Sorption of Cobalt (II) Ions from Aqueous Solutions Using Chemically Modified Chitosan

Abstract

<p>Removal of Co(II) ions from aqueous solutions using chitosan-vanillin (polymer I) and chitosan-ortho-vanillin (polymer II) adsorbents has been investigated under different experimental conditions. The effect of pH, contact time, adsorbent mass, temperature, and initial concentration of studied ion on the sorption process has been studied using batch experiments. The quantity of residual ion has been estimated via atomic absorption spectrometry. The highest removal of Co(II) ions has been achieved at pH 4 with a maximum removal of 93.2% of ions after two hours of agitation. Langmuir isotherm model represents the best fit for the experimental data; whereas the highest chelation capacity was 5.899 mg g-1 and 7.651 mg g-1 for polymers I and II, respectively. Results from this study imply that chemisorption is the rate-determining step and thermodynamic parameters indicate that the uptake process is spontaneous and endothermic in nature.</p>

Recent Application Prospects of Chitosan Based Composites for the Metal Contaminated Wastewater Treatment

“…The adsorption of CS/Fe 3 O 4 NPs is mainly due to the ion exchange on the hydroxyl groups of CS/Fe 3 O 4 NPs and the chelation action of the abundant amine groups in CS [ 90 ]. CS is a natural bio-sorbent for toxic metallic ions due to a large number of hydroxyl and amino groups that serve as sorption sites and the flexibility of the polymer chain structure that enables complexation with metal ions [ 97 ]. The chelation capacity of CS depends on the degree of deacetylation, distribution of –NH 2 groups, the physical state of CS, the nature of the metal ion, and the pH of the solution [ 97 , 98 ].…”

“…CS is a natural bio-sorbent for toxic metallic ions due to a large number of hydroxyl and amino groups that serve as sorption sites and the flexibility of the polymer chain structure that enables complexation with metal ions [ 97 ]. The chelation capacity of CS depends on the degree of deacetylation, distribution of –NH 2 groups, the physical state of CS, the nature of the metal ion, and the pH of the solution [ 97 , 98 ]. Higher degrees of deacetylation result in better chelation [ 98 ].…”

“…CS is protonated in acidic media and exhibits electrostatic characteristics, and the adsorption occurs via an anion exchange mechanism [ 99 ]. To increase the density of sorption sites for metal ion adsorption, CS has been modified through the addition of new functional groups to the CS backbone, resulting in numerous CS derivatives [ 97 ].…”

“…Magnetic graphene oxide/CS [ 75 ], Fe 3 O 4 /CS/polyethylenimine [ 101 ], Fe 3 O 4 /CS NPs [ 90 ], CS/vanillin CS/ortho-vanillin [ 97 ], CS/bentonite [ 102 ], and TiO 2 /CS [ 94 ] were well fitted with Langmuir isotherm providing a suggestion of monolayer adsorption of various heavy metals.…”

Preconcentration of the cobalt using modified forms of the transcarpathian clinoptylolite

“…Відомими сорбентами Со(ІІ) є композиції на основі силікагелю [4][5][6], пінополіуретану [7], хітозан [8], силіційорганічні сполуки [9], глини [6,[10][11][12], синтетичні [13] та природні цеоліти. Автори [12,[14][15][16] у статичних умовах дослідили сорбційні властивості природного та кислотно модифікованого закарпатського клиноптилоліту, а також його Na-форми стосовно високих концентрацій Со 2+ .…”