Effect of electric field intensity on the performance of positively charged quaternized chitosan nanofiltration membranes

The positively charged nanofiltration membrane has a good anti-bacterial and anti-fouling performance. It often shows high rejection to multi-charged inorganic ions and great flux at relative low operation pressure which is meaningful for desalination and wastewater treatment. In this work, the performance of positively charged quaternized chitosan nanofiltration membranes is studied at low voltage direct current (LVDC) electric field. It is found that the involved electric charge in the membrane surface improved the rejection to inorganic salts. With the electric field intensity rising from 0 to 16 V/cm, the membrane rejections to MgCl2 can increase from 54.1% to 81.2%. However, the membrane fluxes changes little and electric current is about 0 A which showed great energy efficiency at desalination process.