Development of Inexpensive Adsorbent from Agro-Waste for Phenol Adsorption

Potential adsorption of phenols- major pollutants present in various industrial wastewaters onto adsorbent powdered activated mustard cake (PAMC) derived from (mustard cake MC) agriculture waste materials was evaluated. The PAMC had meso porous pore size distribution with surface area (27 m(2) g(-1)), The adsorption characteristics of the PAMC primarily attributed to the presence of silica or mixed oxides of Ca, Mg, Al and Fe not by the carbon. The Langmuir, Freundlich, Redlich-Peterson and Temkin models were applied to evaluate the adsorption parameters. The adsorption decreased in the order of p-nitrophenol > p-chlorophenol > phenol. Adsorption kinetics was examined using different kinetics model (Lagergren first order, pseudo second order and intra particle diffusion model). The best results were achieved with the Langmuir isotherm equilibrium model and followed pseudo second order kinetics (R-2 = 0.99). The possible adsorption interactions were discussed: The adsorption mechanism is verified by FT-JR, PZC, effects of pH, urea, ionic strength and comparison between adsorption of phenols derivatives on PAMC. The adsorption mechanism is governed by complex interplay of electrostatic, pi-pi dispersive as well as by a charge transfer interaction. In cost analysis, it was found that the cost of PAMC ($ 9.5/- only) have very little compared to commercial activated carbon. The PAMC was found to be very effective for removal of phenols from their aqueous solutions.