Study of water soluble dyes adsorption from aqueous solution by Prosopis spicigera L. wood (PSLW) carbon

Prosopis spicigera L.wood (PSLW), a plant material used as fuel by the rural mass in India is carbonized and used as an adsorbent for the removal of Methylene Blue and Erythrosine B dyes from aqueous solution by batch and column methods. The adsorbent is characterized by BET method (Nitrogen adsorption at 77 K) for pore and textural properties, scanning electron microscopy for surface morphology, potentiometric titration for pHZPC, FTIR for surface functional group and Boehm estimation of surface functional groups. The adsorption of Methylene Blue and Erythrosine B dyes on PSLW carbon has been carried out at different pH, adsorbate concentrations and contact time, adsorbent dosage and temperature conditions to determine the optimum condition for adsorption. Batch adsorption experiments show that maximum adsorption of Methylene Blue and Erythrosine B dyes is found at pH 2.0 and 3.0 respectively. Pseudo second order kinetics (Lagergren), surface mass transfer and pore diffusion models were used to evaluate the kinetic parameters and adsorption mechanism. To describe the equilibrium isotherm process, the data are analyzed using Langmuir model. Thermodynamic parameters indicate the adsorption interaction is found to be spontaneous and exothermic in nature. Column data fits to the Thomas Model