Adsorption of As(III) from aqueous solutions using MnO2 strengthened WTRs-chitosan beads made by homogenous method with freeze-drying

In this study, a chitosan hydrogel supported with ceria (labelled Ce-CTS) was prepared by an encapsulation technique and used for the efficient removal of excess B(III) from aqueous solutions. The functionalisation of chitosan with Ce(IV) and the improvement in the adsorptive behaviour of the hydrogel were determined by SEM-EDS, FTIR, XRD, and inductively coupled plasma optical emission spectrometer (ICP-OES) analyses and discussed. The results demonstrate that Ce-CTS removes boric acid from aqueous solutions more efficiently than either cerium dioxide hydrate or raw chitosan beads, the precursors of the Ce-CTS biosorbent. The maximum adsorption capacity of 13.5 ± 0.9 mg/g was achieved at pH 7 after 24 h. The equilibrium data of boron adsorption on Ce-CTS fitted the Freundlich isotherm model, while the kinetic data followed the Elovich pseudo-second-order model, which indicated that the process was non-homogeneous. The dominant mechanism of removal was the reaction between boric acid molecules and hydroxyl groups bound to the ceria chelated by chitosan active centres. Due to its high efficiency in removing boron, good regeneration capacity and convenient form, Ce-CTS may be considered a promising biosorbent in water purification.

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Freeze-drying of aqueous solutions: Maximum allowable operating temperature

Cryobiology ◽

10.1016/0011-2240(72)90179-4 ◽

1972 ◽

Vol 9 (6) ◽

pp. 559-561 ◽

Cited By ~ 69

Author(s):

Richard J. Bellows ◽

C.Judson King

Keyword(s):

Aqueous Solutions ◽

Freeze Drying ◽

Operating Temperature

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Adsorption of Chromium(VI) from Aqueous Solutions Using Cross-Linked Magnetic Chitosan Beads

Industrial & Engineering Chemistry Research ◽

10.1021/ie800814h ◽

2009 ◽

Vol 48 (5) ◽

pp. 2646-2651 ◽

Cited By ~ 103

Author(s):

Guolin Huang ◽

Hongyan Zhang ◽

Jeffrey X. Shi ◽

Tim A. G. Langrish

Keyword(s):

Aqueous Solutions ◽

Chitosan Beads ◽

Magnetic Chitosan ◽

Chromium Vi

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Elimination of reactive blue 4 from aqueous solutions using 3-aminopropyl triethoxysilane modified chitosan beads

Carbohydrate Polymers ◽

10.1016/j.carbpol.2015.05.080 ◽

2015 ◽

Vol 132 ◽

pp. 89-96 ◽

Cited By ~ 44

Author(s):

Mohammadtaghi Vakili ◽

Mohd Rafatullah ◽

Babak Salamatinia ◽

Mahamad Hakimi Ibrahim ◽

Ahmad Zuhairi Abdullah

Keyword(s):

Aqueous Solutions ◽

Chitosan Beads ◽

Modified Chitosan ◽

Reactive Blue 4

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Nanoparticle Beads of Chitosan-Ethylene Glycol Diglycidyl Ether/Fe for the Removal of Aldrin

Journal of Chemistry ◽

10.1155/2021/8421840 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

G. García Rosales ◽

P. Ávila-Pérez ◽

J.O. Reza-García ◽

A. Cabral-Prieto ◽

E.O. Pérez-Gómez

Keyword(s):

Electron Microscopy ◽

Aqueous Solutions ◽

Iron Nanoparticles ◽

Sorption Process ◽

Diglycidyl Ether ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

Sem Images ◽

Chitosan Beads ◽

Transmission Electron

This article reports on the preparation of iron nanoparticles (FeNPs) supported in chitosan beads (Chi-EDGE-Fe) for removing aldrin from aqueous solutions. The FeNPs and Chi-EDGE-Fe beads were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and the Mössbauer spectroscopy (MS) techniques. TEM, XRD, and MS showed that the FeNPs had core-shell structures consisting of a core of either Fe0 or Fe2B and a shell of magnetite. Furthermore, SEM images showed that Chi-EDGE-Fe beads were spherical with irregular surfaces and certain degrees of roughness and porosity, whilst the sorbent mean pore size was 204 nm, and the occluded iron nanoparticles in the chitosan material had diameters of 70 nm and formed agglomerates. The sorbent beads consisted of carbon, oxygen, chlorine, aluminum, silicon, and iron according to the SEM-EDS analysis. Functional groups such as O-H, C-H, -CH2, N-H, C-O, C-OH, and Fe-OH were detected in the FTIR spectra. In addition, a characteristic band appeared at about 1700 cm−1 after the sorption process involving aldrin. MS also showed that the iron nanoparticles in the beads probably oxidized into NPs of α-Fe2O3 as a result of the supporting process. The isotherm of the aldrin removal followed the Langmuir–Freundlich model and presented a maximum adsorption capacity of 74.84 mg/g, demonstrating that chitosan-Fe beads are promising sorbents for the removal of toxic pollutants in aqueous solutions.

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Regularities and mechanism of heavy metal cations sorption and (or) proton desorption by chitosan from aqueous solutions

Canadian Journal of Chemistry ◽

10.1139/cjc-2018-0384 ◽

2019 ◽

Vol 97 (8) ◽

pp. 621-628 ◽

Cited By ~ 4

Author(s):

T.E. Nikiforova ◽

V.A. Kozlov ◽

M.K. Islyaikin

Keyword(s):

Heavy Metal ◽

Aqueous Solutions ◽

Metal Ions ◽

Metal Ion ◽

Heavy Metal Ions ◽

Metal Cations ◽

Batch Adsorption ◽

Amino Groups ◽

Acidic Media ◽

Chitosan Beads

The sorption process of heavy metal ions from aqueous solutions using chitosan flakes and chitosan beads was studied. Chitosan gel beads were prepared using covalent crosslinking of chitosan chains by epichlorohydrin with ionic gelation by sodium tripolyphosphate. The capability of chitosan beads to absorb the heavy metal ions from aqueous solutions was studied, and the physicochemical characteristics of the sorbent were evaluated using SEM and FTIR on the model solution treatment. It was found that competitive proton sorption takes place in acidic media, which results in a transformation of amino groups into inactive ammonium-salt form and decreases in heavy metal sorption onto chitosan from aqueous acidic media. Batch adsorption experiments were performed to examine the influence of various factors such as the initial concentration of metal salts, pH, and agitation duration on the process. It was established that metal ion sorption is pH dependent and has an optimum effect at a pH of 6.0. Following the Langmuir equation, the maximum sorption of Cu2+ions is estimated to be 1,6 mol/kg of modified chitosan. The kinetic study revealed that the adsorption kinetics are well-fitted to the kinetic equation of pseudo second order. Thus, sorption of heavy metal ions by chitosan is considered to be a competitive process that occurs on amino groups of the sorbent with equivalent coordinated participation of metal cations, protons, and anions.

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