Radiation induced in-situ cationic polymerization of polystyrene organogel for selective absorption of cholorophenols from petrochemical wastewater

Abstract

A new in-situ cationic polymerization was performed to synthesize a cross-linked (91%) polystyrene (PS) organogel through tetrachloroethylene radiolysis assisted by ⁶⁰Co gamma rays. Hoernschemeyer diagram and swelling capacity test show a better selectivity of PS organogel to chlorinated molecules compared to ester, hydrocarbons and alcohols organic molecules by 80-184 folds. Response surface modeling (RSM) of CPs (2,4,6-trichlorophenol) sorption from artificial wastewater confirm superiority of PS organogel to absorb 1746 μmol CPs/g (∼345 mg CPs/g) at broad pH (4-10) and temperature (25-45 °C). Based on ANOVA statistic, simulated CPs absorption model onto PS organogel was successfully developed, with accuracy of prediction of R²≈ R_Adj² of 0.991-0.995 and lower coefficient of variation of 2.73% with F_model of 611.4 at p < .0001. Particularly, the usage of PS organogel for petroleum wastewater reclamation exhibited higher absorption affinities for all the organic contaminants especially for CPs (>99%) by non-covalent and/or dispersive interaction mechanisms with a well-term reusability and good stability up to 5 cycles.

Keywords: Cationic polymerization; Chlorophenols; Gamma ray; Petrochemical wastewater treatment; Polystyrene organogel; Response surface absorption modeling.