Applicability of bio-adsorbents synthesized from maize/corn plant residues for heavy metals removal from aquatic environments: an insight review

Abstract

The underutilization of agricultural waste products in recent years has resulted in environmental issues owing to improper disposal. As a result, heavy metals removal from aqueous systems utilizing sorbent materials produced from agricultural wastes has received a lot of attention. The current study provides an insightful review of the use of bio-adsorbents synthesized from maize/corn residues to decontaminate various toxicants from wastewater. Although bio-adsorbents made from maize/corn residues have shown to be efficient in the sequestration of heavy metals from wastewater, no study has looked at hybrid bio-adsorbents made from various parts of the maize/corn plant. Moreover, all studies practically investigate the sorption processes using the one-factor design technique, which exceedingly consumes time and is expensive for a significant number of biosorption/adsorption factors. Besides, the majority of the studies used bio-adsorbents produced from maize/corn biomass to remove heavy metals from single sorption systems. Furthermore, very few studies have focussed on heavy metals desorption from the exhausted maize/corn bio-adsorbents following the adsorption process to recycle the spent bio-adsorbents for future usage, which would be more cost-effective. Based on the gaps revealed in this review, it is recommended that further investigations on the usefulness of bio-adsorbents derived from maize/corn biomass in cleansing different water toxicants should be carried out.