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2 Thermodynamics, Kinetics and Desorption Studies …
2.2 Materials and Methods
2.2.1 Materials
The chemical substances used in this analysis were of analytical degree. Chitosan
(85% deacetylation, Mwt 195 kDa) powder, epichlorohydrin and 4-aminobenzoic
acid (almost 99.5%), hydrochloric acid (almost 999%), acetic acid (almost 99%) and
sodium hydroxide (almost 99%) were acquired from Sigma-Aldrich SA. pH sensors
(Hanna HI 8421) were also acquired from Sigma-Aldrich. Distilled water from a pure
water distiller (Ultima 888 water distiller) was obtained from the school laboratory.
For adsorption equilibrium experiments, a shaker (Labcon Incubator) was utilized.
For the comprehensive investigation of ions Pb(II), Cu(II), Ni(II), and Zn(II), the
atomic adsorption spectrophotometer (Varian SpectrAA-10) was used.
2.2.2 Methods
2.2.2.1 Adsorbate Preparation
The stock solution used in this research was formulated by selectively disintegrating
in distilled water a specified quantity of CuSO 4 · 5H 2 O, Zn (NO 3 )2 · 6H 2 O, Pb
(NO 3 )2 and NiSO 4 · 6H 2 O. This stock mixture was distilled again with purified
water to achieve the initial concentrations of 40–160 mg/L of metal ions available.
2.2.2.2 Preparation of Grafted-Cross-Linked Chitosan Beads
The adsorbent was formulated as follows: first, by disintegrating 30 g of chitosan
powder in 1 L of 5.0% (v/v) acetic acid solution. Second, the processed mixture was
filtered to eliminate any insoluble solvent molecules, and the filtrate was injected
through a glass pipette to a 1 M solution of sodium hydroxide to produce a chitosan
gel bead. The gel beads were washed thoroughly multiple times with distilled water
to eliminate possible sodium hydroxide traces. Third, in an attempt for cross-linking
reaction to occur the beads were treated with 2.5% epichlorohydrin solution with
occasional hand shaking for 6 h. The cross-linked gel beads were washed with water
to eliminate any residual of epichlorohydrin. Furthermore, approximately 4 g of the
cross-linking gel beads was mixed in 0.5 M 4-amino benzoic acid in an open neck
flask. The flask was transferred to a microwave oven and subjected to a medium to
low-intensity microwave irradiation for 20 min. Once again, the grafted-cross-linked
beads were washed with distilled water and available for investigation.
2 Thermodynamics, Kinetics and Desorption Studies …
2.2 Materials and Methods
2.2.1 Materials
The chemical substances used in this analysis were of analytical degree. Chitosan
(85% deacetylation, Mwt 195 kDa) powder, epichlorohydrin and 4-aminobenzoic
acid (almost 99.5%), hydrochloric acid (almost 999%), acetic acid (almost 99%) and
sodium hydroxide (almost 99%) were acquired from Sigma-Aldrich SA. pH sensors
(Hanna HI 8421) were also acquired from Sigma-Aldrich. Distilled water from a pure
water distiller (Ultima 888 water distiller) was obtained from the school laboratory.
For adsorption equilibrium experiments, a shaker (Labcon Incubator) was utilized.
For the comprehensive investigation of ions Pb(II), Cu(II), Ni(II), and Zn(II), the
atomic adsorption spectrophotometer (Varian SpectrAA-10) was used.
2.2.2 Methods
2.2.2.1 Adsorbate Preparation
The stock solution used in this research was formulated by selectively disintegrating
in distilled water a specified quantity of CuSO 4 · 5H 2 O, Zn (NO 3 )2 · 6H 2 O, Pb
(NO 3 )2 and NiSO 4 · 6H 2 O. This stock mixture was distilled again with purified
water to achieve the initial concentrations of 40–160 mg/L of metal ions available.
2.2.2.2 Preparation of Grafted-Cross-Linked Chitosan Beads
The adsorbent was formulated as follows: first, by disintegrating 30 g of chitosan
powder in 1 L of 5.0% (v/v) acetic acid solution. Second, the processed mixture was
filtered to eliminate any insoluble solvent molecules, and the filtrate was injected
through a glass pipette to a 1 M solution of sodium hydroxide to produce a chitosan
gel bead. The gel beads were washed thoroughly multiple times with distilled water
to eliminate possible sodium hydroxide traces. Third, in an attempt for cross-linking
reaction to occur the beads were treated with 2.5% epichlorohydrin solution with
occasional hand shaking for 6 h. The cross-linked gel beads were washed with water
to eliminate any residual of epichlorohydrin. Furthermore, approximately 4 g of the
cross-linking gel beads was mixed in 0.5 M 4-amino benzoic acid in an open neck
flask. The flask was transferred to a microwave oven and subjected to a medium to
low-intensity microwave irradiation for 20 min. Once again, the grafted-cross-linked
beads were washed with distilled water and available for investigation.