Experimental study on the characteristics of methanotrophs in degrading coal seam methane using a RL-TW80 formulation

Abstract

Deep coal seams exhibit strong hydrophobicity and significant gas–liquid-solid interfacial mass transfer resistance, which severely limit methane degradation by methanotrophs . To address this, an interfacial chemical modification method combining anionic and nonionic surfactants with bacterial suspensions was proposed. First, a community of methanotrophs was screened and enriched, and their growth characteristics and methane degradation capabilities in different surfactant solutions were investigated. Subsequently, experiments on wettability, interfacial tension, and quantitative adsorption were conducted to study the effects of the composite system on interfacial wetting properties and bacterial adhesion. The results indicate that the methane degradation rate of the enriched bacterial community reached 54.86% within 24 h. The optimal RL:TW80 blend system (total concentration 0.048%, RL:TW80 = 7:3) improved methane degradation performance by approximately 15%, while reducing the surface tension to 41.81 mN/m and the stabilized contact angle on coal surfaces to 26.7°. The blend system also increased the maximum microbial adhesion capacity by 8.21% and significantly shortened the time required to reach the stable adhesion state. These results indicate that the primary advantage of this blend system lies in simultaneously improving microbial compatibility and gas–liquid–solid interfacial mass transfer, thereby enhancing the microbial degradation efficiency of methane and providing a new technical approach for the biological treatment of coal mine gas.