發(fā)布時間：2018-07-16 07:46

【摘要】：鐵作為地殼中豐度第四的元素廣泛存在于土壤、沉積物、沉積巖里的粘土礦物中。粘土礦物由于其巨大的比表面積、表面活性以及陽離子交換能力,通常與沉積物中的有機質(zhì)結(jié)合在一起。粘土礦物通過對陸地環(huán)境中有機質(zhì)的吸附、富集和埋藏,對大氣中氧的上升起到了非常中要的作用。微生物是地表鐵循環(huán)的核心參與者,以細胞體外發(fā)生鐵的氧化還原反應為特征的異化作用是自然界鐵循環(huán)的重要驅(qū)動力。研究微生物與有機粘土礦物之間的相互作用關(guān)系,對于研究Si、Al、Fe和C等重要的化學元素在地質(zhì)過程中的循環(huán)、污染物遷移、有機質(zhì)埋藏和石油產(chǎn)生方面,都具有重要的意義。本文從微生物的鐵還原作用對粘土礦物保存有機質(zhì)的影響和微生物對粘土礦物中有機質(zhì)的利用情況兩點出發(fā),對微生物與有機質(zhì)-綠脫石復合體相互作用進行了初步探索。在微生物的鐵還原作用對粘土礦物保存有機質(zhì)的影響實驗中,選擇有機質(zhì)12-氨基十二酸(ALA)插層到綠脫石NAu-2中,合成有機粘土ALA-NAu-2,與高溫菌Thermus scotoductus SA-01(65 oC)和超高溫菌Geoglobus ahangari(85 oC)分別進行微生物與有機粘土礦物相互作用研究。實驗結(jié)果表明有機質(zhì)進入粘土礦物層間后抑制了微生物對結(jié)構(gòu)Fe(Ⅲ)的還原。經(jīng)過微生物作用后,粘土礦物發(fā)生還原溶解,層間有機質(zhì)隨著不斷從粘土礦物中釋放出來,由于微生物還原能力有限(30%),總體來說有機質(zhì)在粘土礦物中可以得到很好的保存。超高溫環(huán)境相對于高溫環(huán)境有機質(zhì)釋放的含量較多,表明溫度越高越不利于有機質(zhì)的保存。在微生物對綠脫石中有機質(zhì)利用的研究實驗中,選取嗜熱菌Thermus scotoductus SA-01(65℃),以及常溫菌Shewanella putrefaciens CN32(30℃)為異化鐵還原菌,分別在沒有外加碳源的情況下對NAu-2結(jié)構(gòu)鐵進行還原。實驗結(jié)果表明相對于常溫菌CN-32,嗜熱菌SA-01可以有效利用綠脫石中含有的微量有機質(zhì)作為碳源。由此可知,粘土礦物經(jīng)微生物作用后發(fā)生還原溶解,其吸附的有機質(zhì)會隨著溶解程度的升高不斷釋放到周圍環(huán)境中;粘土礦物含有的有機質(zhì)組分成分復雜,在不同溫度環(huán)境下釋放出來的有機質(zhì)速率與種類有所不同。
[Abstract]:Iron, the fourth most abundant element in the crust, is widely found in clay minerals in soils, sediments, and sedimentary rocks. Clay minerals are usually combined with organic matter in sediments due to their large specific surface area, surface activity and cation exchange ability. Clay minerals play a very important role in the increase of oxygen in the atmosphere through the adsorption, enrichment and burial of organic matter in terrestrial environment. Microbes are the core participants in the surface iron cycling. The dissimilation characterized by the redox reaction of iron in the cells in vitro is an important driving force of iron cycling in nature. The study of the interaction between microbes and organic clay minerals is of great significance in the study of the circulation of important chemical elements such as Si-AlFe and C in geological processes, pollutant migration, organic matter burial and petroleum generation. In this paper, the interaction between microorganism and organic matter in clay minerals has been preliminarily explored from two aspects: the effect of iron reduction by microorganisms on the preservation of organic matter in clay minerals and the utilization of organic matter in clay minerals by microorganisms. In the experiment of the effect of microorganism iron reduction on the preservation of organic matter in clay minerals, the organic matter 12-amindodecanoic acid (Ala) was intercalated into the green demineralized NAu-2. The organic clay ALA-NAu-2 was synthesized, and the interaction between microbes and organic clay minerals was studied with Thermus scotoductus SA-01 (65oC) and Geoglobus ahangari (85oC), respectively. The results show that organic matter can inhibit the reduction of structural Fe (鈪，

本文編號：2125721