Bacteria are common microbial contaminants in water, typically ranging in size from 0.5 to 5 micrometers. Reverse osmosis membranes, with pore sizes of approximately 0.1 nanometers, are much smaller than bacteria. Reverse osmosis membranes can directly trap bacteria through physical sieving, preventing them from passing through the membrane pores. Bacterial surfaces often carry an electrical charge, and reverse osmosis membrane materials may also possess some electrical charge. Through charge interaction, the membrane can further adsorb or repel bacteria, enhancing the removal efficiency.
Studies show that reverse osmosis membranes generally have a high bacterial removal rate and can significantly reduce the risk of microorganisms in water. It is important to note that reverse osmosis membranes are not a well-known sterile barrier, but their high efficiency in practical applications has been widely validated.