Catalytic steam gasification of food waste using Ni-loaded rice husk derived biochar for hydrogen production

The disposal of food waste (FW) is a major cause of environmental contamination. This study reports an environmentally friendly FW disposal method in the form of catalytic steam gasification using various types of Ni-loaded chars (untreated char, steam-treated char, and ZnCl₂-treated char). The results were also compared with the gasification results from the Ni catalysts supported on commercial α-alumina (Ni/α-Al₂O₃). The Ni/steam-treated char showed the maximum hydrogen generation (0.471 mol/(g feedstock•g cat)) because of the high reducibility, high nickel dispersion, large amount of inherent K and Ca, and moderate surface area. The overall gas and H₂ yield were observed in the following order: Ni/steam-treated char > Ni/ZnCl₂ treated char > Ni/untreated char > Ni/α-Al₂O₃. Brunauer-Emmett-Teller analysis of various catalysts showed that the treated chars have a mesoporous structure, and the X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy – energy dispersive spectroscopy showed that the presence of silica in the chars providing the stable support for the Ni loading and prevented coke formation. The chars obtained from biomass pretreatment could be a potential solution for preventing coke formation at high temperatures, thereby increasing the gas yield and enhancing hydrogen generation.