Adsorption technique for pollutants removal; current new trends and future challenges – A Review

Abstract

1 st natural adsorbents 2 nd low cost adsorbents 3 rd nano-materials 4 th by products 5 th agricultural wastes 6 th isotherms; kinetics 7 th batch operation; continuous operation 8 th interference pollutants Water pollution is a challenging problem facing the human beings. In order to get treated water and wastewater, many techniques were proposed such as floatation, coagulation, ion exchange, biological treatment, adsorption, membrane etc. Among these methods, adsorption technique has proved to be an effective and low cost manner for the removal of inorganic pollutants (i.e heavy metals), synthetic dyes and organic pollutants (i.e phenols, methylene blue, methyl orange, benzene …) from polluted water. This review summarizes the most used adsorbents such as Activated Carbon (AC), nanomaterials, natural adsorbents, industrial by-products, agricultural wastes and bio-sorbents and their performance, cost and regeneration studies. This review also discusses the mechanism of adsorption, kinetics and isotherms used in adsorption process. The effect of binary and ternary systems of ions was also discussed. The difference between batch mood and continuous flow mood (packed bed column studies) and the parameters considered in each type were also investigated. Future recommendations and trends were finally proposed to enhance the adsorption process from all aspects.