128
E. Emekdar and U. K. ¸
Sahin
6 An Alternative Composite Structure Study
In the present composite structure study, firstly, chitosan modification is done to turn
it into carboxymethyl chitosan. 50 mL NaOH solution (20 wt%) is used to swell
5 g chitosan for 12 h and filtration applied to the mixture. Filtered chitosan is taken
into a volumetric flask, and 50 mL ethyl alcohol is added to stir for 30 min. 4 g
butanetetracarboxylic acid addition is done, and the mixture is stirred for half an
hour 30 min more. After that, cooling is done to make the temperature of the mixture
20 °C, and the mixture is kept at 20 °C for 1 h. Filtration is applied to the treated
sample, and distilled water is used for dissolving filtered sample. Further, acetic acid
is added to set pH as 7.0. The mixture is poured into ethyl alcohol to yield foam gel
precipitation, and pouring is applied to take the white precipitation into Petri dishes.
Ethanol with a ratio of 70% is used to wash the precipitate for three times by using,
and ethyl alcohol is used for one time. Drying of the CMCTS is done by putting Petri
dishes into the oven at 80 °C. Finally, CMCTS is turned into dust form by scraping
off from the Petri dishes [30].
In the case of a clay and modified chitosan combination, firstly, 1 g clay is swelled
at the 100 mL distilled water. Secondly, the CMCTS solution is prepared with the
distilled water which refers to a 5:1 weight ratio of CMCTS-clay at nanocomposite.
Further, the CMCTS solution and clay suspension is mixed slowly, and stirring is
done at 60 °C for 6 h. Then, washing of nanocomposites is done until the supernatant
pH becomes 7.0 by using distilled water. After pH setting, oven at 60 °C is used for
drying of composite for 12 h. Finally, the CMCTS-clay nanocomposite is turned into
dust form by scraping off [30].
The composite was tried with cationic dyestuff [30, 31] previously, and very high
adsorption values are yielded. In this study, anionic dyestuff is used to observe the
anionic adsorption and prove the amphoteric characteristic of the composite thanks to
the anionic characteristic of the carboxymethyl end group and cationic characteristic
of chitosan. Dye bath simulating solution is prepared by using 200 mL pure water and
0.5 g dyestuff which is Nyloset Brilliant Red from Seta¸ s Color Center and anionic
dyestuff for nylon dyeing. Water is used to observe the real usage of dyestuff under
natural pH instead of observing the full performance of composite by using other
solvents. 2 g composite is added to the simulating dye bath, and the bath is mixed
with a magnetic stirrer for 12 h. Then, UV-visible spectrophotometer analysis is done
for dye bathes before and after the adsorbent addition. Adsorption graph is presented
in Fig. 9.
Removal amount is calculated by using Formula 1, and R refers to removal percent,
while c 0 attributes to the initial concentration of solution and c f attributes to the final
concentration of the solution. As a result, anionic dyestuff removal is 42% as given
in Table 4. This result shows that in addition to adsorbing cationic dyestuff, the
composite can adsorb anionic dyestuff thanks to its amphoteric characteristic. This
also proves that the modification chitosan is applied well enough to hold anionic
dyestuff.
E. Emekdar and U. K. ¸
Sahin
6 An Alternative Composite Structure Study
In the present composite structure study, firstly, chitosan modification is done to turn
it into carboxymethyl chitosan. 50 mL NaOH solution (20 wt%) is used to swell
5 g chitosan for 12 h and filtration applied to the mixture. Filtered chitosan is taken
into a volumetric flask, and 50 mL ethyl alcohol is added to stir for 30 min. 4 g
butanetetracarboxylic acid addition is done, and the mixture is stirred for half an
hour 30 min more. After that, cooling is done to make the temperature of the mixture
20 °C, and the mixture is kept at 20 °C for 1 h. Filtration is applied to the treated
sample, and distilled water is used for dissolving filtered sample. Further, acetic acid
is added to set pH as 7.0. The mixture is poured into ethyl alcohol to yield foam gel
precipitation, and pouring is applied to take the white precipitation into Petri dishes.
Ethanol with a ratio of 70% is used to wash the precipitate for three times by using,
and ethyl alcohol is used for one time. Drying of the CMCTS is done by putting Petri
dishes into the oven at 80 °C. Finally, CMCTS is turned into dust form by scraping
off from the Petri dishes [30].
In the case of a clay and modified chitosan combination, firstly, 1 g clay is swelled
at the 100 mL distilled water. Secondly, the CMCTS solution is prepared with the
distilled water which refers to a 5:1 weight ratio of CMCTS-clay at nanocomposite.
Further, the CMCTS solution and clay suspension is mixed slowly, and stirring is
done at 60 °C for 6 h. Then, washing of nanocomposites is done until the supernatant
pH becomes 7.0 by using distilled water. After pH setting, oven at 60 °C is used for
drying of composite for 12 h. Finally, the CMCTS-clay nanocomposite is turned into
dust form by scraping off [30].
The composite was tried with cationic dyestuff [30, 31] previously, and very high
adsorption values are yielded. In this study, anionic dyestuff is used to observe the
anionic adsorption and prove the amphoteric characteristic of the composite thanks to
the anionic characteristic of the carboxymethyl end group and cationic characteristic
of chitosan. Dye bath simulating solution is prepared by using 200 mL pure water and
0.5 g dyestuff which is Nyloset Brilliant Red from Seta¸ s Color Center and anionic
dyestuff for nylon dyeing. Water is used to observe the real usage of dyestuff under
natural pH instead of observing the full performance of composite by using other
solvents. 2 g composite is added to the simulating dye bath, and the bath is mixed
with a magnetic stirrer for 12 h. Then, UV-visible spectrophotometer analysis is done
for dye bathes before and after the adsorbent addition. Adsorption graph is presented
in Fig. 9.
Removal amount is calculated by using Formula 1, and R refers to removal percent,
while c 0 attributes to the initial concentration of solution and c f attributes to the final
concentration of the solution. As a result, anionic dyestuff removal is 42% as given
in Table 4. This result shows that in addition to adsorbing cationic dyestuff, the
composite can adsorb anionic dyestuff thanks to its amphoteric characteristic. This
also proves that the modification chitosan is applied well enough to hold anionic
dyestuff.