Production and performance of activated carbon from rice husks for removal of natural organic matter from water: A review

Adsorption by activated carbon has great potential to improve natural organic matter (NOM) removal from water. However, the high production and regeneration costs limit its wide scale application. To address these limitations, research efforts have been focused on finding low cost materials that can be transformed into activated carbon. Rice husk is one of such materials of research focus, especially in the developing countries, where over 96% of rice husks are generated globally. Although numerous investigations have been made concerning the production of activated carbon from rice husks, the existing scientific information still remains widely scattered in literature. Furthermore, the scientific information regarding performance of rice husk activated carbon during NOM removal from water still remains poorly documented. This review article therefore provides ample information on efforts made by various researchers concerning production of activated carbon from rice husks and its adsorption performance in relation to NOM removal from water. Properties and pretreatment of rice husks in relation to production of activated carbon are discussed. Activation of rice husks by physical and chemical methods under numerous conditions is reviewed. Factors affecting NOM adsorption by activated carbon are briefly discussed. Adsorption performance of rice husk activated carbon is also reviewed with respect to NOM removal from water, and where possible compared with other source derived activated carbons. The data from literature revealed that NOM removal by rice husk activated carbon can be as effective as commercial activated carbon. Consequently, rice husk activated carbon has potential to serve as an alternative to commercial activated carbon. (C) 2017 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.