Membrane technologies involve the use of selective barriers, or membranes, to separate substances in liquids or gases. These membranes allow certain molecules to pass through while blocking others, making them useful for processes like water purification, gas separation, and food processing. Common types of membranes include microfiltration, ultrafiltration, and reverse osmosis. These technologies are increasingly important in various industries, including environmental management and pharmaceuticals. They help improve efficiency and reduce waste by enabling the recovery of valuable resources from waste streams. Overall, membrane technologies play a crucial role in sustainable practices and resource conservation.