天然和水热合成针铁矿对有机物厌氧分解释放CH4的影响

以乙酸钠为碳源,通过序批式实验研究了天然和水热合成针铁矿对铁还原菌-甲烷菌厌氧微生物生化系统中CH4释放量的影响.通过对实验过程中气体组分、溶液中总有机碳(TOC)、总无机碳(TIC)、Fe2+等主要组分的分析测定和固体产物的X-射线衍射(XRD)分析,结合对矿物的比表面(BET)、XRD、X-射线荧光光谱(XRF)分析表征,探讨了针铁矿在铁还原菌存在下对有机物厌氧消化产CH4的影响和作用机制.利用修正Gompertz方程对累计产CH4和CO2量进行拟合.结果表明,与对照实验组相比,添加针铁矿能使CH4累计释放量提前60～78 d达到最大值,并且能有效降低CO2释放量达30%～67%,添加水热合成针铁矿较之天然针铁矿更能促进CH4释放和减少CO2释放;固体产物分析表明添加针铁矿促使菱铁矿形成固定部分CO2.

Effect of Natural and Hydrothermal Synthetic Goethite on the Release of Methane in the Anaerobic Decomposition Process of Organic Matter

The effects of natural goethite (NGt) and synthetic goethite (SGt) on the release of methane in the anaerobic biochemical system consisted of dissimilatory iron-reducing bacteria (DIRB) and methane-producing bacteria (MPB) were investigated through batch tests with sodium acetate as the carbon source. To explore the effects and mechanisms of both mineral materials on the release of methane in the anaerobic decomposition process of organic matter in the presence of DIRB, the main gas components and total organic carbon (TOC), total inorganic carbon (TIC), and Fe²⁺ in the aqueous phase of the experimental process were determined and XRD analyses were conducted for the solid-phase product. Moreover, the minerals were analyzed by specific surface area (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF). Modified Gompertz equation was used to fit the cumulative methane and carbon dioxide. Results showed that the maximum cumulative production of methane was brought forward by 60-78 days by the addition of goethite and CO₂ was effectively reduced by 30%-67% compared with the control samples. SGt was more effective than NGt in promoting the release of CH₄ and reducing the CO₂ emission. Furthermore, the analysis of the solid product showed that the addition of goethite can fix part of CO₂ by the formation of siderite.