Formation of Zinc oxide nanoparticles using alginate as a template for purification of waste water

Abstract Recycling of wastewater topped up the research area in recent years. Besides its environmental impact, wastewater treatment becomes a promising solution for deficiency of fresh water. Unique properties of nanoparticles enhance scientists to take advantage of them in removing of organic pollutants. In current work, Zinc oxide nanoparticles were prepared via polymer template methods and utilized for eliminating of cationic dye (i.e., Methylene blue (MB)). Zn ions were used for ionic gelation of alginate, and later ZnO nanoparticles were formulated via calcination of the obtained gel at a suitable temperature. Different physical characterization tools such as SEM, TEM, FT-IR, and XRD were applied to investigate the physicochemical character of the developed nanoparticles. Batch experiments were used to study the applicability of zinc oxide nanoparticles as methylene blue removal from aqueous solutions under different preparation conditions. The effects of initial MB concentration, pH, adsorbent dosage, contact time and temperature on the removal process were also optimized. In addition, the overall process is kinetically pseudo-second-order with respect to MB. Further, the intra-particle diffusion provided a good fitting to the experimental kinetic data indicating a significant role in the adsorption process. Results indicate that the removal efficiency of methylene blue increased from 5.99% to 60.13% with increasing zinc oxide nanoparticles dosage from 0.025 g to 0.3 g. Furthermore, the removal percent dose from 33.87% to 45.38% by increasing the calcination temperature up to 50 °C, While it decreased with increasing initial concentration of methylene blue. The optimum removal condition was recorded at pH 7. Overall, the obtained results indicate that the developed zinc oxide nanoparticles could be efficiently used as adsorbents for removal of methylene blue from aqueous solutions.