Dyestuff Adsorbing Natural Composites for Wastewater Treatments
111
3.3 Advantages and Disadvantages
Using adsorbent materials in wastewater treatment processes has some disadvantages
such as waste production and weak selectivity, but these can be eliminated with
various enhancements or reuse strategies. If the waste adsorbent can be reused in some
other processes with different forms as filler, dyestuff source, etc., waste products
can be decreased or zeroed, and some modifications on adsorbent can enhance the
selectivity of the adsorbent. However, adsorbent usage at refining of wastewater has
more advantages than disadvantages as high performance, low cost, wide pH range
for process conditions, and ease of operation for treatment [23].
4 Adsorbent Composite Production
Adsorbent materials have many advantages compared to each other; however, more
properties can be needed to maintain the desired conditions, or sometimes, abilities
of the adsorbents must be improved for different cases. In these cases, composite
structure can come to screen to yield the abilities of at least two materials or to
enhance the functions. With composite production stability, applicability, ease of
use, working conditions, cost, end-use, and reusability after waste treatment can
be improved. Also, the composite structure can offer lower costs and reduction of
process time. Composite structures are yielded by combining at least one layered
material such as silica balls and nanotubes and one or two polymer-based materials.
The composite structure can be classified into two groups as micro- and nanocomposites. If polymer component covers around the layered structure without any separation of layers, then it is called microcomposite. Nanocomposites are produced
when layered structure deforms by enlarging or separation. If the gap between layers
enlarge and polymer component penetrates the enlarged gaps, then it is called intercalated nanocomposites. If the layers are totally separated from each other and polymer
component covers individual layers thanks to even distribution of layers, then it is
named as exfoliated composite. All types of composites can be used according to
end uses, characteristics of the wastewaters, and needed removal amounts, but more
uniform composites are produced with exfoliated structures [24].
Structures of composite types are given in Fig. 3, and advantages and disadvantages of them are given in Table 1.
There are three main composite production methods with layered units and
polymer units as solution intercalation, melt intercalation, and in situ polymerization.
In situ polymerization method uses a layered unit as clay and monomer units. They
are putting in together, and after swelling of layers, monomers are located around the
separated or enlarged layers thanks to surface energy and polarity of monomers. Then,
curing chemicals are added to turn monomers into polymers. When polymerization
occurs, then in situ polymerized composite is formed and layers catch up more polar
111
3.3 Advantages and Disadvantages
Using adsorbent materials in wastewater treatment processes has some disadvantages
such as waste production and weak selectivity, but these can be eliminated with
various enhancements or reuse strategies. If the waste adsorbent can be reused in some
other processes with different forms as filler, dyestuff source, etc., waste products
can be decreased or zeroed, and some modifications on adsorbent can enhance the
selectivity of the adsorbent. However, adsorbent usage at refining of wastewater has
more advantages than disadvantages as high performance, low cost, wide pH range
for process conditions, and ease of operation for treatment [23].
4 Adsorbent Composite Production
Adsorbent materials have many advantages compared to each other; however, more
properties can be needed to maintain the desired conditions, or sometimes, abilities
of the adsorbents must be improved for different cases. In these cases, composite
structure can come to screen to yield the abilities of at least two materials or to
enhance the functions. With composite production stability, applicability, ease of
use, working conditions, cost, end-use, and reusability after waste treatment can
be improved. Also, the composite structure can offer lower costs and reduction of
process time. Composite structures are yielded by combining at least one layered
material such as silica balls and nanotubes and one or two polymer-based materials.
The composite structure can be classified into two groups as micro- and nanocomposites. If polymer component covers around the layered structure without any separation of layers, then it is called microcomposite. Nanocomposites are produced
when layered structure deforms by enlarging or separation. If the gap between layers
enlarge and polymer component penetrates the enlarged gaps, then it is called intercalated nanocomposites. If the layers are totally separated from each other and polymer
component covers individual layers thanks to even distribution of layers, then it is
named as exfoliated composite. All types of composites can be used according to
end uses, characteristics of the wastewaters, and needed removal amounts, but more
uniform composites are produced with exfoliated structures [24].
Structures of composite types are given in Fig. 3, and advantages and disadvantages of them are given in Table 1.
There are three main composite production methods with layered units and
polymer units as solution intercalation, melt intercalation, and in situ polymerization.
In situ polymerization method uses a layered unit as clay and monomer units. They
are putting in together, and after swelling of layers, monomers are located around the
separated or enlarged layers thanks to surface energy and polarity of monomers. Then,
curing chemicals are added to turn monomers into polymers. When polymerization
occurs, then in situ polymerized composite is formed and layers catch up more polar