溶解性有机质对典型土壤吸附苯并三唑的影响研究

发布时间：2018-05-02 17:32

本文选题：土壤 + 苯并三唑　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：溶解性有机质(DOM)普遍存在于水土环境中,研究表明,其对重金属和有机污染物的吸附均有显著影响。但是,目前关于DOM对新兴极性有机污染物苯并三唑(BTA)吸附的影响机理还不清楚。因此本研究采用批实验的方法,选取华北平原土壤(GSS13)和珠江三角洲土壤(GSS16)为吸附剂,以腐殖酸(HA)和单宁酸(TA)为DOM的典型代表,研究了GSS13土壤对BTA的吸附特征以及两种土壤对DOM的吸附。在此基础上,研究了HA和TA对土壤吸附BTA的影响。主要得出以下结论:(1)土壤对BTA的吸附过程可划分为初始快速吸附阶段和随后缓慢吸附阶段。溶液初始p H值在4.5-10.5范围内时,其变化对BTA的吸附无明显影响,浓度为0.01-0.05 M的Ca2+可与BTA之间发生络合作用而促进吸附,而同浓度的Na+对BTA吸附的影响不明显。(2)土壤对DOM的吸附机理包括静电作用和配体交换等。当背景溶液电解质为Na Cl时,GSS13土壤对HA和TA的吸附要强于Na2SO4背景溶液中的吸附,主要是由于SO42-与带负电的DOM竞争土壤上带正电吸附点位的能力强于Cl-。土壤中金属氧化物表面上的羟基与DOM中羧基等官能团之间的配体交换是DOM吸附到土壤上的一个主要机制,由于TA中的羧基官能团数量多于HA,土壤对TA的吸附要强于对HA的吸附。(3)DOM对土壤吸附BTA有一定的促进作用,随着加入DOM浓度的增大,土壤吸附BTA的能力增强。DOM促进BTA吸附的主要机理是氢键作用,这种极性作用使得BTA吸附的非线性程度增加。但是平衡溶液p H值的变化会影响DOM上羧基等官能团的去质子化作用,从而影响DOM对土壤吸附BTA的促进作用。
[Abstract]:Dissolved organic matter (DOM) is widely found in soil and water environment. The results show that it has a significant effect on the adsorption of heavy metals and organic pollutants. However, the effect of DOM on the adsorption of benzotriazole is not clear. Therefore, in this study, batch experiments were used to select GSS13) from North China Plain and GSS16 from the Pearl River Delta as adsorbents, and HA and TAA) as typical representatives of DOM. The adsorption characteristics of BTA on GSS13 soil and the adsorption of DOM on two soils were studied. On this basis, the effects of HA and TA on soil adsorption of BTA were studied. The main conclusions are as follows: (1) the adsorption process of BTA on soil can be divided into the initial fast adsorption stage and the later slow adsorption stage. When the initial pH value of the solution was within the range of 4.5-10.5, the change of pH value had no significant effect on the adsorption of BTA, and the concentration of 0.01-0.05M of Ca2 could promote the adsorption by complexing with BTA. However, the effect of Na on BTA adsorption was not obvious. 2) the adsorption mechanism of DOM on soil included electrostatic interaction and ligand exchange. When the electrolyte of the background solution is NaCl, the adsorption of HA and TA in GSS13 soil is stronger than that in the background solution of Na2SO4, mainly because the ability of SO42- to compete with negatively charged DOM on the soil with positive adsorption point is stronger than that of Cl-. The ligand exchange between hydroxyl groups on the surface of metal oxides and carboxyl groups in DOM is one of the main mechanisms of DOM adsorption on soil. The main mechanism of enhancing the ability of soil to adsorb BTA. Dom promoted the adsorption of BTA was hydrogen bonding. This polarity increased the degree of nonlinearity of BTA adsorption. However, the change of pH value of equilibrium solution will affect the deprotonation of carboxyl and other functional groups on DOM, thus affecting the promotion of BTA adsorption by DOM.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X131.3

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