Removal of NaCl using facilitated up-hill transport through bulk liquid membranes containing dibenzo-18-crown-6

Abstract

Desalination using liquid membranes (LMs) has been investigated in our laboratory using emulsion, supported and flowing LMs. However, bulk liquid membranes (BLMs) have not yet been applied as is clear from the literature cited. Accordingly, in the present work, the aforementioned technique was investigated for removal of sodium chloride from solutions of different concentrations as an attempt for desalination. Variables investigated included: type and quantity of LM, quantity of mobile carrier (MC) in LM, and type and quantity of sequestering agent in receptor phase (RP). Results indicated that: a mixture of 1:1 b.v. dichloroethane (DCE) plus chlorobenzene (CB) was a better LM than CB alone, and that DCE was almost equivalent to nitrobenzene (NB). As to the effect of sequestering agent, soluble starch gave better complexation with NaCl than sorbitol in the RP. It was also shown that the presence of the selected MC was efficient. An optimum quantity of MC led to the highest percentage of extraction of NaCl. The smaller volume of LM leads to higher extraction due to shorter diffusion path of the complex of NaCl plus MC through the LM. The highest extraction obtained was about 75%.

Keywords:

• Bulk liquid membranes
• Crown ether (dibenzo-18-crown-6)
• Chlorobenzene
• Dichloroethane
• Nitrobenzene
• Facilitated up-hill transport

Acknowledgement

The authors wish to acknowledge the kind support of Science and Technology Development Funds (STDF) of Egypt for funding a research project (ID: 4067) on desalination of sea water through application of liquid membrane techniques.