Synergetic co-carbonization of rice husk and manure sludge for enhanced catalytic support in dry reforming of methane

Abstract

Methane dry reforming process is a promising method which utilizes carbon dioxide and methane to produce syngas composed of hydrogen and carbon monoxide, which has the advantage of utilizing greenhouse gases that cause global warming while also producing useful chemical feedstocks. In this study, swine manure sludge, which can deliver high alkaline earth metal content when carbonized, and rice husk, which can provide relatively high surface area during carbonization, were co-carbonized in various proportions to synthesize activated carbon and check its performance as a catalyst support for dry reforming with nickel. The catalytic supports from co- carbonization of swine manure sludge and rice husk in 1:2 and 1:4 mass ratios showed higher surface area than the carbonized manure sludge and higher alkaline earth metal content than the carbonized rice husk, and improved performance in the methane dry reforming reaction at 850 °C. Several chemical activation strategies were then applied to the activated carbon with 1:4 mass ratio, which showed the highest catalytic activity, to evaluate their effects on the physicochemical properties and activity of the catalyst. As a result, pretreatment with strong acids and hydrogen peroxide, which increase oxygen-containing functional groups through surface oxidation, increase the initial reaction efficiency of the catalyst, while acid washing and alkaline activation, which lead to alkaline earth metal removal, resulted in an overall decrease in activity despite an largely expanded surface area. These results confirm that co-carbonization and chemical activation can affect the physicochemical properties and catalytic performance of waste-derived biochar/activated carbon. The results of this study are expected to improve the understanding of methane dry reforming using waste-based catalysts and help to establish long-term greenhouse gas and waste utilization strategies.