Transport of NaCl, MgSO₄, MgCl₂ and Na₂SO₄ across DL type nanofiltration membrane

Abstract

The separation of inorganic ions by membrane filtration of aqueous solutions through NF-membranes was investigated. The single and binary salt solutions of NaCl, MgCl₂, Na₂SO₄ and MgSO₄ were used in this study. These salts are the most commonly found in natural water resources. From the research literature it was stated that NaCl has a very low rejection range with NF membranes while MgCl₂ is moderately rejected, Na₂SO₄ and MgSO₄ are very highly rejected salts. Thus, these four salts provide a full range of rejection behavior for the NF system and hence constitute an ideal system. In addition, these salts have a very high solubility in water so there would not be any cake layer formed due to precipitation of salts at the surface of the membrane where a significantly higher concentration of salt can be developed due to concentration polarization.