Articles
Separation and Purification Technology (13835866)354
Janus membranes have asymmetric wettability on each side. This contrasting structure gives them an internal driving force for spontaneous fluid transport (caused by Laplace pressure). The objective of this research is to attain the maximum Laplace pressure for electrospun PVDF/PAN Janus membranes by adjusting the fiber diameter and, consequently, the pore size and contact angle in each layer of the membrane. To achieve this goal, the Taguchi method was employed, and the parameters of the electrospinning process were modified to determine the optimal conditions for obtaining the smallest and largest fiber diameters for PAN and PVDF polymers. Accordingly, four distinct types of Janus membranes with different morphologies in each layer were synthesized. SEM analysis was employed to characterize the structural and morphological properties of the fibers in each layer. Additionally, the contact angle (CA) was measured to assess the hydrophilicity of each layer and determine the droplet penetration rate across the membrane. According to the results, the maximum Laplace pressure (205.60 kPa calculated by the analysis of SEM images and 197.4 kPa calculated by the bubble point test) and highest droplet penetration rate (0.83 µL/s) were attributed to the Janus membrane with the lowest pore size in the hydrophilic layer (0.65 µm) and the highest pore size in the hydrophobic layer (3.44 µm). The performance of the optimized membrane was evaluated with respect to unidirectional water transport and water–oil mixture separation. The results showed a rectification ratio of 3.92, a permeate flux of 7.9 × 104 L·m−2·h−1·bar−1, and a separation efficiency of 96.8 %. Finally, it was demonstrated that the Laplace pressure of the optimal Janus membrane in this study is 2.66 times superior to that of the best similar one in previous studies. The appropriate and allowable range for pore size and contact angle, necessary to attain a satisfactory Laplace pressure (exceeding 100 kPa), has been explored, determined, and recommended for future researchers to foster inspiration in the field of Janus membranes. © 2024 Elsevier B.V.
Journal of Water Process Engineering (22147144)71
This research explores the separation of the antitumor drug doxorubicin (DOX) using smart membranes that respond to pH changes. To address the challenge of evaluating the efficiency of membranes with open and close gates, four types of membranes were synthesized: open gate (PADD0/PSf), bifunctional open gate (PADD1/PSf), close gate (PAADD0/PSf), and a combination of close/open gate (PAADD1/PSf). The results demonstrated that open gate membranes effectively separated DOX through molecular screening mechanism, with enhanced performance achieved through bi-functionalization and pH adjustments. The PADD0/PSf membrane exhibited a 93 % rejection rate at pH 7, which increased to approximately 99 % for the bifunctional PADD1/PSf at pH 2.7. In contrast, the PAADD0/PSf close gate membrane revealed only an 87 % rejection rate at pH 7, relying on Donnan repulsion for separation while achieving higher flux. Given the significance of treatment rates in membrane processes, the PADD0/PSf and PADD1/PSf membranes recorded fluxes of 4.6 LMH and 5 LMH at pH 7, respectively, while the PAADD0/PSf close gate membrane exhibited a significantly higher flux (226 %). The PAADD1/PSf close/open gate membrane was synthesized to optimize both separation and flux, achieving the highest flux at pH 2.7 with a 90 % DOX separation rate. At pH 11.2, it reached a separation rate of 95 % with a flux of 21 LMH, surpassing all other membranes across different pHs. Overall performance assessments indicated that PAADD1/PSf achieved an overall performance parameter of 1704 at pH = 2.7, compared to values of 78 for PADD0/PSf, 90 for PADD1/PSf, and 727 for PAADD1/PSf. © 2025 Elsevier Ltd
Chemical Engineering Science (00092509)316
Membrane fouling, a major challenge in filtration which lowers performance and membrane lifespan, is the focus of this research. The study introduces a key novelty by examining the combined effects of modifier type (mineral nanoparticles vs. organic substances) and their specific loading site (sublayer vs. top layer) on fouling mitigation, an aspect that has not been comprehensively addressed in prior studies. Hydrophilic mineral nanoparticles (CdSe, ZnSe, ZnTe) and dopamine hydrophilic organic substance were loaded in the sublayers of mixed matrix membranes (MMM) and the top layer of thin-film composite (TFC). Mineral modifiers outperformed organic counterparts. ZnSe nanoparticles was the most effective modifier; its strong hydrophilicity enhanced hydration layer formation, delayed phase inversion, and resulted in smaller pores and lower tortuosity in MMM (0,ZnSe), with the lowest pore fouling. Highlighting the significance of research, MMM membranes containing mineral modifiers (especially ZnSe) are suggested for lower pore fouling (4.62% vs 67.31%). In contrast, for lower cake fouling and higher rejection (98.00% vs 75.09%), TFC membranes containing both organic (dopamine) and mineral (especially ZnSe) modifiers are recommended. © 2025 Elsevier Ltd
This research principally aimed to present a suitable strategy for membrane-fouling mitigation in membrane-bioreactors (MBRs). The current strategies for membrane-fouling mitigation before initiating the process in many cases, are unmodifiable for a specific MBR system along the operations. Thus, membrane-fouling strategies during filtration should be applied. To select the best and most economical method for controlling fouling during the operations, the quality (site and mechanism) as well as quantity (thickness, mass, and porosity of the cake layer, and pore resistances) of fouling should be predicted. Accordingly, in this research, two powerful tools, i.e. modeling and simulation, have been used for predicting the quality and quantity of fouling, respectively. Through modeling, the best model describing the site and mechanism of fouling was chosen. Through simulation, the thickness, mass and porosity of the cake layer, along with resistance of cake and pores were calculated. In addition, the match between the results of modeling, simulation, and experimental results confirmed the accuracy of the performed predictions. Ultimately, to achieve the minimum membrane-fouling during filtration, based on the modeling results, the general solution of washing (physical or chemical), and based on the simulation results, its intensity (low, medium, and high) were proposed. © 2024 The Authors
