Synthesis of poly(ionic liquid)s with high specific surface areas for m-cresol adsorption

Developing ideal adsorbents for moving phenolic compounds from aqueous solutions remains a challenge. Herein, novel poly(ionic liquid)s (PILs) of PIL-Ba-x and PIL-An-5 were prepared via Friedel-Crafts alkylation using benzyl alcohol and aniline auxiliary cross-linking agents, respectively, for the adsorption of m-cresol in the aqueous phase. The specific surface areas and pore volumes of the synthesized PILs can be adjusted by prepolymerization time, thereby realizing the regulation of the adsorption property of m-cresol. Results showed that the adsorption kinetics of PILs conformed to pseudo-second-order kinetics and reached adsorption equilibrium within 6 min. Their adsorption thermodynamics conformed to the Langmuir models. Based on the fitting data of the Langmuir model, the maximum adsorption capacity of m-cresol by PIL-Ba-5 can reach 228 mg/g. Moreover, the mechanism analysis showed that hydrogen bonding, electrostatic interaction, and 7C-7C interaction promoted the adsorption of m-cresol by PIL-Ba. After the adsorption of m-cresol was separated by anhydrous ethanol, the adsorbent was recovered at least five times, and the removal efficiency was stable.

Automated summary

In this study, the adsorption properties of m-cresol in aqueous phase were regulated by preparing poly(ionic liquid)s (PILs). The PILs showed high adsorption capacity and the adsorption kinetics followed pseudo-second-order kinetics. The adsorption thermodynamics were described well by the Langmuir model. The adsorbent could be separated and recycled, maintaining stable removal efficiency.