The microporous PVDF fibers (0.1 mm pore size, 1.2 mm OD,
0.7 mm ID; ECONITY, Korea), cut in length of 19.5 cm and sealed
with epoxy and hardener mixture, were used for the fabrication of
HFMMs, as described in previous study [18]. In order to investigate
the effect of total external surface area of hollow fiber membranes,
different number (10, 20, and 40) of fibers was used to fabricate
modules. In comparison, alumina bubbler (pore size: 16–40 mm)
was used.