Rapid and effective adsorption of selected heavy metals from battery wastewater using silicon-oxide nanoparticles derived rice husk

Adsorption technology has been demonstrated to be a viable option for producing treated water that satisfies drinking water requirements. In this study, a novel, sustainable and effective silicon-oxide nanoparticles derived rice husk (SiO2NPs) was developed for the removal of lead(II), iron(III) and nickel(II) ions from battery wastewater. The developed SiO2NPs@25 was characterized using techniques such as Scanning election microscopy coupled with Energy–dispersive x-ray, spectroscopy (SEM/EDX), Fourier transform infrared spectra (FTIR), Brunauer- Emmett-Teller (BET) and X-ray diffraction (XRD) to examine the surface morphology, surface functional group, textural properties, and crystal structure. The BET surface area of SiO2-NPs@25 was found to be 409.91 m2/g, which is significantly higher than that of rice husk ash which was 73.06 m2/g. The adsorptive performance of SiO2-NPs@25 towards the selected heavy metals was tested in a batch system and the influence of pH, contact time, temperature, adsorbent dosage was also examined. The equilibrium adsorption data followed Freundlich isotherm model, suggesting that the adsorption process assumes a multilayer adsorption. Also, the kinetics study revealed that adsorption process was well described by the pseudo-second order kinetics based on the higher correlation coefficient (R2) and smaller SSE values. The adsorption capacity (Qmax) of lead(II), iron(III) and nickel(II) ions were found to be 270.63 mg/g, 21.69 mg/g and 52.14 mg/g respectively. The thermodynamic parameters indicated that the adsorption process was spontaneous, endothermic, and physical in nature.