Physico-chemical modification of elephant grass (Pennisetum purpureum) by steam explosion and surfactant impregnation for Cr (III) adsorption

In this study was evaluated the adsorption capacity of trivalent chromium by using commercial activated carbon as adsorbent and elephant grass (Pennisetum purpureum) as bioadsorbent, which was prior treated by steam explosion technique and surfactant impregnated. The samples were characterized by SEM, XRD, XRF and FT-IR analysis. The effect of initial concentration of metal, pH, adsorbent dosage, contact time and temperature were further investigated in batch experiments. Isotherm, kinetic and thermodynamic studies were carried out in optimal process condition. The adsorption capacity reached a maximum of 28.36 mg g for modified SEEG sample. Thermodynamic parameters reveal that Cr adsorption is a non-spontaneous and exothermic chemical process. The Langmuir isotherm model showed a well fit unless to the in nature Elephant Grass, which fitted well to Freundlich model. Furthermore, experimental data adjusted better to PSO kinetic model. So that, it was found that the modification techniques employed significantly enhanced the adsorption capacity of Cr.