Comprehensive review on synthesis and application of activated carbon from agricultural residues for the remediation of venomous pollutants in wastewater

Various agricultural wastes such as Rice husk, wheat bran, coconut coir pith, wheat husk, tea waste, and teff husk have received attention to the remediation of toxic pollutants due to their adsorption efficiency, low expenditure, and accessibility. Because of that, activated carbon adsorbents made from locally available agricultural wastes/by-products have been used for the removal of different organic and inorganic pollutants from wastewater. This review presents the details of activated carbon from various agricultural wastes with their adsorption capacities based on the reported literature. The paper compares adsorption using AC with other waste treatment technologies. In view of that, waste treatment with AC from agricultural wastes is more feasible based on the performance, adsorption capabilities, and cost. Porosity and the source of the agricultural waste are among the factors affecting the adsorption capacity of AC. The review also reveals that indeed agricultural wastes can produce activated carbons with properties comparable to commercial ones. In this case, developing countries where agricultureis dominant, for example, Ethiopia, stand a chance of benefitting both economically and environmentally if they utilize the agricultural wastes for large-scale production of activated carbons. Although the industrial application of AC from agricultural wastes has been started, it is not yet widely expanded, especially in developing countries. Therefore, it is worthwhile exploring the possibility of venturing into the business of commercial activated carbon production from agricultural wastes. Therefore, it should be a research field of increasing interest as it deals with the problem of the disposal of agro-residues, at the same time producing an added-value product that can be used in a number of environmental applications.