Phenolic hydroxyl-functionalized hyper-cross-linked polymers for efficient adsorptive removal of aniline

Herein, three phenolic hydroxyl-functionalized hyper-cross-linked polymers were synthesized according to two sequential Friedel-Crafts alkylation reactions at two different temperatures and they were used to adsorb aniline. The first reaction at 293 K brought abundant phenolic -OH (up to 17.95 wt%) to the intermediates, and the followed reaction at 353 K offered the resultant products with a hyper-cross-linked frameworks composed of plentiful rigid methylene bridges. The resulting polymers were promising for the adsorption of aniline, and the maximum capacities (qmax) arrived at 210.9 mg/g. As the initial concentration of aniline was<100 mg/L, the adsorption efficiency reached>95 %, and the final concentration was lower than 0.1 mg/L, much lower than the emission concentration limit of aniline in China (1.0 mg/L). The adsorption mechanism discovered that acid-base interaction, electrostatic interaction and hydrogen bonding, especially the micropore-filling were important for the adsorption.