摘要
以大分子络合物没食子酸(GA)-Cr(Ⅲ)与小分子络合物柠檬酸(CA)-Cr(Ⅲ)为对象,考察了二硫代氨基甲酸盐(DTC)类重金属捕集剂和季铵盐(QAS)类重金属捕集剂对Cr(Ⅲ)的去除效果,比较了混凝沉淀、超声等辅助处理技术对GA-Cr(Ⅲ)溶液中Cr(Ⅲ)去除效果的影响,筛选出适宜的除铬工艺为“混凝沉淀—重金属捕集”,并考察了该工艺对实际制革废水的处理效果。结果表明:在GA-Cr(Ⅲ)溶液中,Cr(Ⅲ)与GA络合形成了大分子聚合物,使Cr(Ⅲ)被包裹在分子内部,导致重金属捕集剂难以发挥作用,去除效果较差;经超声处理后,GA-Cr(Ⅲ)的络合结构遭到破坏,促使包裹在有机物间的Cr(Ⅲ)裸露出来,从而有利于重金属捕集剂捕集;混凝沉淀与DTC类重金属捕集剂联用时,对Cr(Ⅲ)的去除效果最好,GA-Cr(Ⅲ)溶液经该工艺处理后,Cr(Ⅲ)去除率可达79.6%;采用混凝沉淀与DTC/QAS类重金属捕集剂联用的方法对实际制革废水处理后,出水ρ(Cr)均低于1.5 mg/L,满足《污水综合排放标准》(GB8978—1996)中总铬的排放限值要求。
The removal effects of heavy metal traps of dithiocarbamate(DTC)and quaternary ammonium salt(QAS)on Cr(Ⅲ)were investigated by using the large molecule complex gallic acid(GA)-Cr(Ⅲ)and the small molecule complex citric acid(CA)-Cr(Ⅲ),and the influence of coagulation and precipitation,ultrasound treatment,and other auxiliary techniques on the removal effects of Cr(Ⅲ)in GA-Cr(Ⅲ)were compared.A suitable chromium removal process of“coagulation and precipitation-heavy metal trapping”was selected,and the effect of this process on the treatment of actual tannery wastewater was investigated.The results show that in the GA-Cr(Ⅲ)solution,Cr(Ⅲ)complexes with GA to form a large-molecule polymer,which wraps Cr(Ⅲ)inside the molecule,making it difficult for the heavy metal trap to play a role and leading to poor removal effect.After ultrasound treatment,the complex structure of GA-Cr(Ⅲ)is destroyed,which leads to the Cr(Ⅲ)wrapped up in the organic matter being exposed,thus facilitating the removal of Cr(Ⅲ)by the heavy metal trap.The removal effect of Cr(Ⅲ)is the best when coagulation and precipitation and heavy metal trap of DTC are used together,and the removal rate of Cr(Ⅲ)can reach 79.6%after GA-Cr(Ⅲ)solution is treated by this process.After the treatment of actual tannery wastewater by coagulation and precipitation and heavy metal trap of DTC/QAS,the effluentρ(Cr)is lower than 1.5 mg/L,which meets the total chromium discharge limit in the Integrated Wastewater Discharge Standard(GB8978—1996).
作者
霍昉
马宏瑞
郝永永
李琴莲
HUO Fang;MA Hongrui;HAO Yongyong;LI Qinlian(School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China)
出处
《化工环保》
CAS
CSCD
北大核心
2024年第3期377-383,共7页
Environmental Protection of Chemical Industry
基金
国家自然科学基金项目(22076113)。
