【摘要】：目前,固化穩(wěn)定化技術(shù)已廣泛應(yīng)用于重金屬污染場地治理,同時酸雨對污染土體的影響不容忽視。有必要對固化穩(wěn)定化重金屬污染土在酸雨條件下的浸出特性及環(huán)境安全性進行研究。本文依托國家863計劃項目《有色冶金企業(yè)場地高風(fēng)險污染土壤的固化穩(wěn)定化工藝技術(shù)研究與示范》(2013AA06A206),國家自然科學(xué)基金《城市化過程中天然沉積土污染演化機理與控制技術(shù)研究》(41330641)及江蘇省杰出青年科學(xué)基金項目《特殊路基填土固化穩(wěn)定再生利用的關(guān)鍵問題研究》(BK2012022)等課題,選擇磷酸鹽固化穩(wěn)定化鉛鋅鎘污染土,通過室內(nèi)試驗研究了降雨作用下磷酸鹽固化穩(wěn)定化重金屬污染土的物理化學(xué)特性、重金屬浸出特性、模型試驗下滲流及重金屬的浸出特性；并采用Geostudio軟件對模型試驗進行數(shù)值分析。取得以下主要成果：(1)通過對固化土進行硫酸硝酸法浸出試驗、解吸附試驗和半動態(tài)浸出試驗,研究固化土的浸出特性。結(jié)果表明,固化土重金屬Pb、Zn、Cd的硫酸硝酸法浸出較未固化污染土分別降低了66%、27%、50%；三種重金屬的解吸附曲線符合Freundlich模型；固化土中Pb、Zn、Cd的浸出機理均為擴散控制。根據(jù)US EPA Method 1315計算得到Pb、Zn、Cd的表觀擴散系數(shù)分別為1.05×10-16 m2/s.7.84×10-13 m2/s、2.11×10-12 m2/s;根據(jù)ASTM C1308-08方法計算得到Pb、Zn、Cd擴散系數(shù)分別為1.33×10-16 m2/s、1.01×10-12 m2/s、2.89×10-12m2/s。(2)滲透試驗和土水特征曲線試驗結(jié)果表明,固化土的飽和滲透系數(shù)為3.46×10-6 m/s,其土水特征曲線的Fredlund-Xing模型擬合參數(shù)分別為a=26.6kPa, n=3.68, m=0.51。(3)固化土土柱模型試驗研究結(jié)果表明：土柱底部滲出液中重金屬Pb、Zn、Cd的濃度隨時間的變化為初始階段較高,隨后迅速下降,最后保持穩(wěn)定；同時重金屬濃度與滲出液pH值具有較好的線性負(fù)相關(guān)關(guān)系,而與滲出液EC有很好的線性正相關(guān)關(guān)系。(4)土柱模型的Geostudio數(shù)值模擬結(jié)果表明,當(dāng)降雨時間足夠長時,土體體積含水率、底部滲出速率最終達(dá)到穩(wěn)定狀態(tài),模型底部滲出液中Pb、Zn、Cd濃度的數(shù)值模擬結(jié)果與模型試驗結(jié)果相近,GeoStudio軟件可較好的模擬土柱模型中重金屬污染物的運移和浸出。并且通過擬合得到土柱底部重金屬累積浸出率隨水土比(降雨入滲量與土柱體積之比)變化的雙常數(shù)預(yù)測方程。
[Abstract]:At present, solidification and stabilization technology has been widely used in the treatment of heavy metal contaminated sites, and the influence of acid rain on contaminated soil can not be ignored. It is necessary to study the leaching characteristics and environmental safety of stabilized heavy metal contaminated soils under acid rain. In this paper, based on the National 863 Project "Research and demonstration of solidification and Stabilization Technology of High risk contaminated soil in Non-ferrous Metallurgical Enterprise" (2013AA06A206), the National Natural Science Foundation of China < pollution Evolution Mechanism of Natural Sedimentary soil in the process of urbanization and its Application Research on Control Technology (41330641) and Project of Jiangsu Province Outstanding Youth Science Foundation, Research on key problems of solidified and stable Recycling of Special subgrade fill (BK2012022), etc. The physical and chemical properties and heavy metal leaching characteristics of Phosphate stabilized heavy metal contaminated soil under rainfall were studied through laboratory experiments. The characteristics of seepage and heavy metal leaching under model test were analyzed numerically by Geostudio software. The main results are as follows: (1) the leaching characteristics of solidified soil were studied by sulfuric acid leaching test, desorption test and semi-dynamic leaching test. The results showed that the sulfuric acid leaching of heavy metal Pb ~ (2 +) Zn ~ (2 +) CD in solidified soil was lower than that of unsolidified contaminated soil by sulfuric acid, the desorption curves of three heavy metals were in accordance with Freundlich model, and the leaching mechanism of Pb ~ (2 +) ZnN ~ (2 +) CD in solidified soil was controlled by diffusion control. The apparent diffusion coefficient of US EPA Method 1315 is 1.05 脳 10 -16 m2/s.7.84 脳 10 -13 m 2 / s 2.11 脳 10 -12 m 2 / s, respectively, and the diffusion coefficient of ASTM C1308-08 is 1.33 脳 10 -16 m 2 / s 1.01 脳 10 -12 m 2 / s 2.89 脳 10 -12 m 2 路s. (2) the results of permeation test and soil-water characteristic curve test show that the diffusion coefficient is 1.33 脳 10 ~ (-16) m ~ (-2) 路s ~ (-1) ~ (-1) 脳 10 ~ (-12) m ~ (2) 路s ~ (-1). The saturated permeability coefficient of solidified soil is 3.46 脳 10 ~ (-6) m / s, and the fitting parameters of Fredlund-Xing model of soil-water characteristic curve are a 26.6 KPA, 3.68, 0.51 respectively. (3) the results of model test of solidified soil column show that the concentration of heavy metal Pb ~ (2 +) ~ (2 +) Zn ~ (2 +) in the exudate at the bottom of the soil column varies with time. Into a higher initial stage, The heavy metal concentration has a good linear negative correlation with the exudate pH value, while it has a good linear positive correlation with the exudate EC. (4) the Geostudio numerical simulation results of the soil column model show that there is a good linear and positive correlation between the heavy metal concentration and the pH value of the exudate. (4) the Geostudio numerical simulation results of the soil column model show that, When the rainfall time is long enough, the soil volume moisture content and the bottom seepage rate finally reach the stable state. The numerical simulation results of Pb ~ (2 +) Zn ~ (2 +) CD concentration in the exudate at the bottom of the model are similar to the results of the model test. GeoStudio software can simulate the migration and leaching of heavy metal pollutants in the soil column model. The double constant prediction equation is obtained by fitting the cumulative leaching rate of heavy metals at the bottom of the soil column with the ratio of soil and water (the ratio of rainfall infiltration to the volume of soil column).
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53

【引證文獻】

相關(guān)碩士學(xué)位論文 前1條

1 于博偉;SS-B穩(wěn)定化重金屬污染土的綠化種植再利用及環(huán)境安全性[D];東南大學(xué);2016年

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本文編號：2150192