Synthesis, Characterization of Zirconium Dioxide Nanoparticles and Its Adsorption Kinetics

Abstract

This study presents the synthesis of zirconium dioxide (ZrO2) nanoparticles using a green synthesis method with aqueous neem leaf extract as the reducing agent. The synthesized nanoparticles were characterized using UV-Visible spectroscopy which gave an absorbance at 350 nm, X-ray diffraction (XRD) which shows the crystallinity class of the ZrO2 NPs to be tetragonal, and scanning electron microscopy (SEM) showed spherical like shapes, homogenous dispersion in nature and agglomeration. The application of these nanoparticles in wastewater treatment was explored by analyzing adsorption effects under varying conditions such as temperature which indicated a maximum dye removal of 97% at 30oC , a high pH favoured higher removal of dye at 98.9% , adsorbent dose increased from (0.15 g = 87% to 1.05 g = 97%), as the agitation speed increased the removal percentage increased from 87 to 94%, initial concentration showed an initial increase, and contact time peaked at (30 min = 98% to 105 min = 90%). The adsorption process was further evaluated using isotherm models which showed a Freundlich value n of 1.4963 and kinetic model result showed a pseudo-second order kinetic model with a high correlation coefficient (R2 = 0.9993). The thermodynamic parameter revealed that the adsorption process is spontaneous, feasible and endothermic. This study demonstrates the potential of ZrO2 nanoparticles as an effective adsorbent for wastewater treatment.