Adsorptive removal of Cr(III) and Fe(III) from aqueous solution by chitosan/attapulgite composites: Equilibrium, thermodynamics and kinetics
Introduction
Human activities such as electro-plating, smelting contaminated the wastewaters with heavy metal ions, which would be harm to the environment [1]. The concentrations of traces of heavy metal ions in matrices as environmental samples are below the detection limit, a preconcentration–separation procedure is needed to improve the detection limits. The widely used preconcentration–separation methods for heavy metal ions include solvent extraction [2], co-precipitation [3], cloud point extraction [4], [5], ion exchange [6], membrane filtration [7] and solid-phase extraction (SPE) [8], [9]. Among the preconcentration–separation techniques mentioned above, SPE is one of the efficient techniques for the trace or ultratrace amount of heavy metal ions duo to its simplicity and economy [10].
Chitosan (CTS) has many reactive amino groups and hydroxyl groups, which is beneficial for the adsorption of metals from solution [11], [12], [13]. However, CTS is only soluble in few dilute acid solutions due to its crystalline nature, and it has drawbacks of swelling and unsatisfying mechanical property, which limits its applications. To improve the properties of CTS, abundant studies have been devoted to the modification of the CTS surface by cross-linking with functional agents, such as glutaraldehyde, ethyleneglycol diglycidyl ether and epichlorhydrin [14], [15]. Recent researches proved CTS-based inorganic composites could be applied to adsorptive remove of heavy metal ions. Various inorganic materials such as silica gel [16], clay minerals [17], zeolite [18], metallic oxide [19] and carbon nanotubes [20] have been used up to now.
Attapulgite (ATP) is a hydrated octahedral layered magnesium aluminum silicate mineral with large surface area, excellent chemical stability and strong adsorption [21], [22]. Although ATP possesses high adsorption capabilities, the modification of its structure can successfully improve its capabilities. In this work, CTS/ATP composites are applied as an adsorbent for the removal of chromium and iron ions from aqueous solution of both single and binary systems. The adsorption properties such as equilibrium, kinetics and thermodynamics were demonstrated by batch mode adsorption experiments.
Section snippets
Instruments and apparatus
Scanning electron microscopy (SEM) images were obtained at 15.0 kV on the field emission scanning electron microscope (USA) after gold plating. X-ray diffraction (XRD) was performed on Siemens D5005 powder X-ray diffractometer. Infrared spectra (4000–400 cm−1) was recorded on a Nicolet NEXUS 470 FT-IR apparatus (U.S.A.). The specific surface area, pore volume of the adsorbents were measured according to the Brunauer–Emmett–Teller (BET) model using single point analysis and a Flowsorb II 2300 from
Characteristic of CTS/ATP composites
The elemental analysis shows that the lignin had the following percentage composition (%): C, 2.625; H, 1.117; N, 9.651. The average pore diameter was 1.527 Å and the specific surface area of the CTS/APT composites was 64.68 m2 g−1 measured by the N2-BET method.
To characterize the size and shape of the CTS/APT composites, SEM was conducted. Fig. 1 presents the typical SEM images of ATP and the CTS/APT composites, indicating that the products are well-dispersed with CTS. It is seen from the
Conclusions
The combination of CTS and ATP was performed. The adsorptions of metal ions by CTS/ATP were significantly higher than those of ATP and CTS. Equilibrium data were well described by Freundlich isotherm models, indicating multilayer adsorption for Cr(III) and Fe(III) onto CTS/ATP composites. Kinetics experiments showed that CTS/ATP composites offered fast kinetics for adsorption of Cr(III) and Fe(III), and the diffusion-controlled process as the essential adsorption rate-controlling step was also
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (nos. 21077046and 30970309) and Ph.D. Programs Foundation of Ministry of Education of China (no. 20093227110015).
References (45)
- et al.
Determination of copper, cadmium and lead in seawater and mineral water by flame atomic absorption spectrometry after coprecipitation with aluminum hydroxide
Anal. Chim. Acta
(2005) - et al.
Development of 1-(2-pyridylazo)-2-naphthol-modified polymeric membranes for the effective batch pre-concentration and determination of zinc traces with flame atomic absorption spectrometry
Talanta
(2002) - et al.
Sodium dodecyl sulfate coated poly (vinyl) chloride: an alternative support for solid phase extraction of some transition and heavy metals
Chemosphere
(2009) - et al.
Flame atomic absorption spectrometric determination of cadmium(II) and lead(II) after their solid phase extraction as dibenzyldithiocarbamate chelates on Dowex Optipore V-493
Anal. Chim. Acta
(2006) - et al.
Flame atomic absorption spectrometric determination of zinc, nickel, iron and lead in different matrixes after solid phase extraction on sodium dodecyl sulfate (SDS)-coated alumina as their bis (2-hydroxyacetophenone)-1,3-propanediimine chelates
J. Hazard. Mater.
(2009) - et al.
Comparative adsorption of Cu(II), Zn(II), and Pb(II) ions in aqueous solution on the crosslinked chitosan with epichlorohydrin
J. Hazard. Mater.
(2008) Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment
Prog. Polym. Sci.
(2005)Interactions of metal ions with chitosan-based sorbents: a review
Sep. Purif. Technol.
(2004)- et al.
The influence of the degree of cross-linking on the adsorption properties of chitosan beads
Bioresour. Technol.
(2008) - et al.
Removal of copper(II) ions from aqueous solution onto chitosan and cross-linked chitosan beads
React. Funct. Polym.
(2002)
Preconcentration and determination of Cu(II) in a fresh water sample using modified silica gel as a solid phase extraction adsorbent
J. Hazard. Mater.
Fast removal of copper ions from aqueous solution by chitosan-g-poly(acrylic acid)/attapulgite composites
J. Hazard. Mater.
Study on solid phase extraction and flame atomic absorption spectrometry for the selective determination of cadmium in water and plant samples with modified clinoptilolite
J. Hazard. Mater.
Synthesis, characterization, and adsorption performance of Pb(II)-imprinted polymer in nano-TiO2 matrix
J. Environ. Sci.
Multiwalled carbon nanotubes for speciation of chromium in environmental samples
J. Hazard. Mater.
Comparison of Ni2+ sorption to bare and ACT-graft attapulgites: effect of pH, temperature and foreign ions
Surf. Sci.
Study on superabsorbent composite. VI. Preparation, characterization and swelling behaviors of starch phosphate-graft-crylamide/attapulgite superabsorbent composite
Carbohydr. Polym.
Chitosan intercalated montmorillonite: preparation, characterization and cationic dye adsorption
Appl. Clay. Sci.
Equilibrium theory based design of simulated moving bed processes for a generalized Langmuir isotherm
J. Chromatogr. A
Adsorption isotherm models for basic dye adsorption by peat in single and binary component systems
J. Colloid Interface Sci.
Adsorptive removal of Pb(II) by activated carbon prepared from Spartina alterniflora: equilibrium, kinetics and thermodynamics
Bioresour. Technol.
Adsorption of dyes using shale oil ash
Water Res.
Cited by (128)
A facile fabrication of PU/rGO/MoS<inf>2</inf> self-cleaning fibrous membrane for oil-water separation
2024, Journal of Environmental Chemical EngineeringSynthesis of a micro-nano FeO<inf>x</inf>/MnO<inf>x</inf> modified large volume non-enamel ceramsites for selective and efficient adsorption of cadmium
2023, Journal of Environmental Chemical EngineeringSustainable nanocomposite porous absorbent and membrane sieves: Definition, classification, history, properties, synthesis, applications, and future prospects
2023, Journal of Environmental Chemical EngineeringApplications of biodegradable polymer nanocomposites in water and wastewater treatment
2023, Biodegradable and Biocompatible Polymer Nanocomposites: Processing, Characterization, and ApplicationsCadmium removal from wastewater by foamed magnetic solid waste-based sulfoaluminate composite biochar: Preparation, performance, and mechanism
2022, Chemical Engineering Research and DesignCitation Excerpt :Through the comparison of R2 values (0.9913 >0.9898), the Cd2+ adsorption kinetics on FMSB were found to conform to the pseudo-second-order model. This finding implied that the predominant mechanism in the adsorption process may be the chemisorption of Cd2+, which involved various chemical interactions between Cd2+ and functional groups on the adsorbent, such as ion exchange and chelation reactions (Zou et al., 2011). Fig. 7 shows the adsorption isotherms for Cd2+ on FMSB at different temperatures, and the isotherm parameters are listed in Table S6.