Tang Yufei, Liu Zhaowei, Zhao Kang, Fu Song
Department of Materials Science and Engineering, Xi'an University of Technology Xi'an 710048 PR China
RSC Adv. 2018 Apr 9;8(23):13018-13025. doi: 10.1039/c8ra01899e. eCollection 2018 Apr 3.
Tiny particles with a negative charge in water can be removed effectively by inorganic positively charged nanofiber membranes due to their physical separation and electrostatic adsorption properties. However, the charged positive and isoelectric points (IEP) on the surface of the positively charged nanofiber membranes need to be further improved to meet the requirements of the Environmental Protection Agency for virus filters (excellent adsorption and separation properties in solutions with pH between 5 and 9). The positively charged SiO@ZrO nanofibrous membrane was fabricated by electrospinning combined with the impregnation method and calcined in an anoxic atmosphere. The effects of the impregnating solution concentration and centrifugal speeds on the morphology, pore size and nanofiber diameter of the composite nanofibrous membrane were investigated. The phase composition, the element valence state, the surface charge and the adsorption separation properties of the composite nanofibrous membranes were characterized. Flexible SiO@ZrO nanofibrous membranes with high specific surface area and water flux were obtained. The surface isoelectric point is 7.3 when calcined in a mixed atmosphere of N (96%)/H (4%), which is higher than that when calcined in air and vacuum. Some oxygen vacancies were present on the surface of the ZrO (0 < < 2) shell, resulting in the tetragonal zirconia still being available at room temperature. The interception rate of the positively charged SiO@ZrO nanofibrous membranes for a titan yellow solution with a concentration of 10 mg L reaches 99.996%. Its maximum adsorption capacity can reach 63.27 mg cm when filtering a 1 L titan yellow solution. The resulting nanofibrous membranes have potential application for the separation of bacteria and viruses from water.
水中带负电荷的微小颗粒可通过无机带正电荷的纳米纤维膜有效去除，这归因于其物理分离和静电吸附特性。然而，带正电荷的纳米纤维膜表面的带电正点和等电点（IEP）需要进一步改进，以满足美国环境保护局对病毒过滤器的要求（在pH值为5至9的溶液中具有优异的吸附和分离性能）。通过静电纺丝结合浸渍法制备了带正电荷的SiO@ZrO纳米纤维膜，并在缺氧气氛中进行煅烧。研究了浸渍溶液浓度和离心速度对复合纳米纤维膜的形态、孔径和纳米纤维直径的影响。对复合纳米纤维膜的相组成、元素价态、表面电荷和吸附分离性能进行了表征。获得了具有高比表面积和水通量的柔性SiO@ZrO纳米纤维膜。在N₂（96%）/H₂（4%）的混合气氛中煅烧时，表面等电点为7.3，高于在空气和真空中煅烧时的等电点。ZrO₂（0＜x＜2）壳层表面存在一些氧空位，使得四方氧化锆在室温下仍然可用。带正电荷的SiO@ZrO纳米纤维膜对浓度为10 mg L⁻¹的钛黄溶液的截留率达到99.996%。过滤1 L钛黄溶液时，其最大吸附容量可达63.27 mg cm⁻²。所得纳米纤维膜在从水中分离细菌和病毒方面具有潜在应用。
