P adsorption on R-FARs and H 300-FARs.Under different pH values,the adsorption processes of different P species can be well described by the pseudo-second-order model.According to the kinetic analysis,the initial adsorption rates of pyrophosphate and phytate are relatively higher than others,while that of glycerophosphate is minimum.The adsorption rates are mainly controlled by the adsorption reaction processes.However,compared with RFARs,the thermal activation can reduce the effect of pH on the adsorption of different P species.