Synthesis and characteristics of chelating fibers containing imidazoline group or thioamide group

Abstract

Two types of chelating fibers containing an imidazoline or thioamide group were prepared through the functionalization of hydrazine-modified polyacrylonitrile fiber by ethylenediamine and through the amination and sulfurization reaction of the hydrazine-modified polyacrylonitrile fiber under appropriate conditions, respectively. It is shown that the reaction temperature, time, and agent concentration are the dominant factors in the synthesis of fibrous sorbents. The increase of the ethylenediamine concentration from 33 to 45% (v/v) at 95-98°C results in a twofold higher increase of the fibrous sorbent with the imidazoline group, and a doubling of the reaction time from 2 to 4 h leads to a weight increase of the fibrous sorbent from 10 to 25% (w/w). Raising the temperature by about 5°C significantly accelerates the amination reaction of the hydrazine-modified fiber, but the temperature is an insensitive factor in the thioamidefunctionalized reaction of the aminated fiber. The introduction of a thioamide or imidazoline group is further verified by IR spectroscopy analysis. X-ray diffraction spectroscopy indicates the absolute disappearance of crystalline peaks for the fibers containing an imidazoline or thioamide group. However, the crosslinking reaction of the polyacrylonitrile fiber by hydrazine may make up for the effect of the crystallinity on the mechanical strength of the fibers, and the surface crackles of fibrous sorbents are not found by SEM photographs. The adsorption experiment results show that the newly prepared sorbents have high sorption capacities for noble metals in a high acidity, and it is also proved that Au(III) loaded on the chelating fibers may be reduced to Au(0).

Adsorption of Fluoride, Phosphate, and Arsenate Ions on a New Type of Ion Exchange Fiber

“…• C for 7 h. By infrared spectroscopy analysis, the introduction of the imidazoline group is further verified, and the nitrogen and oxygen contents of the modified fiber, determined by the ST-02 element analyzer, were respectively 14.47 and 13.70% (36). Then the product was soaked in diluted hydrochloric acid for 2 h, washed with hot deionized water (50-60…”

Modified Mesoporous Silicate MCM‐41 for Zinc Ion Adsorption: Synthesis, Characterization and Its Adsorption Behavior

“…1,7 The polymeric adsorbents derivatized from imidazole and thiol functional groups have been used in noble metal separation. [8][9][10] Following our work on the synthesis of new modified mesoporous sorbents, 11 in this paper, we report the synthesis of amino-thiol-functionalized mesoporous silica MCM-41, its properties and sorption behavior for 18 metal ions.…”

Facile Synthesis of Nanoporous Hydroquinone/Catechol Formaldehyde Resins and their Highly Selective, Efficient and Regenerate Reactive Adsorption for Gold Ions

“…Adsorption is one of the most-common methods of recovering dissolved precious metals from waste solutions, due to its low cost, easy operation, simple maintenance, and large capacity. [1] Effective metal-ion adsorbents have been prepared by the immobilization of N-and S-containing groups onto the surface of various substrates, including silica gel, [2,3] zirconia, [4] carbon, [5,6] polymers [7] and, most recently, mesoporous silica. [8][9][10][11][12] However, the selectivities of these materials are usually unsatisfactory because the interaction between metal ions and these typical functional groups is a common acid-base interaction and a number of different metal ions have the ability to bind with them.…”

“…[8][9][10][11][12] However, the selectivities of these materials are usually unsatisfactory because the interaction between metal ions and these typical functional groups is a common acid-base interaction and a number of different metal ions have the ability to bind with them. In addition to the acid-base interaction, the oxidationreduction (O-R) interaction between absorbents and metal ions has been found for several absorbents, such as poly- (1,8-diaminonaphthalene) microparticles, [13,14] sulfanyl absorbents, [7,15,16] tannin gel, [17] crosslinked lignophenol gel, [18,19] and active carbon. [20][21][22] The O-R interaction usually leads to very-high selectivity for precious-metal ions with strong oxidizing ability, such as gold(III) ions.…”