Modeling studies for the removal of methylene blue from aqueous solution using Acacia fumosa seed shell activated carbon

Abstract

The activated carbon was prepared from Acacia fumosa seed shell using hydrochloric acid. Batch adsorption studies were conducted in varying the parameters such as concentration of dye, quantity of adsorbent, time, temperature and pH. The adsorption efficiency of the prepared activated carbon was estimated by using various isotherms, kinetics and thermodynamic equations. The isotherm parameters of the process were determined by using Freundlich and Langmuir isotherm equations. In Langmuir isotherm equation various forms of linearized equations were used. The Langmuir isotherm feasibility was checked with the dimensionless separation factor (RL). The tempkin isotherm was ascertained for the prediction of adsorbate and adsorbent interaction. The kinetic parameters were predicted with Lagergren's pseudo-first order and pseudo-second order equations. The mode of diffusion mechanism the adsorption process was found with the help of intraparticle diffusion model equation. The effect of temperature of the adsorption process was determined by using the thermodynamic parameters like change in entropy (ΔS0), Gibbs free energy (ΔG0), change in enthalpy (ΔH0) using Van’t Hoff equation. The characterization of the surface functional groups of the adsorbent material was done using Fourier Transform Infrared spectroscopy (FTIR).