Bioorganic activated carbon from cashew nut shells for H2 adsorption and H2/CO2, H2/CH4, CO2/CH4, H2/CO2/CH4 selectivity in industrial applications

Abstract

This research explores the production of activated carbon (AC) from cashew nut shells using a potassium hydroxide (KOH) activation method, with a focus on its application in high-pressure gas adsorption. Among the synthesized samples, AC850 demonstrated the highest efficiency, displaying a specific surface area of 1972 m2/g and total and micropore volumes of 0.847 cm3/g and 0.724 cm3/g, respectively. The bioorganic activated carbon exhibited significant sorption capabilities for H2, with uptake values of 13.34 mmol/g (2.69 wt%) at 10 bar and 25 °C, and a H2/CH4 selectivity range between 43.4 and 2.6. Calculations were also conducted for selectivity in a mixture of three gases (H2, CO2, and CH4) in industrial settings. Advanced characterization methods such as N2/CO2 adsorption isotherms, FT-IR, Raman spectroscopy, SEM, and TGA were employed to analyze the structural and chemical properties of the produced AC, including its functional groups and molecular structure. The research underscores the potential of utilizing agricultural waste, particularly cashew nut shells, to develop efficient materials for H2 storage and purification. The high-pressure adsorption capability and eco-friendly nature of the manufactured activated carbon make it suitable for both environmental and industrial applications.