Facile Conversion of Polystyrene Waste into an Efficient Sorbent for Water Purification

Abstract

In this work, we convert a plastic waste, i.e., polystyrene (PS), into a sorbent by a simple sulfonation process. The sulfonation time was optimized and the structures of the resulting sulfonated polystyrene (SPS) was characterized by field emission scanning electron microscopy, energy-dispersive X-ray and contact angle tests. The results showed that the sulfonation time of 7 h can introduce abundant sulfonic groups and preserve the self-standing structure. Additionally, the SPS has a three-dimensional porous structure and hydrophilic surface because of the presence of numerous sulfonic groups, which could serve as effective binding sites for immobilizing varying pollutants. Furthermore, as a proof-of-concept, the adsorption performance of the SPS foams was evaluated using three pollutants, namely Pb2+, lysozyme and methylene blue. The adsorption isotherms were fitted by the Langmuir and Freundlich models, while the kinetics of the adsorption processes were analyzed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. It was found that the adsorption isotherms of Pb2+ and lysozyme can be better described by the Langmuir model, leading to maximum equilibrium adsorption uptakes of 10.5 and 15.7 mg g−1 for the adsorption of Pb2+ and lysozyme, respectively. Importantly, the pollutant-saturated SPS is readily regenerated by acid washing, and the recovered sorbents exhibit outstanding cyclic performance. The abundant availability of feedstock, facile preparation and regeneration processes render the SPS foams a promising sorbent for practical applications.

Artificial photosynthesis bringing new vigor into plastic wastes

“…The issues concerning the selective plastic oxidation to desired chemicals may be addressed by designing or selecting appropriate catalysts that can generate mild oxygenous radicals that are capable of avoiding the deep plastic oxidation. Several typical examples extracted from the previous reports concerning the selective oxidation of plastic wastes were presented 127,128 . Using the research by Xiao et al as an example, 91 several solid acids have been found to enable the PS transformation into benzoic acid, formic acid, as well as acetophenone under light irradiation.…”

“…Several typical examples extracted from the previous reports concerning the selective oxidation of plastic wastes were presented. 127,128 Using the research by Xiao et al as an example, 91 several solid acids have been found to enable the PS transformation into benzoic acid, formic acid, as well as acetophenone under light irradiation. It was mentioned that organic solvent adopted in this system not only favored the PS dissolution but also was a contributor to the catalytic performance.…”

Statistical Optimization of Operational Parameters on Congo Red Adsorption Using Upscaled Polystyrene

“…By introducing the carboxyl group into discarded expanded polystyrene, the adsorption capability for different dyes, including methylene blue (MB) and safranine T, from aqueous solutions was significantly enhanced [20].Chemical modification of expanded polystyrene waste with maleic-anhydride successfully introduced an amino group, enhancing its adsorption efficiency for removing toxic dyes namely Eriochrome Black T, and CR dye from water [21]. Sulfonated waste-polystyrene was a cost-effective adsorbent for MB dye removal [22], while a sulfonated waste polystyrenemetal nanocomposite degraded Calcon dye [23]. Chandran et al achieved efficient MB dye removal by incorporating calixarene with waste polystyrene [24].…”