Effect of laser pulse repetition rate in the synthesis of nickel oxide nanoparticles in PVA solution on the adsorption efficiency against phosphate ions

Eutrophication of the receiving confined water bodies could be caused by the presence of phosphate traces in treated wastewater from municipalities and factory businesses. One of the promising methods for phosphate removal is adsorption, which could be used in conjunction with the phosphate ions in the wastewater sectors, to meet discharge requirements when the biological media performance is compromised by changes in operating conditions. For that, pulsed laser ablation in liquid media process was used to create nickel oxide nanoparticles and embed them with poly vinyl alcohol to create nanocomposite structures. Their effectiveness in removing phosphate from the water was then investigated under various aquatic environmental circumstances. Addi-tionally, the novelty was appeared for the first time to vary their particle sizes using different laser ablation parameters, like repetition rate. To determine how surface characteristics affect the phosphate adsorption behavior, the surface structure of the materials was examined using X-ray diffraction, a N2-adsorption-desorption technique, UV-visible absorption spectroscopy, a transmission electron microscope, and Fourier transform infrared spectroscopy. After that, in the adsorption investigation, adsorption isotherms, pH effects, and a desorbability study were all investigated during the adsorption test. The findings demonstrated that the prepared nanocomposite with a lower particle size of NiO NPs had higher adsorption efficiency than that with a larger particle size of NiO NPs because of the changes in surface structure of the materials. The results also demon-strated that the adsorbed amounts of phosphate tended to reduce with increasing pH for all samples. Thus, phosphate could be absorbed by the NiO/PVA nanocomposite structure in complicated solutions.