Abstract
Poly(acrylic acidโcoโacrylamide) (PAAAM) hydrogels have been prepared from partly neutralized acrylic acid (AA) and acrylamide (AM) by solution polymerization, and their absorbency and adsorption in both CuCl~2~ and FeCl~3~ solutions have been investigated. PAAAM hydrogels and their complexes with Cu^2+^ or Fe^3+^ have been characterized by FTIR. The absorbency of PAAAM in both CuCl~2~ and FeCl~3~ solutions increases initially and then decreases as the absorbing time increases. The adsorption of PAAAM in both CuCl~2~ and FeCl~3~ solutions can be described by the pseudoโsecond order chemisorption kinetics proposed by Ho and McKay, and the equilibrium uptake of Cu^2+^ on PAAAM can well be fit with the Langmuir adsorption isotherm. However, the equilibrium uptake of Fe^3+^ on PAAAM increases as the initial Fe^3+^ concentration increases for Fe^3+^ concentration smaller than 5.625 ร 10^โ3^ mol/L, and then decreases with Fe^3+^ concentration. The largest uptakes for Cu^2+^ and Fe^3+^ are 247 and 173 mg/g, respectively. The results also show that the uptake of Cu^2+^ and Fe^3+^ on PAAAM increases remarkably when pH of the solution is changed from 2.3 to 4.2 and from 1.0 and 2.1, respectively. ยฉ 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007