Efficient removal of methylene blue dye from wastewater specimen using polystyrene coated nanoparticles of silica

Utilization of suitable methodologies for recovery of wastewater and its reuse in various applications is highly stimulated. In agreement with this objective, the current research study presents new adsorbents, composed of silica nanoparticles coated by a polystyrene shell, for use in the purification of wastewater from methylene blue (MB) dye, as a contaminant. Firstly, silica nanoparticles were prepared and covered by a layer of Polystyrene made via the high internal phase emulation (HIPE) polymerization technique. Three composite structures having different contents of silica nanoparticles (by weight %) were designated as adsorbents in this research work. The chemical and structural properties of these adsorbents were verified by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy while their textural characteristics were acquired by scanning electron microscopy (SEM) and N2 adsorption-desorption surface area analysis. The efficiencies of these adsorbents toward disposal of MB dye from wastewater were next investigated at different operating parameters. The introduced composites of polystyrene@silica nanoparticles revealed promising capacities toward adsorption of MB dye which came up to a maximum of 23.1 mg g-1. The observed removals of MB dye by these composites during the process of water purification are attributed to the presence of both organic and inorganic functional groups within their structures. Thus, various adsorption mechanisms could take place through the elimination of MB particles from the effluent water during the treatment process. Kinetic and isotherm studies for the adsorption of MB species were found to fit the models of pseudo-second-order and Langmuir respectively. Furthermore, the thermodynamics of MB adsorption could indicate the nature of such process as feasible, spontaneous, physisorption, and exothermic.