Chemical cleaning of reverse osmosis membranes

Membrane technology has become of great interest for treatment of different water feeds including seawater. Depending on the membrane type, materials in the feed and process conditions the membrane will lose its performance during time. Fouling is the most important problem associated with the application of membranes. A strategy for membrane regeneration is chemical cleaning of the fouled membranes. One of the major applications of reverse osmosis membranes is processing of water from different resources or for various applications. This includes seawater desalination or ion removal for makeup water for boilers. In all cases fouling restricts membrane performance. In this work reverse osmosis membranes were fouled with water. Chemical cleaning of the RO membranes using acid, alkaline, surfactant and detergent solutions has been discussed. Cleaning efficiency depends on the type of the cleaning agent and its concentration. It has been shown that the efficiency increases with increasing the concentration of the cleaning agent. The concentration that provides the highest cleaning efficiency can be considered as the optimum concentration. This depends on the type of the cleaning agent. Operating conditions such as crossflow velocity, turbulence in the vicinity of the membrane surface, temperature, pH and cleaning time also play a role in the cleaning process. Optimum membrane cleaning requires in depth understanding of the interactions between the foulants and the membrane as well as the effect of the cleaning procedure on deposit removal and membrane performance. In this paper the mechanism of deposit removal is also investigated.