Nanofiltration membranes, including FRP nanofiltration and sanitary grade nanofiltration, are selective filtration membranes operating at the nanoscale. FRP nanofiltration membranes are used in industrial applications for the removal of divalent ions while retaining monovalent ions. Sanitary grade nanofiltration membranes are designed for food, beverage, and pharmaceutical industries, removing contaminants while retaining desirable components. These membranes provide effective separation and purification solutions based on size and charge, meeting specific industry requirements.