Effect of Natural and Hydrothermal Synthetic Goethite on the Release of Methane in the Anaerobic Decomposition Process of Organic Matter
天然和水热合成针铁矿对有机物厌氧分解释放CH4的影响

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.