Characterization of magnetic zeolite-polymer composites for Cu(II) and Cr(III) removal from aqueous solutions

Abstract

The aim of this study was to synthesize and characterize zeolite-based magnetic polymer composites (m-ZPC) for Cu(II) and Cr(III) removal from aqueous solutions. Synthetic zeolite NaA and magnetic iron oxide nanoparticles were immobilized into blended polymer hydrogels composed of poly(vinylidene fluoride) (PVDF) and poly(vinyl alcohol) (PVA) in order to prepare m-ZPC (average particle diameter = 2.97 +/- 0.18 mm). Stability tests for m-ZPC against acidic and alkaline solutions indicate that it was stable between solution pHs of 2.0 and 9.0. Batch experiments demonstrate that the maximum adsorption capacities for Cu(II) and Cr(III) were 3.90 and 2.04 mg/g, respectively. The removal of Cu(II) and Cr(III) increased as the pH increased from 2.0 to 5.0. The removal of Cu(II) and Cr(III) was enhanced with a rise of temperature from 15 degrees C to 45 degrees C. In addition, m-ZPC could be reused for Cu(II) removal after regeneration with 5 M NaCl solution. Thermodynamic analyses indicate that the removal of Cu(II) and Cr(III) was endothermic and spontaneous sorption processes (Cu(II):Lambda H degrees = 115.0 kJ/mol; Lambda G degrees = -5.13 to -17.64 kJ/mol, and Cr(III): Lambda H degrees = 73.0 kJ/mol; Lambda G degrees = -2.50 to -10.36 kJ/mol). This study demonstrates that m-ZPC can be used as a magnetic adsorbent for heavy metal removal in combination with magnetic separation.