Background Chemistry of Molybdenum
Adsorption from solution
The heterogeneous isotopic anion exchange between calcium molybdate and sodium molybdate solutions have been studied by using 99Mo as tracer.
Atun, G., Bodur, N., Ayyildiz, H., Ayar, N., and Bilgin, B., Kinetics of isotopic exchange between calcium molybdate and molybdate ions in aqueous solution, Radiochimica Acta, 2007, 95, 177-182.
Molybdate, [MoO4]2-, was adsorbed reversibly by pyrite forming labile bidentate, mononuclear surface complexes. Tetrathiomolybdate, [MoS4]2-, formed Mo-Fe-S cubane-type clusters. Because of the high affinity of [MoS4]2- for FeS2 and its resistance to desorption thiomolybdate species may be the reactive Mo constituents in reduced sediments and may control Mo enrichment in anoxic marine environments.
Bostick, B.C., Fendorf, S., and Helz, G. R., Differential adsorption of molybdate and tetrathiomolybdate on pyrite (FeS2), Environmental Science & Technology, 2003, 37, 285-291.
The removal of sulfate and molybdate anions (among other anions) from mining liquid effluents is attracting much interest because of environmental legislation and the need for water recycling and reuse. Adsorption of sulfate and molybdate ions on chitin-based materials was investigated. From mining effluents, 71% sulphate and 85% Mo from a Cu-Mo flotation mill effluent were removed. The regeneration of the adsorbent material was possible through the anions desorption in alkaline medium.
Moret, A. and Rubio, J., Sulphate and molybdate ions uptake by chitin-based shrimp shells, Minerals Engineering, 2003, 16, 715-722.
Bead sorbent Perloza MT 50 was used for selective removal of metal W, Mo, V, Ge, and Sb oxoanions. All experiments were carried out by dynamic column sorption. Sorption of tungstate and molybdate anions was successful. The sorption capacity decreased with increasing concentration of accompanying anions (chlorides, sulphates) and with increasing pH (3.5-5.5). Sorption of vanadate anion was possible but the sorption capacity was very low. Sorption of Ge(IV) and Sb(III) oxoanion was negligible.