摘要
冷冻法在有机废水处理方面取得了良好的应用效果,但其分离机理缺乏深入的研究。为深入研究冷冻法对有机污染物的处理效果及分离机理,采用悬浮冷冻结晶法,对废水中己烷、正己酸、正己醇和正己醛4种具有不同官能团的有机物污染物进行分离实验,并采用量子化学方法计算了氢键结合能,进一步探讨了有机物官能团对冰晶杂质浓度的影响机理。悬浮结晶实验结果表明,废水中己烷、正己酸、正己醇和正己醛的去除率分别可达67.07%、87.75%、94.71%和95.32%。量子化学计算结果表明,极性有机物官能团和水分子间缔结的氢键结合能越大,其对应的冰晶杂质浓度越高,从而导致有机物去除率越低。正己醛3种极性有机物(正己酸、正己醇和正己醛)中和水分子间氢键结合能最小,对应的去除率最高。而己烷作为非极性有机物,无法和水分子间缔结产生氢键,因而极易在悬浮结晶时析出,与悬浮冰晶混合于溶液上层,故其去除率最低。以上研究结果从分子水平加深了对冷冻法在有机废水处理中作用机理的理解,可为该技术在水处理领域的深入研究提供参考。
The freezing method has been applied very well in treating organic wastewater,but its separation mechanism still needs in-depth investigation.In order to further study the treatment effect and separation mechanism of organic pollutants by freezing method.In this study,suspension crystallization method was used to separate four organic pollutants with different functional groups,including hexane,hexanoic acid,N-hexanol and N-hexanal.Quantum chemistry method was used to calculate the hydrogen bonding energy,and the influence mechanism of organic functional groups on the concentration of ice crystal impurities was further discussed.The results of suspension crystallization experiments showed that the removal rates of hexane,hexanoic acid,N-hexanol and N-hexanal in wastewater could reach 67.07%,87.75%,94.71%and 95.32%,respectively.Quantum chemical calculation results indicated that the greater the hydrogen bonding energy between the polar organic functional groups and water molecule,the higher the concentration of the corresponding ice crystal impurities,resulting in a lower organic removal rate.Among the three polar organic substances(hexanoic acid,N-hexanol and N-hexanal),N-hexanal had the smallest hydrogen bonding energy and the highest removal rate.As a non-polar organic substance,hexane cannot form hydrogen bonds with water molecules,so it was easily to precipitate during suspension crystallization and mixed with suspended ice crystals in the upper layer of the solution,so its removal rate was the lowest.The above research results have deepened the understanding of the mechanism of the freezing method in organic wastewater treatment in the view of the molecular level,and can provide a reference for the in-depth study of this technology in the field of water treatment.
作者
刘勰
陈鹏
范成李
殷迪
金亮
张乐华
闫莹
LIU Xie;CHEN Peng;FAN Chengli;YIN Di;JIN Liang;ZHANG Lehua;YAN Ying(State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process,School of Resources and Environmental Engineering,East China University of Science and Technology,Shanghai 200237,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2021年第1期57-64,共8页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(21876050)。
关键词
氢键
官能团
冰晶杂质
量子化学
去除率
hydrogen bond
functional groups
ice impurity
quantum chemistry
removal rate
