Adsorptive Sequestration of Nitrophenol from Phenol Mixture onto Locust Bean Tree Sawdust

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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