The Reverse Osmosis (RO) membrane is the crucial, semi-permeable core component responsible for achieving the highest level of purification in an RO system. Typically constructed as a Thin-Film Composite (TFC) in a spiral-wound configuration, it acts as a molecular filter. Under high pressure, water molecules are forced through the membrane while contaminants—including dissolved salts, heavy metals, bacteria, viruses, and chemical residues—are rejected, achieving up to 99% rejection of Total Dissolved Solids (TDS). This filtration provides the ultra-pure water essential for both drinking and industrial processes.