Porous hollow microspheres based on industrial solid waste enhance biomethane recovery from corn straw

The increasing production of industrial solid waste requires better disposal solutions. Porous hollow microspheres (PHM) are small inorganic materials with high surface area and adsorption capacity, but their potential for use in anaerobic digestion (AD) has not been explored. With PHM as additive, the effects of different industrial solid wastes (waste glass, steel slag, and fly ash) with different loadings (2 %-8 %), respectively, on the AD of corn straw were investigated in this study. The results showed that PHM could supplement trace elements and promote biofilm formation, which effectively shortened the lag period (25.00-60.87 %) and increased the methane yield (4.75 %-16.28 %). The 2 % PHM loading based on steel slag gave the highest methane yield (300.16 NmL/g VS_add). Microbial and PICRUSt2 analyses indicated that PHM enriched hydrolytic and acidogenic bacteria, increased the abundance of methanogenesis-related enzyme genes. This study provides a theoretical basis for the comprehensive utilization of coupled industrial and agricultural wastes.