Porous Spherical Cellulose Carrier Modified with Polyethyleneimine and Its Adsorption for Cr(III) and Fe(III) from Aqueous Solutions

An efficient porous spherical polyethyleneimine-cellulose (PEI-cell) absorbent was synthesized and characterized. The main influencing factors and adsorption mechanism for two typical metal ions, Cr3+ and Fe3+, were investigated. The adsorption performance primarily depends on the initial concentration of metal ions, pH value and temperature, and the chelation action between N atoms of PEI-cell and metal ions plays an important role. Under dynamic adsorption conditions, the saturation adsorption of polyethyleneimine-cellulose is 83.98 mg.g(-1) for Cr(III) and 377.19 mg.g(-1) for Fe(III), higher than reported data and that of unmodified cellulose. The adsorption can be well described with second-order kinetic equation and Freundlich adsorption model, and Delta H, Delta G and Delta S of the adsorption are all negative. With 5% HCl as eluent, the elution ratio of Cr(III) and Fe(III) achieved 99.88% and 97.74% at 313 K, respectively. After the porous PEI-cell was reused 6 times, it still presented satisfactory adsorption performance. Above results show the advantages such as easily-acquired raw material, high efficiency, stable recycling performance and biodegradability. (c) 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.