Cationic dyes removal from wastewater by adsorptive method: A systematic in-depth review

One of the most pressing environmental problems is the existence of synthetic dyes in industrial wastewaters. The presence of dyes in wastewater can cause severe problems to human beings and aquatic life, and that warrants removal from aqueous medium. Amongst the multiple strategies to treat dye-contaminated water, adsorption is considered superior because of low cost, flexibility, ease of operation and lower energy consumption. Many adsorbents, including carbon-based materials, biomaterials, nanomaterials, Schiff bases, metal-organic frameworks as well as natural and synthetic polymers, have been successfully applied in cationic dyes remediation. The current review article provides literature information about cationic dyes, various treatment strategies, principles of adsorption and recent trends in adsorbents application were discussed at length. The applicability of various isotherms and kinetic models for cationic dyes removal by diversified adsorbents is also highlighted here. Conclusions have been drawn from the literature reviewed and recommendations for future research perspectives are proposed.