【摘要】：鐵礦的采選不僅造成大量固體廢物的排放和堆存,而且選礦藥劑和重金屬污染還會(huì)通過不同方式進(jìn)入大氣、水體和土壤中,造成嚴(yán)重的環(huán)境污染。因此鐵尾礦的土壤化、資源化利用不僅是突破鐵礦產(chǎn)業(yè)環(huán)境瓶頸的重要措施,而且可以解決礦山修復(fù)過程中土壤資源不足的問題。本研究可為微生物技術(shù)修復(fù)土壤中的重金屬污染提供理論基礎(chǔ),具有極為重要的應(yīng)用價(jià)值。傳統(tǒng)的修復(fù)重金屬污染的鐵尾礦的方法根據(jù)原理可分為化學(xué)法、物理法和生物法�；瘜W(xué)法使用的添加劑會(huì)導(dǎo)致土壤的二次污染,而物理修復(fù)技術(shù)成本高,流程及設(shè)備操作復(fù)雜。生物修復(fù)技術(shù)綠色環(huán)保且不會(huì)產(chǎn)生二次污染,在重金屬污染修復(fù)領(lǐng)域展現(xiàn)了廣闊的應(yīng)用前景,近年來逐漸成為污染土壤原位修復(fù)的首選技術(shù)。本文針對(duì)鞍山鐵尾礦重金屬污染的實(shí)際狀況,篩選出了耐受Pb、Mn和Zn的土著菌種,并優(yōu)化修復(fù)作用條件以提高修復(fù)效率,然后研究其在鐵尾礦土壤化利用過程中的應(yīng)用,有效改善鐵尾礦肥力,提高鐵尾礦利用效率。主要研究?jī)?nèi)容和結(jié)論如下:通過富集培養(yǎng)技術(shù),對(duì)鐵尾礦樣品進(jìn)行馴化后,獲得了能夠耐受Pb、Mn和Zn重金屬污染的菌種。對(duì)菌種的內(nèi)轉(zhuǎn)錄區(qū)間經(jīng)過擴(kuò)增后比對(duì),分別繪制各菌種的系統(tǒng)進(jìn)化樹。三種菌種分別為能夠耐受Pb污染的土著菌種-卷枝毛霉,耐受Mn污染的土著菌種-棘孢木霉,耐受Zn污染的土著菌種-被孢霉,三種菌種在液體培養(yǎng)基中培養(yǎng)12h后基本達(dá)到對(duì)數(shù)生長期,生物學(xué)特征明顯,對(duì)重金屬污染具有較強(qiáng)的耐受能力,同時(shí)能很好地適應(yīng)環(huán)境,為重金屬污染鐵尾礦的微生物修復(fù)提供了技術(shù)支持。通過吸附實(shí)驗(yàn),以三種真菌活化后的菌絲作為吸附劑,分別用卷枝毛霉吸附Pb2+,棘孢木霉吸附Mn2+,被孢霉吸附Zn2+,分別考察了溫度、pH和初始接種量對(duì)各菌種吸附效果的影響。結(jié)果表明卷枝毛霉對(duì)Pb2+和棘孢木霉對(duì)Mn2+的吸附作用最佳pH為6,被孢霉對(duì)Zn2+的最佳pH為7;卷枝毛霉對(duì)Pb2+、被孢霉對(duì)Zn2+吸附作用的最佳溫度都為26℃,而棘孢木霉對(duì)Mn2+的吸附作用的最佳溫度為28℃;卷枝毛霉和棘孢木霉分別對(duì)Pb2+和Mn2+的吸附率在初始接種量為1.0ml的時(shí)達(dá)到最大值,而在初始接種量為1.2ml的條件下被孢酶對(duì)Zn2+的吸附率最大。在初始重金屬離子濃度設(shè)置為20mg/L時(shí),卷枝毛霉菌種對(duì)Pb2+、棘孢木霉菌種對(duì)Mn2+以及被孢霉菌種對(duì)Zn2+的吸附率分別達(dá)到了 95.46%、92.78%和86.89%。三種菌種都可以很好的吸附溶液中的重金屬離子,吸附能力最強(qiáng)的為卷枝毛霉,其次是棘孢木霉,最小的是被孢霉。通過吸附實(shí)驗(yàn),分別研究了最佳實(shí)驗(yàn)條件下卷枝毛霉菌種對(duì)Pb2+、棘孢木霉菌種對(duì)Mn2+以及被孢霉菌種對(duì)Zn2+的吸附熱力學(xué)和動(dòng)力學(xué)曲線,發(fā)現(xiàn)Langmuir型等溫吸附模型可以用于擬合三種菌種分別對(duì)重金屬離子的吸附作用過程,并且根據(jù)公式算得的卷枝毛霉對(duì)Pb2+、棘孢木霉對(duì)Mn2+、被孢霉對(duì)Zn2+的最大吸附量分別為79.76、76.42和78.16 mg/g,R2分別為0.9932、0.9693和0.9759,比較R2可知,卷枝毛霉對(duì)Pb2+的親和力大于另外兩種菌種的親和力。將卷枝毛霉對(duì)Pb2+、棘孢木霉對(duì)Mn2+、被孢霉對(duì)Zn2+的吸附曲線分別進(jìn)行擬合發(fā)現(xiàn),擬合曲線符合偽二級(jí)動(dòng)力學(xué)模型,說明菌種主要通過離子交換和絡(luò)合等反應(yīng)吸附重金屬,卷枝毛霉對(duì)Pb2+,棘孢木霉對(duì)Mn2+以及被孢霉對(duì)Zn2+的最大吸附量分別為77.42、75.00和68.57 mg/g;R2分別為0.9991、0.9192和0.9844,卷枝毛霉對(duì)Pb2+的吸附曲線擬合效果較好,三種菌種對(duì)重金屬吸附量都較高,說明它們?cè)谥亟饘傥廴捐F尾礦的原位修復(fù)中具有較高的應(yīng)用潛力。通過現(xiàn)場(chǎng)應(yīng)用研究,分析混合菌劑對(duì)鐵尾礦中重金屬可交換態(tài)、酶活性以及微生物多樣性的影響。將菌種混合培養(yǎng)后制成微生物菌劑,應(yīng)用到鐵尾礦土壤化利用的過程中。結(jié)果表明,實(shí)驗(yàn)室微生物菌劑對(duì)重金屬具有較好的固定作用,固定效率分別為74.98%(Zn)、85.29%(Pb)和79.41%(Mn),微生物菌劑的添加使得鐵尾礦中的微生物數(shù)量增加(p0.05),其中細(xì)菌、真菌和放線菌的數(shù)量分別比施加菌劑前分別增加了 16.81%、34.62%和27.63%。同時(shí)經(jīng)微生物菌劑處理的鐵尾礦過氧化氫酶和脲酶的活性比施加菌劑前分別增加了 68.79%和56.47%,說明隨著鐵尾礦中重金屬可交換態(tài)的含量的降低對(duì)酶活性的抑制作用減弱,且微生物數(shù)量與酶活呈顯著相關(guān)。鐵尾礦的微生物多樣性指數(shù)(Shannon-Wiener指數(shù))由3.7增加到了 4.05,說明微生物菌劑的添加對(duì)鐵尾礦中微生物的多樣性有促進(jìn)作用,有效改良了鐵尾礦的生物群落結(jié)構(gòu),促進(jìn)了鐵尾礦中微生物的生長和繁殖(p0.05)。
[Abstract]:The selection of iron ore not only leads to the discharge and pollution of large quantities of solid waste, but also the ore dressing agent and heavy metal pollution can enter the atmosphere, water and soil in different ways, causing serious environmental pollution. Therefore, the soil treatment and resource utilization of iron tailings is not only an important measure to break through the environmental bottleneck of iron ore industry, but also can solve the problem of insufficient soil resources in mine tailings. This study can provide a theoretical basis for the remediation of heavy metal pollution in soil by microbial technology, and it has extremely important application value. The traditional method for repairing heavy metal contaminated iron tailings can be divided into chemical, physical and biological methods according to the principle. The additive used in the chemical method can lead to secondary pollution of the soil, and the physical repair technology has high cost, and the flow and equipment operation is complicated. The bioremediation technology is green and environment-friendly and does not generate secondary pollution, has a wide application prospect in the field of heavy metal pollution remediation, and gradually becomes the preferred technology for in-situ remediation of polluted soil in recent years. In the light of the actual situation of heavy metal pollution in iron tailings tailings, this paper selects indigenous strains tolerant of Pb, Mn and Zn, and optimizes the repair conditions to improve the efficiency of remediation, and then studies its application in the process of soil utilization of iron tailings, and effectively improves the fertility of iron tailings. and the utilization efficiency of the iron tailings is improved. The main research contents and conclusions are as follows: After acclimation of iron tailings samples by enrichment culture technique, strains which can tolerate heavy metal pollution of Pb, Mn and Zn are obtained. The internal transcribed region of the strain is amplified and compared with each other, and the phylogenetic tree of each strain is respectively drawn. The three strains are indigenous strains capable of tolerating Pb pollution, chaetchaete chrysosporium, indigenous strains resistant to Mn pollution, and indigenous species-Mortierella sp. which are tolerant of Zn pollution, and three strains are cultured in a liquid culture medium for 12h to basically reach logarithmic growth phase, and the biological characteristics are obvious. has strong tolerance to heavy metal pollution, can well adapt to the environment, and provides technical support for bioremediation of heavy metal contaminated iron tailings. The effects of temperature, pH and initial inoculum on the adsorption of strains were studied by adsorption experiments and adsorption of the mycelium of three kinds of fungi as adsorbent. The results showed that the optimum pH of the adsorption of M _ 2 + was 6, the optimum pH was 7, the optimum pH was 26 鈩，

本文編號(hào)：2274466