Equilibrium, Kinetic and Thermodynamic Studies of an Elaeis Guineensis Fingers Biochar-Doped ZnO Nanoparticles prepared using Chemical Bath Deposition Technique

Abstract

This study investigated the equilibrium, kinetics and thermodynamics of doping ZnO nanoparticles with biochar prepared from elaeis guineensis fruit bunch fingers using chemical bath deposition. The dopant and doped samples were characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscope coupled with energy dispersive x-ray spectroscopy (SEM-EDX) and Brunauer–Emmett–Teller (BET) surface area analyzer. FTIR showed important functional groups such as –NH₂, and -OH which were instrumental to the successful doping. The doped sample showed a prominent Raman spectra peak at 412 cm^-1, indicating the wurtzite structure of ZnO NPs. EDX showed some important groups II-IV metals with Zn-O combination ratio of 1:2. SEM micrograph of doped sample showed homogeneous and flower-like images while the dopant presented porous and irregular-large particles. BET showed increase in surface properties such as specific surface area, pore volume and pore diameter for the doped sample with both samples having meso-pore diameters. Adsorption and kinetics studies indicated that the in-situ deposition on the doped ZnO NPs followed Langmuir and Pseudo-second order while thermodynamics showed that the process was spontaneous and endothermic. The study indicated that the biochar has potentials either as dopant or biosorbent in thin films or adsorption studies respectively, and also revealed that proper understanding of the mechanism of the deposition process is crucial for optimal film performance.