RO Filtration Membranes

There are two types of reverse osmosis filtering membranes. Thin film composite membranes (PA) are made from polymide, polysulfone and a fabric support sheet.

An asymmetric membrane (CA) is composed of cellulose acetate in a single dense layer supported by a secondary spongy layer.

The table below compares the two.

Parameters PA Membrane CA Membrane
Operating pH range 2~12 4~6
Operating Pressure (Kg/cm2 ) 15 30
Salt Rejection (%)                                      TDS 99+ 98
                                                        Silica (SiO2) 99+ <95
Salt Rejection Change   after 3years 99%→98.7% 98%→96%
Chlorine Tolerance <0.1 ppm 1 ppm
Membrane Fouling High Low