【摘要】：上個(gè)世紀(jì)我國工業(yè)快速發(fā)展,因規(guī)劃設(shè)計(jì)和經(jīng)濟(jì)結(jié)構(gòu)不合理等原因,至使一些處于城區(qū)內(nèi)的生產(chǎn)場地出現(xiàn)了環(huán)境問題。某公司大量回收廢舊電池堆放于廠區(qū)內(nèi),經(jīng)機(jī)械磨損和腐蝕,大量重金屬及酸等電解質(zhì)溶液滲出,致使堆放場地的重金屬污染,經(jīng)測定其中Pb含量高達(dá)900-1800mg/Kg,嚴(yán)重超出土壤背景值。本文采用電動(dòng)力學(xué)法通過實(shí)驗(yàn)室模擬和實(shí)際污染相結(jié)合的方法,考察電動(dòng)力學(xué)修復(fù)該污染土壤的可行性,研究了電動(dòng)力修復(fù)時(shí)間、電壓梯度、交換電極方向、間歇通電和陰極p H值控制對重金屬去除效果的影響,并在最佳實(shí)驗(yàn)條件下,研究電動(dòng)力修復(fù)對土壤土壤肥力的影響。通過一系列的實(shí)驗(yàn)研究得到以下結(jié)果:(1)重金屬Pb去除率隨修復(fù)時(shí)間及電壓的增大不斷升高,電能消耗隨之增高。當(dāng)修復(fù)時(shí)間和電壓為96h、1.0 V/cm時(shí),土壤中Pb從1500mg/kg降為941mg/kg,去除率為37.25%,電能消耗80.5 k W·h/g。(2)間歇通電和交換電極方向修復(fù)方式可以有效降低電能消耗,提高重金屬去除率。實(shí)驗(yàn)得到最佳間歇通電方式為通24h停12h通24h停12h通24h,此種修復(fù)方式下重金屬去除率45.3%,電能消耗33.53k W·h/g。實(shí)驗(yàn)設(shè)定交換電極方向頻率為48h,此條件下Pb去除率升高到64.5%,電能消耗為44.43 k W·h/g。(3)陰極p H控制方式可有效防止陰極p H值過高導(dǎo)致的重金屬沉淀,土壤中Pb去除率大幅度提高,由1500mg/kg降為390mg/kg,去除率為74%,電能消耗32.6k W·h/g。在此修復(fù)方式下,Pb去除率最高且能耗最低,因此確定最佳實(shí)驗(yàn)條件為電壓1.0 V/cm、時(shí)間96h、0.1mol/L HNO3為循環(huán)陰極液。此條件下土壤中速效氮、速效磷、速效鉀含量均有不同程度的升高,修復(fù)后速效氮、磷、鉀平均含量分別高于初始含量17.66mg/kg,37.25mg/kg,59.04mg/kg。研究表明,電動(dòng)力修復(fù)不但可以有效去除土壤中重金屬,還可有效提高土壤肥力,是一種環(huán)境友好的修復(fù)技術(shù),因此電動(dòng)力修復(fù)還可廣泛應(yīng)用于農(nóng)用土壤及其他類型污染土壤的修復(fù)。
[Abstract]:The rapid development of China's industry in the last century caused environmental problems in some production sites located in urban areas due to unreasonable planning and design and economic structure. A large number of recycled batteries were stacked in the factory area, and after mechanical wear and corrosion, a large number of heavy metals and acid electrolyte solutions seepage out, resulting in heavy metal pollution in the storage site, the Pb content of which is as high as 900-1800 mg / kg, which seriously exceeds the soil background value. In this paper, the feasibility of electrodynamic remediation of contaminated soil was investigated by means of laboratory simulation and actual pollution. The time of electrodynamic remediation, voltage gradient and the direction of exchange electrode were studied. The effects of intermittent electrification and cathodic pH control on the removal of heavy metals were studied. Under the optimum experimental conditions, the effects of electrodynamic remediation on soil fertility were studied. The following results were obtained through a series of experimental studies: (1) the removal rate of heavy metal Pb increased with the increase of repair time and voltage, and the power consumption increased. When the repair time and voltage were 96 h ~ (-1) V/cm, the Pb content in soil decreased from 941 mg / kg to 941 mg / kg, the removal rate was 37.25%, and the power consumption was 80.5 kW 路h / g 路g. (2) intermittent electrification and repair in the direction of exchange electrode could effectively reduce the power consumption and increase the removal rate of heavy metals. The results showed that the best intermittent mode of power supply was 24 h, 12h, 12h, 24h, and the removal rate of heavy metals was 45.3%, and the energy consumption was 33.53kW / h 路g. When the direction frequency of the exchange electrode is set at 48 h, the removal rate of Pb is increased to 64.55.The power consumption is 44.43 kHz / g. (3) the cathodic pH control method can effectively prevent heavy metal precipitation caused by excessive cathodic pH value, and the removal rate of Pb in soil can be greatly increased. The 1500mg/kg is reduced to 390 mg / kg, the removal rate is 74%, and the power consumption is 32.6 kh / g. In this way, the removal rate of Pb is the highest and the energy consumption is the lowest. Therefore, the optimum experimental conditions are as follows: voltage 1.0 V / cm, time 96 h 0.1 mol / L HNO3 as circulating cathode solution. Under this condition, the contents of available nitrogen, available phosphorus and available potassium in soil were all increased in varying degrees. The average content of available nitrogen, phosphorus and potassium after restoration was higher than that of initial content of 17.66 mg / kg ~ 37.25 mg / kg ~ (-1) ~ 59.04 mg / kg ~ (-1) 路kg ~ (-1). The results show that electrodynamic remediation can not only effectively remove heavy metals in soil, but also improve soil fertility effectively. It is an environmentally friendly remediation technology. Therefore, electrodynamic remediation can also be widely used in agricultural soil and other types of contaminated soil remediation.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53

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本文編號：2188025