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

Abstract

A sustainable and flexible approach for the extraction and separation of rhenium and molybdate species based on a polymeric aqueous two-phase system (ATPS) is proposed in which the high metal content in concentrated copper effluents is directly used as the driver of phase demixing. The partition coefficient and selectivity of Re, Mo, and Cu are studied in the proposed polymer-CuSO 4 -H 2 O ATPS as a function of additive concentration and polymer hydrophobicity. The electrolyte selection and concentration have a marked influence on the partition of Mo to the polymer phase, while increasing the hydrophobicity of the polymeric agent significantly improves the extraction of Mo. A selective precipitation based on the addition of quaternary ammonium salts directly to the polymer-rich phase is subsequently used for the quantitative recovery of Mo. A final polyoxometallate [N 2222 ] 2 Mo 6 O 19 hybrid complex is obtained with high purity. The resulting process achieves high separation yields, relies exclusively on cheap chemicals with low toxicity and could be a more sustainable alternative for the extraction of Re and Mo from copper mine effluents. By using sulfate salts as the salting-out agent, the main component of the ore leachate drives the separation thereby avoiding the use of additional complexing agents.

Fusion-Based Neutron Generator Production of Tc-99m and Tc-101: A Prospective Avenue to Technetium Theranostics

“…The solution chemistry of Mo is much more intricate than that of Tc, where Mo speciation is highly dependent upon pH due to protonation/condensation/oligomerisation reactions, and it is quite sensitive to its chemical environment [ 53 , 54 ]. This behaviour is particularly apparent in acidic pHs where an assortment of anionic polymolydates with varying degrees of hydration and charge densities, and even cationic or neutral species, can (co)exist [ 53 , 54 , 55 ]. In solution, polyanionic Mo species, such as [MoO 4 ] 2− , are known to form hydrogen bonds stronger than in the surrounding bulk water, classifying them as cosmotropic in nature [ 56 ].…”

Treatment of Rhenium-Containing Effluents Using Environmentally Friendly Sorbent, Saccharomyces cerevisiae Biomass

“…Nevertheless, unique physical and chemical characteristics make rhenium a critical metal of high industrial importance. Presently, rhenium is applied in the aerospace industry, production of alloys, electromagnets, catalysts, semiconductors, thermocouples, heating elements, metallic coatings, vacuum tubes, X-ray tubes, and medical devices [ 2 , 3 , 4 ]. Rhenium does not form its own deposits.…”

“…In industry, 80% of sources of rhenium raw materials are molybdenum and copper sulfide concentrates, produced by Chile, Kazakhstan, France, Germany, Russia, the U.S., China, Great Britain, the Netherlands, and Poland [ 1 , 5 ]. The techniques of rhenium extraction involve removing Re 2 O 7 from the sulfurous gas phase generated during hearth roasting or smelting [ 4 ]. During the process of extraction, part of rhenium is dispersed as volatile Re 2 O 7 in soils and as ReO 4 − ions in industrial effluents and water [ 5 ].…”

A Highly Efficient Environmental-Friendly Adsorbent Based on Schiff Base for Removal of Cu(II) from Aqueous Solutions: A Combined Experimental and Theoretical Study

“…A suitable method is thus needed for removing and selectively recovering Cu(II) from drinkable water. Currently, several remediation approaches and techniques have been applied to capture Cu(II) ions, such as ion exchange [ 4 ], coagulation [ 5 ], liquid-phase extraction [ 6 ], membrane separation [ 7 ], electrodeposition [ 8 ] and reverse osmosis [ 9 ].…”