Speciation of aqueous Ni(II)-carboxylate and Ni(II)-fulvic acid solutions: Combined ATR-FTIR and XAFS analysis

NiMoO4 preparation from polyampholytic hybrid precursors: Benefiting of the memory effect in the oxidative dehydrogenation of propane

“…FTIR results have evidenced that nickel ions are interacting with the carboxylate moieties of the C6 copolymer matrix. Indeed, the shift to lower wavenumbers of the COO − anti-symmetric band indicates that nickel ions are coordinated to the carboxylate functions [22]. It seems to be proportional to the amount of the carboxylate functions that interacts with a nickel ion.…”

“…These chemical functions are characterised by two specific infra-red bands: the symmetric stretching ( s COO − ) at 1410 cm −1 and the antisymmetric stretching ( as COO − ) at 1577 cm −1 (Fig. 3) [21,22]. In the presence of inorganic ions, the first one is hidden by the NO 3 − broad and intense band at 1382 cm −1 .…”

“…3). According to Strathmann and Myneni, such a band shift represents the nickel complexation by the carboxylate functions of the C6 matrix [22]. Nickel ions are thus interacting with the C6 matrix.…”

The influence of citrate anion on Ni(II) removal by raw red mud from aluminum industry

“…It was also suggested that alcoholic hydroxyl group in citrate, although a poor ligand donor, can noticeably enhance the degree of Ni(II) complex formation [37]. The reactions between nickel and citrate can be presented as follows:…”

“…Stability constants for Ni(II)-citrate species, found in the literature, vary considerably with the change of the ionic strength [37]. Generally, in acidic media, the degree of nickel complexation by citrate is low and the most abundant nickel species is Ni 2+ , followed by NiH 2 Citrate + (Eq.…”