强化混凝和改性活性炭对二级出水DON的作用机制  

Mechanism of enhanced coagulation and modified activated carbon on DON in the secondary effluent

作　　者：刘冰 郑煜铭[2] 古励[3] 李清飞[1] 余国忠 翟慧敏 

机构地区：[1]信阳师范学院地理科学学院,河南信阳464000 [2]中国科学院城市环境研究所,福建厦门361021 [3]重庆大学城市建设与环境工程学院,重庆重庆400044

出　　处：《中国环境科学》2018年第1期136-149,共14页China Environmental Science

基　　金：国家自然科学基金项目(51208448);河南省高等学校青年骨干教师资助计划(2015GGJS-136);河南省科技厅科技攻关项目(162102310498);河南省教育厅科学技术研究重点项目(14A610004);信阳师范学院"南湖学者"奖励计划青年项目

摘　　要：探讨强化混凝和改性活性炭对城市污水厂二级出水中溶解性有机氮(DON)作用机制,分析相对分子量以及亲疏水组分变化,并考察氯化消毒副产物生成势变化特征,结合三维荧光(3DEEM)光谱分析手段,对强化混凝和活性炭吸附前后DON组成,化学结构特征进行研究.结果表明:强化混凝可以明显提高DON的去除效果,DON去除率通过p H值强化混凝提高到1.45倍,臭氧强化混凝提高到2.06倍,PAC强化混凝提高到2.09倍,PAM强化混凝提高到1.96倍.活性炭对DON吸附过程更符合准二级动力学模型.DON吸附过程中,酸改性活性炭表面主要是π-π色散力作用机理,而碱改性活性炭表面主要是给电子-受电子复合物形成机制.在强化混凝和活性炭吸附作用下,DON的相对分子量和组分发生较大变化,而消毒副产物的生成势大幅下降.经3DEEM和光谱区域体积积分法(FRI)分析,在强化混凝和活性炭吸附过程中DON及消毒副产物生成潜势与荧光区域Ⅱ和区域Ⅳ所代表物质有关.In order to explore the mechanism on dissolved organic nitrogen （DON） removal in the secondary effluent of wastewater treatment plant by enhanced coagulation and modified activated carbon adsorption, the molecular weight distribution and hydrophobicity/hydrophilicity of DON were analyzed. Besides, chlorinated disinfection by-product （DBP） formation potential was investigated. Combined with three dimensional （3DEEM）, DON compositions and their chemical structures before and after coagulation and adsorption were also studied. The results showed that （1） enhanced coagulation could significantly improve DON removal efficiency, with an increase in DON removal rate of 1.45-fold, 2.06-fold, 2.09-fold and 1.96-fold by pH enhanced coagulation, pre-ozonation enhanced coagulation, PAC enhanced coagulation and PAM enhanced coagulation, respectively; （2） the adsorption process of DON by the activated carbon was better correlated with the quasi-second-order kinetic model. During DON adsorption process, π-π dispersion mechanism mainly exists on the surface of acid-modified activated carbon, and electron donor-acceptor formation mechanism is present on the surface of alkali modified activated carbon; （3） after the enhanced coagulation and activated carbon adsorption, the molecular weight and composition of DON changed greatly, and DBP formation potential decreased significantly; （4） finally, the 3DEEM and fluorescence spectral region volume integral analysis suggested DON concentration and DBP formation potential were related with the fluorescent regions II and IV in enhanced coagulation and activated carbon adsorption process.

关 键 词：二级出水 溶解性有机氮 强化混凝 改性活性炭 三维荧光光谱 

分 类 号：X703[环境科学与工程—环境工程]