Which membrane allows only water to pass while filtering out pathogens, salts, and minerals?

The correct choice allows only water molecules to pass through while effectively blocking pathogens, salts, and minerals due to its ultra-fine filtration capabilities. Reverse Osmosis utilizes a semi-permeable membrane with incredibly small pores, typically around 0.0001 microns in diameter. This design is specifically intended to separate impurities from water, achieving a high level of purification.

In reverse osmosis, the process involves applying pressure to overcome osmotic pressure and drive water molecules through the membrane. This mechanism not only filters large contaminants, such as salts and minerals, but also removes virtually all pathogens, including bacteria and viruses, ensuring that the water produced is clean and safe for consumption or industrial use.

Other filtration methods, such as microfiltration, ultrafiltration, and nanofiltration, have larger pore sizes compared to reverse osmosis and are effective for specific applications, such as removing larger particles or certain bacteria, but they do not achieve the same level of solute rejection as reverse osmosis. Therefore, they would allow some salts or minerals to pass through, making them less effective for the goal of achieving pure water.