Abstract
Adsorption of phenol, 2-chlorophenol and 2-nitrophenol on zirconium-ferrite nanoparticles, has been studied. Zirconium-ferrite nanoparticles were synthesized using a reported method and characterized using different analytical techniques, such as, X-ray diffraction pattern, BET surface area analysis, scanning electron microscopy- energy dispersive X-ray spectroscopy, transmission electron microscopy, thermal gravimetric analysis, zeta potential analysis, Fourier transform infrared spectroscopy and Raman spectral studies. It was found to be associated with improved nanofeatures in terms of high surface area (392 m(2)/g) and less pore volume (0.1723 cm(3)/g). The synthesized material showed high adsorption affinity towards all three phenols. The adsorption data were found to follow Langmuir adsorption isotherm with the square of the regression coefficient (R-2) 0.994, 0.995 and 0.995 for phenol, 2-chlorophenol and 2-nitrophenol, respectively, at 288 K. The adsorption capacity of zirconium-ferrite nanoparticles was found to be 334.44, 354.61 and 375.93 mg/g for phenol, 2-chlorophenol and 2-nitrophenol, respectively, under the optimized conditions, namely, pH, contact time, concentration of adsorbate, amount of adsorbent and temperature. The thermodynamic parameter, namely, change in Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) have been determined by conducting the adsorption experiments at 288, 303, 318 and 333 K. The values of Delta G degrees, Delta H degrees and Delta S degrees were found to be negative which showed that the adsorption was unfavorable by Delta S degrees but highly favorable by Delta H degrees and the spontaneity of the adsorption was governed by the overall negative value of Delta G degrees. The kinetic study showed that the adsorption of all the three phenols on zirconium-ferrite nanoparticles showed pseudo-second-order kinetic models.