Acylamino-functionalized hyper-cross-linked polymers for efficient adsorption removal of phenol in aqueous solution

Abstract

Chemically functionalized hyper-cross-linked polymers (HCLPs) with high Brunauer-Emmett-Teller (BET) surface area (SBET) and pore volume (Vtotal) are efficient polymeric adsorbents for the adsorption of polar phenolic substances. Herein, chloromethylated polystyrene (CMPS) was used as the raw material and two consecutive Friedel-Crafts reactions were adopted to prepare the acylamino-functionalized HCLPs, and they were used to adsorb phenol in aqueous solution. In the first reaction, considerable acylamino groups were successfully loaded on the polymers, and the N and O contents were measured to be 1.03 wt% and 3.59 wt%, respectively. In particular, a great deal of rigid methylene joined the polymer chains in the second reaction as using dichloromethane as the novel external cross-linker, and hence acylamino-functionalized HCLPs with high SBET (up to 914 m2/g) and Vtotal (up to 1.01 cm3/g) were prepared. The resulting HCLPs exhibited excellent adsorption of phenol, the fitted maximum capacity (qmax) was measured to be 318.6 mg/g, and the adsorption reached the equilibrium within 120 min. The dynamic adsorption demonstrated that up to 79 BV (bed volume, 1 BV = 8 mL) of phenol could be removed at the initial concentration of 1000.5 mg/L and the dynamic capacity was scaled to be 316.1 mg/g, and ethanol could desorb phenol from the polymer column completely. The adsorption mechanism revealed that hydrogen bonding, π–π stacking, micropore-filling were the main driving forces for the adsorption.