Storage, disinfection, and life of cellulose acetate reverse osmosis membranes

Abstract

Cellulose acetate reverse osmosis membranes were stored in 20 different solutions for periods of time up to 45 months. Where the pH of the storage solution was controlled to minimize hydrolysis, the samples showed good transport properties after storage. Although copious growth of microorganisms occurred in some storage solutions, there was no evidence that these organisms changed the transport characteristics of the membrane. Cupric sulfate controlled such growth and apparently did not damage the membrane. Benzoic acid controlled the growth of biological organisms but attacked the membrane. Chlorine was an effective disinfectant for reverse osmosis systems;at low pH, as much as 95% of the chlorine was transported through the membrane. When used in high concentrations, chlorine attacked the membrane. Stabilized chlorine dioxide was not readily transported through the cellulose acetate membrane.