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 waste-water. 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 func-tional 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 fol-lowed 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 thermo-dynamic parameters indicated that the adsorption process was spontaneous, endothermic, and physical in nature.