2.3.2. Preparation of thin-film composite and nanocomposite
membranes
All thin composite films on the HPAN membrane surface were obtainedin situ using an interfacial polymerization route, as presented
in Scheme 1. First, the HPAN membranes were immersed in a 1.0% (w/v)
DETA aqueous solution. After 30 min, the membranes were pulled out of
the solution and the excess DETA solution on them was removed using a
rubber roller. Subsequently, UiO-66(Zr/Ti)-NH2 powder
was dispersed in a 0.1% (w/v) solution of TMC in n -hexane via
ultrasonication for 1 h at 25 °C and was poured onto the surface of the
amine-saturated HPAN substrate to react for 3 min. The obtained
UiO-66(Zr/Ti)-NH2-containing TFN membrane was denoted as
TFN-(Zr/Ti) membrane. We
fabricated TFN-(Zr/Ti)-1 and
TFN-(Zr/Ti)-2 membranes with UiO-66(Zr/Ti)-NH2 loadings
of 0.01% and 0.03% (w/v) in 50 mL of n -hexane solution,
respectively. For comparison, we also prepared thin-film composite (TFC)
membranes that did not contain MOF nanoparticles and TFN-(Zr) membranes
with UiO-66(Zr)-NH2 nanoparticles. Using the same
strategy, we fabricated TFN-(Zr)-1 and TFN-(Zr)-2 membranes with
UiO-66(Zr)-NH2 nanoparticle loadings of 0.01% and
0.03% (w/v), respectively. All MOF-based membranes were dried and
subsequently stored in DI water for further use.