本文關(guān)鍵詞： 重金屬 原位鈍化修復(fù) 穩(wěn)定性　出處：《山東師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著土壤重金屬污染的日益嚴(yán)重，重金屬污染土壤的修復(fù)已經(jīng)成為環(huán)境問題的熱點。原位鈍化修復(fù)技術(shù)是一種向土壤中添加鈍化劑，通過鈍化劑對重金屬的吸附、沉淀、絡(luò)合、離子交換和氧化還原等一系列反應(yīng)，以降低重金屬的可遷移性和生物有效性的技術(shù)。因該技術(shù)成本低、修復(fù)效率高、且操作簡單，對于中低濃度污染土壤的修復(fù)具有較好的應(yīng)用前景。然而該技術(shù)致命性弱點是經(jīng)鈍化穩(wěn)定后的重金屬仍留存在土壤中，只是降低了重金屬在土壤中的可遷移性和生物有效性，隨時間的延長或環(huán)境條件的變化，重金屬有再次活化的威脅。 本文從鈍化劑本身穩(wěn)定性和鈍化劑與重金屬結(jié)合穩(wěn)定性兩方面來研究原位鈍化修復(fù)的穩(wěn)定性。選取以交換吸附機理為主的粘土礦物—鈉基膨潤土和螯合吸附機理為主的—改性納米黑碳兩種鈍化劑，通過模擬實驗和培養(yǎng)實驗研究鈍化劑本身的熱穩(wěn)定性、化學(xué)穩(wěn)定性（化學(xué)氧化穩(wěn)定性和酸堿穩(wěn)定性）、生物學(xué)穩(wěn)定性；通過吸附解吸實驗研究鈍化劑與重金屬結(jié)合的穩(wěn)定性及其影響因素；通過盆栽實驗研究鈍化劑在實際應(yīng)用中的穩(wěn)定性。其目的是為鈍化劑實際應(yīng)用于原位鈍化修復(fù)重金屬污染土壤提供理論依據(jù)。 本文獲得的主要研究結(jié)果如下： 選取改性納米黑碳為鈍化材料研究其本身穩(wěn)定性，結(jié)果發(fā)現(xiàn)：（1）改性納米黑碳的熱穩(wěn)定性很好，利用熱重分析儀將改性納米黑碳從室溫逐步加熱到700℃，改性納米黑碳的質(zhì)量僅降低13.01%。（2）改性納米黑碳的化學(xué)穩(wěn)定性強。利用333mmo·L-1的KMnO4對改性納米黑碳進行氧化24小時后，達到最大降解率僅為4.22%。改性納米黑碳的酸堿穩(wěn)定性較強，用不同酸堿度的溶液對改性納米黑碳進行酸堿腐蝕，pH為2時，降解率為1.933%，pH為12時，降解率為5.334%。（3）改性納米黑碳在濃度低于1×105cfu·mL-1的枯草芽孢桿菌作用下生物學(xué)穩(wěn)定性較好。當(dāng)濃度高于1×105cfu·mL-1時，隨著枯草芽孢桿菌濃度增高生物學(xué)穩(wěn)定性變差，在濃度為1×107cfu·mL-1下培養(yǎng)30天時，改性納米黑碳的最大降解率為11%。改性納米黑碳的生物降解作用大于化學(xué)氧化作用。 選取以交換吸附機理為主的粘土礦物—鈉基膨潤土和螯合吸附機理為主的—改性納米黑碳兩種鈍化劑，選擇Cu和Cd兩種重金屬，通過吸附動力學(xué)、吸附等溫線實驗研究兩種材料對兩種重金屬的吸附特性。結(jié)果發(fā)現(xiàn)，改性納米黑碳和鈉基膨潤土對Cu2+和Cd2+的吸附可以用準(zhǔn)二級動力學(xué)和Langmuir方程很好的擬合。重金屬在鈍化劑上的吸附分為快慢兩個階段。用Langmuir方程計算出改性納米黑碳對Cu2+和Cd2+的最大吸附量分別為23809mg·kg-1和24390mg·kg-1，鈉基膨潤土對Cu2+和Cd2+的最大吸附量分別為4681mg·kg-1和5356mg·kg-1。Freundlich擬合出的n值均大于1，表明兩種重金屬在兩種吸附劑上均為優(yōu)惠吸附。改性納米黑碳對兩種重金屬的吸附能力大于鈉基膨潤土，Cu2+在兩種鈍化劑上的吸附能力大于Cd2+。 用0.01mol·L-1CaCl2在不同環(huán)境條件下對吸附了重金屬的兩種材料進行解吸，結(jié)果發(fā)現(xiàn)，溫度和鹽離子濃度對解吸率的影響不大，說明鈍化穩(wěn)定性受溫度和鹽離子濃度的影響不大；pH對解吸率的影響很大，隨著pH的降低解吸率迅速增大，說明土壤pH越高，鈍化穩(wěn)定性越強；土壤pH越低，鈍化穩(wěn)定性越差；土壤pH的變化對鈍化穩(wěn)定性影響很大。 將兩種鈍化劑實際應(yīng)用于銅污染土壤修復(fù)中，結(jié)果發(fā)現(xiàn)，施入改性納米黑碳后，三種土壤中有效態(tài)含量均在40天后無顯著變化，說明改性納米黑碳的鈍化穩(wěn)定性強。改性納米黑碳施入三種土壤中后，褐土中有效態(tài)的減少最為迅速，10-20內(nèi)有效態(tài)含量減少最多，30天內(nèi)基本完成有效態(tài)的減少。棕壤中30-40天有效態(tài)含量減少最多，40天內(nèi)基本完成有效態(tài)的減少。酸性棕壤中10-30天內(nèi)有效態(tài)含量增加，有效態(tài)含量的減少主要發(fā)生在30-40天時。施入鈉基膨潤土后，棕壤和褐土中重金屬有效態(tài)含量均在40天后無顯著變化，說明鈍化穩(wěn)定性好。在酸性棕壤中，重金屬有效態(tài)含量變化無規(guī)律，說明鈍化穩(wěn)定性差。鈉基膨潤土施入三種土壤中后，褐土中有效態(tài)的減少最為迅速，10-20內(nèi)有效態(tài)含量減少最多，30天內(nèi)基本完成有效態(tài)的減少。棕壤中10-20天有效態(tài)含量減少最多，40天內(nèi)基本完成有效態(tài)的減少。 黑麥草的生長對鈍化穩(wěn)定性具有促進作用，，在施入改性納米黑碳和鈉基膨潤土的土壤中，種植黑麥草的土壤中重金屬有效態(tài)含量均低于未種植黑麥草的土壤。原因可能是，植物在生長過程中根部對重金屬的吸附、從根部向地上部的轉(zhuǎn)移等降低了土壤中有效態(tài)重金屬含量。
[Abstract]:With increasing heavy metal pollution, hot repair of soil heavy metal pollution has become the environmental problem. In situ remediation technology is a kind of passivating agent is added to the soil, the adsorption of heavy metal passivator, precipitation, complexation, ion exchange and a series of redox reaction, in order to reduce the heavy metal migration technology and the biological effectiveness. Because of the technology of low cost, high repair efficiency, simple operation and has a good application prospect for the repair of low concentration of polluted soil. However, the fatal weakness is the passivation of heavy metals in the stable still remained in the soil, only to reduce the heavy metal in the soil can be transferred and the biological effectiveness, change with time or environmental conditions, heavy metals have again activated the threat.
This paper from the stability of passivating agent itself stability and passivation agent and heavy metal combining two aspects to study the stability of in situ remediation. Two kinds of modified nano carbon black passivating agent selected to exchange adsorption mechanism of main clay minerals - sodium bentonite and chelating adsorption mechanism mainly, cultivation of thermal stability experiments of passivating agent itself through the simulation experiment and chemical stability (chemical oxidation stability and pH stability), biological stability; through the factors of the stability of adsorption and desorption experiment study on passivation agent and heavy metal binding and influence; through the pot experiment of passivating agent stability in practical application. Its purpose is for the passivation agent applied to the in situ remediation of heavy metal contaminated soils with passivation on the basis of the theory.
The main results obtained in this paper are as follows:
For the selection of passivation materials research itself the stability of modified nano black carbon results showed that: (1) the thermal stability of the modified nano carbon black is very good, using thermogravimetric analyzer using modified nano carbon black gradually heating from room temperature to 700 degrees Celsius, the quality of the modified nano carbon black only decreased 13.01%. (2) chemical stability the modified nano carbon black. The oxidation of 24 hours of modified nano black carbon by 333mmo L-1 KMnO4, the maximum degradation rate of only 4.22%. modified nano carbon black acid has strong stability, acid alkali corrosion of modified nano carbon black solution with different pH, pH 2 and the degradation rate was 1.933%, pH was 12, the degradation rate of 5.334%. (3) modified nano carbon black at a concentration of less than Bacillus subtilis 1 * 105CFU mL-1 of the biological stability. When the concentration is above 1 * 105CFU - mL-1, with higher concentration of biological stability of Bacillus subtilis The maximum degradation rate of modified nano black carbon is 11%. when the concentration is 1 * 107cfu / mL-1 for 30 days. The biodegradation of modified nano black carbon is greater than that of chemical oxidation.
Two kinds of modified nano carbon black passivating agent selected to exchange adsorption mechanism mainly clay minerals - sodium bentonite and chelating adsorption mechanism based, Cu and Cd two kinds of heavy metals, the adsorption kinetics, adsorption isotherm experiments of two kinds of materials of two kinds of heavy metal adsorption properties. The results showed that the adsorption the Cu2+ and Cd2+ can be used to fit the quasi two kinetics and Langmuir equation well modified nano carbon black and sodium bentonite. The adsorption of heavy metals in the passivating agent is divided into different two stages. Using Langmuir equation to calculate the maximum adsorption capacity of Cu2+ and Cd2+ modified nano black carbon 23809mg kg-1 and 24390mg kg-1 respectively, the maximum adsorption of Cu2+ and Cd2+ of sodium bentonite were 4681mg - kg-1 and 5356mg - kg-1.Freundlich fitted n values are greater than 1, showed that two kinds of heavy metals in the two adsorbents were changed to preferential adsorption. The adsorption capacity of nano black carbon to two kinds of heavy metals is greater than that of sodium bentonite. The adsorption capacity of Cu2+ on two kinds of passivating agents is greater than that of Cd2+.
For desorption, two kinds of materials on the adsorption of heavy metals in different environmental conditions by 0.01mol and L-1CaCl2 results show that the temperature and salt concentration has little effect on the desorption rate, that stability is not affected by the passivation temperature and salt ion concentration; pH has a great effect on the desorption rate, with the decrease of pH desorption rate increases rapidly. PH, indicating that the soil is higher, more stable passivation; the lower the soil pH, passivation stability is worse; the pH variation of soil has great influence on the stability of the passivation.
The two passivation agent applied in copper contaminated soil remediation, results show that the application of modified nano carbon black, three kinds of available content in soil after 40 days were no significant change, indicating the passivation stability of modified nano - black carbon. The modified nano black carbon into three kinds of soils, available in cinnamon soil decreased most rapidly, the effective content of 10-20 reduced by up to 30 days to complete the basic state. The most effective to reduce the effective content of soil decreased by 30-40 days, 40 days to complete the basic state. Effectively reduce the increase in acid brown soil within 10-30 days of the effective content, reduce the content of available mainly occurred in 30-40 days. Application of sodium bentonite, available heavy metal content in brown soil and cinnamon soil in 40 days no significant change, indicating good stability in acid brown soil. The passivation, change of available heavy metal content without the law, that passive stability When sodium base bentonite was applied to three soils, the effective state of cinnamon soil decreased most rapidly, the effective content of 10-20 decreased most, and the effective state decreased basically within 30 days. The content of 10-20 days effective state in brown soil decreased the most, and the effective state was basically reduced within 40 days.
The growth of ryegrass can promote stability in application of passivation, modified nano carbon black and sodium bentonite in soil available heavy metal content in soil ryegrass were lower than those of non ryegrass planting soil. The reason may be that in the growth process of plant roots on adsorption of heavy metals, from the root to the ground the upper part of the transfer to reduce the content of available heavy metal in soil.

【學(xué)位授予單位】：山東師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X53

【參考文獻】

相關(guān)期刊論文 前10條

1 楊蘇才;南忠仁;曾靜靜;;土壤重金屬污染現(xiàn)狀與治理途徑研究進展[J];安徽農(nóng)業(yè)科學(xué);2006年03期

2 范稚蓮;莫良玉;韋瓊山;奉雪;楊貴福;;石灰修復(fù)重金屬污染土壤及其對水稻效應(yīng)[J];安徽農(nóng)業(yè)科學(xué);2008年03期

3 徐良將;張明禮;楊浩;;土壤重金屬污染修復(fù)方法的研究進展[J];安徽農(nóng)業(yè)科學(xué);2011年06期

4 崔斌;王凌;張國印;孫世友;耿暖;茹淑華;陳貴今;;土壤重金屬污染現(xiàn)狀與危害及修復(fù)技術(shù)研究進展[J];安徽農(nóng)業(yè)科學(xué);2012年01期

5 彭剛?cè)A;土壤銅污染對水稻生長及產(chǎn)量的影響研究[J];福建環(huán)境;2000年06期

6 趙小虎;劉文清;張沖;王富華;王紀(jì)陽;鄢珊;趙沛華;羅紅輝;;蔬菜種植前施用石灰對土壤中有效態(tài)重金屬含量的影響[J];廣東農(nóng)業(yè)科學(xué);2007年07期

7 丁淑芳;謝正苗;吳衛(wèi)紅;周溶冰;陳建軍;;含磷物質(zhì)原位化學(xué)鈍化重金屬污染土壤的研究進展[J];安徽農(nóng)業(yè)科學(xué);2012年35期

8 王昕;顏碧蘭;汪瀾;劉晨;劉晶;;鈣礬石對Cr~(6+)和Cr~(2+)的固化及穩(wěn)定性[J];硅酸鹽通報;2013年02期

9 楊亞鴿;崔立強;嚴(yán)金龍;丁成;;鎘污染土壤生物質(zhì)炭修復(fù)的化學(xué)穩(wěn)定機制[J];安徽農(nóng)業(yè)科學(xué);2013年05期

10 王哲;鄭鵬;包明山;白靈燕;;粉煤灰鈍化污泥實驗研究[J];環(huán)境科學(xué)與技術(shù);2013年S2期

本文編號：1546038