Transport of NaCl, MgSO_4, MgCl_2 and Na_2SO_4 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, MgCl 2 , Na 2 SO 4 and MgSO 4 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 MgCl 2 is moderately rejected, Na 2 SO 4 and MgSO 4 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.

Effect of pH on Total Volume Membrane Charge Density in the Nanofiltration of Aqueous Solutions of Nitrate Salts of Heavy Metals

“…The NF process can recover metallic ions, or at least retain them, and it can be used to concentrate solutions containing multivalent salts or to fractionate salts based on the different charge densities and hydrated sizes of the ions [ 22 , 23 ]. Examples of applications of ions and hardness recovery with use of NF processes are presented in many reports [ 16 , 24 , 25 , 26 ]. With the growing interest in NF as a separation technique for a wide range of applications, even under harsh conditions, ZrO 2 or TiO 2 membranes are increasingly preferred due to their high chemical, thermal and mechanical resistance [ 27 , 28 ] and easy interaction between metallic species and ceramic materials [ 25 ].…”

Development of braid reinforced hollow fiber membranes as both ultrafiltration and nanofiltration membranes: Effect of pore forming additive on structure and performance

“…Enhancing the PVP ratio had a positive effect on NaCl removal efficiency as well as MgSO 4 , which provided better TFC thus NaCl removal in the membrane using 8% PVP was approximately 49%. Similarly, Ramadan et al reported that rejection of MgSO 4 salt is higher than NaCl salt because of ion transmission 50 …”

Assessment of the Total Volume Membrane Charge Density through Mathematical Modeling for Separation of Succinic Acid Aqueous Solutions on Ceramic Nanofiltration Membrane

“…Bowen and co-authors [25,[43][44][45] proposed the Donnan-steric-partitioning model (DSPM) which arose from the eN-P equation. The DSPM has been also used by many authors [32,[46][47][48][49] with fairy good results. However, prediction of separation or membrane charge is very limited, and modeling is used to describe and correlate rejection results.…”