Modified waste polystyrene as a novel adsorbent for removal of methylene blue from aqueous media

This research deals with the sequent sulfonation and magnetization of waste polystyrene to form a novel adsorbent. The novelty is assigned by an anionic surface that can adsorb cationic dye and by a magnetic property allowing it to be separated quickly and practically. The sulfonation was conducted using H۲SO۴, and the magnetization was performed by the coprecipitation of Fe۳O۴. The prepared adsorbents were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) machines. The adsorption capacity was evaluated for the removal of methylene blue (MB) dye from aqueous media conducted by batch experiment. The contact time, adsorbent weight, and solution pH were optimized. The parameters of kinetic and isotherm adsorptions were also determined. The characterization data showed evidence that sulfonated magnetic polystyrene was successfully produced. The adsorbent with ۵۰ wt% of Fe۳O۴ showed good adsorption capacity and separability effectiveness. The optimum condition of the adsorption of ۱۰ mg/L MB in a ۴۰ mL solution was reached by ۱۵ mg of the adsorbent weight within ۴۵ minutes and at pH ۷ with an effectiveness of about ۹۸%. The adsorption kinetics is best suited to a pseudo-second-order with an adsorption rate constant of ۰.۳۶۴ g mg-۱ min-۱ and is well explained by the Langmuir isotherm model with an adsorption capacity of ۴۶.۵۶ mg/g. 

Keywords:

Waste polystyrene , Sulfonation , Magnetization , Novel adsorbent , Methylene Blue