Adsorptive removal of phenol from aqueous solution using chemically modified Saccharum officinarum biomass: modelling and process optimisation

This article proposes a way to extract phenol from aqueous solution as synthetic wastewater through the biomass (saccharum officinarum)-derived ZnCl2-activated carbon named as SBAC. The surface area and pore radius of SBAC were found to be 415.960 m(2)/g and 0.725 nm, respectively. Batch adsorption studies were carried out to analyse the percentage removal of phenol under various conditions, such as initial concentration (50-500 mg/L), initial pH (212), adsorbent dosage (2-40 g/L), temperature (283-303 K) and contact time (30-360 min). The proposed study has achieved similar to 94% of maximum phenol extraction, with the adsorption capacity of 9.44 mg/g at an initial concentration of 50 mg/L, dose of 5 g/L, pH of 5.5, contact time of 60 min and temperature of 303 K. The kinetic and equilibrium studies confirmed pseudo-second-order reaction and Radke-Prausnitz isotherm as the best fit. In thermodynamic study, the negative values of Delta G degrees(ads) (-21.448 to -24.330 kJ/mol), Delta H degrees (-1.059 kJ/mol) and positive value of Delta S degrees (0.072 kJ/m& K) confirmed the spontaneity, exothermic nature and randomness of adsorption process, respectively. Regeneration and reusability of SBAC showed 86.45% removal of phenol till fifth consecutive cycles. Cost analysis revealed that the developed SBAC was 14 times less expensive (similar to 718 INR/ 9 $) than commercial activated carbon. From the present study, the developed adsorbent found to be good for wastewater treatment under ambient reaction conditions to achieve clean water.