金属离子改性腐植酸钠吸附剂的制备及其除氟性能

Synthesis and defluoridation performance of humic acid sodium base absorbent modified by metalion

为提高水中F-的吸附去除效率,以腐植酸钠（NaA）为原料,用铝盐和钙盐通过凝胶聚合法对其改性,制备了金属离子改性腐植酸钠吸附剂（标记为 MMNaA）.用 SEM 及 XRD 表征吸附剂的结构和形貌,通过静态吸附实验探讨了 MMNaA 对水中 F-的吸附性能并与传统的γ-Al2O3吸附剂进行比较.结果表明,MMNaA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208.77mg/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 5-9时MMNaA对水中F-具有较高的吸附去除率.当吸附剂用于深度处理实际含氟废水时,与γ-Al2O3相比,MMNaA适用的pH值范围更广,满足达标排放时所需的投加量更小、吸附时间更短.

Metal ion-modified humic acid sodium absorbent （devoted as MMNaA） had been developed to improve the removal efficiency of fluoride ion in aqueous solution by gel polymerization method using aluminum salt and calcium salt as raw materials. The crystal structures and microstructures of the materials were measured by XRD and SEM; and the adsorption performance of the materials for fluoride ion in aqueous solution was investigated by static adsorption experiment. The results showed that a good matching between the adsorption isotherm behavior of MMNaA and Langmuir equation was observed; the adsorption capacity of 208.77mg/g calculated from Langmuir equation was obtained; the adsorption process could be expressed as pseudo-second-order kinetic model; and the absorption rate was determined by the liquid film diffusion and the intra-particle diffusion. Maximum fluoride adsorption of MMNaA in contaminated water was reached at the pH values of 5-9.As compared with γ-Al2O3, MMNaA had a much wider range of pH, less dose and shorter absorption time.