Vito Lubes

Bio: Vito Lubes is an academic researcher from Simón Bolívar University. The author has contributed to research in topics: Picolinic acid & Amino acid. The author has an hindex of 9, co-authored 70 publications receiving 322 citations.

Vanadium(III) Complexes with Picolinic Acid and Dipicolinic Acid in Aqueous Solution

Abstract: The complex species formed in aqueous solution (25 ∘C, I = 3.0 mol-dm−3 KCl ionic medium) between V3+ cation and the ligands: picolinic acid (Hpic, HL) and dipicolinic acid (H2dipic, H2L), have been studied potentiometrically and by spectrophotometric measurements. The application of the least-squares computer program LETAGROP to the experimental emf (H) data, taking into account the hydrolytic species of V3+ ion, indicates that under the employed experimental conditions, the formation of the complexes [VL]2+, [V(OH)L]+, [VL2]+, [VL3], [V2OL4] with picolinic acid and the complexes [VL]+, [V(OH)L], [V(OH)2L]−, [V(HL)(L)], and [VL2]− with dipicolinic acid were observed. The stability constants of the complexes formed were determined by potentiometric measurements, and spectrophotometric measurements were done in order to perform a qualitative characterization of the complexes formed in aqueous solution.

Determination of stability constants of ternary copper(II) complexes formed with picolinic acid and several amino acids

Abstract: In this work, the formation of ternary complexes with their respective formation constants in the systems formed by copper (II), picolinic acid and the amino acids = histidine (His), aspartic acid ...

Ternary Complex Formation between Chromium(III)-Picolinic Acid, Chromium(III)-Dipicolinic Acid, and Small Blood Serum Bioligands

Abstract: The complex species formed between chromium(III) picolinic and chromium(III) dipicolinic acids and small blood serum bioligands such as lactic, oxalic, citric, and phosphoric acids were studied in aqueous solution by means of electromotive force measurement emf(H) at 25 °C and 1.5 mol‚dm -3 KCl as the ionic medium. The binary and ternary complexes were studied by the aging solution method, consisting of the preparation of different molar ligand/metal ratios at different pH values: solutions were maintained at room temperature (25 ( 1 °C) for 45 days; potentiometric measurements were then done; and the data were analyzed by means of the least-squares computational program LETAGROP, obtaining the respective stability constants and the stoichiometric coefficients of the complexes formed in aqueous solution.

Vanadium(iii) complexes in aqueous solution with the dicarboxylic oxalic, malonic and succinic acids

Abstract: The complex species formed in aqueous solution (25 °C, I = 3.0 mol.dm-3 KCl ionic medium) between V 3+ cation and the dicarboxylic acids oxalic, malonic and succinic (H2L) have been studied potentiometrically. The application of the least-squares computer program LETAGROP to the experimental (emf H) data, taking into account the hydrolytic species of V 3+ ion, indicates that under the experimental conditions employed the formation of the complexes [VHL] 2+ , [VL] + , [V(OH)L], [V(OH)2L] - , [VL2] - , [V(OH)L2] 2- , [VL3] 3- and [V(OH)L3] 4- with oxalic acid, [VHL] 2+ , [VL] + , [VL2] - , [V(OH)L2] 2- , [V(OH)2L2] 3- , [VL3] 3- and [V(OH)L3] 4- with malonic acid, [VL] + and [V(OH)L] with succinic acid. The stability constants of the complexes formed were determined.

Dissolved Organic Matter in Natural Waters

Abstract: Organic matter (OM) in water is composed of two major fractions: dissolved and non-dissolved, defined on the basis of the isolation technique using filters (0.1–0.7 μm). Dissolved organic matter (DOM) is the fraction of organic substances that passes the filter, while particulate organic matter (POM) remains on the filter (Danielsson 1982; Kennedy et al. 1974; Liu et al. 2007; Mostofa et al. 2009a). DOM is generally originated from three major sources: (i) allochthonous Dissolved Organic Matter in Natural Waters

A literature review on leaching and recovery of vanadium

Abstract: Vanadium as an important national strategy resource is widely used in many fields due to its excellent physicochemical properties. Much attention had been focused on recovering vanadium from vanadium titano-magnetite and stone coal as they were the main vanadium resources in China. Sodium roasting technology was the earliest technology applied in recovering vanadium, high recovery efficiency of vanadium was obtained along with serious environment problem like corrosive gases and hazardous wastewater. Calcium roasting technology avoided above problems, but high energy-cost and low recovery was remained. Non-salt roasting technology was suitable for limited vanadium resource. Vanadium was leached out after roasting and the leaching medium was divided into three parts according to the roasting technology. Recover process of vanadium depended on the vanadium species and pH in the leaching solution. Hydrolysis was the easily technology with most impurities. Ammonium precipitation was the common process for every technology. And high purity of V2O5 was obtained by calcining precipitation of recovery process. Overall, the industry of vanadium leaching was still underdeveloped, and much intensive research work was needed.