Ultrafiltration membrane cleaning technology and mechanism based on seawater desalination pilot equipment

In order to clean the ultrafiltration membrane in the process of seawater desalination, this paper studied the cleaning effects of backwash water and chemical agents on the ultrafiltration membrane by using the ultrafiltration pilot equipment. Effects of different backwash water on the transmembrane pressure difference were studied. The results showed that the cleaning effect was in the order of fresh water (tap water) > ultrafiltration water > reverse osmosis concentrated water. In addition, cleaning effect was as follows: citric acid > oxalate > hydrochloric acid > sodium hypochlorite > sodium hydroxide. Citric acid had the best cleaning effect, and the pure water penetration rate could be restored from 283.24 L/(m²·h) to 571.56 L/(m²·h). Moreover, the effect of alkali washing and acid washing together is better than that of cleaning alone. After cleaning with sodium hydroxide and then citric acid, the pure water transmission rate can recover from 283.24 L/(m²·h) to 818.81 L/(m²·h). The results of this study have a good application prospect for the maintenance of ultrafiltration membrane in seawater desalination.