Modification of agricultural wastes to improve sorption capacities for pollutant removal from water – a review

Abstract

Water pollution is a great risk to aquatic ecosystems and human health. Among water pollution remediation strategies, adsorption mechanisms provide strong efficacy for a wide variety of pollutants. Several recent efforts examined the development of low cost adsorbents utilizing commonly available agricultural wastes. However, raw (i.e., unaltered) agricultural wastes typically exhibit low sorption capacity for pollutants due to their non-reactive structural/composition properties. Hence, modifications of raw agricultural wastes to enhance their sorption capacities for various aquatic pollutants are necessary to optimize their performance for pollutant removal. Numerous modification techniques are effective in altering agricultural wastes for improved sorption performance. This paper reviews the development of modified agricultural waste materials for pollutant removal from water. We compiled an extensive inventory of modification techniques applied to agricultural wastes to enhance their adsorption capacities for removal of a wide range of pollutants. Modification strategies and their effects on sorption properties were rigorously examined to highlight key advancements in the preparation of adsorbents from agricultural wastes. Finally, the costs of these materials were examined, along with the benefits and drawbacks concerning their use. This review provides a thorough assessment for advancing the utilization of agricultural wastes for preparing adsorbents for water treatment. Graphical Abstract: [Figure not available: see fulltext.]