腐殖土中溶解有机组分对棕壤和黑土吸附苯并三唑的影响

发布时间：2018-05-07 10:34

本文选题：溶解性有机质 + 苯并三唑　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：溶解性有机质(DOM)影响着有机污染物在土壤中的吸附。为了了解DOM对苯并三唑(BTA)在土壤中吸附的影响,本研究从天然腐殖土中提取了DOM(记为DOMbulk),并按照亲疏水性进行了分级。在分析了DOM不同组分特征基础上,采用吸附批实验方法研究了DOM不同组分对棕壤和黑土吸附BTA的影响。结论如下:(1)DOMbulk中各组分的质量比分别为疏水酸性(HOA)61%、疏水中性(HON)17%、亲水酸性(HIA)6%、亲水碱性(HIB)2%和亲水中性(HIN)14%。HOA和HON的E4/E6较高,(O+N)/C较低,说明疏水组分分子量较大、结构较复杂,且极性较低。HIB中含有最多的羟基,HIA中含有最多的羧基。(2)由于黑土有机碳含量高于棕壤,黑土对BTA和DOM组分的吸附能力均大于棕壤。BTA在土壤中的吸附主要受有机碳含量的控制。相对于黑土,棕壤吸附DOMbulk的标化分配系数Koc较高,其原因是棕壤中含有较多的对吸附DOMbulk起重要作用的粘粒。HIN和HOA极性相似,HOA中羧基会解离带负电,与土壤的排斥作用使土壤对HOA的吸附弱于HIN。引起土壤对HON的吸附最弱的原因是:HON使土壤SOM溶出或SOM会抑制土壤对外源疏水性DOM的吸附。(3)由于透析实验中DOM浓度较低(40 mg·L-1),且有水分子占据其结合点位,在溶液中DOM各组分对BTA吸附作用较弱。各DOM组分中,HIN在土壤上吸附最强。HIN的吸附增加了土壤吸附BTA的点位,增加的点位对吸附的促进作用大于HIN与BTA的竞争吸附作用,最终表现为促进吸附。HOA与HON在土壤上的吸附较弱,产生的新吸附点位较少,主要通过竞争吸附作用抑制土壤对BTA的吸附。DOMbulk对BTA吸附的影响与主要的疏水组分(占DOMbulk的78%)相似,对土壤吸附污染物的影响可以用DOMbulk中的不同结构性组分进行预测。
[Abstract]:Dissolved organic matter (DOM) affects the adsorption of organic pollutants in soil. In order to understand the effect of DOM on the adsorption of benzotriazole in soil, DOM was extracted from natural humus and classified according to hydrophobicity. On the basis of analyzing the characteristics of different components of DOM, the effects of different components of DOM on the adsorption of BTA in brown soil and black soil were studied by adsorption batch experiment. The results showed that the mass ratios of each component in DOMbulk were as follows: hydrophobic acid, hydrophobic neutral, hydrophilic acid, hydrophilic basic HIBN 2% and hydrophilic neutral HIN14, HOA and HON, which indicated that the molecular weight of hydrophobic components was higher, and the structure of the hydrophobic component was more complex, which indicated that the molecular weight of the hydrophobic component was higher and the structure of the hydrophobic component was more complex than that of the hydrophilic acid, which indicated that the molecular weight of the hydrophobic component was higher and the structure was more complex. The adsorption ability of BTA and DOM components in black soil is higher than that in brown soil, which is mainly controlled by the content of organic carbon. Compared with black soil, the standard partition coefficient (Koc) of DOMbulk adsorbed by brown soil is higher, because there are more clay particles. HIN and HOA have similar polarity to adsorb DOMbulk, and the carboxyl groups in HOA have negative dissociation band. The repulsive action with soil makes the adsorption of HOA to soil weaker than that of HIN. The weakest reason for the adsorption of HON in soil is that the solution of SOM to soil by: HON or that SOM can inhibit the adsorption of exogenous hydrophobic DOM by SOM.) in dialysis experiments, the concentration of DOM is lower than 40 mg / L ~ (-1), and water molecules occupy the binding site. The adsorption of BTA by DOM was weak in solution. The adsorption of HIN on soil increased the site of BTA adsorption, and the increase of the sites promoted the adsorption of HIN and BTA more than the competitive adsorption of HIN and BTA. The results showed that the adsorption of HOA and HON on the soil was weak, and the new adsorption sites were less. The influence of the adsorption of BTA on BTA was similar to that of the main hydrophobic component (78% of DOMbulk), which was mainly inhibited by competitive adsorption. The effect of soil adsorption on pollutants can be predicted by different structural components of DOMbulk.
【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】：2017
【分类号】：X53

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