The
current study focuses on the preparation of a polydopamine
(PD)-modified PVDF membrane and its application for drug removal.
The effect of adding an inorganic compound (TEOS) on the characteristics
and performance of the PD/PVDF thin-film composite (TFC) membrane
has also been investigated. For this purpose, the PD layer was coated
using TEOS for in situ synthesis of a silica layer. The resultant
membrane was coated at different dosages of as-synthesized TNTs to
prepare thin-film nanocomposite membranes (TFN(S-T)). The prepared
TNT, TFC, and TFN membranes were characterized by employing transmission
electron microscopy (TEM), attenuated total reflection Fourier transform
infrared (ATR-IR) spectroscopy, field emission scanning electron microscopy
(FESEM), energy-dispersive X-ray (EDX), atomic force microscopy (AFM),
ζ potential, and contact angle measurements. The results confirmed
the formation of a hydrophilic nanocomposite layer with a negative
charge. The separation performance of the as-prepared membranes was
evaluated via diclofenac removal. The results revealed that diclofenac
rejection increased from 81.5% for the PVDF membrane to 91.6% for
the PD/silica/PVDF membrane with a permeability of 2.5 L/(m2·h·bar). In the case of the TFN(S-T) membrane, drug rejection
increased to 93.2% at 0.1% TNTs and the permeability improved to 5.8
L/(m2·h·bar). Also, the effects of pH and feed
concentration on diclofenac separation performance were studied. The
results implied that the rejection of diclofenac increased from 93.2
to 95.6% with an increase in pH from 7 to 10.