title: Removal of p-nitrophenol by a water-compatible hypercrosslinked resin functionalized with formaldehyde carbonyl groups and XAD-4 in aqueous solution: A comparative study.
abstract: Chloromethylated styrene-divinylbenzene copolymers were post-crosslinked through Fredel-Crafts alkylation reaction and a water-compatible hypercrosslinked resin HJ-1 was developed successfully. It can be wetted directly by water and can be used without any wetting process. It was applied to remove p-nitrophenol in aqueous solution in comparison with the commercial Amberlite XAD-4 resin. Their adsorption behaviors for p-nitrophenol were conducted and it was found the adsorption dynamics obeyed the pseudo-second-order rate equation and the intra-particle diffusion was the rate-limiting step. The adsorption isotherms can be correlated to Freundlich isotherm and the adsorption capacity onto HJ-1 resin was much larger than XAD-4. The maximum adsorption capacity of p-nitrophenol for HJ-1 resin was measured to be 179.4 mg/g with the equilibrium concentration at 178.9 mg/l and the maximum removal percentage was predicted to be 98.3%. The adsorption thermodynamic parameters were calculated and the adsorption was mainly driven by enthalpy change. The micropore structure, the size matching between the pore diameter of HJ-1 resin and the molecular size of p-nitrophenol, and polarity matching between the formaldehyde carbonyl groups of HJ-1 resin and p-nitrophenol bring the larger adsorption capacity and higher adsorption affinity.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, People's Republic of China. xiaomeijiangou@yahoo.com.cn
authors.forename: Jianhan
authors.initials: J
authors.lastname: Huang
authors.forename: Cheng
authors.initials: C
authors.lastname: Yan
authors.forename: Kelong
authors.initials: K
authors.lastname: Huang
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D019277:Entropy; D006863:Hydrogen-Ion Concentration; D008751:Methylene Blue / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D001546:Bentonite; D008751:Methylene Blue