Adsorption of polyaromatic pollutants from water system using carbon/ZnFe2O4 nanocomposite: Equilibrium, kinetic and thermodynamic mechanism

Abstract

In present study, ZnFe2O4 nanoparticles were encapsulated into carbon (C) matrix to synthesize the superparamagnetic carbon/ZnFe2O4 (C/ZnFe2O4) nanocomposites by refluxing method. The microstructure and magnetic behavior of nanocomposites have been discussed using Fourier transform infrared spectrogram (FTIR), X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) method, field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM) and electron dispersive X-ray (EDX) techniques. BET surface area and pore diameter of C/ZnFe2O4 nanocomposite was found to be 280.87m2/g and 2.0nm, respectively. The C/ZnFe2O4 nanocomposite has been explored as adsorbent for the amputation of naphthalene and 2-naphthol from aquatic system. The influence of various parameters were studied and optimized for maximum uptake of pollutants. The isotherms and kinetic models have been examined to correlate and linearly fitting the experimental data. Langmuir and pseudo-first-order model provides better linear fit (R2=0.99) as compared to other models. Furthermore, thermodynamic parameters such as ∆H°, ∆S° and ∆G° were calculated to determine the nature of adsorption. The adsorption of pollutants has found to be endothermic, feasible and spontaneous in nature. The four cycles of repetitive testing were attempted in different desorbing agents and C/ZnFe2O4 nanocomposite was efficiently regenerated using NaOH-ethanol. Thus, this work presents a neoteric benchmark for the sorption of poly-aromatic hydrocarbons (PAHs) and delivers a new perspective for eliminating PAHs from unhygienic water for environmental reclamation.