Preparation of acrylamide/acrylic acid cellulose hydrogels for the adsorption of heavy metal ions

Modified cellulose hydrogels were prepared by blending and cross-linking with acrylamide and acrylic acid. The structure of hydrogels was characterized and analyzed with fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Under the optimized conditions, the maximum absorption capacity in modified cellulose hydrogels of Cu (II), Pb (II) and Cd (II) ions were 157.51, 393.28 and 289.97 mg/g, respectively. In addition, the metal ion adsorption process accorded with pseudo-second-order rate equation and Langmuir adsorption isotherm. Based on the microstructure analysis and adsorption kinetics, the adsorption mechanisms such as physical, chemical, and electrostatic interactions are discussed. The adsorption process was controlled by the ion-exchange mechanism.