本文關(guān)鍵詞：重金屬?gòu)?fù)合污染土壤固定修復(fù)中鈍化劑篩選及其作用機(jī)制　出處：《昆明理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 土壤 重金屬 鈍化劑 生物有效態(tài) 吸附

【摘要】：由于工業(yè)的飛速發(fā)展及各種人類活動(dòng)的干擾,農(nóng)田土壤重金屬污染已嚴(yán)重威脅到農(nóng)作物食品安全及人體健康。面對(duì)土壤重金屬污染,在眾多的修復(fù)技術(shù)中,化學(xué)鈍化修復(fù)技術(shù)因其修復(fù)快、時(shí)間短、操作易、成本低而備受關(guān)注。該修復(fù)技術(shù)的關(guān)鍵在于鈍化劑的選擇。本研究為篩選出能有效鈍化復(fù)合污染土壤中多種重金屬的鈍化劑,首先通過(guò)野外調(diào)查和預(yù)實(shí)驗(yàn)選擇了鋼渣、磷礦粉、坡縷石和木炭作為鈍化劑,在室內(nèi)條件下,采用重金屬生物有效態(tài)單級(jí)提取(二乙三胺五醋酸(DTPA)提取)和重金屬各賦存形態(tài)分級(jí)提取兩種方法,研究了鈍化劑在不同添加濃度(0,5%,20%,鈍化劑與土壤質(zhì)量比)下,對(duì)重金屬(Pb、Cd、Cu、Zn、As)的生物有效態(tài)及各賦存形態(tài)的影響,評(píng)價(jià)了各鈍化劑對(duì)重金屬鈍化效果；其次,于室內(nèi)進(jìn)行了盆栽試驗(yàn),研究了4種鈍化劑對(duì)芹菜、胡蘿卜、番茄的生物量及不同部位重金屬吸收的影響；最后通過(guò)室內(nèi)等溫吸附解吸試驗(yàn),采用x射線衍射法(XRD)和比表面-孔徑分布儀測(cè)定了鈍化劑的物相組成、比表面積和孔徑特征,進(jìn)一步探討了4種鈍化劑與重金屬之間的相互作用機(jī)制。主要研究結(jié)果表明：(1)研究區(qū)域土壤重金屬Pb、Zn、Cu、Cd、As含量嚴(yán)重超過(guò)國(guó)家土壤環(huán)境質(zhì)量標(biāo)準(zhǔn)(GB 15618-1995)的二級(jí)標(biāo)準(zhǔn)。與對(duì)照相比,在施加20%的濃度處理下,坡縷石、鋼渣、磷礦粉能降低土壤中5種重金屬的生物有效態(tài)含量,差異顯著；20%坡縷石、鋼渣、磷礦粉處理均能使土壤pH值顯著提高。(2)土壤重金屬各賦存形態(tài)的分級(jí)提取結(jié)果表明,20%坡縷石能使植物易吸收的土壤可交換態(tài)Pb顯著減少,而使難吸收的殘?jiān)鼞B(tài)Pb顯著增加；20%坡縷石、鋼渣或磷礦粉能顯著降低土壤中可交換態(tài)Cd含量；20%鋼渣或20%磷礦粉處理后可交換態(tài)和碳酸鹽結(jié)合態(tài)Zn含量明顯減少,坡縷石處理使殘?jiān)鼞B(tài)Zn顯著增加；鋼渣或20%磷礦粉能顯著增加殘?jiān)鼞B(tài)Cu含量；添加20%磷礦粉后生物難吸收的鈣型砷含量顯著增加。(3)與對(duì)照相比,20%的鋼渣、磷礦粉、木炭處理均能使胡蘿卜、番茄株高顯著增加；20%的坡縷石能使胡蘿卜株高顯著增加。鋼渣和坡縷石處理能使胡蘿卜生物量顯著增加；4種鈍化劑添加處理后,芹菜生物量與對(duì)照相比顯著增加。鋼渣、磷礦粉能顯著降低胡蘿卜地上、地下部分的As含量,坡縷石、鋼渣、磷礦粉能顯著降低番茄可食部位(果實(shí))中的As含量。4種鈍化劑均顯著降低芹菜葉中的As含量。相比對(duì)照,4種鈍化劑均能顯著降低芹菜根葉和胡蘿卜地下部的Cd含量。4種鈍化劑處理能顯著降低芹菜莖中的Pb含量；坡縷石、鋼渣、磷礦粉處理后,能顯著降低胡蘿卜地下部的Pb含量；磷礦粉和坡縷石處理后能顯著降低番茄可食部位(果實(shí))中的Pb含量。(4)室內(nèi)等溫吸附解吸試驗(yàn)結(jié)果表明,鋼渣、坡縷石、磷礦粉對(duì)重金屬離子Cu、Cd、Pb、As、Zn都有很好的吸附作用；吸附等溫線符合Langmuir方程和Freundlich方程。4種鈍化劑隨初始濃度的增加,對(duì)5種重金屬離子Cu、Cd、 Pb、As、Zn的吸附量均有增加的趨勢(shì)。在相同初始濃度條件下,4種鈍化劑對(duì)重金屬離子的吸附量不同。在相同的平衡濃度條件下,4種鈍化劑對(duì)Cu的吸附量表現(xiàn)為坡縷石鋼渣磷礦木炭；對(duì)的Cd的吸附量表現(xiàn)為鋼渣磷礦粉≈坡縷石木炭；對(duì)的Pb吸附量表現(xiàn)為磷礦粉坡縷石鋼渣木炭；對(duì)As的吸附量表現(xiàn)為在低濃度條件下鋼渣磷礦粉坡縷石木炭,而在高濃度條件下,木炭、磷礦粉、坡縷石對(duì)As的吸附量較為接近；對(duì)的Zn吸附量表現(xiàn)為鋼渣坡縷石磷礦粉木炭。(5)解吸試驗(yàn)表明,鋼渣對(duì)重金屬離子Cd、As、Zn的解吸量較小,磷礦粉、木炭、坡縷石對(duì)5種重金屬離子的解吸量均隨吸附量的增大而增大,具體為：在最大吸附量處,4種鈍化劑對(duì)Zn的解吸量為木炭磷礦粉坡縷石鋼渣；對(duì)As的解吸量為坡縷石木炭磷礦粉鋼渣；對(duì)Pb的解吸量為木炭坡縷石鋼渣磷礦粉；對(duì)Cd解吸量為木炭坡縷石磷礦粉鋼渣；對(duì)Cu解吸量為木炭鋼渣磷礦粉坡縷石。比較發(fā)現(xiàn)4種鈍化劑中木炭對(duì)5種重金屬離子的解吸量均較大。(6)4種鈍化劑中,木炭和坡縷石具有較大的比表面積和孔容,對(duì)重金屬的鈍化機(jī)制可能以物理吸附和離子交換吸附為主；鋼渣和磷礦粉雖然比表面和孔容較小,但具有較高的pH值,對(duì)重金屬的鈍化機(jī)制可能以化學(xué)沉淀反應(yīng)為主。
[Abstract]:Due to the rapid development of industrial interference and various human activities, soil heavy metal pollution has been a serious threat to food safety and human health. In the face of soil heavy metal pollution, in the repair of all kinds of technologies, chemical remediation technology for the repair time is short, fast, easy operation, low cost and concern. The key to the repair technology is the selection of passivator. This study selected the passivation agent can effectively passivated various compound pollution of heavy metals in soil, firstly, through field investigation and experiment selected steel slag, phosphorite powder, palygorskite and charcoal as a passivating agent under indoor conditions with heavy metal bioavailability of single stage extraction (two B three amine five acetic acid (DTPA) extraction) two methods and the heavy metal speciation extraction, passivation agent is added in different concentrations (0,5%, 20%, passivator and soil mass ratio), the money Genera (Pb, Cd, Cu, Zn, As) affect the bioavailability and speciation, evaluation of the effect of the passivation agent for heavy metal passivation; secondly, in the indoor pot experiment, 4 kinds of Passivator on celery, carrot, tomato and heavily influence the biomass of different parts of absorption finally through the interior; isothermal adsorption desorption experiment, using X ray diffraction (XRD) and the passivation determination of specific surface area pore distribution for phase composition, specific surface area and pore characteristics, to further explore the interaction mechanism between the 4 kinds of passivating agent and heavy metals. The main research results are as follows: (1) study on Regional soil heavy metals Pb, Zn, Cu, Cd, As content is more than the national soil environmental quality standard (GB 15618-1995) level two standard. Compared with the control, the concentration of applied 20%, palygorskite, steel slag, phosphate rock powder can reduce 5 kinds of heavy metals in soil organisms Available content, significant difference; 20% palygorskite, steel slag, rock phosphate treatment can significantly increase pH values in soils. (2) the extraction of soil heavy metals in the species showed that 20% palygorskite can make the plant easily absorbed by soil exchangeable Pb decreased significantly, while the hard suction residue Pb increased significantly; 20% palygorskite, steel slag or phosphate powder can significantly reduce the exchangeable Cd concentration in soil; 20% or 20% slag phosphate powder after treatment of exchangeable and carbonate fractions of Zn were significantly reduced, palygorskite treatment residual Zn increased significantly; steel slag or 20% phosphate powder can significantly increase the content of residual Cu; calcium phosphate powder after adding 20% content of arsenic in biological difficult absorption increased significantly. (3) compared with the control group, 20% steel slag, phosphorite powder, charcoal treatment can make the carrot, tomato plant height increased significantly; 20% palygorskite can make Hu Luo, the plant height was significantly Increase of steel slag and palygorskite treatment can make the carrot biomass significantly increased; 4 passivation agent is added after the treatment, the celery biomass increased significantly comparing with the control. The steel slag, phosphate powder can significantly reduce the carrot, As content in the underground part of palygorskite, steel slag, phosphate powder can significantly reduce edible tomato part (fruit) content of As.4 in passivation agent significantly decreased As content in celery leaves. Compared to the control, 4 kinds of passivating agent can significantly reduce celery root leaf and root Cd content of carrot.4 passivation agent can significantly reduce the content of Pb in celery stalk; palygorskite, steel slag after treatment, phosphate rock powder, can significantly reduce the Pb content of carrot root; phosphate powder and palygorskite after treatment can significantly reduce the tomato edible parts (fruit) Pb content. (4) indoor isothermal adsorption desorption test results show that steel slag, palygorskite, phosphorite powder on heavy metals Cd, ion Cu, Pb, As, Zn have good adsorption effect; adsorption isotherm accords with the increase of Langmuir equation and Freundlich equation.4 passivation agent with the initial concentration of the 5 kinds of heavy metal ions Cu, Cd, Pb, As, Zn adsorption were increased. Under the same initial concentration condition 4, the adsorption of heavy metal ions on the passivation agent is different. In the equilibrium concentration under the same conditions, the adsorption capacity of 4 passivation agent on Cu performance of palygorskite phosphate slag charcoal; adsorption capacity of Cd for the performance of steel slag is phosphate palygorskite charcoal; adsorption amount of Pb on the performance of phosphate rock palygorskite slag powder charcoal; adsorption performance of As in steel slag under the condition of low concentration phosphate powder palygorskite charcoal, while in high concentration, charcoal, phosphorite powder, the adsorption capacity of Palygorskite on As is close to Zn; the adsorption capacity of steel slag for the performance of palygorskite phosphorus powder charcoal (5) desorption. The test shows that the slag of heavy metal ions Cd, As, Zn small amount, phosphorite powder, charcoal, palygorskite for 5 kinds of heavy metal ions adsorption desorption increase with the increase of the amount, in particular: the maximum adsorption capacity, 4 kinds of Passivator on Zn desorption of phosphate powder for charcoal palygorskite slag; on As desorption of palygorskite charcoal phosphate slag; on Pb desorption for charcoal palygorskite phosphate slag; on Cd desorption for charcoal palygorskite phosphate slag; on Cu desorption for charcoal slag phosphate powder of palygorskite. Compared 4 kinds of charcoal in passivation agent for 5 kinds of heavy metal ion desorption were larger. (6) 4 kinds of passivator, charcoal and palygorskite has larger surface area and Kong Rong passivation mechanism of heavy metals by physical adsorption and ion exchange adsorption; steel slag and phosphate rock surface and Kong Rong although smaller, but out With high pH value, the passivation mechanism for heavy metals may be dominated by chemical precipitation.

【學(xué)位授予單位】：昆明理工大學(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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本文編號(hào)：1409248