Superacid-catalyzed waste foamed polystyrene plastics-based hypercrosslinked polymers for adsorption of monocyclic aromatic hydrocarbons

A strategy for efficiently conversion waste polystyrene foam into hypercrosslinked polymers (HCPs) used for VOCs adsorption has been developed. Superacid CF 3 SO 3 H was used as a highly active metal-free catalyst, which greatly shortened the preparation and purification time of HCPs. The prepared HCPs were characterized by N 2 adsorption-desorption, SEM, TEM, TGA, FTIR, 13 C solid-state NMR, XPS and EDS. The obtained HCPs showed good adsorption performance for monocyclic aromatic hydrocarbons. Among all the prepared HCPs, HCP-0.5 displayed the best adsorption capability (O-xylene: 422 mg/g, toluene: 283 mg/g, benzene: 116 mg/g), good hydrophobicity and reusability. The adsorption properties of these low-cost HCPs surpassed current popular nanoporous materials such as metal organic frameworks (MOFs), porous clay heterostructures (PCH) and other HCPs, indicating their potential applications as valuable adsorbent for removal of VOCs. Additionally, the interaction between aromatic pollutants and HCP was simulated by quantum chemistry calculation. The adsorption process of three aromatics VOCs on HCP-0.5 were more in accordance with the pseudo-first order kinetic model and Freundlich isotherm model, indicating that the adsorption process was dominated by multilayer physical adsorption. Weber-Morris kinetic model was used to illustrate the rate-controlling mechanism, and the results indicated that the intra-particle diffusion was the control stage of adsorption rate.