PEI-Modified CMKGM/GO Porous Biocomposite for Superior Removal of Pb(II)

Using polyethylenimine-modified carboxylmethyl konjac glucomannan as a matrix and graphene oxide as nanofillers, a novel porous biocomposite named as PCGt was synthesized by a facile chemical cross-linking method. The structure of prepared PCGt was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and X-ray photoelectron spectroscopy. Batch adsorption experiments was designed to exploit key factors on Pb­(II) removal such as the pH, dose, contact time, initial concentration, and temperature. According to the data from pseudo-second-order kinetic and Freundlich isotherm models, the adsorption process was controlled by chemisorption and occurred on heterogeneous surfaces. The maximum adsorption capacity of PCGt on Pb­(II) was up to 977 mg g–1 at 303.15 K. In thermodynamic analysis, positive enthalpy change and negative Gibbs free energy change exposed that the adsorption was endothermic and spontaneous at 308.15 K. The recyclability of PCGt was confirmed by leaching and desorption experiments. The adsorption mechanism was proposed that the chemical complexation between Pb­(II) with the functional groups on PCGt. All outcomes effectively revealed that the biocomposite PCGt was a good candidate to remove Pb­(II) from aqueous solution for the waste disposal industry.