| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 642064 | Separation and Purification Technology | 2012 | 8 Pages |
Reverse osmosis (RO) is an efficient and often used technique for water desalination and industrial demineralized water production. The use of polyamide based membranes provides higher permeate fluxes than other polymers, while the resistance to oxidant agents is very low. The efficient lifetime of polyamide membranes varies between 3 and 5 years. To improve this lifetime, the membranes can be submitted to a chemical treatment that could recover permeate flux and salt rejection characteristics. The purpose of this work is to investigate the efficiency of a rejuvenation procedure using tannic acid as a rejuvenating agent. The experiments were performed in a bench scale RO system with two different commercial polyamide membranes. Several conditions were analyzed, including tannic acid concentration, solution pH, transmembrane pressure and membrane cleaning conditions. Saline rejection and permeate flux were the parameters used to evaluate the efficiency of the process. The results obtained in the bench scale experiments were used to perform a test in an industrial membrane module that had been operating in an industrial demineralization plant for 5 years. The effects of the operating conditions of membrane cleaning on the efficiency of the rejuvenation treatment are also provided.
► Tannic acid is an efficient rejuvenating agent for polyamide membranes. ► The rejuvenation treatment recovered the NaCl rejection of the membrane. ► The efficiency of rejuvenation is dependent on pH and tannic acid concentration. ► Rejuvenating treatment is more likely a “surface treatment” than a “hole plugging”. ► The membrane cleaning conditions are very important to improve membrane rejuvenation.
