Synthesis of a polyacrylamidoxime chelating fiber and its efficiency in the retention of palladium ions

Abstract

ABSTRACT:A chelating fibrous polymer with metal complexing ability was prepared by partial conversion of the nitrile groups of melana (an acrylonitrile-based synthetic fiber) into amidoxime groups -C(NH 2 ) ϭ NOH using a solution of 3% hydroxylamine in methanol by refluxing at 80°C. The molar ratio of NH 2 OH/CN and the reaction time were adjusted to values of 0.9 and 2 h, respectively. The amidoximated polyacrylonitrile fiber with a 2.89 meq/g ionexchange capacity functions as an efficient chelating adsorbent for palladium ions. The pH dependence, the contact time, and the temperature of palladium ion retention from a model solution on amidoximated acrylic fiber were studied.The fibrous chelating adsorbent exhibited high affinity for palladium ions in acidic solution (pH ϭ 2-6) at high temperature (50 -60°C). The values of parameters q m and K L (from the Langmuir equation) determined at different temperatures of adsorption and the thermodynamic quantities ⌬G, ⌬H, and ⌬S were calculated. The adsorbed palladium ions can be quantitatively desorbed by elution with a 0.3% hydrochloric solution of thiourea.

Amidoxime functionalized Trametes trogii pellets for removal of uranium(VI) from aqueous medium

“…After modification with amidoxime groups (Fig. 3b), the appearance of new bands at 1622 and 1058 cm -1 are assigned to C=N and oxime groups stretching, respectively [33]. As observed above FTIR spectra, the potential functional groups for binding U(VI) ions should be carboxyl, hydroxyl, phosphoryl, amide, and amidoxime groups.…”

“…Magnetically modified Rhodotorula glutinis 73.5 [31] Methanol modified Rhodotorula glutinis 350.0 [32] Ca-pretreated Cystoseira indica alga 318.2 [33] Chlorine dioxide modified Bacillus sp. 385.0 [34] Chemically modified diatoms 158.8 [35] Tetraethylenepentamine modified chitosan 428.4 [36] Citric acid modified chitosan 191.0 [37] Amidoxime modified Trametes trogii 447.4 Present Study J Radioanal Nucl Chem equilibrium biosorption capacity q e , the biosorption rate is very fast and the equilibrium time short.…”

Preparation of aminated-polyacrylonitrile nanofiber membranes for the adsorption of metal ions: Comparison with microfibers

“…The positive nature of these parameters ( H • > 0; S • > 0) indicates that the process was endothermic and that, during the process, randomness was increased at the solid-solution interface. This type of increase might be due to the H 2 O hydrated molecules, or the sulfate ions [28].By definition, adsorption with a heat reaction between 20.9 kJ/mol and 418.4 kJ/mol is a chemical adsorption. Therefore, the obtained enthalpy indicates that the adsorption of copper ions on the aminated polyacrylonitrile can be regarded as a chemical adsorption event [5,32].…”

“…This adsorbent, which is fabricated using PAN fibers, has been recognized as a highly efficient materials for the removal and recovery of metal ions, which is especially true for dilute solutions because of the high adsorption capacity, fast adsorption equilibrium, high recycling rate, and low cost. Furthermore, PAN fibers have desirable chemical resistance, thermal stability, low flammability, and good mechanical properties [2][3][4][6][7][8][27][28].…”

Preparation of chelating fibrous polymer by different diamines and study on their physical and chemical properties

“…Experiments were carried out in an Erlenmeyer flask at the desired pH and 25 C temperature. The flask were agitated on shaker for 2h, which is more than the adsorption equilibrium time for AAFs [1,3,10]. The chromium(III) and lead(II) solutions were prepared at the concentration of 100ppm.…”