Ong Maria Dominique, Vasquez Isabel, Alvarez Brandon, Cho Dylan R, Williams Malik B, Vincent Donovan, Ali Md Arafat, Aich Nirupam, Pinto Alexandre H, Choudhury Mahbuboor Rahman
Civil and Environmental Engineering Department, Manhattan College, Riverdale, NY 10471, USA.
Chemistry and Biochemistry Department, Manhattan College, Riverdale, NY 10471, USA.
Membranes (Basel). 2023 Jan 22;13(2):143. doi: 10.3390/membranes13020143.
Pressure-based membrane processes represent excellent water resource recovery prospects from industrial waste streams. In contrast with conventional pretreatment technologies, studies have shown that membrane pretreatment applications, such as microfiltration (MF), are more cost-effective and improve the results of the overall treatment processes. Hence, enhancing rejection efficiency of MF will enhance the performance of any downstream treatment processes. In this study, 0.45 µm cellulose acetate (CA) microfiltration membranes were modified by vacuum filtration-assisted layer-by-layer deposition of bilayers composed of negatively charged graphene oxide (GO) and positively charged polyethyleneimine (PEI). The performance of 1-, 2-, and 4-bilayer GO-PEI-modified membranes were investigated for their dye-rejection of anionic eriochrome black T (EBT) dye and cationic methylene blue (MB) dye in a cross-flow membrane module. As the number of bilayers on the membrane increased, the membrane thicknesses increased, and the deionized (DI) water flux through the membranes decreased from 4877 LMH/bar for the control (no bilayer) membrane to 2890 LMH/bar for the 4-bilayer membrane. Conversely, the dye-rejection performance of the modified membranes increased as increasing bilayers of GO-PEI deposited on the membranes. The anionic EBT dye saw superior rejection (90% rejection) compared to the cationic MB dye (80% rejection), which can be attributable to the electrostatic repulsion between the negatively charged GO surface and anionic EBT dye. After 50% recovery of the saline and dye-laden feed water, there was an observed drop in DI water fluxes of ~40-41% and 36%, respectively. There was also a slight increase in EBT dye-rejection during the composite feed-water experiments, attributed to the precipitation of salts on the membrane feed side or pore spaces, which subsequently reduce the membrane pore sizes.
基于压力的膜工艺在从工业废水中回收水资源方面展现出了良好的前景。与传统预处理技术相比，研究表明，膜预处理应用，如微滤（MF），更具成本效益，并且能改善整个处理过程的效果。因此，提高微滤的截留效率将提升任何下游处理工艺的性能。在本研究中，通过真空过滤辅助的层层沉积法，用带负电荷的氧化石墨烯（GO）和带正电荷的聚乙烯亚胺（PEI）组成的双层膜对0.45 µm的醋酸纤维素（CA）微滤膜进行了改性。在错流膜组件中，研究了1层、2层和4层GO-PEI改性膜对阴离子铬黑T（EBT）染料和阳离子亚甲基蓝（MB）染料的截留性能。随着膜上双层膜数量的增加，膜厚度增加，通过膜的去离子（DI）水通量从对照（无双层膜）膜的4877 LMH/bar降至4层膜的2890 LMH/bar。相反，随着沉积在膜上的GO-PEI双层膜数量增加，改性膜的染料截留性能提高。与阳离子MB染料（80%截留率）相比，阴离子EBT染料的截留效果更佳（90%截留率），这可归因于带负电荷的GO表面与阴离子EBT染料之间的静电排斥作用。在对含盐和含染料的进水进行50%的回收后，观察到DI水通量分别下降了约40 - 41%和36%。在复合进水实验期间，EBT染料的截留率也略有增加，这归因于盐在膜进料侧或孔隙空间的沉淀，这随后减小了膜孔径。
