Agricultural Solid Wastes in Aqueous Phase Dye Adsorption: A Review
Sharmeen Afroze, Tushar Kanti Sen * and Ming Ang
Department of Chemical Engineering, Curtin University, Australia
Wastewater from many industries such as textile, leather, paper, printing, food, etc. contains large amount of hazardous dyes. Dyes are not biodegradable and photodegradable due to its synthetic origin and complex aromatic nature. Among various physiochemical processes, adsorption techniques are usually widely used to treat dyes laden wastewater. Although commercial activated carbon is the most widely used adsorbent with large success, its use is limited due to high cost and difficulties in regeneration. Therefore there have been explosive growths in research concerning the use of alternative cost effective non-conventional effective adsorbents in the removal of dyes from aqueous solution. In this research direction, agricultural by-product solid wastes which are available in large quantities worldwide with almost through away price are utilized as effective adsorbents in the removal of inorganics and organics from wastewater. The focus of this book chapter is to review extensive literature information about dyes, its classification and toxicity, various treatment methods and finally dye adsorption characteristics by various agricultural by-products solid wastes as adsorbents. The major objective of this chapter is to organize the scattered available information on the adsorptive removal of dyes from its aqueous solution by raw and treated agricultural by-products. Selectively widely used agricultural solid waste adsorbents in the removal of dyes have also been discussed in details here. Finally mechanism, kinetics and adsorptive behaviour of adsorbents under various physicochemical process parameters have been critically analysed and compared. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed.
Keywords: adsorption characteristics; dye removal; low cost adsorbents; activated carbon