Response surface modeling and optimization of lead uptake from aqueous solution by porous graphitic carbon synthesized from Egyptian bituminous coal

Author(s): Essam A. Mohamed, Ahmed M. Zayed, Ali Q. Selim, Suzan S. Ibrahim, Moaaz K. Seliem*

Abstract

El Maghara bituminous coal, collected from northern Sinai, Egypt, was used as a precursor material in the synthesis of porous graphitic carbon by chemical and thermal treatment. The activation process was carried out using phosphoric acid followed by thermal treatment at 800ºC in an electric muffle furnace for 1h. The raw coal and the synthetic porous carbon were characterized by polarized light microscope (PLM), XRD, SEM and FTIR. Experiments were conducted based on a central composite rotatable statistical design (CCRD) and analyzed using response surface methodology (RSM). The sorption process was investigated as a function of four independent parameters, initial solution pH (2–7), initial lead concentration (50–150 mg/l), contact time (30-240 min) and porous carbon dose (0.1–0.5 g). According to the F-values, the second order polynomial model was found to be highly significant for lead uptake with only a 0.01% noise. Also, the matching between the actual and the predicted results (R2 > 0.98) reflects the suitability of the design to represent the sorption process. The experimental optimum conditions for the uptake of lead by the porous carbon at pH 4 were found to be120 min, 50 mg/L, 0.3 g for contact time, initial concentration and adsorbent mass, respectively. By studying the effect of the selected parameters and the interaction between them, the applied model can enhance the adsorbed amount of lead (qe) and the removal efficiency (%) through a series of suggested solutions.

10.21746/ijbio.2016.06.005

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