本文選題：微生物燃料電池(MFC) + 非緩沖　； 參考：《江南大學(xué)》2017年碩士論文

【摘要】：微生物燃料電池(Microbial fuel cell,MFC)可同步實(shí)現(xiàn)能源轉(zhuǎn)換及廢棄物處置,是環(huán)境技術(shù)研究熱點(diǎn)。目前,實(shí)驗(yàn)室小型MFC運(yùn)行過(guò)程中,一般需要加入PBS緩沖液或NaHCO3溶液,用以維持一定的離子強(qiáng)度和pH值,保障體系高效穩(wěn)定的運(yùn)行。然而,未來(lái)MFC在污水處理領(lǐng)域的大規(guī)模應(yīng)用需要在無(wú)緩沖條件下進(jìn)行,因?yàn)樘砑泳彌_鹽會(huì)增大運(yùn)行成本,且可能造成出水富營(yíng)養(yǎng)化等環(huán)境問(wèn)題。非緩沖MFC體系中,陽(yáng)極表面不斷產(chǎn)生并積累質(zhì)子(H+),出現(xiàn)“陽(yáng)極酸化”現(xiàn)象,嚴(yán)重限制產(chǎn)電微生物的生長(zhǎng)和活性。因此,欲進(jìn)一步提高非緩沖MFC體系產(chǎn)電能力,使其更具實(shí)用價(jià)值,解決“陽(yáng)極酸化”問(wèn)題是關(guān)鍵。本課題通過(guò)外加短期堿性調(diào)控和陽(yáng)極液回用的方法,緩解了非緩沖空氣陰極MFC體系的“陽(yáng)極酸化”問(wèn)題,強(qiáng)化了體系產(chǎn)電性能。主要研究?jī)?nèi)容與結(jié)果如下:(1)利用堿處理陰離子交換樹(shù)脂(AER)中和陽(yáng)極液中積累的H+,以此緩解產(chǎn)電初期“陽(yáng)極酸化”對(duì)產(chǎn)電微生物生長(zhǎng)和活性的限制。實(shí)驗(yàn)結(jié)果表明,運(yùn)行過(guò)程中,以KCl溶液為陽(yáng)極液的KCl-MFC體系的pH值從7.09下降到5.82,出現(xiàn)了“陽(yáng)極酸化”現(xiàn)象。將堿處理AER置于KCl陽(yáng)極液中,在運(yùn)行中前四天內(nèi),AER表面的OH-被完全釋放,此后陽(yáng)極液pH值先快速降低到5.87后回升到6.66,并保持穩(wěn)定。兩個(gè)周期的短期堿性干預(yù),促進(jìn)了陽(yáng)極表面電化學(xué)活性Geobacter的增殖,提高了陽(yáng)極生物膜的電化學(xué)活性,最終KCl-AER-MFC體系的最大功率密度(Pmax)由307.5 mW/m2顯著提高到542.8 m W/m2。(2)通過(guò)對(duì)非緩沖KCl陽(yáng)極液初始pH值進(jìn)行短期堿性調(diào)控,緩解了“陽(yáng)極酸化”對(duì)體系運(yùn)行初期陽(yáng)極表面產(chǎn)電微生物增殖和生物膜形成的影響,最終提高了MFC體系的產(chǎn)電性能。實(shí)驗(yàn)確定了陽(yáng)極液初始pH值調(diào)控的最佳方案,即在5個(gè)運(yùn)行周期內(nèi)將陽(yáng)極液初始pH值調(diào)為9。KCl-pH9-MFC體系短期的陽(yáng)極液初始pH值調(diào)控,促進(jìn)了電化學(xué)活性微生物Geobacter在陽(yáng)極表面的繁殖,其相對(duì)豐度由59.01%升高到75.12%,陽(yáng)極電化學(xué)活性顯著提高,電子生成效率提高。因此,在H+擴(kuò)散限制的條件下,空氣陰極利用電子產(chǎn)生OH-的效率相對(duì)較高,提高了陽(yáng)極液的整體pH值,最終體系的Pmax由321.04 mW/m2顯著提高到536.38 mW/m2。短期的堿性調(diào)控建立了陽(yáng)極液pH值與陽(yáng)極生物膜產(chǎn)電活性之間新的平衡關(guān)系,使得體系較高產(chǎn)電性能具有可持續(xù)性。(3)通過(guò)對(duì)非緩沖陽(yáng)極液進(jìn)行一定比例的回用,加快陽(yáng)極反應(yīng)產(chǎn)生的自生緩沖物質(zhì)(H2CO3和HCO3-)的積累,消除非緩沖MFC體系的“陽(yáng)極酸化”現(xiàn)象。KCl-R-MFC體系陽(yáng)極液前3個(gè)周期pH值快速升高,第4周期陽(yáng)極液起始pH值已經(jīng)達(dá)到8.19并隨著運(yùn)行周期的增多而緩慢上升。陽(yáng)極液中相應(yīng)無(wú)機(jī)碳(IC)濃度也由15.85 mmol/L升高到59.10 mmol/L。經(jīng)過(guò)多個(gè)周期的回用后,KCl-R-MFC體系的Pmax由322.91 mW/m2增加到527.22 m W/m2,與PBS-MFC體系相近(523.74 mW/m2)。
[Abstract]:Microbial fuel cell (MFCs), which can realize energy conversion and waste disposal synchronously, is a hotspot of environmental technology research. At present, in order to maintain certain ionic strength and pH value, it is necessary to add PBS buffer or NaHCO3 solution in the process of small-scale MFC operation in laboratory to ensure the efficient and stable operation of the system. However, the future large-scale application of MFC in the field of sewage treatment needs to be carried out without buffer, because adding buffer salt will increase the operation cost and may cause environmental problems such as eutrophication of effluent. In the non-buffer MFC system, proton H ~ (2 +) is produced and accumulated on the anode surface, and the phenomenon of "anodic acidification" occurs, which seriously limits the growth and activity of electroproducing microorganisms. Therefore, in order to further improve the power generation capacity of non-buffer MFC system and make it more practical, the key to solve the problem of "anodic acidification" is to solve the problem of anodic acidification. In this paper, the problem of "anodic acidification" of non-buffer air cathode MFC system was alleviated by adding short-term alkaline control and anodic solution reuse, and the electrical performance of the system was strengthened. The main contents and results are as follows: (1) neutralizing H accumulation in anion exchange resin (AER1) by alkali treatment, so as to alleviate the limitation of "anodic acidification" on the growth and activity of electroproducing microorganisms in the early stage of electricity production. The results showed that the pH value of KCl-MFC system with KCl solution as anodic solution decreased from 7.09 to 5.82 during the operation, and the phenomenon of "anodic acidification" appeared. After alkaline treatment of AER in KCl anodic solution, OH- on the surface of KCl was completely released within four days before operation. After that, the pH value of the anodic solution decreased rapidly to 5.87 and then increased to 6.66, and remained stable. The short-term alkaline intervention of two cycles promoted the proliferation of electrochemical activity of Geobacter on anode surface and enhanced the electrochemical activity of anode biofilm. In the end, the maximum power density (Pmax) of KCl-AER-MFC system was significantly increased from 307.5 mW/m2 to 542.8 MW / m2). The effect of "anodic acidification" on the proliferation of electroproducing microorganisms and biofilm formation on the anode surface at the initial stage of the system was alleviated, and the electrical properties of the MFC system were finally improved. The optimal control scheme of initial pH value of anodic solution was determined, that is, the initial pH value of anodic solution was adjusted to the initial pH value of 9.KCl-pH9-MFC system for a short period in five operating cycles, which promoted the propagation of electrochemical active microorganism Geobacter on the anode surface. The relative abundance increased from 59.01% to 75.12%, the electrochemical activity of anode and the efficiency of electron generation were improved significantly. Therefore, under the condition of H diffusion limitation, the efficiency of using electron to produce OH- in the air cathode is relatively high, and the overall pH value of the anodic solution is increased. The Pmax of the final system is increased from 321.04 mW/m2 to 536.38 MW / m2. The new equilibrium relationship between the pH value of the anode solution and the electrochemical activity of the anode biofilm was established by the short-term alkaline control, which made the system have the sustainability of higher electrical properties. (3) by reusing the non-buffer anode solution in a certain proportion, the pH value of the anode solution and the electroproduction activity of the anode biofilm were reused. The accumulation of endogenous buffer substances (H2CO3 and HCO3-) from anodic reaction was accelerated, and the "anodic acidification" phenomenon in non-buffer MFC system was eliminated. The pH value of anodic solution in KCl-R-MFC system increased rapidly during the first three cycles. The initial pH of the anodic solution reached 8.19 in the fourth cycle and increased slowly with the increase of the operating cycle. The concentration of inorganic carbon in anodic solution also increased from 15.85 mmol/L to 59.10 mmol / L. After several cycles of reuse, the Pmax of KCl-R-MFC system increased from 322.91 mW/m2 to 527.22 MW / m2, which was similar to that of PBS-MFC system (523.74 MW / m2).
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TM911.45

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相關(guān)期刊論文 前1條

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本文編號(hào)：1872674