Preparing of poly(acrylonitrile co maleic acid) nanofiber mats for removal of Ni(II) and Cr(VI) ions from water
Generally, heavy metal ions derived from different industrial sources are absorbed by organisms' ecosystems, causing serious illnesses. Therefore, removing them by a new and practical technique is essential. In this study, poly(acrylonitrile co maleic acid) nanofibers were prepared by the electrospinning technique for the removal of heavy metal ions Ni(II) and Cr(VI) from water. Firstly, polymer concentration (w/w %), applied voltage (kV), and the distance tip to collector (cm) values were optimized to find the finest nanofiber by employing response surface methodology. The minimum average of the nanofiber diameters of SEM images and the minimum standard deviation without beads were considered as the criteria for the selection of the aforementioned parameters; also, they were converged at 5.2%, 10.2 kV, and 16.3 cm, respectively. The nanofiber diameter averaged was obtained to be 180.7 nm. Secondly, the effects of contact time (min), stirring rate (rpm) and the pH of the mixed nanofibers and heavy metal ions solutions were investigated to find the maximum adsorption of ions by the nanofiber mats. These values were, respectively, obtained to be 20 and 15 min, 1250, and 1000 rpm; also, they were 6 and 4 for Ni(II) and Cr(VI) ions, respectively. In addition, the adsorption values of heavy metal ions by the nanofiber mats were reported in this study, showing that the nanofiber sites for adsorption Ni(II) ions could be more appropriate than its Cr(VI) ions.