Siriwardane Induni W, Sandaruwan Chanaka, de Silva Rohini M, Williams Gareth R, Gurgul Sebastian J, Dziemidowicz Karolina, de Silva K M Nalin
Centre for Advanced Materials and Devices (CAMD), Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka.
Sri Lanka Institute of Nanotechnology (SLINTEC), Nanotechnology and Science Park, Mahenwatte, Pitipana, Homagama 10200, Sri Lanka.
ACS Omega. 2021 Oct 14;6(42):28171-28181. doi: 10.1021/acsomega.1c04238. eCollection 2021 Oct 26.
This work reports the fabrication of nanomagnetite- and nanotitania-incorporated polyacrylonitrile nanofibers (MTPANs) by an electrospinning process, which has the potential to be used as a membrane material for the selective removal of Cd(II) and As(V) in water. The fiber morphology was characterized by scanning electron microscopy (SEM). The incorporation of nanomagnetite and nanotitania in the composite fiber matrix was confirmed by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The fibers doped with nanomagnetite and nanotitania (MPAN and TPAN fibers, respectively), as well as MTPAN and neat polycrylonitrile (PAN) fibers, after thermally stabilizing at 275 °C in air, were assessed for their comparative As(V)- and Cd(II)-ion removal capacities. The isotherm studies indicated that the highest adsorption of Cd(II) was shown by MTPAN, following the Langmuir model with a of 51.5 mg/m. On the other hand, MPAN showed the highest As(V)adsorption capacity, following the Freundlich model with a of 0.49. The mechanism of adsorption of both Cd(II) and As(V) by fibers was found to be electrostatically driven, which was confirmed by correlating the point of zero charges (PZC) exhibited by fibers with the pH of maximum ion adsorptions. The As(V) adsorption on MPAN occurs by an inner-sphere mechanism, whereas Cd(II) adsorption on MTPAN is via both surface complexation and an As(V)-assisted inner-sphere mechanism. Even though the presence of coexistent cations, Ca(II) and Mg(II), has been shown to affect the Cd(II) removal by MTPAN, the MTPAN structure shows >50% removal efficiency even for minute concentrations (0.5 ppm) of Cd(II) in the presence of high common ion concentrations (10 ppm). Therefore, the novel polyacrylonitrile-based nanofiber material has the potential to be used in polymeric filter materials used in water purification to remove As(V) and Cd(II) simultaneously.
本研究报道了通过静电纺丝工艺制备纳米磁铁矿和纳米二氧化钛掺杂的聚丙烯腈纳米纤维（MTPAN），该材料有潜力用作膜材料，用于选择性去除水中的Cd(II)和As(V)。通过扫描电子显微镜（SEM）对纤维形态进行了表征。通过能量色散X射线光谱（EDX）、X射线衍射（XRD）和傅里叶变换红外（FT-IR）光谱证实了纳米磁铁矿和纳米二氧化钛在复合纤维基质中的掺入。分别掺杂纳米磁铁矿和纳米二氧化钛的纤维（分别为MPAN和TPAN纤维），以及MTPAN和纯聚丙烯腈（PAN）纤维，在空气中275℃热稳定后，评估了它们对As(V)和Cd(II)离子的相对去除能力。等温线研究表明，MTPAN对Cd(II)的吸附量最高，符合Langmuir模型，吸附量为51.5 mg/m。另一方面，MPAN对As(V)的吸附容量最高，符合Freundlich模型，吸附量为0.49。发现纤维对Cd(II)和As(V)的吸附机制是由静电驱动的，这通过将纤维表现出的零电荷点（PZC）与最大离子吸附pH值相关联得到证实。MPAN对As(V)的吸附通过内球机制发生，而MTPAN对Cd(II)的吸附是通过表面络合和As(V)辅助的内球机制。尽管已表明共存阳离子Ca(II)和Mg(II)的存在会影响MTPAN对Cd(II)的去除，但即使在高共离子浓度（10 ppm）存在下，对于低浓度（0.5 ppm）的Cd(II)，MTPAN结构仍显示出>50%的去除效率。因此，这种新型聚丙烯腈基纳米纤维材料有潜力用于水净化中同时去除As(V)和Cd(II)的聚合物过滤材料。
