ABSTRACT
This study investigated the removal of nickel(ii) ions by using two sizes of graphene oxide nanoparticles (GO - 450 nm and GO - 200 nm). The thickness and lateral sheet dimensions of GO are considered to be an important adsorbent and promising method for sufficient removal of metals like nickel, lead, copper, etc. The graphite oxide was prepared by oxidation-reduction reaction (Hummers method), and the final product was labelled as GO - 450 nm. A tip sonicator was used to reduce the size of particles to 200 nm under controlled conditions (time and power of sonication). FTIR spectroscopy shows that both sizes of GO particles contain several types of oxygen groups distributed onto the surface of GO particles. Scanning electron microscopy (SEM) and the statistical analysis confirmed the formation of these two sizes of GO particles. The GO - 200 nm performed better removal of Ni(ii) compared with GO - 450 nm, due to more surfaces being available. The adsorption capacity of GO particles increased drastically from 45 mg g-1 to 75 mg g-1 for GO - 450 nm and GO - 200 nm respectively, these values were carried out after 2 h of incubation. The kinetics of adsorption and several parameters like initial concentration at equilibrium, pH, temperature, and adsorbent dose are controlled and studied by using UV-visible spectroscopy. The results indicated a significant potential of GO - 200 nm as an adsorbent for Ni(ii) ion removal. An additional experiment was performed to estimate the surface area of GO - 450 nm and GO - 200 nm, the results show that the surface areas of GO - 450 nm and GO - 200 nm are 747.8 m2 g-1 and 1052.2 m2 g-1 respectively.
