Activated carbon derived from pistachio hull biomass for the effective removal of parabens from aqueous solutions: isotherms, kinetics, and free energy studies
Hamid Rashidi Nodeh, Hassan Sereshti, Sahar Ataolahi, Amirarshia Toloutehrani, Ali Ramezani
Abstract
ABSTRACT In this study, activated carbon biomass was prepared from pistachio hull (PiH-AC). The PiH-AC was used for removal of methylparaben (MP) and propylparaben (PP) from aqueous media. The biomass was fully characterized using Fourier transform-infrared spectroscopy, field emission-scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller surface morphology. The important parameters including pH of the solution, adsorbent dosage, ionic strength, contact time, initial solution concentration, and temperature were investigated. Furthermore, the process was fitted with adsorption isotherms, kinetics, and thermodynamic models to validate and predict the adsorption nature and mechanism. The Langmuir adsorption isotherm and pseudo-second-order kinetic models were best fitted to the experimental data. Langmuir isotherm was predicted monolayer pattern for selected parabens sorption with appropriate adsorption capacity of 55 and 50 mg g –1 for MP and PP, respectively. The value of free energy (E a = ~2.45 kJ mol –1 ) suggests a physisorption mechanism for selected parabens uptake onto the PiH-AC.