Fast and Efficient Elimination of Malachite Green Dye by Activated Carbon Derived from Fresh Water Micro Algae: Kinetics and Thermodynamic studies

Abstract

The adsorption process of “Malachite green (MG)” dye was carried out by graphitic activated carbon derived from fresh water micro algae calcined at various temperatures. The batch mode experiments were studiedwith algal residue activated carbonsamples calcined at 400, 500 and 6000 C (ARAC). At varying constraintslikepreliminary MG strength, interaction time, pH and temperature, ARAC(600)exhibited highest removal of MG (93.9%) having initial concentration 20 ppm, within 15 minutes at pH~9. The powdered XRD analysis of the sample indicated the presence of carbon with C(002) plane and the “scanning electron microscopy(SEM)” image presenteda presence of micro and macro-pores. The adsorption process fitted well to “Langmuir isotherm model”signifying monolayer adsorption with uniform energies and no migration of adsorbate in the plane of the surface. The adsorption of MG onto ARAC followed a “pseudo-second order kinetics” depicting chemisorption mechanism as the rate controlling step. The standard parameters of thermodynamics (?S0, ?G0 and ?H0) designated adsorption was endothermic and spontaneous. These results proved the fastness and high efficiency of ARAC as anencouraging adsorbent for dye exclusion that are frequently found in surface water.