Selective Separation of Singly Charged Chloride and Dihydrogen Phosphate Anions by Electrobaromembrane Method with Nanoporous Membranes

• Published in: Membranes (Basel) 2023-04, Vol.13 (5), p.455
• Main Authors: Butylskii, Dmitrii, Troitskiy, Vasiliy, Chuprynina, Daria, Kharchenko, Ivan, Ryzhkov, Ilya, Apel, Pavel, Pismenskaya, Natalia, Nikonenko, Victor
• Format: Article
• Language: English
• Subjects: Acids; Aluminum; Aluminum compounds; Aluminum oxide; Anions; Aqueous solutions; Chemical elements; Chlorides; Convective flow; countercurrent electromigration; Electric fields; electrobaromembrane separation; Electrolytes; Evaluation; Fluxes; highly selective separation; ion separation; Ions; Membranes; Methods; nanoporous membranes; Natural waters; phosphate; Phosphates; Phosphorus; Phosphorus compounds; Polyethylene terephthalate; Pores; Potassium; Pressure drop; Properties; Separation; Separation (Technology); Sodium chloride; Sodium phosphate
• ISSN: 2077-0375; 2077-0375
• DOI: 10.3390/membranes13050455

The entrance of even a small amount of phosphorus compounds into natural waters leads to global problems that require the use of modern purification technologies. This paper presents the results of testing a hybrid electrobaromembrane (EBM) method for the selective separation of Cl (always present in phosphorus-containing waters) and H PO anions. Separated ions of the same charge sign move in an electric field through the pores of a nanoporous membrane to the corresponding electrode, while a commensurate counter-convective flow in the pores is created by a pressure drop across the membrane. It has been shown that EBM technology provides high fluxes of ions being separated across the membrane as well as a high selectivity coefficient compared to other membrane methods. During the processing of solution containing 0.05 M NaCl and 0.05 M NaH PO , the flux of phosphates through a track-etched membrane can reach 0.29 mol/(m ×h). Another possibility for separation is the EBM extraction of chlorides from the solution. Its flux can reach 0.40 mol/(m ×h) through the track-etched membrane and 0.33 mol/(m ×h) through a porous aluminum membrane. The separation efficiency can be very high by using both the porous anodic alumina membrane with positive fixed charges and the track-etched membrane with negative fixed charges due to the possibility of directing the fluxes of separated ions in opposite sides.