Synthesis and characterization of acrylamide-acrylic add hydrogels and adsorption of some textile dyes

Acrylamide (AAm)-acrylic acid (AAc) hydrogels have been prepared at AAm ini tial compositions of 15%, 20% and 30%. AAm-AAc monomer mixtures have been i rradiated in a Co-60-gamma source at different doses and percent conversion s have been determined gravimetrically. 100% conversion of monomers into hy drogels was achieved at 8 kGy dose. These hydrogels were swollen in distill ed water at pH 3.03, 4.18, 4.68, 5.05, 5.30, 6.0, 7.0, 8.0. The results of swelling tests at pH 8.0 indicated that poly(AAm-AAc) hydrogels prepared fr om solution containing 15% (mol%) AAm showed maximum % swelling as 3000%. P oly(AAm-AAc) hydrogels have been considered for the removal of some textile dyes from aqueous solutions. Among the two common textile dyes tested, Jan us Green B (JGB) has showed the highest adsorption capacity while Congo Red (CR) was not adsorbed by these hydrogels. Adsorption isotherms were constr ucted for JGB and poly(AAm/AAc) gel systems. It is concluded that cross-lin ked poly(AAm/AAc) hydrogels can be successfully used in the purification of waste water containing certain textile dyes. (C) 1999 Elsevier Science B.V . All rights reserved.