Preparation of electrospun polyvinylidene fluoride/amidoximized polyacrylonitrile nanofibers for trace metal ions removal from contaminated water

In this study, a mixture of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and dimethylformamide (DMF) as solvent were reacted with hydroxylamine hydrochloride to produce polyvinylidene fluoride (PVDF)/amidoximized polyacrylonitrile (AOPAN) spinning solution, and then a novel composite PVDF/AOPAN was fabricated by electrospinning technique. Later the electrospun PVDF/AOPAN nanofibers (NFs) were treated with KOH and pitched in (plunged in) mini-column to be used as an adsorbent material under continuous flow. The structural and morphological characterization of nanofibers membrane was determined using scanning electron microscope equipped with an energy dispersive spectrometer(SEM/EDS), Fourier transform infrared spectrometer (FTIR), and goniometer, the inductively coupled plasma optical emission spectrometer (ICP-OES) analysis was used to evaluate the adsorption capability. The effects of pH and metal ions concentration on the transport properties of PVDF/AOPAN nanofibers were also studied. The Langmuir model fits well with isotherm data for lead and copper and the Redlich–Peterson model for nickel, whereas pseudo-second order was the best to clearly delineate the investigated kinetics. The modified PVDF/AOPAN NFs showed excellent adsorption capability with very fast kinetics reaching the equilibrium in 90 min for lead, copper, and 60 min for nickel. EDS analysis of PVDF/AOPAN after metal adsorption confirmed the attachment of the metals. Obtained results illustrate that converting PAN to AOPAN enhanced the hydrophilicity drastically. The removal rate for lead, copper, and nickel reached 99.5% 99.5% 99.6% under 10 mg L−1 respectively, more interestingly for lead, even the concentration was 100 mg L−1, the removal rate still reached 98.1%. Moreover, the adsorbent displayed an excellent regeneration ability by using 0.5 M HCl. This study showed that PVDF/AOPAN is an effective adsorbent for Pb(II), Cu(II), and Ni(II) removal in trace amount.