Surface Modification of NiO Nanoparticles Using Stearic Acid and Their Application as Adsorbent

Abstract

NiO is a p-type semiconductor which shows interesting catalytic, electrical and magnetic properties due to finite size effects. NiO nanoparticles are used in various applications such as adsorption, supercapacitors, Li-ion batteries and catalysis. NiO nanoparticles have some limitations as an adsorbent. To overcome these limitations, surface of NiO nanoparticles has been modified with different surface modifying agents such as stearic acid, silane coupling agents, dodecanoic acid, etc. The surface modifiers chemically alter the surface properties of NiO nanoparticles without affecting their bulk properties. The surface-modified NiO nanoparticles can be employed in various applications such as adsorption, heavy metal ions removal and oil–water separation. In the current study, NiO nanoparticles have been synthesized using sol–gel method. The synthesized NiO nanoparticles were characterized using various analytical techniques such as X-ray diffraction, infrared spectroscopy and electron microscopy. Then, a simple and cost-effective strategy was used to modify the surface of NiO nanoparticles using stearic acid (SA). Varying amounts of stearic acid were used to modify the surface of NiO nanoparticles. The surface modification of NiO nanoparticles with stearic acid was confirmed by different analytical techniques such as FT-IR, TGA and CHO analyses. FT-IR analysis shows characteristic IR bands due to stearic acid confirming the presence of stearic acid on the surface of NiO nanoparticles. TGA and CHO analyses also confirm the presence of stearic acid on the surface of NiO nanoparticles. The stearic acid-modified NiO nanoparticles were tested as adsorbent and they perform as better adsorbent for the removal of crystal violet (CV) from an aqueous solution compared to pure NiO nanoparticles.