功能化介孔硅分子筛吸附剂除磷性能的研究

Removal of phosphate from water by functionalized mesoporous silica adsorbent

分别在甲基二甲氧基硅烷改性介孔分子筛MCM41上锚定Al和Fe离子,成功制备了功能化的介孔硅分子筛有机/无机杂化吸附剂Al-NN-MCM41和Fe-NN-MCM41。详细考察了磷溶液初始浓度、吸附时间,溶液pH值和共存离子等对吸附剂磷吸附性能的影响。实验结果表明:Langmiur等温方程比Freundlich等温方程能更好地描述磷酸根离子在两种吸附剂上的吸附,两种吸附剂的吸附动力学过程更适合动力学准二级方程(r2>0.99)。磷溶液的pH值对吸附剂的磷吸附容量有显著影响。此外,同时添加NO33-、Cl-、SO42-、CO32-四种共存离子对吸附剂磷吸附效率没有显著影响。

The inorganic/organic hybrid mesoporous silica adsorbents,Al-NN-MCM41 and Fe-NN-MCM41,were successfully syn-thesized by introducing aluminum and iron ions onto diamino modified MCM-41,respectively. Effect of the initial phosphate concen-trations,contact times,pH values,and coexisting anions on adsorption capacity of the synthesized adsorbents was also systematically studied. The Langmuir and Freundlich isotherm models were used to simulate the adsorption equilibrium,and the results show that the Langmuir model fit the experiment data better than the Freundlich model. For kinetic study,the phosphate adsorption of the ad-sorbents could be well-described by the pseudo-second-order equation with correlation coefficients greater than 0. 99. The results show that pH value of the phosphate solution plays a dramatic role in determining the adsorption capacity, and the presence of NO3^-,C^l-, SO4^2- and CO3^2- has negliable influence on the adsorption capacity of phosphate on Al-NN-MCM41 and Fe-NN-MCM41.