复合污染条件下改性壳聚糖对抗生素的絮凝脱除研究
发布时间：2019-01-30 08:07
【摘要】：水是人类赖以生存的重要资源。随着抗生素的大量生产和滥用,各种抗生素物质进入到水环境中,对人类健康造成了巨大的威胁。传统的水处理剂对抗生素污染物处理效果甚微。针对不同复合污染条件下抗生素的赋存形态特征,本文选取了具有成本低、可再生、来源广泛等特点的壳聚糖为基材,以2-氯-4,6-二甲氨基-1,3,5-三嗪、色氨酸和酪氨酸为改性试剂,制备了多类改性壳聚糖絮凝剂(BDAT-CTS、Ctrp和Ctyr),系统地考察了复合污染条件下多种因素(包括:水体pH、絮凝剂投加量、共存悬浮无机颗粒物、共存溶解型无机污染物、以及共存天然有机质等)等对抗生素的絮凝脱除性能的影响,并对不同絮凝剂对不同污染体系的絮凝机理进行深入分析。结果表明:(1)在重金属Cu(Ⅱ)共存条件下,BDAT-CTS对四环素TC有良好的絮凝脱除效果。对于Cu(Ⅱ)-TC复合污染水体的絮凝净化中,电中和作用是主要的絮凝机理。带正电的絮凝剂BDAT-CTS和带负电的羟基络合铜离子通过静电吸引作用结合;同时,BDAT-CTS上带正电的芳环与TC中带负电的芳环结构还存在较强的ππ相互作用。因此,BDAT-CTS、Cu(Ⅱ)、TC三者通过两两相互作用紧密结合,促进了絮体的形成,并实现了四环素的高效脱除。(2)在悬浮颗粒物高岭土和天然溶解有机物腐殖酸共存条件下,不同结构的氨基酸改性絮凝剂Ctrp和Ctyr对三种典型抗生素NOR、SDZ、TYL均表现出较好的絮凝效果。其中,含有负电性的苯酚基的Ctyr更有利于通过ππ电子给体-受体作用(EDA)絮凝带正电的NOR和TYL;而含有正电性的吲哚基团的Ctrp对SDZ的絮凝脱除效果更佳。此外,在与原料壳聚糖和商用絮凝剂聚合氯化铝的对比实验中发现,在絮凝剂投加量、絮凝效率和环境友好性上,Ctrp和Ctyr均具有优势显著。(3)基于两种絮凝剂Ctrp/Ctyr对含共存污染物kaolin和HA的三种抗生素NOR、SDZ、TYL体系的研究基础上,进一步考察在Ca(Ⅱ)、Cu(Ⅱ)复合影响下对抗生素絮凝脱。通过U30*(307)均匀设计表设计实验,运用DesignExpert软件进行响应曲面图分析和最优条件拟合,发现:调节kaolin、HA、Ca(Ⅱ)、Cu(Ⅱ)和絮凝剂的浓度可以实现对抗生素污染物NOR、SDZ的进一步脱除。这可为真实水体中对抗生素的脱除提供指导。综上所述,通过改性壳聚糖基从而进行不同结构的修饰,可对多种复合污染的抗生素污染水体表现出较为理想的絮凝脱除效果;而多因素污染物的复合研究,从而探究物质迁移转化的规律,对真实水体的处理中有着良好的应用意义。
[Abstract]:Water is an important resource for human survival. With the mass production and abuse of antibiotics, a variety of antibiotic substances enter the water environment, which poses a great threat to human health. Traditional water treatment agents have little effect on the treatment of antibiotic pollutants. In view of the morphological characteristics of antibiotics under different complex pollution conditions, chitosan with the characteristics of low cost, renewable and wide source was selected as the base material. A variety of modified chitosan flocculants (BDAT-CTS,Ctrp and Ctyr),) were prepared with tryptophan and tyrosine as modification reagents. The effects of co-existing suspended inorganic particles, co-dissolved inorganic pollutants and co-existing natural organic matter on the flocculation and removal performance of antibiotics were discussed. The flocculation mechanism of different flocculants on different pollution systems was also analyzed. The results showed that: (1) under the condition of coexistence of heavy metal Cu (鈪，
本文编号：2417927
[Abstract]:Water is an important resource for human survival. With the mass production and abuse of antibiotics, a variety of antibiotic substances enter the water environment, which poses a great threat to human health. Traditional water treatment agents have little effect on the treatment of antibiotic pollutants. In view of the morphological characteristics of antibiotics under different complex pollution conditions, chitosan with the characteristics of low cost, renewable and wide source was selected as the base material. A variety of modified chitosan flocculants (BDAT-CTS,Ctrp and Ctyr),) were prepared with tryptophan and tyrosine as modification reagents. The effects of co-existing suspended inorganic particles, co-dissolved inorganic pollutants and co-existing natural organic matter on the flocculation and removal performance of antibiotics were discussed. The flocculation mechanism of different flocculants on different pollution systems was also analyzed. The results showed that: (1) under the condition of coexistence of heavy metal Cu (鈪，
本文编号：2417927
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