Adsorption of copper ion from solution by polyethylenimine modified wheat straw

Abstract

Wheat straw (WS) was modified by polyethylenimine (PEI) to enhance its adsorption capacity toward copper ions from solution through epichlorohydrin (ECH) as grafting agent and PEI-WS was the product. Adsorption property of PEI-WS toward Cu2+ was performed from solution in batch mode and fixed-bed column mode. The results showed that adsorption quantity became larger with the rise of solution pH, initial copper concentration while the co-existing ion had little effect. Adsorption quantity was to 48.6 mg/g from experiments at 293 K. Equilibrium experimental data were better fitted by Langmuir model while kinetic processes were better fitted by Elovich model. In column mode, effects of flow rate, bed depth and initial Cu2+ concentration on breakthrough curves were studied and Yan model was suitable to fit the results. Cu-loaded adsorbent was efficiently regenerated by 0.1 mol/L HCl solution. It is implied that PEI-WS be used to remove metal ions from aqueous solution.