A Synthetic Analog of the Mineral Ivanyukite: Sorption Behavior to Lead Cations

Abstract

The production of electrolytic nickel includes the stage of leaching of captured firing nickel matte dust. The solutions formed during this process contain considerable amounts of Pb, which is difficult to extraction due to its low concentration upon the high-salt background. The sorption of lead from model solutions with various compositions by synthetic and natural titanosilicate sorbents (synthetic ivanyukite-Na-T (SIV), ivanyukite-Na-T, and AM-4) have been investigated. The maximal sorption capacity of Pb is up to 400 mg/g and was demonstrated by synthetic ivanyukite In solutions with the high content of Cl− (20 g/L), extraction was observed only with a high amount of Na (150 g/L). Molecular mechanisms and kinetics of lead incorporation into ivanyukite were studied by the combination of single-crystal and powder X-ray diffraction, microprobe analysis, and Raman spectroscopy. Incorporation of lead into natural ivanyukite-Na-T with the R3m symmetry by the substitution 2Na+ + 2O2− ↔ Pb2+ + □ + 2OH− leds to its transformation into the cubic P−43m Pb-exchanged form with the empirical formulae Pb1.26[Ti4O2.52(OH)1.48(SiO4)3]·3.32(H2O).

The AM-4 Family of Layered Titanosilicates: Single-Crystal-to-Single-Crystal Transformation, Synthesis and Ionic Conductivity

“…The Raman spectra of lintisite with L3 and kukisvumite with K3 forms are shown at Figure 14 a,b, respectively. The Raman data of the AM-4 family compounds have not previously been published and the assignments of the bands were made using analogy with structurally-related titanosilicates [ 8 , 47 , 76 , 77 , 78 ]. In general, the spectra of kukisvumite and lintisite are very close, and differ only by small shifts and in the intensity of different bands.…”

“…AM-4 demonstrates excellent sorption properties with respect to Pb from industrial solutions, but the molecular mechanism of this process remains unexplored [ 47 ]. It has also been observed that, in acidic environments, AM-4 loses extra-framework Na cations and H 2 O molecules, with the acid-activated form being more efficient with respect to the adsorption of N 2 and CO 2 [ 48 ].…”

“…One of the most effective conductors is NASICON [42], which is related to the zirconosilicates and potential mineral species that might be found in alkaline complexes in associations similar to those of the lintisite-kukisvumite-group minerals. AM-4 demonstrates excellent sorption properties with respect to Pb from industrial solutions, but the molecular mechanism of this process remains unexplored [47]. It has also been observed that, in acidic environments, AM-4 loses extra-framework Na cations and H 2 O molecules, with the acid-activated form being more efficient with respect to the adsorption of N 2 and CO 2 [48].…”

Equilibrium Isotherms and Kinetic Effects during the Adsorption of Pb(II) on Titanosilicates Compared with Natural Zeolite Clinoptilolite

“…Amongst the acid-resistant synthetic analogues of zeolites are the titanium silicates. Firstly the Engelhard Titanium Silicate-4, and 10 (ETS-4 and ETS-10) were synthesised [29] and lately the ETS-14 [37] and Grace titanium silicate-1 (GTS-1) [38,39] were also reported. The titanium silicates are characterised by a porous crystal framework with uniform pore size-in the case of ETS-4 about 3.7 Å, for ETS-10 about 10 Å, and for ETS-14 about 14 Å.…”

“…However, the industrial implementation requires adjustment of the activation technique to obtain materials with enhanced properties, e.g., increase the uptake of harmful components. The goal of this work is to expand the data on the sorption/exchange properties of the titanosilicate GTS-1 towards Pb(II) cations, as information on the Pb(II)exchange properties of GTS-1 is very scarce in the scientific literature [38]. The study is focused on obtaining detailed uptake equilibrium and kinetic data for Pb(II) exchange on the synthesised GTS-1 and its produced H-form.…”