Adsorption Properties Of Chitosan Research Articles

Ecofriendly Removal of Aluminum and Cadmium Sulfate Pollution by Adsorption on Hexanoyl-Modified Chitosan

The purity and safety of water as a finite resource is highly important in order to meet current and future human needs. To address this issue, the usage of environmentally friendly and biodegradable adsorbers and flocculants is essential. Chitosan, as a biopolymer, features tremendous properties as an adsorber and flocculant for water treatment. For the application of chitosan as an adsorber under acidic aqueous conditions, such as acid mine drainage, chitosan has been modified with hydrophobic hexanoyl chloride (H-chitosan) to reduce the solubility at a lower pH. In order to investigate the influence of the substitution of the hexanoyl chloride on the adsorption properties of chitosan, two chitosans of different molecular weights and of three different functionalization degrees were analyzed for the adsorption of CdSO4(aq) and Al2(SO4)3(aq). Among biobased adsorbents, H-chitosan derived from the shorter Chitosan exhibited extraordinarily high maximum adsorption capacities of 1.74 mmol/g and 2.06 mmol/g for Cd2+ and sulfate, and 1.76 mmol/g and 2.60 mmol/g for Al3+ and sulfate, respectively.

Review on preparation and adsorption properties of chitosan and chitosan composites

Compared with traditional polymers, biopolymers are more environmentally friendly due to their sustainable sources, easy decomposition and naturally recycled by biological processes. Among all biopolymers, chitosan (CS) proves attractive for several adsorption-related applications such as in gas capture and removal of dyes or heavy metal ions. However, there are considerable drawbacks such as unstable yield, non-uniform sizes, lack of process repeatability, low mechanical strength and chemical resistance. Thus, physical and chemical modifications have been proposed to obtain stable size and improved mechanical property of CS beads, microspheres, film or fiber. This paper introduces the research background of CS and modified CS as an adsorbent and analyzes the modification, application and adsorption mechanism of CS and CS composite materials. The research progress of the adsorption of metal ions, dyes and anions by CS and CS composite materials is reviewed, and the main factors affecting their adsorption performance are summarized. Finally, the development trend of CS as adsorbents is prospected.

Chitosan reinforced with modified CaCO3 nanoparticles to enhance thermal, hydrophobicity properties and removal of cu(II) and cd(II) ions

The role of nanoparticles (NPs) in the enhancement of thermal, wettability and adsorption properties of chitosan (CS) was inspired by loading of CaCO3 modified with diacid (DA) based on L- phenyl aniline (2–8 wt%) within the CS by ultrasound agitation. The diameter of CaCO3-DA into the CS extended from 40 to 70 nm. A thermal test on the CS/CaCO3-DA nanocomposite (NC) 2 wt% revealed that T 5 (temperature with 5% weight loss) was increased up to 312 °C, which is twice the value of the pure polymer. The wettability property of the CS/CaCO3-DA NCs was transformed from hydrophilicity to hydrophobicity as the CaCO3-DA NPs concentration was increased. It is due to decrease of the accessibility of the CS polar groups to water. The CS/CaCO3-DA NC 5 wt% was selected as the adsorbent for uptake of metal ions from the wastewater. It showed maximum adsorption capacity of 21.74 and 29.41 mg.g−1 for Cu(II) and Cd(II), respectively. These are attributed to strong complexation reaction between the metal ions and functional groups in the obtained NC.

Effect of Starch-MWCNT@Valine Nanocomposite on the Optical, Morphological, Thermal, and Adsorption Properties of Chitosan

The overall goal of this research was to develop a practical method for improving chitosan (Chit) properties using Starch-MWCNT@Valine (SMV) nanocomposite (NC) as a new filler. To prevent aggregation and also improve the dispersion of MWCNTs into the chit matrix, first the surface of MWCNTs was covalently modified by valine as a natural amino acid. Then modified MWCNT was embedded into starch matrix for the preparation of SMV NC. In the second step, the desire amount of prepared SMV NC (30, 50 and 70 wt%) were incorporated into the chit matrix by ultrasonication technique for the fabrication of Chit/Starch-MWCNT@Valine NC films. The resulting NC films were characterized using different techniques. Thermogravimetric analysis results illustrated that the thermal stability of NC 70 wt% in comparison to the pure chit was enhanced. The results indicated that prepared NCs were promising adsorbents for the removal of Cd(II) ions from the aqueous solution.

Investigation of adsorption capacity of N-carboxymethyl chitosan for Pb(II) ions

N-carboxymethyl chitosan (NCMC) was prepared by reacting chitosan (CTS) with chloroacetic acid and characterized by (13)C-NMR spectroscopy to confirm that carboxymethylation occurred only in the amino groups. The adsorption properties of CTS, NCMC and O-carboxymethyl chitosan (OCMC) towards Pb(II) ions were evaluated and the order of the adsorption capacity was as follows: NCMC > OCMC > CTS. The effects of initial pH value (2.0-5.5) of the solutions and contact time (5-120 min) on adsorption of Pb(II) were investigated and the kinetic data were evaluated using the pseudo-first-order and pseudo-second-order models. Kinetics study showed that the adsorption process followed second-order kinetics rather than the first-order one. Furthermore, the experimental equilibrium data of Pb(II) on the NCMC were analyzed using the Langmuir and Freundlich isotherm models and the results indicated that the Langmuir model gave a better fit than the Freundlich equation and the maximum adsorption capacity obtained from the Langmuir model was 421.9 mg g(-1).

Characteristics and kinetic study of chitosan prepared from seafood industry waste for oil spills cleanup

Abstract Chitosan being a biodegradable material would be an eco-friendly and effective alternative in the cleaning up of oil spills. In the present study, adsorbent (Chitosan) was prepared from the seafood industry waste, prawn shells for removal of oil from aqueous solution. Batch experiments were carried out to study the kinetics for the removal of oil from oil–water solutions using chitosan. The effect of various influencing parameters such as contact time, pH, initial concentration, and mass of adsorbent were studied. The equilibrium time for adsorption of oil on chitosan was obtained as 6 min. The maximum capacity of chitosan to adsorb oil from oil–water solution was found to be 17.96 g g−1 of adsorbent. The removal efficiency was observed to be higher in the acidic medium. The adsorption properties of chitosan have been attributed mainly to its positive charge. The equilibrium data was tested with the Langmuir isotherm and excellent correlation was obtained.

Study on Synthesis and Adsorption Properties of Chitosan Modified by DMF Grafted β-CD

The synthesis chitosan modified by N,N-dimethylformamide(DMF) grafted β-CD (CTS), adsorption experiments of lanthanide ions, a new type water treatment agent, are discussed in this paper. First, the chitosan was modified by DMF, and then β-cyclodextrin (β-CD) was grafted onto chitosan skeleton by epoxy chloropropane. The effects of temperature, pH value, adsorption time on adsorption content were studied. The water treatment agent have a high lanthanide adsorption rate up to 98% compared to chitosan, b-CD and chitosan derivative bearing β-cyclodextrin.

Chitosan pyrolysis and adsorption properties of chitosan and its carbonizate

Chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and elemental analysis (EA). The thin chitosan films obtained by the casting method were heated in vacuum from room temperature to 600 °C. The progress of thermal degradation and carbonization process was monitored by FTIR spectroscopy in a vacuum cell, which allows the elimination of the influence of atmospheric humidity on the chitosan and carbonizate properties. The adsorption of water on the degassed chitosan and its carbonizate as well the oxidation process was also investigated by FTIR spectroscopy. The surface morphology of initial chitosan and obtained carbonaceous material was observed using atomic force microscopy (AFM). Detailed characterization of raw material and carbonization conditions is necessary for tailoring reproducible adsorbent properties.