Chemical cleaning of a polyamide membrane

In this paper the results obtained from investigations on a polyamide reverse osmosis membrane fouled by precipitation of materials which exist in water are presented. In these studies, the effect of different cleaning agents on recovery of the fouled membrane has been shown. Results show that a combination of sodium dodecyl sulphate, NaED TA and sodium hydroxide must be used as a cleaning material to reach the optimum recovery of the polyamide membrane employed in petrochemical industries. It was found that cleaning efficiency depends on the type of cleaning agent and its concentration. It has been shown that the efficiency increases with increasing the concentration of the cleaning agent and reaches a maximum value. The concentration that provides the highest cleaning efficiency can be considered as the optimum concentration. This depends on the type of cleaning agents. Operating conditions such as cross flow velocity, turbulence in the vicinity of the membrane surface, temperature, pH and cleaning time also play an important role in the cleaning processes. Membrane cleaning requires deep understanding of the interactions between the foulants and the membrane as well as the effect of the cleaning procedure on deposit removal. In this paper the mechanism of deposit removal is also investigated.