CONGO RED COLORING POWDER ADSORPTION IN COCONUT PEELS

Abstract

Introduction:
Industrial products, especially those linked to unsustainable development model, are seriously damaging to environment, and textile industry is one of those that tops the list due to difficulty of treating its waste. Removal capacity exhibited by plant origin
compounds is known, therefore in this work a study of Congo Red dye adsorption in coconut shell powder is carried out.
Objective:
To determine kinetic model and adsorption isotherm corresponding to the heterogeneous system of an aqueous solution of Congo Red dye and coconut shell powder at temperatures of 298 and 323 K
Materials and methods:
Coconut shell powder is physically and chemically characterized. Kinetic models that best reflect adsorptive processes are determined from coefficients determination at 298 and 323 K. variation of free energy, enthalpy and adsorption entropy, effective diffusion coefficients at working temperatures are shown. Different isotherm models are exposed, finding the best according to statistic used. 
Results and Discussion:
A pseudo-second order model reflects adsorptive process at both temperatures. Spontaneous, exothermic process and with a small process randomness.
Conclusions:
Adsorption of Congo Red dye in aqueous solution obeys a pseudo-second order model. BET isotherm accurately reflects adsorption process equilibrium.