Adsorption of Aluminum Ion from Water on Alginate-Modified Polyurethane

Abstract

A dual purpose absorbent Alginate-modified polyurethane (APU) has been prepared for the removal of residual aluminum ions by adsorption from treated wastewater. The structure of APU was confirmed by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (H-1-NMR) spectroscopy. Physical characterization was preformed according to the BET method. Surface analysis using SEM/EDS revealed that an average of 0.57% aluminum by weight was adsorbed on APU. The adsorption isotherm of aluminum for APU fitted well to the Freundlich model. The analysis kinetic data suggests that adsorption of aluminum follows pseudo-first-order kinetics. The adsorption of aluminum on APU increased slightly from 25 to 35 degrees C, indicating endothermic adsorption. The activation energy of adsorption, 8.16 kJ/mol, characterizes the dominant chemiosorption nature of this adsorption. The optimum pH for aluminum adsorption on APU (applied pH: 3-8) was found to be within the pH range of wastewater effluent. The adsorption capacity of APU for aluminum using real wastewater effluent was 3.8 mg Al/g, which demonstrates the feasibility of applying APU to the treatment of water of complex compositions.