TY - JOUR
T1 - Creating saturated sodium chloride solutions through osmotically assisted reverse osmosis
AU - Bargeman, Gerrald
N1 - Funding Information:
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Publisher Copyright:
© 2022 The Author
PY - 2022/7/15
Y1 - 2022/7/15
N2 - Increasing sustainability awareness has created opportunities for the recovery and reuse of salt solutions in industrial processes. Osmotically assisted reverse osmosis (OARO) has the potential to concentrate these salt solutions. Until now OARO research focussed on the production of purified water yielding an unsaturated salt solution as retentate, whereas a saturated salt solution is often needed for reuse. OARO featuring recycling of part of the saturated salt solution to the permeate side of the membrane has now been investigated. The introduction of a saturated NaCl solution results in strongly changing osmotic pressure difference and flux profiles along the length of the modules, with a maximum osmotic pressure difference and a minimum flux close to the outlet of the OARO system. In contrast to the NaCl retention of the membrane, the NaCl feed concentration does not have an influence on the maximum osmotic pressure difference. The osmotic pressure difference and membrane flux are strongly dependent on the applied concentrate split factor, which has a strong effect on the required membrane area per feed flow supplied as well. The amount of surface area required per flow of saturated NaCl solution leaving the OARO unit has an optimum as function of the concentrate split factor. This is due to two counteracting effects, the lower osmotic pressure difference, and the lower fraction of saturated NaCl solution leaving the OARO for a higher concentrate split factor. Based on the modelling, essential knowledge has been generated for the further research and development of OARO.
AB - Increasing sustainability awareness has created opportunities for the recovery and reuse of salt solutions in industrial processes. Osmotically assisted reverse osmosis (OARO) has the potential to concentrate these salt solutions. Until now OARO research focussed on the production of purified water yielding an unsaturated salt solution as retentate, whereas a saturated salt solution is often needed for reuse. OARO featuring recycling of part of the saturated salt solution to the permeate side of the membrane has now been investigated. The introduction of a saturated NaCl solution results in strongly changing osmotic pressure difference and flux profiles along the length of the modules, with a maximum osmotic pressure difference and a minimum flux close to the outlet of the OARO system. In contrast to the NaCl retention of the membrane, the NaCl feed concentration does not have an influence on the maximum osmotic pressure difference. The osmotic pressure difference and membrane flux are strongly dependent on the applied concentrate split factor, which has a strong effect on the required membrane area per feed flow supplied as well. The amount of surface area required per flow of saturated NaCl solution leaving the OARO unit has an optimum as function of the concentrate split factor. This is due to two counteracting effects, the lower osmotic pressure difference, and the lower fraction of saturated NaCl solution leaving the OARO for a higher concentrate split factor. Based on the modelling, essential knowledge has been generated for the further research and development of OARO.
KW - Concentrate-split
KW - Osmotically assisted reverse osmosis
KW - Salt
KW - Saturated solution
KW - Split factor
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85129131652&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2022.121113
DO - 10.1016/j.seppur.2022.121113
M3 - Article
AN - SCOPUS:85129131652
VL - 293
JO - Separation and purification technology
JF - Separation and purification technology
SN - 1383-5866
M1 - 121113
ER -