Photocatalytic reduction and recovery of copper by polyoxomelalates

Troupis, A; Hiskia, A; Papaconstantinou, E

dc.contributor.author	Troupis, A	en
dc.contributor.author	Hiskia, A	en
dc.contributor.author	Papaconstantinou, E	en
dc.date.accessioned	2014-03-01T01:18:12Z
dc.date.available	2014-03-01T01:18:12Z
dc.date.issued	2002	en
dc.identifier.issn	0013-936X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14863
dc.subject.classification	Engineering, Environmental	en
dc.subject.classification	Environmental Sciences	en
dc.subject.other	Catalysts	en
dc.subject.other	Copper	en
dc.subject.other	Light absorption	en
dc.subject.other	Oxidation	en
dc.subject.other	Precipitation (chemical)	en
dc.subject.other	Reducing agent	en
dc.subject.other	Photocatalysis	en
dc.subject.other	chloride ion	en
dc.subject.other	copper	en
dc.subject.other	metal derivative	en
dc.subject.other	acetic acid derivative	en
dc.subject.other	chlorate	en
dc.subject.other	chloride	en
dc.subject.other	nitrate	en
dc.subject.other	polymer	en
dc.subject.other	silicon derivative	en
dc.subject.other	tungsten derivative	en
dc.subject.other	photochemistry	en
dc.subject.other	article	en
dc.subject.other	catalysis	en
dc.subject.other	concentration (parameters)	en
dc.subject.other	light absorption	en
dc.subject.other	molecular stability	en
dc.subject.other	oxidation	en
dc.subject.other	particulate matter	en
dc.subject.other	pH	en
dc.subject.other	pollution	en
dc.subject.other	reaction analysis	en
dc.subject.other	reduction	en
dc.subject.other	algorithm	en
dc.subject.other	chemical model	en
dc.subject.other	chemistry	en
dc.subject.other	light	en
dc.subject.other	oxidation reduction reaction	en
dc.subject.other	radiation exposure	en
dc.subject.other	Acetates	en
dc.subject.other	Algorithms	en
dc.subject.other	Chlorates	en
dc.subject.other	Chlorides	en
dc.subject.other	Copper	en
dc.subject.other	Hydrogen-Ion Concentration	en
dc.subject.other	Light	en
dc.subject.other	Models, Chemical	en
dc.subject.other	Nitrates	en
dc.subject.other	Oxidation-Reduction	en
dc.subject.other	Polymers	en
dc.subject.other	Silicon Compounds	en
dc.subject.other	Tungsten Compounds	en
dc.title	Photocatalytic reduction and recovery of copper by polyoxomelalates	en
heal.type	journalArticle	en
heal.identifier.primary	10.1021/es020933q	en
heal.identifier.secondary	http://dx.doi.org/10.1021/es020933q	en
heal.language	English	en
heal.publicationDate	2002	en
heal.abstract	A series of polyoxometalates PW12O403-, SiW12O404-, and P2Mo18O626- have been used as photocatalysts for recovery, of copper and production of fine metal particles. The process involves absorption of light by polyoxometalates, oxidation of an organic substrate, for instance, propan-2-ol as sacrificial reducing reagent, and reoxidation of the reduced polyoxometalates by Cu2+ ions, closing the photocatalytic cycle. Copper(II) ions are reduced to copper-(I) and finally to zero-state particles in a 2-electron process, as also suggested by the half-order dependence. Increase of catalyst or propan-2-ol concentration, or both, accelerates the photodeposition of copper until a saturation value is reached. The method is operational at a wide range of copper concentrations varying from 3 to 1300 ppm, leading to very low final concentrations (<0.2 ppm). The presence of dioxygen suppresses the initiation of copper recovery, though the process is equally effective after dioxygen is consumed. The process is independent of pH within the range 0.3-5.0. Addition of ClO4-, NO3-, or CH3COO- has no effect on the removal of copper ions. Chloride ions retard the enhancement of copper precipitation through stabilization of copper(I). This homogeneous, polyoxometalate-based process exhibits some benefits in comparison with the semiconductor-based (heterogeneous) recovery of metals: The final zero-state metal particles are obtained in pure form. No separation from the catalyst is needed, and moreover, the process is catalytic as the photodeposited metal particulates do not hinder the photocatalytic action of polyoxometalate anions.	en
heal.publisher	AMER CHEMICAL SOC	en
heal.journalName	Environmental Science and Technology	en
dc.identifier.doi	10.1021/es020933q	en
dc.identifier.isi	ISI:000179833400011	en
dc.identifier.volume	36	en
dc.identifier.issue	24	en
dc.identifier.spage	5355	en
dc.identifier.epage	5362	en