Thermally regenerable multi-functional membrane for heavy-metal detection and removal

Abstract

Phthalocyanine (Pc) derivatives and hyperbranched poly(amidoamine) (HPAMAM) were synthesized and then modified with maleimide groups. They were then coupled to a poly(tetrafluoroethylene) (PTFE) membrane modified with furan groups through a Diels-Alder (DA) reaction. In this multi-functional PTFE membrane, Pc fluorescence was quenched by heavy-metal-ions, while HPAMAM adsorbed them to prevent leakage. In addition, HPAMAM hydrophilicity improved water permeability through the membrane. Thermally reversible DA bonding between furan and maleimide groups also allows selective regeneration and replacement of the functional materials on the membrane. Modification and functionality of the membrane were characterized with Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, fluorescence spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The analyses revealed a renewable, multi-functional membrane that detected and eliminated heavy metal ions. © 2019 Elsevier Ltd