Conversion of post consumer waste polystyrene into a high value adsorbent and its sorptive properties for Congo Red removal from aqueous solution

•A CMP was synthesised from waste polystyrene and activated into a sulphonic-group carrying resin..•Surface chemistry confirmed successful crosslinking.•Pore sizes comparable to other CMPs..•Remarkable monolayer adsorption capacities for Congo Red.

Using post-consumer waste polystyrene (WPS), a conjugated microporous polymer (CMP) was synthesised and activated into a sulphonic-group carrying resin (SCMP). The surface chemistry of the materials showed a decline in both the aromatic CH and aliphatic CH2 stretching vibrations confirming successful crosslinking. The synthesised polymers were thermally stable with decomposition temperatures above 300 °C, had surface heterogeneity, and BET surface areas of 752 and 510 m2/g, respectively. A distribution of pores ranging from meso- to micro-pores was comparable to other CMPs. The materials had maximum adsorption capacities of 500 and 357 mg/g for Congo Red (CR) on CMP and SCMP, respectively. Converting waste polystyrene to an adsorbent is a cost effective way of handling waste and simultaneously providing material for wastewater remediation.

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