颗粒13X分子筛/凹凸棒土对重金属Pb^(2+)的吸附及其影响因素研究

Study on the preparation of granular 13X molecular sieve/attapulgite and its effect of adsorbing heavy metal Pb^(2+)

以凹凸棒土为粘接剂制备颗粒13X分子筛/凹凸棒土吸附剂,考察不同煅烧温度下所制复合材料的孔结构、表面形貌、热稳定性及其对Pb^(2+)去除率,并以所制吸附剂为填料进行柱实验,研究其去除Pb^(2+)的机理及废水中Pb^(2+)浓度和水力负荷对吸附效果的影响。结果表明,适当提高煅烧温度,可增大复合材料的比表面积和孔体积,有利于废水中Pb^(2+)的吸附,但当煅烧温度高于700℃时,材料的晶体结构被破坏,比表面积由492.50 m^2·g^(-1)急剧下降至2.80 m^2·g^(-1);13X分子筛/凹凸棒土吸附剂可通过中和沉淀、过滤截留和离子交换吸附等方式有效去除废水中的Pb^(2+),填充柱的穿透时间随水力负荷和Pb^(2+)浓度的增大而缩短,当水力负荷为7.4 m^3·m^(-2)·h^(-1)时,13X分子筛/凹凸棒土颗粒的饱和吸附量最大,为542 mg·g^(-1)。

Grannular 13X molecular sieve/attapulgite adsorbent was prepared by using attapulgite powder as the adhesive agent. The effects of the calcination temperature of composite material on the porous struc- ture, surface morphology, thermal stability and Pb2＋ removal rate was investigated. The column tests were conducted with the prepared adsorbent as a filler in order to study the mechanism of removing Pb2＋ as well as the influence of initial Pb2＋ concentration and hydraulic loading on its adsorption effect. The results showed that with increase of calcination temperature, the specific area and porous volume of the composite material increased, which was beneficial to the adsorption of Pb2＋ in waste water. However, the crystal structure was damaged and the specific area dropped from 492.50 m2 · g -1 to 2.80 m2·g -1 when the calcination temperature over 700℃. The adsorption of Pb2＋ on 13X molecular sieves/attapulgite was achieved by neutralization precipitation, filtration interception and ion exchange adsorption. The breakthrough time of 13X molecular sieve/attapulgite packing column reduced with increase of hydraulic loading and Pb2＋ concentration. The saturated adsorption amount of 13X/attapulgite reached the maximum 542 mg ·g-1 as the hydraulic loading was 7.4 m3·m-2· h-1