Membrane systems are technologies that use selective barriers, or membranes, to separate substances in various applications. These membranes allow certain molecules to pass through while blocking others, making them useful in processes like water purification, gas separation, and food processing. They can be made from various materials, including polymers and ceramics, depending on the specific application. In water treatment, for example, membrane systems can remove contaminants from drinking water, ensuring it is safe for consumption. Additionally, in the field of biotechnology, membranes are used to isolate specific proteins or cells, enhancing research and development in medical and industrial applications.