Synthesis and characterization of magnetic amidoximated chitosan-g poly(polyacrylonitrile)/laponite RD nanocomposites with enhanced adsorption capacity for Cu$^{2+}$

Abstract

Magnetic amidoximated nanocomposites based on a combination of chitosan and magnetic laponite RD were prepared and examined for the removal of Cu 2+ from aqueous solutions. Magnetic laponite RD was prepared by an in situ method. In order to prepare magnetic amidoximated nanocomposites, acrylonitrile was grafted to chitosan in the presence of magnetic laponite RD. Then the nitrile pendants on magnetic chitosan-g-polyacrylonitrile/laponite RD (mChtioPANLap) were converted to amidoxime groups. We developed a polyamidoximated magnetic nanocomposite based on a mixture of chitosan/laponite RD, possessing a high adsorption capacity for Cu 2+ . By introducing magnetic laponite RD the adsorption capacity of nanocomposites for Cu 2+ was significantly improved. The effects of contact time, initial concentration of Cu 2+ , initial pH of Cu 2+ solutions, and temperature on adsorption process were investigated.Studying adsorption kinetics showed that the experimental data are described better by the pseudo-second-order kinetic model. The adsorption of Cu 2+ on nanocomposites followed the Langmuir isotherm model well. Additionally, the fitting of isotherm data by the Dubinin-Radushkevich model showed that the adsorption process occurred by physisorption mechanism. The thermodynamic data indicated that the adsorption process was spontaneous and endothermic.

Adsorption of Cu(II) on three adsorbents, Fe$_{3}$O$_{4}$/Ni/Ni$_{x}$B nanocomposite, carob (Ceratonia siliqua), and grape seeds: a comparative study

“…As shown in Table 4, the maximum adsorption capacity of the Fe 3 O 4 /Ni/Ni x B nanocomposite was much higher than the other adsorbents compared (except that of one previous study). 9 The maximum adsorption capacities of the carob and grape seeds were also close to those of natural seed materials and cashew nut shells. The equilibrium data of most of the adsorbents better fitted to the Langmuir isotherm.…”

“…The PSO model is based on the assumption that the rate-limiting step is chemical adsorption or chemisorptions involving valence forces through sharing or exchange of electrons between the adsorbent and adsorbate as covalent forces. 9 The Weber-Morris intraparticle diffusion model was also used for verifying the influence of mass resistance on the binding of Cu(II) on the adsorbents. If intraparticle diffusion is assumed to be the sole rate-controlling step, the plot passes through the origin.…”

Uranium(VI) and zirconium(IV) sorption on magnetic chitosan derivatives – effect of different functional groups on separation properties

“…Figure S3 shows the XRD spectra of the two sorbents, despite the poor resolution it is possible to identify a series of peaks at 2 θ = 21.4°, 30.3°, 35.7°, 43.2°, 57.2° and 62.6°. Similar peaks were reported for magnetic clay composite with indices associated to (220), (311), (400), (511) and (440) planes for 2 θ = 30.5°, 35.6°, 43.2°, 57.5° and 63.0°, respectively. The coating with chitosan and polyacrylonitrile (PAN) and the further amidoximation introduced some additional peaks (mainly associated with the crystalline structure of PAN).…”

Recent Progress on the Design and Applications of Polysaccharide‐Based Graft Copolymer Hydrogels as Adsorbents for Wastewater Purification

“…Carrageenan based hydrogels have mainly been used in drug delivery applications, [91][92][93][94][95][96][97] but some of carrageenan hydrogels have also been used as adsorbents for impurities from wastewater. [ 98,99 ] For example, a hydrogel nanocomposite of kappa -carrageenan, PVA, and Fe 3 O 4 magnetic nanoparticles as used for the adsorption of cationic dyes, e.g., crystal violet, from aqueous solutions. [ 98 ] In another study, the carrageenan, alginate, and sodium-montmorillonite-based hydrogel nanocomposites were used for the adsorption of crystal violet and had a maximum adsorption capacity of 88.8 mg g −1 .…”

“…[ 98,99 ] For example, a hydrogel nanocomposite of kappa -carrageenan, PVA, and Fe 3 O 4 magnetic nanoparticles as used for the adsorption of cationic dyes, e.g., crystal violet, from aqueous solutions. [ 98 ] In another study, the carrageenan, alginate, and sodium-montmorillonite-based hydrogel nanocomposites were used for the adsorption of crystal violet and had a maximum adsorption capacity of 88.8 mg g −1 . [ 99 ]…”