本文選題：鐵氧化菌 + 生物成因　； 參考：《中國地質(zhì)大學(xué)(北京)》2016年博士論文

【摘要】：砷是一種自然界中常見的有毒物質(zhì),其通過世界范圍內(nèi)廣泛分布的高砷地下水威脅成千上萬人的身體健康,對高砷水進行處理顯得尤為重要。高砷地下水往往含有較高濃度的亞鐵離子,因此利用鐵氧化菌氧化亞鐵離子產(chǎn)生的鐵氧化物礦物除砷是目前除砷領(lǐng)域研究的熱點之一。本文以好氧菌Pseudomonas sp.strain GE-1和厭氧菌Pseudogulbenkiania sp.strain 2002為研究對象,利用室內(nèi)實驗,研究了這兩株菌的氧化Fe(II)特征和機理,揭示了在不同除砷條件下鐵氧化菌氧化Fe(II)過程的除砷效果和影響因素,并利用譜學(xué)手段揭示了除砷機理。Strain GE-1的亞鐵氧化過程以硝酸鹽作為電子受體,生成弱結(jié)晶的兩線水鐵礦。高濃度砷存在時,特別是As(III)存在時,strain GE-1的亞鐵氧化過程、能量物質(zhì)ATP的變化以及硝酸鹽的還原等出現(xiàn)滯后現(xiàn)象。不論As(III)還是As(V),都可以被GE-1介導(dǎo)的共沉淀和吸附過程有效地去除。共沉淀過程對As(V)的去除效果較好,而吸附過程則對As(III)的去除效果較好。培養(yǎng)液中砷形態(tài)的檢測顯示,共沉淀過程中As(V)被還原成As(III),而吸附過程則沒有檢測到As(V)的還原。在無氧條件下,strain GE-1介導(dǎo)產(chǎn)生的兩線水鐵礦對砷的吸附符合假二級動力學(xué)模型,擴散過程是吸附過程的主要控制步驟,在此過程中沒有觀察到As(III)的氧化或As(V)的還原。然而,在好氧條件下,無論是共沉淀還是吸附過程,As(III)在GE-1誘導(dǎo)產(chǎn)生的水鐵礦表面均被氧化成As(V)。Strain 2002具有很強的耐砷能力,特別是As(V),其最大As(V)的耐受能力約為1000 mg/L。當(dāng)有高濃度的砷存在時,strain 2002的形貌趨于變短。非生長條件下strain 2002可以迅速氧化亞鐵,并產(chǎn)生纖鐵礦沉淀,而且在不改變砷形態(tài)的情況下,有效去除培養(yǎng)液中的As(III)和As(V)。當(dāng)初始Fe/As保持不變時,較高初始濃度的亞鐵產(chǎn)生較好的除砷效果,并使砷在纖鐵礦表面的覆蓋度升高。X射線精細(xì)結(jié)構(gòu)結(jié)果表明,當(dāng)固定初始As(III)或As(V)濃度時,初始亞鐵濃度的改變并不影響砷的表面絡(luò)合模式(雙齒雙核共角表面絡(luò)合)。當(dāng)固定初始亞鐵濃度時,初始As濃度的升高導(dǎo)致砷在纖鐵礦中的表面覆蓋度升高;其中,As(III)表面覆蓋度的升高與雙齒雙核共角表面絡(luò)合模式和雙齒單核共邊表面絡(luò)合模式的共存有關(guān);而As(V)表面覆蓋度的升高是雙齒雙核共角表面絡(luò)合模式和單齒單核共邊表面絡(luò)合模式共存的結(jié)果。無論是好氧菌GE-1還是厭氧菌strain 2002,其亞鐵氧化過程都具有很好的除砷效果,并且這兩種菌的生長都可以利用硝酸鹽作為電子受體,這給砷-硝酸鹽共污染水體的原位治理提供了非常有效的潛在治理方案。
[Abstract]:Arsenic is a common toxic substance in nature. It threatens the health of thousands of people through the widespread distribution of high arsenic groundwater in the world, so it is particularly important to treat high arsenic water. High arsenic groundwater often contains high concentration of ferrous ions, so iron oxide minerals produced by ferric oxide oxidized by ferric oxide bacteria are one of the hot spots in the field of arsenic removal. In this paper, using aerobic Pseudomonas sp.strain GE-1 and anaerobes Pseudogulbenkiania sp.strain 2002 as research objects, the characteristics and mechanism of FeII oxidation of these two strains were studied by laboratory experiments, and the effect of removing arsenic and influencing factors on the oxidation of FeII by ferric oxidizing bacteria under different arsenic removal conditions were revealed. The mechanism of arsenic removal in ferrite oxidation process of Strain GE-1 was revealed by means of spectroscopic method. Nitrates were used as electron receptors to form weakly crystallized two-wire hydrite. In the presence of high concentration of arsenic, especially in the presence of As-III, the process of ferrous oxidation of strain GE-1, the change of ATP, and the reduction of nitrate are delayed. Both ASI and ASV can be effectively removed by GE-1 mediated coprecipitation and adsorption processes. The coprecipitation process has a better removal efficiency of ASV, while the adsorption process has a better removal effect of AS-III. The determination of arsenic forms in the culture medium showed that during the coprecipitation process, AsHV was reduced to AsHIIIN, but no reduction was detected during the adsorption process. The adsorption of arsenic by two-wire water ore induced by strain GE-1 under anaerobic conditions accords with the pseudo-second-order kinetic model. The diffusion process is the main control step of the adsorption process, and no oxidation of AsHI-III or reduction of As-V) is observed in this process. However, under aerobic conditions, both coprecipitation and adsorption processes have been oxidized to As(V).Strain 2002 on the surface of the water ore induced by GE-1. It is found that As(V).Strain 2002 has a strong arsenic tolerance, especially the maximum aspartic V (1000 mg / L). The morphology of strain 2002 tends to be shorter in the presence of high concentration of arsenic. Under non-growth condition, strain 2002 can oxidize ferrous rapidly and produce pyrite precipitate. Without changing the arsenic form, strain 2002 can effectively remove the ascorbic acid and ascorbic acid in the culture medium. When the initial Fe/As remained constant, the high initial concentration of ferrous produced a better arsenic removal effect, and the coverage of arsenic on the surface of the fiberite was increased. The results of X-ray fine structure showed that when the initial concentration of as II I or AsV) was fixed, The change of initial ferrous concentration does not affect the surface complexation mode of arsenic. When the initial ferrous concentration is fixed, the increase of as concentration leads to the increase of surface coverage of arsenic in pyrite. The increase of the surface coverage is related to the coexistence of the co-angular surface complexation mode and the co-edge surface complexation mode of the bicententate mononuclear. However, the increase of surface coverage is the result of the coexistence of the coplanar surface complexation mode of double-tooth binuclear and single-toothed mononuclear coplanar surface complexation mode. Both aerobic GE-1 and anaerobes strain 2002 have a good arsenic removal effect in the process of ferrous oxidation, and the growth of both bacteria can use nitrate as an electron receptor. This provides a very effective and potential treatment scheme for arsenic-nitrate co-polluted water in situ treatment.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：X52;X172

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