A green method for extracting molybdenum (VI) from aqueous solution with aqueous two-phase system without any extractant

Sustainable Extraction and Separation of Rhenium and Molybdenum from Model Copper Mining Effluents Using a Polymeric Aqueous Two-Phase System

“…In accordance with the greater charge density of OH – compared to the tested oxyanions, the distribution coefficient was primarily controlled by NaOH addition with a small contribution from the additional phase-forming salts (Na 2 MoO 4 or Na 2 WO 4 ) . The partition of MoO 4 2– in ATPS composed of the nonionic surfactant Triton-100 and (NH 4 ) 2 SO 4 is strongly dependent on the pH of the aqueous solution due to the change of molybdate speciation and the formation of species with variable charge densities . Previously reported results on the mechanism of ATPS formation with CuSO 4 in the presence of MoO 4 2– and ReO 4 – , respectively, as a function of pH and temperature serve as the basis for this work. , In the ATPS composed of CuSO 4 -PEG 4000-H 2 O, a maximal molybdenum extraction of 93% was achieved in the pH range 1.5–2.5 at T = 35 °C .…”

“…First proposed by Rogers and co-workers for the extraction of oxyanions, − a polymer-based aqueous two-phase system (ATPS) has emerged as an environmentally friendlier alternative to solvent extraction for the separation of metals. ,, Contrary to solvent extraction, ATPS occurs in fully aqueous media and relies on the difference in hydration energy between components in a ternary system, in this case water, polymer, and salt. , Concretely, ATPS allows for the predictable and reversible transition from a monophasic system to a biphasic one, composed of two phases with differing polarities, by manipulation of the system composition through the addition of an inorganic salt, for example. The partition of ions in ATPS is influenced by pH, temperature, surface properties, concentration, and the type of polymers and salts employed.…”

Thermoseparative Regeneration of Triblock Copolymer after Aqueous Biphasic Extraction of Molybdate Species

“…At a higher pH (6 and above), the extraction decreases and becomes almost negligible. The reason behind this pH-dependent extraction may be explained on the basis of the fact that molybdate species are polymerized in acidic medium to H 2 Mo 7 O 24 4– and HMo 7 O 24 5– which have higher hydrophobicity due to low charge density of the species . Therefore, the extraction of the species in the polymer-rich phase becomes feasible.…”

“…Different cationic species have been extracted in the polymer-rich phase with the aid of different extracting agents. , Metal oxo anions like TcO 4 2– , Cr 2 O 7 2– , AsO 2 – , and AsO 4 3– , are, however, more easily extracted in the polymer-rich phase owing to their lower hydration energy, higher chaotropicity, and hydrogen bonding abilities as compared to the positively charged metal ions. Molybdate species were reported to have been extracted in the surfactant-rich phase of a Triton X-100/(NH 4 ) 2 SO 4 system . Sodium molybdate and ammonium heptamolybdate salts were reported to have quantitative extractions in the PEG-rich phase of PEG/CuSO 4 ABS at acidic pH .…”

Detergent Compatible Extracellular Lipase from Streptomyces cellulosae AU‐10: A Green Alternative for the Detergent Industry

“…An aqueous two-phase system (ATPS) is an alternative bioseparation tool for biomolecules (Lee, Khoiroh, Ling, & Show, 2017). ATPS compared with the traditional organic solvent extraction process is a new green method, which has the advantage of being nontoxic, biocompatible, efficient, fast, relatively simple, and low-cost (Zhang, Liu, et al, 2016;Zhang, Sun, et al, 2016). This technique involves mixing of two different, incompatible substances in an aqueous solution to obtain a separate liquid-liquid phase.…”