Biodecolourisation of Bismarck Brown dye using Orange peel

Abstract

Dyes discharged from dyeing units and textile industries pollute the environment, particularly aquatic systems and cause considerable damage to organisms. Removal of colour is a prerequisite for discharge of treated textile effluents into the environment. Though several physical and chemical methods are available for decolourisation, biosorption is considered as cost effective and ecofriendly technique. Hence, in the present study, we explored possibilities of using orange peel for decolourisation of Bismarck brown dye, one of most common dyes used in the textile industry. Orange peel in different quantities (0.2, 0.4, 0.6 and 0.8 g/100 mL) was tested with 0, 100, 200, 300 and 400 ppm concentrations of Bismarck Brown dye for ten days. The decolourisation activity proportionally increased with the increase in the treatment period. The dye concentration of 100 ppm was tested with 0.4 g orange peel in different pH ranges of 2, 4, 6, 8 and 10 and the absorption was high in acidic pH. The increase in contact time also resulted in increased dye removal. Over all, the adsorption of dye onto orange peels was influenced by initial dye concentration, pH, amount of adsorbent and contact time. Four grams of orange peel showed highest decolourisation after 200 min, and it was proportional to the contact time. The dye removal was the maximum at pH 2. Both Langmuir (R2 = 0.922) and Freundlich (R2 = 0.999) adsorption isotherms were calculated.