Extraction chromatographic separation of Ga(III) with the high molecular mass liquid cation exchanger SRS-100

1041-1046A selective method has been developed for the extraction chromatographic separation of Ga(III) with SRS-100 (liquid cation exchanger) coated on silanised silica gel. Its quantitative extraction has been achieved in 2.5 h from 0.1 M acetate buffer (pH 5.5-6.5). The effects of pH, flow-rate and stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Ga(III) has been determined. Breakthrough capacity and preconcentration factor at different pH values have been investigated. The effect of pH on Rf in ion exchange paper chromatography has also been investigated. Ga(III) has been separated from its synthetic binary and multi-component mixtures containing various metal ions as are found in ores and alloy samples. The method effectively permits sequential separation of Ga(III) from synthetic quaternary mixtures containing its congeners Al(III), In(III) and Tl(III). A plausible mechanism for the extraction of Ga(III) is also suggested

Solid phase extraction of cerium(IV) with crosslinked poly(acrylic acid) coated on silica gel

1528-1532A selective method has been developed for extraction and separation of Ce(IV) with the high molecular mass crosslinked poly(acrylic acid), coated on silanized silica gel. The coated materials act as stationary phase for the extraction. The structure and thermal stability of crosslinked poy(acrylic acid) has been elucidated with the help of FTIR and TGA. Ion exchange and breakthrough capacity of the exchanger have been measured. Surface morphology of the exchanger has been studied by SEM. Ce(IV) has been separated quantitatively from various synthetic mixtures containing metal ions commonly present in thorium and uranium ores, minerals and fission products. The developed method has been tested for some real samples. A plausible mechanism for Ce(IV) extraction and elution has been suggested

Characterization and Density Functional Theory Optimization of a Simultaneous Binder (FSG-XO) of Two Different Species Exploiting HOMO–LUMO Levels: Photoelectronic and Analytical Applications

A cost-time effective mesoporous ion-exchange material (FSG-XO) has been synthesized by immobilizing xylenol orange on functionalized silica gel. Its spatially separated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) have been used for the simultaneous sorption of two different metal centers at their respective high and low oxidation states. The characterization of its corresponding nanomaterial, {Si­[OSi]_{<i>p</i>=2–4}[OH]_{<i>m</i>=2–0} <i>x</i>H_<i>2</i>O}_<i>n</i>[−Si­(CH₃)₂–NH–C₆H₄–NN–XO]₄ has been assessed by a set of sophisticated analysis. FSG-XO possesses high SA_BET (346.22 m²/g), PV (0.431549 cm³/g), uniform pore size (width, 47.1; and diameter, 50.3 nm), high chemical (4 M HNO₃) and thermal stability (140 °C), high level of reusability (<1000 cycles), high BTC (240 μM g^–1) and high PF (111). The spatially well separated (931.6 pm) HOMO (−6.1631 eV)–LUMO (4.2795 eV) with a band gap of 10.44 eV denies any sort of charge recombination and proves its utility as a light emitting diode source and it shows its applicability as good donor–acceptor organic electronic device. The extractor exhibits its outstanding performance in binding molecular I₂ at its LUMO and enhances its breakthrough capacity by the same amount as obtained after the full saturation of HOMO by an electrophile (Zn­(II))

Ex Cathedra Immobilization of 8‑Hydroxyquinoline to Inorganic Carriers via a New Silane Coupling Reagent for Extractive Sample Cleanup of Iron(III)

By the use of a new silane coupling reagent, dimethyldichlorosilane (DMDCS), effective and instantaneous immobilization of 8-hydroxyquinoline (HQ) on an inorganic carrier (silica gel, SG) has been carried out for the facile synthesis of an extractor material (composition: {Si­(OSi)_<i>p</i>=4(H₂O)_{<i>x=</i>0.16}}_<i>n</i>=11[−Si­(CH₃)₂–NH–C₆H₄–NN–HQ]_<i>z</i>=4·25H₂O; molar mass: 4010.3 g/mol). The material (thermal stability: ≤100 °C; chemical stability: ≤8 M HNO₃) possesses a high Brunauer–Emmett–Teller surface area (BET-SA_Fe(III): 1170 m²·g^–1), an appreciable preconcentration factor (PF_Fe(III): 145.1), and high breakthrough capacity (BTC_Fe(III): column exchange capacity, 269 μmol·g^–l; Langmuir <i>Q</i>₀, 278.6 μmol·g^–1) for Fe­(III). Along with these discernible analytical qualities, a high level of reusability (<800 cycles @ 95% recovery) reflects the material warranty. Fe­(III), present as [Fe­(OH)­(H₂O)₅]²⁺ at the recommended pH (1.90 ± 0.15), binds at the highest occupied molecular orbital (HOMO) of the sorbent (η = 7.69 eV) through hard–soft binding with an appreciable binding energy (−14.2 eV). The breakthrough capacity (BTC: 269–278.6 μmol·g^–1) was found to be the product of the amount of extractor HOMO (280 μmol·g^–1) and the degree of polymerization of the adsorbed metal ion, <i>x</i> (i.e., BTC = [amount of HOMO_extractor (μmol·g^–1)] × <i>x</i> for monomeric (<i>x</i> = 1) and polymeric (<i>x</i> > 1) species). The findings reveal substantial improvement of Weetall–Hill immobilization of chelating ligands on inorganic carriers

Fluorescent Resin-Assisted Extraction for Selective Separation and Preconcentration of Mercury(II) and Its Online Detection

Dimethyldichlorosilane (DMDCS) driven silane coupling is enabled by productive immobilization of an azo-dye to inorganic carrier through <i>m</i>-nitroaniline as a bridging component. The material has been utilized for the selective sample cleanup of zinc­(II), cadmium­(II), and mercury­(II), respectively, extracted as [Zn₅(OH)₆(H₂O)₂]⁴⁺, [Cd₄(OH)₄(H₂O)₃]⁴⁺, and [Hg₄(OH)₃(H₂O)₂]⁵⁺. The corresponding luminescent nanomaterial was used for selective detection of mercury­(II) at trace level (LOD ≥ 0.04 × 10^–5 M) amid a matrix of possible interferences. Breakthrough capacity (BTC) and preconcentration factor (PF) for the respective metal ions (BTC_Zinc(II), 600; BTC_Cadmium(II), 460; BTC_Mercury(II), 540 μM g^–1; and PF_Zinc(II), 197; PF_Cadmium(II), 148; PF_Mercury(II), 145) were found to be excellent. Sequential separation of zinc­(II), cadmium­(II), and mercury­(II) was achieved by employing selective eluents (mineral acids of very low concentration, 5 × 10³ μM). BTC (530 ± 70 μM g^–1) was found to be the product of the amount of extractor frontier orbitals (132 μM g^–1) and polynuclear state of sorbed species, <i>x</i> (i.e., BTC = {amount of HOMO}× <i>x</i>; <i>x</i> = 4 for cadmium­(II), mercury­(II); and <i>x</i> = 5 for zinc­(II)). Along with these analytical qualities, ease of synthesis, high level of reusability (≤2700 cycles @ 95% exchange capacity), and chemical stability (post treatment BTC with 8 M HNO₃, 8 M HCl, and 5 M H₂SO₄ was ≤95%) is an insignia of the material

Chemically Bonded Pepsin via Its Inert Center to Diazo Functionalized Silica Gel through Multipoint Attachment Mode: A Way of Restoring Biocatalytic Sustainability over “Wider pH” Range

Proteolytic enzymes play a pivotal role in the industry. Still, because of denaturation, the extensive applicability at their level of best catalytic efficiency over a more comprehensive pH range, particularly in alkaline conditions over pH 8, has not been fully developed. On the other hand, enzyme immobilization following a suitable protocol is a long pending issue that determines the conformational stability, specificity, selectivity, enantioselectivity, and activity of the native enzymes at long-range pH. As a bridge between these two findings, in an attempt at a freezing temperature 273–278 K at an alkaline pH, the diazo-functionalized silica gel (SG) surface has been used to rapidly diazo couple pepsin through its inert center, the O-carbon of the phenolic −OH of surface-occupied Tyr residues in a multipoint mode: when all the various protein groups, viz., amino, thiol, phenol, imidazole, carboxy, etc., in the molecular sequence including those belonging to the active sites, remain intact, the inherent inbuilt interactions among themselves remain. Thereby, the macromolecule’s global conformation and helicity preserve the status quo. The dimension of the SG-enzyme conjugate confirms as {Si(OSi)4 (H2O)1.03}n {−O–Si(CH3)2–O–C6H4–NN+}4·{pepsin}·yH2O; where the values of n and y have been determined respectively as 347 and 188. The material performs the catalytic activity much better at 7–8.5 than at pH 2–3.5 and continues for up to six months without any appreciable change