NALAN KABAY ^1* Mohammad Mahdi A. Shirazi ² Enver Güler ³ Marek Bryjak ⁴

• ¹ Ege University, Bornova, Türkiye
• ² University of Saskatchewan, Saskatoon, Saskatchewan, Canada
• ³ Atılım University, Ankara, Ankara, Türkiye
• ⁴ Wrocław University of Technology, Wrocław, Silesian, Poland

The design of membrane modules plays a crucial role in determining the efficiency, scalability, and cost-effectiveness of membrane processes used in various applications such as water treatment, resource recovery, and energy production [1]. A well-optimized module design enhances mass and heat transfer, minimizes fouling, and improves operational stability, making membrane technologies more viable for industrial and municipal use [2,3].The design of membrane modules for membrane processes hinges on several critical parameters to ensure efficiency, durability, and adaptability across various applications. These parameters are shown in Figure 1.Membrane material must be chemically compatible and mechanically durable for long-term performance and cleaning [4]. Module configurations, such as spiral wound or hollow fiber, aim to maximize packing density while ensuring ease of maintenance. A high surface area-tovolume ratio is crucial for enhanced flux but must be balanced against pressure drop considerations [5]. Effective hydrodynamic design ensures uniform flow distribution, reduces dead zones, and minimizes fouling through turbulence promoters or optimized spacers [6].Additionally, fouling and scaling control features, such as anti-fouling coatings or spacer designs, enhance performance and facilitate cleaning, making these parameters integral to robust and efficient module design [7,8].For example, in nanofiltration (NF), module design influences salt rejection rates, flux performance, and energy efficiency, which are critical for applications like softening and desalination [9]. Similarly, in membrane distillation (MD), the module design, including membrane arrangement and thermal integration, significantly impacts the recovery of clean water and valuable resources from challenging feed streams such as brines and industrial effluents [10]. In membrane bioreactors (MBRs), as another example, module design directly affects aeration efficiency, fouling control, and energy consumption, which are crucial for treating municipal and industrial wastewater while maintaining high-quality effluent standards [11,12]. Advances in module designs, such as spacer configurations, hollow fiber membranes, and spiral wound setups, are pivotal for pushing the boundaries of performance and ensuring sustainable and cost-effective solutions in these membrane-based processes [13,14]. The Web of Science Engin shows 15411 hints for the phrase 'membrane module' and counts 946 reviews. This Research Topic covers four review papers on "Membrane modules and processes". The above review papers demonstrate the interdisciplinary fields of membrane science and technology, covering materials, chemistry, chemical engineering and environmental engineering. In addition, these review papers clearly indicate the flexibility of membrane processes in various applications including wastewater treatment and energy production. We consider that much remains to be explored as the field of membrane modules and processes continues to expand.