Sustainability and scalability of low value agro and forestry wastes into activated carbon value chains

This review examined the sustainability and growth potential of converting low-value agro-forestry waste into activated carbon (AC). Various agricultural and forestry residues have been successfully converted into AC, with some demonstrating adsorption capacities greater than commercially available coal-based AC. Amongst the most effective raw materials for removing pollutants like heavy metals, dyes, oils are rice husks, corn cobs and stalks, cotton stalks, fruit peels and seeds, sugarcane bagasse, sawdust, woodchips, shells, and bark. AC production relies primarily on two methods: physical (carbonization followed by activation with gases) and chemical (simultaneous carbonization and activation using chemical agents) methods. Each method presents unique advantages and disadvantages related to the production efficiency and cost. While laboratory-scale results are promising, commercial scalability remains a challenge. Key obstacles include optimisation of activation methods, feedstock availability and consistency, ash removal as well as sustainable supply chain development. Further research should focus on addressing these challenges while exploring advanced activation technologies, high-value applications and circular AC production and regeneration systems through biorefineries. Resolving these challenges would not only reduce waste and mitigate environmental impact but also unlock new economic opportunities in the expanding global AC market.