An overview of equilibrium, kinetic and thermodynamic studies for the sequestration of Maxilon dyes

Abstract

Maxilon dyes are a class of cationic dyes containing different aliphatic and aromatic radicals. Contamination of water by this class of dyes causes serious environmental concern to both man and other animals and plants. Adsorption as a process has been studied by various researchers for Maxilon dye uptake. This work represents a review of published literature discussing the adsorption of Maxilon dyes using various adsorbents. Adsorption operating parameters, kinetic and isotherm models, and thermodynamic models were discussed herein. In the study, it was observed that adsorption parameters such as contact time, adsorbent dosage, solution pH, and temperature affect the uptake of Maxilon dyes. The highest reported uptake of Maxilon dyes by the various adsorbents is 1830 mg/g for Maxilon blue using hydrolyzed (styrene-alt-maleic anhydride) chitosan. For the adsorption of the Maxilon dyes, the pseudo-second order kinetic model was shown to provide the best fit. The Langmuir and Freundlich isotherm models best describe the adsorption of the Maxilon dyes. There were also some proposals for the future. In conclusion, adsorption was found to be an effective approach for removing Maxilon colours from water and wastewater.