【摘要】：隨著工業(yè)的發(fā)展,土壤重金屬污染問(wèn)題日益嚴(yán)重,其主要修復(fù)技術(shù)有:化學(xué)穩(wěn)定/固化、化學(xué)還原、生物修復(fù)、淋洗、電動(dòng)修復(fù)等。其中電動(dòng)修復(fù)技術(shù)作為一個(gè)新興的土壤原位修復(fù)技術(shù)受到國(guó)內(nèi)外研究者們的廣泛關(guān)注。但在修復(fù)的過(guò)程中,會(huì)受到各種因素的影響,如土壤和污染物的特性、電壓梯度、吸附/解吸機(jī)制、聚焦現(xiàn)象、工作液性質(zhì)、溫度、含水率等。這些因素都有可能決定著電動(dòng)修復(fù)的效率和修復(fù)時(shí)間,而數(shù)值模擬可以綜合考慮多方面的影響因素,從而優(yōu)化電動(dòng)修復(fù)過(guò)程,為實(shí)際工程提供了有利的預(yù)測(cè)。國(guó)內(nèi)外研究者們已經(jīng)建立了很多數(shù)學(xué)模型來(lái)預(yù)測(cè)電動(dòng)修復(fù)過(guò)程中污染物的遷移,這些模型結(jié)果與實(shí)驗(yàn)結(jié)果擬合很好,但僅限于對(duì)單一的污染物進(jìn)行數(shù)值模擬。有些模型雖然同時(shí)對(duì)兩、三種離子進(jìn)行模擬,但與實(shí)驗(yàn)結(jié)果的擬合難以令人滿意�，F(xiàn)有電動(dòng)修復(fù)數(shù)值模擬中,離子在土壤中的淌度通常用無(wú)限稀釋溶液下的離子淌度乘以土壤有效淌度系數(shù)k進(jìn)行估算,而k值通常又由土壤孔隙度n和扭曲度τ估算而得,與離子特征及其與土壤顆粒之間的相互作用無(wú)關(guān)。本課題將通過(guò)直接測(cè)量分別在三個(gè)濃度下有色離子Mn O4-離子和Cr O42-離子在高嶺土中的淌度,研究影響離子有效淌度系數(shù)的因素,為電動(dòng)修復(fù)模型中計(jì)算有效離子淌度的表達(dá)式進(jìn)行修正。本實(shí)驗(yàn)結(jié)果證明影響離子有效淌度系數(shù)的因素有土壤幾何特性(f(n,τ))、離子溶液濃度(kc)和土壤顆粒表面電荷與離子之間相互作用(kz)。其中土壤幾何特性用孔隙度n和扭曲度τ的函數(shù)來(lái)表示,只與土壤的結(jié)構(gòu)有關(guān)。離子溶液濃度引起的有效淌度系數(shù)可通過(guò)在溶液中測(cè)量離子淌度計(jì)算而得,結(jié)果表明離子溶液濃度對(duì)有效淌度系數(shù)有影響。土壤顆粒表面電荷與離子之間相互作用引起的有效淌度系數(shù)通過(guò)在高嶺土(或加入陽(yáng)離子樹(shù)脂)中測(cè)量離子淌度計(jì)算而得,結(jié)果表明土壤顆粒表面電荷與離子之間的相互作用對(duì)有效淌度系數(shù)有影響,且在高嶺土中對(duì)不同離子的影響幅度不同。故現(xiàn)有的電動(dòng)修復(fù)模型中對(duì)于有效淌度的計(jì)算表達(dá)式應(yīng)修正為:zce×××=kknfuu￥),( t根據(jù)本研究結(jié)果,可在同一土壤介質(zhì)中同時(shí)對(duì)多個(gè)離子進(jìn)行數(shù)值模擬,其中f(n,τ)取值相同,kc分別測(cè)得,通過(guò)調(diào)整每個(gè)離子的kz值,使數(shù)值模擬結(jié)果與實(shí)驗(yàn)結(jié)果匹配。
[Abstract]:With the development of industry, the problem of heavy metal pollution in soil is becoming more and more serious. The main remediation technologies are chemical stability / curing, chemical reduction, bioremediation, leaching, electric remediation and so on. As a new in-situ soil remediation technology, electric remediation technology has been widely concerned by researchers at home and abroad. However, in the process of remediation, it will be affected by various factors, such as the characteristics of soil and pollutants, voltage gradient, adsorption / desorption mechanism, focusing phenomenon, working liquid properties, temperature, moisture content and so on. These factors may determine the efficiency and repair time of electric repair, and numerical simulation can consider many factors comprehensively, so as to optimize the process of electric repair and provide a favorable prediction for practical engineering. Researchers at home and abroad have established many mathematical models to predict the migration of pollutants in the process of electric remediation. The results of these models fit well with the experimental results, but are limited to the numerical simulation of a single pollutant. Although some models simulate two or three ions at the same time, the fitting with the experimental results is not satisfactory. In the existing numerical simulation of electric remediation, the mobility of ions in soil is usually estimated by multiplying the ion mobility in infinite dilute solution by the soil effective mobility coefficient k, and the k value is usually estimated by soil porosity n and torsional degree tau. It has nothing to do with the characteristics of ions and the interaction between them and soil particles. In this paper, the mobility of colored ions Mn O4-ion and Cr O42-ion in kaolin at three concentrations will be directly measured, and the factors affecting the effective mobility coefficient of ions will be studied. The expression for calculating the effective ion mobility in the electric repair model is modified. The results show that the factors affecting the effective mobility coefficient of ions are soil geometric characteristics (f (n, 蟿), ion solution concentration (kc) and the interaction between soil particle surface charge and ions (kz). The geometric properties of the soil are represented by the functions of porosity n and distortion tau, which are only related to the structure of the soil. The effective mobility coefficient caused by the ion solution concentration can be calculated by measuring the ion mobility in the solution. The results show that the ion solution concentration has an effect on the effective mobility coefficient. The effective mobility coefficient caused by the interaction between the surface charge of soil particles and ions is calculated by measuring the ion mobility in kaolin (or adding cationic resin). The results show that the interaction between surface charge and ions of soil particles has an effect on the effective mobility coefficient, and the effect on different ions in Kaolin is different. Therefore, the calculation expression of effective mobility in the existing electric repair model should be modified to zce 脳 脳 = kknfuu), (t. According to the results of this study, multiple ions can be simulated simultaneously in the same soil medium, in which f (n, can be used to simulate multiple ions at the same time. The values of tau) are the same. Kc measured them respectively. By adjusting the KZ value of each ion, the numerical simulation results match the experimental results.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X53

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