TY - JOUR
T1 - Ultrathin Polyamide Membranes Fabricated from Free-Standing Interfacial Polymerization: Synthesis, Modifications, and Post-treatment
AU - Cui, Yue
AU - Liu, Xiang-Yang
AU - Chung, Neal Tai-Shung
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research is supported by the National Research Foundation, Prime Minister's office, Republic of Singapore, under its Competitive Research Program entitled
PY - 2017/1/4
Y1 - 2017/1/4
N2 - The thin film composite (TFC) membrane synthesized via interfacial polymerization is the workhorse of the prevalent membrane technologies such as nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO), and pressure retarded osmosis (PRO) membranes. The polyamide selective layer usually possesses a high selectivity and permeability, making it the heart of this membrane technology. To further improve and understand its formation, with entirely excluding the effect of substrate, an ultrathin membrane which consists of only the polyamide selective layer has been fabricated via free-standing interfacial polymerization between M-phenylenediamine (MPD) and trimesoyl chloride (TMC) in this study. The influences of monomer concentration on polyamide layer formation is first examined. Different from previous studies which indicated that the variation of MPD concentration might affect the polyamide layer formation even when in excess, the MPD concentration when in excess does not affect membrane properties significantly, while increasing the TMC concentration gradually densifies the polyamide layer and enhances its transport resistance. Adding lithium bromide (LiBr) and sodium dodecyl sulfate (SDS) in MPD solutions is found to facilitate the reaction between the two phases and result in a significant improvement in water permeability. However, a high amount of additives leads to an augmentation in transport resistance. The N,N-dimethylformamide (DMF) treatment on the polyamide membrane shows pronounced improvements on water flux under FO tests and water permeability under RO tests without compromising reverse salt flux and salt rejection because the dense polyamide core stays intact. This study may offer a different perspective on membrane formation and intrinsic properties of the polyamide selective layer and provide useful insights for the development of next-generation TFC membranes.
AB - The thin film composite (TFC) membrane synthesized via interfacial polymerization is the workhorse of the prevalent membrane technologies such as nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO), and pressure retarded osmosis (PRO) membranes. The polyamide selective layer usually possesses a high selectivity and permeability, making it the heart of this membrane technology. To further improve and understand its formation, with entirely excluding the effect of substrate, an ultrathin membrane which consists of only the polyamide selective layer has been fabricated via free-standing interfacial polymerization between M-phenylenediamine (MPD) and trimesoyl chloride (TMC) in this study. The influences of monomer concentration on polyamide layer formation is first examined. Different from previous studies which indicated that the variation of MPD concentration might affect the polyamide layer formation even when in excess, the MPD concentration when in excess does not affect membrane properties significantly, while increasing the TMC concentration gradually densifies the polyamide layer and enhances its transport resistance. Adding lithium bromide (LiBr) and sodium dodecyl sulfate (SDS) in MPD solutions is found to facilitate the reaction between the two phases and result in a significant improvement in water permeability. However, a high amount of additives leads to an augmentation in transport resistance. The N,N-dimethylformamide (DMF) treatment on the polyamide membrane shows pronounced improvements on water flux under FO tests and water permeability under RO tests without compromising reverse salt flux and salt rejection because the dense polyamide core stays intact. This study may offer a different perspective on membrane formation and intrinsic properties of the polyamide selective layer and provide useful insights for the development of next-generation TFC membranes.
UR - http://hdl.handle.net/10754/623431
UR - http://pubs.acs.org/doi/full/10.1021/acs.iecr.6b04283
UR - http://www.scopus.com/inward/record.url?scp=85020401582&partnerID=8YFLogxK
U2 - 10.1021/acs.iecr.6b04283
DO - 10.1021/acs.iecr.6b04283
M3 - Article
SN - 0888-5885
VL - 56
SP - 513
EP - 523
JO - Industrial & Engineering Chemistry Research
JF - Industrial & Engineering Chemistry Research
IS - 2
ER -