The efficacy of an adsorbent prepared from sawdust of Locust bean treeto remove 4-Nitrophenol (4NP), from its aqueous solution and from binary and ternary mixture of phenols (with phenol or / and chlorophenol) was studied. Batch adsorption procedures were carried out to investigate the kinetics, isotherms and thermodynamics of the adsorptive removal, as well as the influence of sawdust dosage, pH, initial concentration of the phenols and temperature on the efficiency of the process. Equilibrium was attained at 12 hours, with the optimum sawdust concentration of 5 g/L. The kinetics of the adsorption could best be described by pseudo-second order model, while Freundlich isotherm gave the best fit in all the systems studied. The adsorption process was thermodynamically non-spontaneous at low temperatures as ∆G was positive; but it was endothermic in the single, binary and ternary systems.
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