Co@AC的包埋固定及其对农药阿特拉津的去除机制

The immobilization of Co@AC for pesticide atrazine removal

阿特拉津作为一种常用的除草剂,已被国际癌症研究机构列为具有致癌风险的2B组类别,这意味着阿特拉津对人类和生态环境有极大的影响.为实现对水中阿特拉津的高效去除,该研究采用包埋固定化技术(EI)将钴改性活性炭粉末(Co@AC)进行包埋固定,制备新型环境功能材料“EI-Co@AC”.当海藻酸钠为2.5%、氯化钙为4.0%、Co@AC为1.0%、膨润土为2.0%时,制备的EI-Co@AC小球具有最优的机械强度和传质性能,且小球内部具有较高的孔隙率、致密的网状结构以及大量的官能团.当EI-Co@AC投加量为16 g·L^(-1)、溶液pH为3.0、温度为25℃时,10 h内小球对50 mL、5.0 mg·L^(-1)的阿特拉津去除率可达92.3%,机理研究表明小球对阿特拉津的去除主要是化学吸附和多分子层吸附.此外,经过5次重复实验后,EI-Co@AC对阿特拉津的去除率仍在75%以上,且小球结构完整,表明EI-Co@AC具有良好的重复使用性能.综上,该研究制备的EI-Co@AC是一种无毒、经济、可重复利用的环境功能材料,可用于水环境中的阿特拉津及其他有机污染物的去除,解决了活性炭在应用时存在的回收困难和二次污染等问题,有着潜在的应用价值.

Atrazine,as a commonly used herbicide,has a great impact on humans and ecological environment,and has been classified as Group 2B with carcinogenic risk by the International Agency for Research on Cancer.In order to achieve efficient removal of atrazine from water,in this study,a novel functional material cobalt-modified activated carbon(Co@AC)was prepared via the embedding immobilization technology(EI).When sodium alginate is 2.5%,calcium chloride is 4.0%,Co@AC is 1.0%and bentonite is 2.0%,the prepared EI-Co@AC pellets possess the highest mechanical strength and optimal mass transfer performance,with high porosity,dense network structure and a large number of functional groups.Under the conditions for EI-Co@AC dosage,solution pH,and the temperature at 16 g·L^(-1),3.0,and 25℃,respectively,the removal efficiency of atrazine(5.0mg·L^(-1))can reach 92.3%within 10 h in 50 mL solution.The mechanism analysis result shows that the removal of atrazine by the pellets is attributed to chemisorption and multi-layer adsorption.In addition,after five repeated cycles,the removal efficiency of atrazine by EI-Co@AC is still above 75%,and the prepared pellet remains an intact structure,indicating that EI-Co@AC has good cyclic performance.In conclusion,the prepared EI-Co@AC is a non-toxic,economic and sustainable environmental functional material,and can be employed to remove atrazine and other organic pollutants in aqueous solution.It also has the potential to solve recycling difficulties and secondary pollution existing in the application of activated carbon.