Abstract
ROLE OF BIO-SORBENTS IN THE DECOLORIZATION OF SOME COMMONLY USED DYES

In the study, a variety of physical adsorbents (Bio-sorbents) were chosen for the decolorization assessment of five most commonly used different dyes viz. Methyl Red, Methyl Orange, Crystal Violet, Erichrome Black and Malachite Green. All these physical adsorbents were dried, grinded and then heat- activated before using them as active Bio-sorbents. Among the physical adsorbents chosen, seeds of Nigella sativa displayed the maximum decolorization percentage against Methyl Orange and Methyl Red dyes i.e. 85% and 83% respectively followed by the results on Moringa oleifera (seeds) that too against Methyl Orange and Methyl Red dyes i.e. 80% and 78% respectively. Carica Papaya (seeds),Tamarindus (seeds) and Azadirachta indica (seeds) displayed a mediocre behaviour against all dyes tested. Least results were obtained for coconut covering (shell) and orange peels. The most accessible dyes for decolorization were Methyl Orange and Methyl Red and the least accessible dye for decolorization was Malachite Green. Powdered Activated Carbon (PAC) was also taken against each dye for comparison. Seeds of Nigella sativa displayed better results than Powdered Activated Carbon (PAC) against each dye tested.