As shown in the table above, by increasing the percentages of nickel
ferrite from 10% to 50%, the total surface area increased, and the
diameter of the pours decreased due to the presence of nickel ferrite
heavy nuclei and their agglomeration [60, 61]. Figure (10)
illustrates the adsorption and desorption isotherms of nitrogen gas. As
can be seen by increasing nitrogen gas at a constant temperature, the
rate of adsorption and by gradually decreasing nitrogen gas the
desorption rate of the samples was measured. As the vapor pressure of
the material increases, the amount of material absorbed increases until
a monolayer is formed on the surface. When the ratio
p/p0 is larger, it indicates that the material has very
narrow pores and is well visible in the hysteresis metal-organic
framework
NiFe2O4@SiO2@HKUST-1
(50%) diagram. The presence of hysteresis indicates the presence of
mesoporous pores, depending on the type of hysteresis, the mesoporous
form will have different shapes.