Poly(acrylamide-allyl glycidyl ether) cryogel as a novel stationary phase for chlorophenol adsorption

Abstract

Poly(acrylamide-allyl glycidyl ether) [poly(AAm-AGE)] cryogel was prepared by bulk polymerization which proceeds in an aqueous solution of monomers frozen inside a glass column (cryo-polymerization). After thawing, the monolithic cryogel contains a continuous polymeric matrix having interconnected pores of 10-100 μm size. Cibacron Blue F3GA was immobilized by covalent binding onto poly(AAm-AGE) cryogel via epoxy groups. Poly(AAm-AGE) cryogel was characterized by swelling studies, FTIR, scanning electron microscopy (SEM) and elemental analysis. The equilibrium swelling degree of the poly(AAm-AGE) monolithic cryogel was 6.84 g H2O/g cryogel. Poly(AAm-AGE) cryogel containing 68.9 μmol Cibacron Blue F3GA/g were used in the adsorption/desorption of chlorophenols (i.e., phenol, m-chlorophenol, p-chlorophenol and 2,4,6-trichlorophenol) from aqueous solutions. The maximum adsorptions of chlorophenols onto the Cibacron Blue carrying cryogels were 128.5 μmol/g for phenol, 144.3 $mu mol/g$ for 2,4,6- trichlorophenol, 155.8 $mu mol/g$ for p-chlorophenol and 164.7 $mu mol/g$ for m-chlorophenol. The affinity order was as follows: m-chlorophenol > p-chlorophenol > 2,4,6-trichlorophenol > phenol. The adsorption of chlorophenols decreased with increasing pH. Desorption of chlorophenols was achieved using methanol solution (30%, v/v). The cibacron Blue F3GA-carrying cryogels are suitable for repeated use for more than ten cycles without noticeable loss of adsorption capacity.