热活化硅酸钙对水溶液中磷吸附动力学研究

Adsorption kinetics of phosphate from aqueous solutions by thermal activated calcium silicate

将硅酸钙进行高温热活化后作为吸附剂,研究了其对水溶液中磷酸盐的吸附动力学特性,考察了热活化硅酸钙投加量、溶液pH对磷去除效果的影响,并对其动力学特性进行了研究。结果表明,投加量为6g/L,pH为8时磷去除率可达99%以上;热活化硅酸钙对磷酸盐吸附过程符合准二级动力学方程和颗粒内扩散方程,其准二级吸附速率常数随磷酸盐浓度的增大而减小;而颗粒内扩散速率常数随磷酸盐浓度的增大而增大,吸附速率主要受颗粒内扩散控制。

The thermal activated calcium silicate was used as adsorbent for removal of phosphate from aqueous solutions. The dynamic adsorption characteristic was researched and the effect of thermal activated calcium silicate dosage,solution pH on phosphate removal efficiency was investigated through the batch experiments. The results showed that the removal rate of phosphate could reach over 99% when solution pH was 8 and adsorbent dosage was 6 g/L. The pseudo-second-order equation and intra-particle diffusion model showed the best agreement for the adsorp- tion systems. With increasing of the initial phosphate concentration,the rate constant of pseudo-second-order equation decreased and that of intra-particle diffusion model increased, revealed that the intra-particle diffusion was the main rate-controlling step.