Membrane processes are techniques that use selective barriers, or membranes, to separate substances in a mixture. These processes can filter out particles, ions, or molecules based on size, charge, or chemical properties. Common applications include water purification, gas separation, and food processing. There are various types of membrane processes, such as reverse osmosis, ultrafiltration, and microfiltration. Each method operates under different conditions and is suited for specific tasks. For example, reverse osmosis is often used to desalinate seawater, while ultrafiltration is effective in removing bacteria from liquids.