Abstract

The article aims to review the research findings on the adsorption of dyes from aqueous media. It was observed from the review that activated carbon and Polymer based nanomaterial are the best class of adsorbents for the removal of dyes from aqueous media. It was observed from the review that nano composite α-Fe2O3/graphene oxide (α-Fe2O3/GO) and PAN–polyamidoamine nanoparticles are the best adsorbents for the removal of dye from aqueous media, with a capacity adsorption (qmax) of 1998.14 and 2000 mg/g, respectively. A wide range of values for the thermodynamic parameters (both negative and positive) were reported for dye across different studies. This suggested that the nature of the adsorbent was the important factor in determining the thermodynamics of dye adsorption. Dye uptake best-fit both the Langmuir and Freundlich isotherm models as well as a pseudo-second order kinetic model. Theoretical modelling of the dye adsorption has received lesser attention; therefore, further investigations are needed to understand adsorbent–adsorbate interactions at molecular level. © 2021