本文選題：膠體吸附 + 膠體再運移��； 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：地下環(huán)境中存在大量膠體,可吸附污染物并促進污染物在土壤和地下水中運移,而有些膠體本身就是污染物,這些污染物進入水體后會對人類身體健康造成危害。近年來,膠體在土壤和地下水中的運移研究成為熱點,研究表明地下環(huán)境的變化會引起土壤膠體的釋放和沉積,研究地下水中土壤膠體的沉積和再運移對包氣帶和含水層中污染物的運移和修復(fù)有著重要的意義。本工作選用直徑為1μm的聚苯乙烯乳膠微球為模擬膠體顆粒,石英砂為多孔介質(zhì),采用室內(nèi)土柱實驗研究了飽和穩(wěn)定流中離子強度對膠體吸附和再運移的影響,并研究了水鐵礦膠體與離子強度對重金屬As~(3+)運移的影響。根據(jù)實驗中所獲取的濃度穿透曲線計算膠體吸附率(attachment coefficient)、再運移率(remobilization coefficient),根據(jù)DLVO理論繪制勢能圖,定量分析實驗結(jié)果。實驗結(jié)果表明,(1)隨著溶液離子強度增加,膠體在多孔介質(zhì)表面的吸附量增加。溶液離子強度為50 mM、60 mM、70 mM時,滯留在砂柱中的膠體量占總注入量的百分比分別是92.96%、94.62%、94.78%。(2)溶液離子強度的瞬間改變,可引起膠體的再運移。溶液離子強度改變相同,從50 mM降到10 mM時膠體再運移量最大,再運移率為3.88%;初始離子強度同為60 mM,離子強度下降至10 mM時膠體再運移量最大,再運移率為1.75%;背景溶液從電解質(zhì)溶液直接轉(zhuǎn)換為超純水時的膠體再運移量比先轉(zhuǎn)換為低濃度電解質(zhì)溶液再轉(zhuǎn)換為超純水時大。表明膠體在飽和多孔介質(zhì)中運移不僅受離子強度大小的影響,還與離子強度變化率和溶液化學(xué)歷史條件有關(guān)。(3)砂柱中存在水鐵礦膠體且不發(fā)生運移時,水鐵礦膠體可吸附As~(3+)而抑制As~(3+)在飽和砂柱中的運移,且吸附量隨離子強度的增加而增加。(4)水鐵礦膠體在砂柱中分布較分散時,As~(3+)因吸附點位增多、與膠體接觸時間增長而在砂柱中的滯留量比水鐵礦膠體在砂柱頂端集中分布時大,表明膠體對As~(3+)在飽和多孔介質(zhì)中運移的影響大于離子強度的影響。以上研究結(jié)果可為制定水土健康標(biāo)準(zhǔn),預(yù)防和控制地下水受到病原性微生物等有機膠體以及膠體顆粒所攜帶的各種有機、無機污染物的污染提供理論基礎(chǔ)和決策依據(jù)。
[Abstract]:There are a large number of colloids in the underground environment which can adsorb pollutants and promote the transport of pollutants in soil and groundwater. Some colloids themselves are pollutants which will cause harm to human health when they enter the water body. In recent years, the study of colloid migration in soil and groundwater has become a hot topic, and it has been shown that the change of underground environment will lead to the release and deposition of soil colloid. It is of great significance to study the deposition and remigration of soil colloids in groundwater for the transport and remediation of pollutants in aeration zones and aquifers. In this work, polystyrene latex microspheres with diameter of 1 渭 m were used as simulated colloidal particles and quartz sand as porous media. The effect of ionic strength on colloid adsorption and migration in saturated steady flow was studied by laboratory soil column experiments. The effects of hydrocolloid and ionic strength on the transport of heavy metal As~(3 were studied. According to the concentration penetration curve obtained in the experiment, the colloid adsorption rate is calculated and the migration rate is removed. According to the DLVO theory, the potential energy diagram is drawn and the experimental results are quantitatively analyzed. The experimental results show that the adsorption amount of the colloid on the porous media increases with the increase of ionic strength of the solution. When the ionic strength of the solution is 50 mm ~ (2) ~ (60) mm ~ (-1) ~ (70 mm), the percentage of colloid in the sand column is 92.96 ~ 94.62 ~ 94.782 ~ 94.78 ~ (2), respectively. The change of the ionic strength of the solution can cause the colloid to migrate again. The change of ionic strength of the solution was the same, the colloidal remigration was the largest and the remigration rate was 3.88 when the ionic strength was reduced from 50 mm to 10 mm, and the initial ionic strength was 60 mm, and the colloidal remigration was the largest when the ionic strength decreased to 10 mm. The remigration rate is 1.75. The colloidal remigration rate of the background solution is higher when the electrolyte solution is directly converted to ultra-pure water than when the solution is first converted to the low-concentration electrolyte solution and then to the ultra-pure water. The results show that the migration of colloids in saturated porous media is not only affected by the ionic strength, but also by the change rate of ionic strength and the chemical history of solution. Water ore colloids can adsorb As~(3) and inhibit the migration of As~(3) in saturated sand columns, and the adsorption capacity increases with the increase of ionic strength. 4) when the distribution of hematite colloids in the sand columns is more dispersed, the adsorption sites of the hematite colloids increase because of the increase of adsorption sites. The contact time with the colloid increased and the retention in the sand column was larger than that at the top of the sand column, indicating that the effect of the colloid on the migration of As~(3 in saturated porous media was greater than that on the ionic strength. The above results can provide theoretical basis and decision basis for the formulation of water and soil health standards and the prevention and control of groundwater contamination by organic colloids such as pathogenic microorganisms and various organic and inorganic pollutants carried by colloidal particles.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X53;X523

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