Reduction of Trace Quantities of Chromium(VI) by Strong Acids
نویسندگان
چکیده
O comportamento químico de Cr(VI) a baixas concentrações (10 to 10 mol L) em vários ácidos fortes foi estudado utilizando-se Cr(VI) de alta atividade específica como marcador. A especiação dos produtos destes sistemas foi realizada por cromatografia de troca iônica com eluição em etapas. Os resultados mostram que traços de Cr(VI), monitorados por radiocromo (Cr), são reduzidos na presença de ácidos minerais tais como perclórico, clorídrico, fluorídrico, sulfúrico, nítrico e trifluormetanosulfônico, mesmo na ausência de agentes redutores convencionais, produzindo várias espécies de Cr(III) diferentes, dependendo do ânion do ácido. Estudos detalhados com soluções de ácido nítrico mostram que a velocidade relativa da redução aumenta com o aumento da concentração do ácido ou com o decréscimo da concentração de Cr(VI).
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