金属离子-腐植酸复合凝胶的制备及其对氟吸附研究

Preparation and F-Adsorption Performances of Composite Gel of Metal Ion-modified Humic Acid

为提高水中F-的吸附去除效率，以腐植酸（HA）为原料，用铝盐和钙盐通过凝胶聚合法对其改性，制备了金属离子-腐植酸复合凝胶吸附剂（标记为SPMA）。用SEM、XRD、IR及N2吸附-脱附实验表征吸附剂的结构和形貌，通过静态吸附实验探讨了SPMA对水中F-的吸附性能。研究结果表明，SPMA对水中F-的等温吸附结果与Langmuir方程能较好地拟合，用Langmuir方程计算出的饱和吸附容量为147．28mg／g；吸附过程遵循准2级动力学方程，其速率控制步骤包括边界层扩散和内部扩散2个过程；在pH值为5～9时SPMA对水中F-具有较高的吸附率，SO42-、NO3-和Cl-对F-的吸附率没有影响，在相同浓度的HCO3-或PO43-存在下，SPMA对F-的吸附率仍达到80％，表现出了-定的抗干扰能力。

In order to increase the removal efficiency of fluoride ion aqueous solution, using humic acid（HA） as raw materials, a com- posite gel of metal ion and humic acid （ abbreviated as SPMA） was synthesized by gel polymerization method. The structures and ap- pearances of adsorption materials were analyzed by SEM, XRD, IR and N2 adsorption-desorption isotherms technique as well. The batch adsorption experiments were carried out. The results indicated that the adsorption isotherm behavior of SPMA followed the Langmuir e- quations, and the maximum adsorption capacity was 147.28 mg/g. The adsorption kinetics followed the pseudo-second-order rate model. The adsorption of F- for SPMA was due to the liquid film diffusion and the intra-particle diffusion. Maximum fluoride adsorption of SP- MA from the contaminated water was reaches at pH 5 - 9, and the SO42- , NO3 - and Cl- has no effect on removal efficiency of F -, SP- MA removed F- at the removal efficiency of 80% in dilute solution even when the HCO3 - and PO43- at the same concentration. There- fore, the SPMA could be used for the selective adsorption for F- in dilute solutions.