Electrochemical reduction of vanadium (V) ions in aqueous solution

Sequeira, CAC; Chen, Y; Anastassakis, G

dc.contributor.author	Sequeira, CAC	en
dc.contributor.author	Chen, Y	en
dc.contributor.author	Anastassakis, G	en
dc.date.accessioned	2014-03-01T02:50:04Z
dc.date.available	2014-03-01T02:50:04Z
dc.date.issued	2005	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/34884
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-32044434421&partnerID=40&md5=cdcac521d74dd32a5c39ae51bbc741f0	en
dc.subject.other	Electrochemistry	en
dc.subject.other	Environmental impact	en
dc.subject.other	Oxidation	en
dc.subject.other	Reduction	en
dc.subject.other	Solutions	en
dc.subject.other	Sulfur	en
dc.subject.other	Toxic materials	en
dc.subject.other	Chemical interaction	en
dc.subject.other	Electrochemical reduction	en
dc.subject.other	Solid oxide films	en
dc.subject.other	Thiometalates	en
dc.subject.other	Vanadium	en
dc.title	Electrochemical reduction of vanadium (V) ions in aqueous solution	en
heal.type	conferenceItem	en
heal.publicationDate	2005	en
heal.abstract	Sulphur and its species have a significant environmental role because of their complexation with many toxic agents and their primary contribution in acidification of the water systems. Consequently, the oxidation of sulphur aqueous species (H2S, HS-, S2-) is of considerable environmental and technological importance as well. It is known that vanadium (V) salts are responsible for the oxidation of hydrosulphide, therefore the oxidising action of vanadium (V) salts stimulated our interest, as reported here. The approach taken was to investigate the V(V)/V(IV) redox couple using electrochemical techniques such as cyclic and pulse voltammetry. Products were identified using UV-visible and esr spectroscopy. The reduction of vanadium (V) was found to be irreversible on a variety of electrode surfaces (mercury, carbon, gold; at 20-40°C: pH 9.2), and led to the formation of solid oxide films (V3O5, V2O3 and VO) rather than to V(IV) solution species. Irreversible behaviour is commonly observed when a large structural rearrangement is necessitated as the reactant is reduced. In the present case, HV2O73- is the probable V(V) species and.V18O4212- is the likely V(IV) species. The fact that vanadium (V) is an effective oxidising agent for hydrogen sulphide suggests that there is some specific chemical interaction between them that facilitates V(V) reduction, such as the formation of thiovanadate complexes. An attempt was made to investigate the redox chemistry of the thiovanadate ion VS43-, using cyclic voltammetry, but large background currents due to the oxidation of HS"" ions obscured any currents that might have been due to the reduction of VS43- ions. A concluding remark is that the search for a more effective sulphide oxidation agent may be best focused on those transition metals which are also known to form thiometalates; for example molybdenum, tungsten, and rhenium.	en
heal.journalName	REWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology	en
dc.identifier.spage	2197	en
dc.identifier.epage	2204	en