title: One-step in situ fabrication of a granular semi-IPN hydrogel based on chitosan and gelatin for fast and efficient adsorption of Cu2+ ion.
abstract: The novel granular semi-IPN hydrogels were in situ prepared in an aqueous solution by the free-radical grafting and crosslinking reactions among chitosan (CTS), acrylic acid (AA), gelatin (GE) and N,N'-methylene-bis-acrylamide. The FTIR spectra and elemental analysis confirmed that the AA monomers were grafted onto CTS backbone, and the GE macromolecular chains interpenetrated through the CTS-g-PAA network. The hydrogels are granular, which are composed of numerous micro-spheres according to the scanning electron microscope observations. The gel strength, adsorption, reuse and recovery properties of the hydrogels for Cu(2+) ion were systematically investigated. The results indicate the hydrogel with 2 wt% GE has the highest adsorption capacity of 261.08 mg/g with the recovery ratio of 95.2%. And the incorporation of 10 wt% GE enhanced the storage modulus by 103.4% (ω=100 rad/s) and 115.1% (ω=0.1 rad/s), and the adsorption rate by 5.67%. Moreover, the adsorption capacity of the hydrogel is still as high as 153.9 mg/g, after five cycles of adsorption-desorption. It was found that the ion-exchange and complexation interactions between the functional groups (-COO(-) and -NH2) of the hydrogels and Cu(2+) ion are the predominant adsorption mechanisms.
authors: Center for Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
authors: Wen-Bo
authors: WB
authors: Wang
authors: Da-Jian
authors: DJ
authors: Huang
authors: Yu-Ru
authors: YR
authors: Kang
authors: Ai-Qin
authors: AQ
authors: Wang
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D005780:Gelatin / Q000737:chemistry*; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D020100:Hydrogels; D003300:Copper; D005780:Gelatin; D048271:Chitosan