磷酸铝吸附除水中氟的研究

采用静态吸附法研究了比表面为308m2/g的无定形磷酸铝吸附除氟性能,研究了接触时间、pH值、吸附剂量等对吸附的影响。结果表明,磷酸铝吸附除氟高效、迅速,30min内可以接近最大吸附量。对含氟50mg/g的溶液,优化条件下的最大除氟率约93%。研究了吸附与溶液pH的关系,得到了优化pH值并解释了吸附机理。吸附的最佳pH值约为5.5。用拟二级动力学方程描述了吸附速率并计算了速率常数。用Langmuir方程拟合了吸附等温线,计算的饱和吸附量为53.5mg/g。吸附剂量对分配系数的影响表明吸附剂表面是不均匀的。

A STUDY ON REMOVAL OF FLUORIDES FROM WATER BY ADSORPTION ONTO ALUMINUM PHOSPHATE

Amorphous aluminum phosphate with specific surface area 308m2/g was studied by static adsorption method to assess its capacity for the adsorption of fluoride from synthetic solutions.Influence of contact time,pH and adsorbent dose on the adsorption was investigated.The adsorbent was found to adsorb fluoride rapidly and effectively.The maximum amount of adsorption nearly reached in 30 minutes.The best percent fluoride removal at optimum condition was about 93% at 50mg/L fluoride concentration.The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH-value and explain the adsorption mechanism.It has been found that maximum adsorption of fluoride from aqueous solutions takes place at pH-value of 5.5.Pseudo-second-order kinetics equation was used to describe the adsorption rate of fluoride and adsorption rate constant was calculated.Adsorption isotherms have been modeled by Langmuir equations and saturated amount of adsorption was calculated as 53.5mg/g.The effect of adsorbent dose on distribution coefficient implied the surface of adsorbent was heterogeneous.