Arrange the following membrane processes in order of decreasing pore size: (A) Nanofiltration (B) Microfiltration (C) Ultrafiltration (D) Hyperfiltration
Choose the correct answer from the options given below:

Correct option is A

The pore sizes of the mentioned filtration methods decrease in the following order:
Microfiltration (B):
Largest pore size, typically in the range of 0.1–10 microns. Used for removing large particles, bacteria, and suspended solids from liquids.
Ultrafiltration (C):
Smaller pore size, in the range of 0.01–0.1 microns. Removes viruses, proteins, and larger macromolecules.
Nanofiltration (A):
Pore size ranges between 0.001–0.01 microns. It removes smaller molecules like divalent salts and organic molecules.
Hyperfiltration (Reverse Osmosis) (D):
Smallest pore size (<0.001 microns). It is used to remove ions, dissolved salts, and very fine contaminants.
Thus, the order of decreasing pore size is:
(B) Microfiltration > (C) Ultrafiltration > (A) Nanofiltration > (D) Hyperfiltration.
Information Booster: 1. Microfiltration (MF): Removes large contaminants like sand, algae, and bacteria.
2. Ultrafiltration (UF): Filters viruses and some dissolved organic molecules.
3. Nanofiltration (NF): Effective for softening water and removing divalent salts.
4. Hyperfiltration (Reverse Osmosis): Filters at the molecular level, often used in desalination and high-purity water production.
5. Membrane technology is widely used in industries such as water treatment, food processing, and pharmaceuticals.