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采用化学接枝技术和简单的真空冷冻干燥方法制备出一种成本低、环境友好的改性海藻酸钙气凝胶(AlgNH2),并用于除去水体中的铅离子。实验结果表明,所制备的Alg-NH2吸附剂对铅离子有很高的选择性和吸附容量,其对铅离子的选择性系数超过40,吸附率达96.4%,最大吸附容量为217.2mg/g。Alg-NH2吸附剂工作区间较大,可应用于pH=3~7的含铅离子废液处理。此外,通过简单的酸性溶液处理即可实现吸附剂的再生和循环使用,且吸附性能保持稳定。通过准一级和准二级方程对动力学实验数据进行拟合,发现吸附过程与准二级动力学方程更为吻合(r=0.9948),表明Alg-NH2吸附剂主要通过化学吸附的方式结合溶液中的铅离子。对吸附前后样品进一步XPS分析表明,Alg-NH2吸附剂主要通过离子交换和化学配位的方式结合铅离子。
A cheaper and more environmentally friendly modified alginate airgel (AlgNH2) was prepared by chemical grafting and a simple vacuum freeze-drying method, and was used to remove lead ions in water. The experimental results show that the prepared Alg-NH2 adsorbent has a high selectivity and adsorption capacity for lead ions. The selectivity to lead ions is over 40, the adsorption rate is 96.4% and the maximum adsorption capacity is 217.2 mg / g . Alg-NH2 adsorbent working range larger, can be applied to pH = 3 ~ 7 leaching of lead-containing waste liquid. In addition, regeneration and recycle of adsorbent can be achieved by simple acid solution treatment, and adsorption performance remains stable. The experimental data of the quasi-first-order and quasi-second-order equations fit the kinetic data and found that the adsorption process is in good agreement with the quasi-second-order kinetic equation (r = 0.9948), indicating that Alg-NH2 adsorbents are mainly combined by chemisorption Lead in solution. Further XPS analysis of samples before and after adsorption showed that Alg-NH2 adsorbent mainly combined with lead ion through ion exchange and chemical coordination.