解聚凹凸棒土负载纳米Fe/Ni材料对水中2,4-二氯酚的脱氯降解性能

Performance of depolymerized attapulgite-loaded nano-Fe/Ni composite in dechlorination of 2,4-dichlorophenol from aqueous solution

采用球磨-冷冻工艺对凹凸棒土进行解聚处理,分别以解聚前后的凹凸棒土为载体负载纳米Fe/Ni,对比研究了所制复合材料的微观结构及对水中2,4-二氯酚(2,4-DCP)的脱氯降解性能,并考察了环境温度、溶液初始pH值对材料脱氯降解2,4-DCP性能的影响。结果表明,经解聚处理后,以棒晶束聚集体存在的凹凸棒土分散形成单独的纳米棒晶,纳米Fe/Ni颗粒团聚情况得到改善,复合材料比表面积增大,对水中2,4-DCP的脱氯降解性能显著提升,适当提升环境温度和合理的溶液pH值(3.0~9.0)均有利于复合材料对2,4-DCP的脱氯降解,其主要途径是直接脱除2个氯原子生成苯酚,次要途径为2,4-DCP先脱去1个氯原子生成2-氯酚或4-氯酚,再脱去另一个氯原子生成苯酚。

In this paper,the attapulites before and after depolymerization by milling-freezing process were used as the carriers to load nano-Fe/Ni.The microstructure and performance of the as-prepared composite materials in dechlorination of 2,4-dichlorophenol(2,4-DCP)from aqueous solution were studied comparatively,and the effects of ambient temperature and initial pH value of the solution on the dechlorination efficiency of 2,4-DCP were investigated.The results show that after depolymerization treatment,the attapulgites that appear as rod-like crystal bundles are dispersed to form separate nanorod crystals,the agglomeration of nano-Fe/Ni particles is improved,and the specific surface area of the as-prepared composite materials is increased.Therefore,its dechlorination performance of 2,4-DCP from aqueous solution is significantly improved.Moreover,appropriate increase of ambient temperature and reasonable initial pH value of the solution(3.0~9.0)promote the dechlorination efficiency of 2,4-DCP by using depolymerized attapulgite-loaded nano-Fe/Ni composite.The main dechlorination pathway of 2,4-DCP is the direct removal of two chlorine atoms to generate phenol,and the secondary way is to first remove one chlorine atom from 2,4-DCP to generate 2-chlorophenol or 4-chlorophenol and then remove another chlorine atom to generate phenol.