Eco-Friendly of Nickel oxide Nanoparticles (NiO): A Comparative Study of Different Precursors

Abstract

The nickel oxide (NiO) nanoparticles were synthesized using an eco-friendly approach involving lettuce leaf extracts as a reducing and stabilizing agent, with two different precursors: NiSO₄ and NiCl₂. Initially, Ni (OH)₂ nanoparticles were obtained by the dropwise addition of sodium hydroxide solution in the presence of lettuce leaf extracts. These Ni (OH)₂ nanoparticles were then subjected to calcination at 500 °C to produce NiO nanoparticles. The synthesized nanoparticles were characterized by XRD, FE-SEM, and TEM, and their surface area was calculated using the Brunauer–Emmett–Teller (BET) method. XRD analysis confirmed the formation of nickel oxide nanoparticles, with average particle sizes of 32.35 nm and 43.16 nm for the NiSO₄ and NiCl₂ precursors, respectively. FE-SEM images revealed that Ni (OH)₂ nanoparticles exhibited a spherical morphology, whereas NiO nanoparticles displayed varying shapes. BET analysis confirmed differences in surface area between the samples. This study aimed to reduce and adsorb heavy metals from water pollution using the Langmuir and the Freundlich isotherm models, which may be used to simulate experimental data on the adsorption of sulfur compounds from crude oil.