136
7 Use of Diethylenetriamine Grafted onto Glyoxal Cross-Linked …
intravascular haemolysis, renal failure, nephritis, fatigue, vertigo, vomiting, epigastric discomfort, acute multisystem organ failure, coma and even death, depending
on the body digestion [6–8]. Various physicochemical techniques used in the past,
including chemical precipitation, membrane separation, ion exchange and electrolysis, are now too expensive or may contribute to environmental contamination [9, 10].
The chase for effective, inexpensive and environmentally safe materials to extract
adsorbate from water and wastewater has led to the development of an adsorption
technique that, as stated by other researchers [11–13], can eliminate up to 99.9% of
water and wastewater contaminants.
Due to its wide surface area, biocompatibility and high porosity, chitosan adsorbent has been vastly researched and used in the comprehensive subject of adsorption
in the past decade [14]. Chitosan material is commonly used in a variety of fields of
research, including the pharmaceutical, chemical, food, artificial skin, photography,
cosmetics, paper and environmental industries [14–17]. Because of the presence of
amine and hydroxyl groups, this material can form complex with adsorbate which
provides coordination with adsorbate adsorption sites. Chitosan, however, appears
to be soluble at a low pH value, which is a big limitation; therefore, researchers
like [18] have presented techniques including cross-linking to enhance the efficiency of chitosan material in acid mixture. Accordingly, investigation has shown
that cross-linking reduces the binding capacity of chitosan material, because certain
amine groups are connected to the cross-linker, they cannot associate with the solution’s metal ions. Thus, the functionalization by grafting of cross-linked chitosan is
important. This technique is a simple way to enhance the efficiency of cross-linked
chitosan in binding process [16, 18–20]. In the past, the interactions between chitosan
biopolymer and transition metal were simulated using a quantum chemical approach.
The density functional theory (DFT) is one of those methods applied to the interaction of Cu(II) and the constituent elements of the chitosan structure, and the results
show that Cu(II) coordination to chitosan occurs in the glycosidic oxygen region
and involves reactions between them nitrogen and oxygen atom [21]. The quantum
chemical approach was applied in a related investigation [22] on the binding of
Pb(II) on chitosan material and was based on the extended Huckel method (EHM).
The findings tend to show electrostatic activity on the NH 2 group and the ionized OH
group leading to adsorbed Pb(II) only. The significant benefits of this work include
an understanding of the degree of grafting to be able to integrate the adsorbent into
an industrial environment, as it has been found that an increase in the degree of
cross-linking has a negative effect on adsorption efficiency. This adsorbent material
with improved firmness in acid mixture can endure the level of acidity present in acid
mine drainage, and hence, the introduction of this adsorbent is expected to enhance
and widen the conditions of application. In this research, the Swan model has been
applied to predict kinetic experimental results, as models make a crucial contribution
to technical advancement from laboratory to industrial scale. The model in question
can also forecast, automate processes and explain experimental data [23]. The adsorption kinetics was fairly described using the Swan model in a previous investigation by
Osifo et al. [18]. Parameters such as the maximum adsorbent capacity and adsorption
equilibrium constant found from the pH model were used to simulate the curves, and
the diffusion coefficient was obtained as (8.0–25.8) × 10
−11 m
2 /s.
7 Use of Diethylenetriamine Grafted onto Glyoxal Cross-Linked …
intravascular haemolysis, renal failure, nephritis, fatigue, vertigo, vomiting, epigastric discomfort, acute multisystem organ failure, coma and even death, depending
on the body digestion [6–8]. Various physicochemical techniques used in the past,
including chemical precipitation, membrane separation, ion exchange and electrolysis, are now too expensive or may contribute to environmental contamination [9, 10].
The chase for effective, inexpensive and environmentally safe materials to extract
adsorbate from water and wastewater has led to the development of an adsorption
technique that, as stated by other researchers [11–13], can eliminate up to 99.9% of
water and wastewater contaminants.
Due to its wide surface area, biocompatibility and high porosity, chitosan adsorbent has been vastly researched and used in the comprehensive subject of adsorption
in the past decade [14]. Chitosan material is commonly used in a variety of fields of
research, including the pharmaceutical, chemical, food, artificial skin, photography,
cosmetics, paper and environmental industries [14–17]. Because of the presence of
amine and hydroxyl groups, this material can form complex with adsorbate which
provides coordination with adsorbate adsorption sites. Chitosan, however, appears
to be soluble at a low pH value, which is a big limitation; therefore, researchers
like [18] have presented techniques including cross-linking to enhance the efficiency of chitosan material in acid mixture. Accordingly, investigation has shown
that cross-linking reduces the binding capacity of chitosan material, because certain
amine groups are connected to the cross-linker, they cannot associate with the solution’s metal ions. Thus, the functionalization by grafting of cross-linked chitosan is
important. This technique is a simple way to enhance the efficiency of cross-linked
chitosan in binding process [16, 18–20]. In the past, the interactions between chitosan
biopolymer and transition metal were simulated using a quantum chemical approach.
The density functional theory (DFT) is one of those methods applied to the interaction of Cu(II) and the constituent elements of the chitosan structure, and the results
show that Cu(II) coordination to chitosan occurs in the glycosidic oxygen region
and involves reactions between them nitrogen and oxygen atom [21]. The quantum
chemical approach was applied in a related investigation [22] on the binding of
Pb(II) on chitosan material and was based on the extended Huckel method (EHM).
The findings tend to show electrostatic activity on the NH 2 group and the ionized OH
group leading to adsorbed Pb(II) only. The significant benefits of this work include
an understanding of the degree of grafting to be able to integrate the adsorbent into
an industrial environment, as it has been found that an increase in the degree of
cross-linking has a negative effect on adsorption efficiency. This adsorbent material
with improved firmness in acid mixture can endure the level of acidity present in acid
mine drainage, and hence, the introduction of this adsorbent is expected to enhance
and widen the conditions of application. In this research, the Swan model has been
applied to predict kinetic experimental results, as models make a crucial contribution
to technical advancement from laboratory to industrial scale. The model in question
can also forecast, automate processes and explain experimental data [23]. The adsorption kinetics was fairly described using the Swan model in a previous investigation by
Osifo et al. [18]. Parameters such as the maximum adsorbent capacity and adsorption
equilibrium constant found from the pH model were used to simulate the curves, and
the diffusion coefficient was obtained as (8.0–25.8) × 10
−11 m
2 /s.