Oxidizing biocides, such as chlorine, are added to kill bacteria, followed by bisulfite dosing to deactivate the chlorine, which can destroy a thin-film composite membrane. There are also inhibitors, which do not kill bacteria, but simply prevent them from growing slime on the membrane surface and plant walls.

There is no real optimal pH. The best pH from rejection point of view for thin film composite membranes.

What happens when sound hits a thin membrane is that it vibrates the tympanic membrane. The tympanic membrane is also known as the eardrum.

plasma membrane

The cell membrane is the thin layer that holds cells together. Cell membranes are used as barriers and for protection.