Fionah Abelline, McLarney Kate, Judd Aviana, Escobar Isabel C
Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA.
Department of Materials and Chemical Engineering, University of Kentucky, Lexington, KY 40506, USA.
Membranes (Basel). 2023 Jul 18;13(7):675. doi: 10.3390/membranes13070675.
The global water crisis growth has led to a tremendous increase in membrane technology research. Membranes are favored over many other technologies for water treatment because, in principle, they require no chemical additives and can be used isothermally at low temperatures. Membranes that can reject contaminants and salts, produce adequate permeate flux values, and require minimal cleaning are highly demanded. However, most synthesized membranes on the market have associated problems, such as membrane fouling; inverse relationships between flux and solute rejection; and the high cost of synthesis, operation, and maintenance. Therefore, there is a continuied need to produce membranes with properties that make them able to sustain flux and selectivity over time. This research study focused on increasing the surface charge and hydrophilicity of polysulfone (PSf) membranes by incorporating sulfonate-functionalized poly-ether-ether-ketone (SPEEK) into PSf/N-Methyl-2-pyrrolidone (PSf/NMP) membranes. The sulfonation of the PEEK provided a net increase in negative charge on the surface of the membranes that enabled charge repulsion to take place, thus increasing the rejection of ions. In this project, the effect of the applied potential on the performance of SPEEK: PSf/NMP membranes was evaluated. The characterization of the as-synthesized membranes was carried out using the surface's structure and morphology, contact angle, and zeta potential. Furthermore, a voltage of 1.5 V was applied to the membranes in the presence of various salts (sodium chloride, calcium chloride, and potassium chloride salts) to evaluate the effects of the applied potential on solute rejection. It was found that both the permeability and the selectivity of the membranes increased when the voltage was applied. The obtained results indicate that incorporating SPEEK into PSf/NMP membranes increased the hydrophilicity of the membranes, and under the applied voltage, the incorporation allowed it to function as an electrodialysis process that is capable of removing ions from water bodies by utilizing the charge repulsion of ions.
全球水危机的加剧促使膜技术研究大幅增加。与许多其他水处理技术相比，膜更受青睐，因为原则上它们无需化学添加剂，且能在低温下等温使用。人们对能够截留污染物和盐分、产生足够渗透通量值且清洗需求最小的膜有很高的需求。然而，市场上大多数合成膜都存在相关问题，如膜污染；通量与溶质截留率之间的反比关系；以及合成、运行和维护成本高昂。因此，持续需要生产具有能随时间维持通量和选择性的性能的膜。本研究聚焦于通过将磺酸盐功能化聚醚醚酮（SPEEK）掺入聚砜（PSf）/N-甲基-2-吡咯烷酮（PSf/NMP）膜中来增加聚砜膜的表面电荷和亲水性。聚醚醚酮的磺化使膜表面的负电荷净增加，从而能够发生电荷排斥，进而提高离子截留率。在本项目中，评估了施加电势对SPEEK:PSf/NMP膜性能的影响。使用表面结构和形态、接触角和zeta电位对合成后的膜进行了表征。此外，在存在各种盐（氯化钠、氯化钙和氯化钾盐）的情况下，对膜施加1.5 V的电压，以评估施加电势对溶质截留的影响。结果发现，施加电压时膜的渗透性和选择性均有所提高。所得结果表明，将SPEEK掺入PSf/NMP膜中增加了膜的亲水性，并且在施加电压的情况下，这种掺入使其能够作为一种电渗析过程发挥作用，该过程能够通过利用离子的电荷排斥从水体中去除离子。
