![]() O comportamento químico de Cr(VI) a baixas concentrações (10 -4 to 10 -7 mol L -1) em vários ácidos fortes foi estudado utilizando-se 51Cr(VI) de alta atividade específica como marcador. Keywords: chromium, chromate, speciation, ion exchange chromatography, acid reduction Detailed studies of the reduction of low concentrations of Cr(VI) with nitric acid have shown that the relative rate of reduction increases as the concentration of the acid increases or as the concentration of the Cr(VI) decreases. The results show that trace quantities of Cr(VI), monitored by means of radiochromium ( 51Cr), are reduced in the presence of mineral acids such as perchloric, hydrochloric, hydrofluoric, sulfuric, nitric and trifluoromethanesulfonic acids, even in the absence of conventional reducing agents, producing different measureable Cr(III) species, depending on the acid anion. The speciation of the products from these systems was carried out by ion exchange chromatography with stepwise elution. The chemical behavior of Cr(VI) at low concentrations (10 -4 to 10 -7 mol L -1) in several strong acids was studied using high specific activity 51Cr(VI) as a tracer. ![]() IIIInstituto de Química, Universidade Estadual de Campinas, CP6154, 13084-971 Campinas - SP, Brazil IICentro Regional de Estudios Nucleares, Universidad Autónoma de Zacatecas, 98000 Zacatecas, ZAC, Mexico ICentro de Ciências Tecnológicas - UDESC, 89223-100 Joinville - SC, Brazil Reduction of trace quantities of chromium(VI) by strong acids
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