Adsorption tests
For the adsorption tests, the dye stock solution was prepared
by dissolving accurately weighted MB in distilled water, in order to
obtain a solution at a concentration of 1000 mg L
−1
. The experimen-tal solutions were prepared by properly diluting the stock solution
at the desired initial MB concentration. The pH of the starting solu-tions was adjusted by adding, when necessary, NaOH [1 M] or HCl
[1 M]. The adsorption tests were carried out in batch conditions by
shaking the keratin nanofibrous membranes immersed in 10 ml of
starting MB solutions. The initial and final dye concentrations were
determined with a PerkinElmer spectrophotometer at wavelength
of 665 nm
D
(3)
The density of the nanofibre mat was calculated by using the
mass of the mat in air (m1) and in n-hexane (m2) through the
following equation:
= (m1h
)/(m1− m2) (4)
where his the density of n-hexane at the temperature of mea-surement.The porosity of the membrane (ε) is obtained by using
the equation:
ε =
Vtot − V
Vtot
(5)
where Vtot is the total (apparent) volume, obtained by measuring
the area and the thickness of the mat, and V is the volume, calculated
from measured mass and density of the nanofibrous membrane