ADSORPTION OF METHYL VIOLET AND CRYSTAL VIOLET DYES FROM AQUEOUS SOLUTION OF DENNETTIA TRIPETALA (PEPPER FRUIT)

Abstract

The potential of pepper fruit (Dennettia tripetala) powder (PFP), for the removal of methyl violet (MV) and gentian violet (CV) dyes from the solution was investigated. Batch adsorption studies were conducted and various parameters like contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to watch their effects on the dye adsorption process. The optimum conditions for the adsorption of MV and CV onto the adsorbent (PFP) were found to be: contact time (80mins), pH (10.0) and temperature (303K) for an initial MV dye concentration of 100mg/L and adsorbent dose 1.0g and get in touch with time (100mins), pH (10.0) and temperature (343K) for an initial CV dye concentration of 100mg/L and adsorbent dose 1.0g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for both MV and CV dye adsorption. the utmost adsorption capacity was found to be 46.72mg/g and 26.896mg/g for the adsorption of MV and CV dyes respectively. The pseudo-second-order kinetic model was according to the kinetic data. Thermodynamic quantities like Gibbs free energy (G0), enthalpy (H0) and entropy (S0) were evaluated and therefore the negative values of G0, H0 and S0 obtained indicated the spontaneous and exothermic nature of the MV adsorption process while positive enthalpy (H0) indicated an endothermic nature of the CV adsorption process.