Optimizing the desalination rate in a photoelectrocatalytic desalination cell (PEDC) by altering operational conditions

Abstract

Desalination of seawater is a promising response to solving the lack of drinkable water. The separation of cations and anions is carried out by inserting a desalination cell in the middle of a novel design of photoelectrocatalytic desalination cell (PEDC). Different parameters were evaluated and optimized for increasing the capability of system to desalt hypersaline water. Ultraviolet illumination (UV) was used as the driving force, exciting coated titanium nanotubes on the anode electrode, producing electron/hole pairs that degraded organic matter. Methylene blue degradation by UV irradiation was performed, owing to a high salt concentration level, and desalinated to produce electrical current. Performance of PEDCs was investigated by salt content, pH, and ion-exchange resin. The results indicated that higher total dissolved solid (TDS) removal occurred in acidic environments in anode chamber whereas the maximum produced electrical current occurred in alkaline environments in the cathode chamber. Also, the higher amount of salt content in the middle chamber resulted in the high TDS removal until the amount of electrical conductivity in the middle chamber reached 190 mS/cm. The TDS removal rates with and without using resins in the middle of the desalination cell after 10 days were 70.69% and 51.37%, respectively. HIGHLIGHTS The effects of salt content, pH, and ionic exchange resin on the performance of photoelectrocatalytic desalination cells were investigated.; The efficiency of the TDS removal was improved in an acidic environment when pH of the anolyte was 3.; Higher TDS removal occurred by adding salt content in the middle chamber.; The speed of TDS removal was increased by addition of ionic exchange resins.;

Keywords

• desalination
• ion-exchange resin
• methylene blue
• ph
• photoelectrocatalytic desalination cell
• salt content