Views: 1667 Author: Kevin Chen Publish Time: 2020-07-08 Origin: Site
| Pollutant | General characteristics | Cleaning method |
| Inorganic salt precipitate | Desalination rate decreased significantly, system pressure drop increased, and system water production decreased slightly | 2% citric acid solution, Ammonia adjusted pH 4.0, temperature 40 ℃; It can also be cleaned with hydrochloric acid aqueous solution with pH 2 ~ 3 (0.5%) |
| Oxide/hydroxide Objects (iron, nickel, copper, etc) | Desalination rate decreased significantly, system pressure drop increased significantly, and system water production decreased significantly | Ammonia adjusted pH 4.0, 2% citric acid solution, temperature 40 ℃; Sometimes it can also be cleaned with a hydrochloric acid aqueous solution of pH 2 ~ 3 (0.5%) |
| Various colloids (iron, organics and silica gel) | The desalination rate is slightly reduced, the system pressure drop is gradually increased, and the system water production is gradually reduced | Sulphuric acid adjusts the pH value to 10.0, 2% sodium tripolyphosphate (STTP) solution, Temperature 40 ℃; sometimes it can be cleaned with aqueous NaOH solution with pH less than 10 |
| Calcium sulphate | Desalination rate decreased significantly, system pressure drop slightly or moderately increased, system water production decreased slightly | pH value 10.0, 2% sodium tripolyphosphate solution, 0.8% EDTA (ethylenediaminetetraacetic acid) tetrasodium (replace with 0.25% sodium dodecylbenzenesulfonate in severe cases), temperature 40 ℃; sometimes it can also use PH<10 NaOH aqueous solution cleaning |
| Organic deposition | Desalination rate may decrease, system pressure drop gradually increases, system water production gradually decreases | pH value 10.0, 2% sodium tripolyphosphate solution, 0.8% EDTA (ethylenediaminetetraacetic acid) tetrasodium (replace with 0.25% sodium dodecylbenzenesulfonate in severe cases), temperature 40 ℃ |
| Bacterial pollution | Desalination rate may decrease, system pressure drop may increase significantly, system water production volume may decrease significantly | pH value 10.0, 2% sodium tripolyphosphate solution, 0.8% EDTA (ethylenediaminetetraacetic acid) tetrasodium (in severe cases, replace with 0.25% dodecylbenzenesulfonic acid Na-DDBS), temperature 40 ℃; 0.1% NaOH and 0.03% sodium dodecyl sulfonate (SDS), PH = 11.5 |
