428
A metal-containing precursor is transported into the chemical vapor deposition
chamber. The precursor is adsorbed on the surface of the substrate and then reacts.
The metal or metal oxide species diffuses to form nuclei, followed by growth process. The chemical vapor deposition technique is relatively complex, and particular
controls and calculations are required.
Physical Vapor Deposition
Physical vapor deposition method is an atomistic deposition synthesis route. During
the physical vapor deposition process, solid or liquid precursors are vaporized in the
form of molecules or atoms. The formed atoms/molecules are then transported
through a low-pressure gas-phase or plasma medium to the substrate. The species
are then condensed on the substrate. Typically, the physical vapor deposition method
is applied to deposit films with nanometer thicknesses. The main categories of physical vapor deposition processing include sputtering deposition, thermal deposition,
ion plating, arc vapor deposition, etc. (Mattox 2010).
Microemulsion
Microemulsions are stable colloidal dispersions which are formed through mixing
oil and water phases in the presence of surfactant. Three types of microemulsions
are possible: oil in water (O/W), water in oil (W/O), and bicontinuous. In the O/W
microemulsion systems, the fraction of oil is low. On the contrary, in the W/O
microemulsions systems, the amount of water is low. The size of droplet usually
varies from 10 to 140 nm. Bicontinuous microemulsions may be formed if oil and
water exist in equal amounts (Sakamoto et al. 2017). Figure 16.14 represents possible microemulsion-based routes for the synthesis of hybrid metals or metal oxides.
As schematically shown in Fig. 16.14a, the prepared reactants A and B are mixed
with each other. During mixing, the droplets are interacted to form coalescences.
The reactant B can be dispersed in the reactant A-containing microemulsion as a
solid phase (Fig. 16.14b). Also, the microemulsion can undergo a thermal treatment
to decompose to target product (Fig. 16.14c) (Khadzhiev et al. 2013). The microemulsion approach can be used for the synthesis of bimetallic compounds, mixed
metal composite (Khalili and Hassanzadeh-Tabrizi 2017), polyamine chelating
adsorbents (Meng et al. 2019), etc.
16.7.3 Application in Dye Removal
Different criteria such as chemical structure, structure architecture, number of
phases used in the chemical structure, etc. can be considered for the classification of
hybrid adsorbents. So there is no comprehensive classification of hybrid sorbents.
The hybrid adsorbents discussed in this chapter are the ones most used in adsorbent
of dyes.
R. M. Moattari and T. Mohammadi
A metal-containing precursor is transported into the chemical vapor deposition
chamber. The precursor is adsorbed on the surface of the substrate and then reacts.
The metal or metal oxide species diffuses to form nuclei, followed by growth process. The chemical vapor deposition technique is relatively complex, and particular
controls and calculations are required.
Physical Vapor Deposition
Physical vapor deposition method is an atomistic deposition synthesis route. During
the physical vapor deposition process, solid or liquid precursors are vaporized in the
form of molecules or atoms. The formed atoms/molecules are then transported
through a low-pressure gas-phase or plasma medium to the substrate. The species
are then condensed on the substrate. Typically, the physical vapor deposition method
is applied to deposit films with nanometer thicknesses. The main categories of physical vapor deposition processing include sputtering deposition, thermal deposition,
ion plating, arc vapor deposition, etc. (Mattox 2010).
Microemulsion
Microemulsions are stable colloidal dispersions which are formed through mixing
oil and water phases in the presence of surfactant. Three types of microemulsions
are possible: oil in water (O/W), water in oil (W/O), and bicontinuous. In the O/W
microemulsion systems, the fraction of oil is low. On the contrary, in the W/O
microemulsions systems, the amount of water is low. The size of droplet usually
varies from 10 to 140 nm. Bicontinuous microemulsions may be formed if oil and
water exist in equal amounts (Sakamoto et al. 2017). Figure 16.14 represents possible microemulsion-based routes for the synthesis of hybrid metals or metal oxides.
As schematically shown in Fig. 16.14a, the prepared reactants A and B are mixed
with each other. During mixing, the droplets are interacted to form coalescences.
The reactant B can be dispersed in the reactant A-containing microemulsion as a
solid phase (Fig. 16.14b). Also, the microemulsion can undergo a thermal treatment
to decompose to target product (Fig. 16.14c) (Khadzhiev et al. 2013). The microemulsion approach can be used for the synthesis of bimetallic compounds, mixed
metal composite (Khalili and Hassanzadeh-Tabrizi 2017), polyamine chelating
adsorbents (Meng et al. 2019), etc.
16.7.3 Application in Dye Removal
Different criteria such as chemical structure, structure architecture, number of
phases used in the chemical structure, etc. can be considered for the classification of
hybrid adsorbents. So there is no comprehensive classification of hybrid sorbents.
The hybrid adsorbents discussed in this chapter are the ones most used in adsorbent
of dyes.
R. M. Moattari and T. Mohammadi