Zinc Oxide Nanoparticles Preparation for Pd2+ Ions Adsorption From Aqueous Wastewaters: A Green Technique

Abstract

ZnO nanoparticles (NPs) were easily synthesized using zinc nitrate through centaurea cyanus extract (as a reducing agent) at ambient conditions. XRD results demonstrated that ZnO NPs have a high-crystalline hexagonal structure with an average size of 48 nm in diameter. FT-IR spectral analysis indicated an active contribution of centaurea cyanus-derived biomolecules in zinc ions bioreduction. According to SEM analysis, ZnO NPs were properly dispersed and had a hexagonal shape. Batch experiments were performed to investigate the impact of several process parameters such as initial pH of solution, adsorption dosage, Pd2+ ions initial concentration and contact time on the Pd2+ ions adsorption from the solution. The Freundlich isothermal model could excellently legitimize a multilayer adsorption. Furthermore, the adsorption process followed a pseudo-second-order reaction kinetic. The maximum adsorption (99.24%) was experimentally found at pH of 5.5, adsorption dosage of 1.63 g.L-1, Pd2+ ions initial concentration of 77.5 mg.L-1 and contact time of 91.25 min.

Development of Adsorptive Materials for Selective Removal of Toxic Metals in Wastewater: A Review

“…The rhombohedral, hexagonal, weakly ferromagnetic hematite nanoparticles are considered the highly stable form of iron oxide, which also exhibits anti-corrosive properties and has been used in energy and catalytic functionalities [80][81][82]. These nanoparticles have been applied in wastewater treatment for metal removal [83].…”

“…ZnO nanoparticles have been fabricated using Centaurea cyanus extract (biosynthesis) at ambient temperature, and the average particle size was 49 nm [82]. The optimum adsorption conditions were adsorption time = 91.25 min., adsorbent dosage = 1.63 g/L, Pb initial concentration = 77.5 mg/L, pH = 5.5, and removal efficiency = 99.24%.…”