Modification of UHMWPE porous fibers by acrylic acid and its adsorption kinetics for Cu2+ removal

Polyacrylic acid-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PAA) fibers were prepared by radiation-induced grafting of acrylic acid onto UHMWPE porous fibers and were examined for Cu2+ removal from aqueous solutions. The developed fibers were characterized using Fourier transform infrared spectroscopy, mechanics test, scanning electron microscopy and energetic dispersive spectroscopy analysis. It was demonstrated that the UHMWPE fibers were modified successfully with grafted acrylic acid, which conferred excellent hydrophilic performance to UHMWPE porous fibers. The mechanics test indicated that considerable mechanical strength (similar to 0.4 GPa) still reserved for the UHMWPE-g-PAA fibers in spite of somewhat radiation degradation. The high-strength, hydrophilic and porous natures render UHMWPE-g-PAA fibers promising as economical adsorbent in wastewater treatment. Prepared under different radiation dose and different degree of grafting of polyacrylic acid (PAA), the adsorption kinetics of the UHMWPE-g-PAA fibers was investigated using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The results reveal a large adsorption capacity of 63 mg g(-1) for the UHMWPE-g-PAA fibers and the adsorption behavior follows perfectly a pseudo-second-order kinetics model regarding the Cu2+ solution adsorption.