Review on adsorption-desorption studies on dye sequestration

This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to study the potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Once adsorption process is over adsorbent is to be discarded as waste. Generation of waste adsorbent is a serious environmental problem. Adsorbents can be regenerated and put to reuse in the same process line. Thus the recovery of adsorbate and subsequent regeneration and reuse of adsorbent are important attributes of this process from economy and environmental point of view. In the current review, the summery of research carried out for recovery and regeneration of adsorbent was presented. It was found that various methods like chemical, electrochemical and thermal methods were used effectively for regeneration of adsorbents. Conclusions have been drawn from the literature reviewed.