4-Vinylpyridine-modified post-cross-linked resins and their adsorption of phenol and Rhodamine B.

Herein 4-vinylpyridine (4-VP) was employed as the functional monomer to copolymerize with divinylbenzene using 1,2-dichloroethane (DCE) as the porogen, and a series of 4-vinylpyridine-modified post-cross-linked resins was fabricated. The effect of 4-VP and DCE percentage on the porosity, polarity, and adsorption was investigated in detail. The results indicate that the porosity and nitrogen (N) content of the as-prepared resins can be easily regulated by changing the 4-VP and DCE percentage. Specifically, HPDN-10%-300% with 10 wt% 4-VP and 300 wt% DCE has the highest specific surface area (S) and pore volume (V), while HPDN-10%-100% with 100 wt% DCE has the greatest micropore area (S) and micropore volume (V). Furthermore, the equilibrium adsorption experiments of the resins exhibit that the adsorption of phenol on HPDN-10%-100% is the most efficient by reason of its greatest S and V, whereas HPDN-10%-300% owns the largest equilibrium capacity to Rhodamine B (RB) because of its highest S, V, and broad pore size distribution (PSD). The kinetic adsorption reveal that HPDN-10%-100% needs the least time to reach equilibrium for the adsorption of phenol while the adsorption of RB on HPDN-10%-300% is the fastest. The temperature is disadvantageous for the adsorption and the isosteric enthalpy at zero fractional loading is predicted to be -40.39 and -56.38 kJ/mol for phenol and RB on the resins, respectively.