Acrylamide-plasma treated electrospun polystyrene nanofibrous adsorbents for cadmium and nickel ions removal from aqueous solutions

The aim of this work was to prepare novel electrospun polystyrene (PS) nanofibrous samples functionalization with acrylamide monomer (AAm) as promising nanoadsorbents by the use of nitrogen gas plasma. To investigate the performance evaluation of the samples for adsorbing cadmium (Cd2+) and nickel (Ni2+) ions, a series of tests in terms of ATR-FTIR spectroscopy, FE-SEM, water contact angle (WCA) measurements and atomic adsorption spectroscopy were carried out. The ATR-FTIR results showed that nitrogen (N-2) plasma was an efficient tool because of the formation of functionalized AAm-PS nanofibrous samples by providing amide (-NCO) and amine (-NH-) groups onto their surfaces. The WCA measurements demonstrated that the N-2 plasma-modified samples in the presence of AAm had a lower contact angle of 42.8o than the other samples. Moreover, FE-SEM micrpgraph images of AAm-treated PS nanofibrous samples indicated that approperiate amount of the functional groups onto the samples surfaces were deposited. Afterwards, AAS analysis along with Langmuir and Freundlich's isotherm models revealed that a high adsorption of the ions was occurred at pH 5 in the order Cd2+ (10 mg g(-1))>Ni2+ (4.9 mg g(-1)) by using the nanoadsorbents dosage 1 g L-1 and the metal ions concentration 25 mg L-1. In addition, the obtained results exhibited the Cd2+ and Ni2+ ions removal efficiencies (%R) were increased up to 96% and 94%, respectively with raising the nanoadsorbents dosage. Moreover, the equilibrium adsorption of the ions showed the best fitting by the Freundlich's model. Finally, the desorption of the optimized samples for regenerating them owing to the effective removal of the ions has been confirmed by applying the recyclability test. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42944.