Determinação de cianocomplexos metálicos em correntes de refinaria por cromatografia de íons com supressão de condutividade

• Autor(a) principal: Silva, Renata Souza e
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal Fluminense (RIUFF)
• Texto Completo: https://app.uff.br/riuff/handle/1/20896
• topic: Cianocomplexos metálicos; Cromatografia de íons; Pareamento iônico; Supressão de condutividade; correntes de refinaria.; Metais - Complexos; Cianeto - Determinação; Cromatografia de íons; Metallic cyanocomplexes; ion chromatography; ion pair; conductivity suppression; refinery streams; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA

The detection and determination of small amounts of species containing cyanide became important because of the intense poisonous effects caused the man, associate to its wide distribution in the environment. Cyanides, under the form of organic and inorganic compounds, are species found frequently in products or industrial waste, that after physicochemical changes can generate free cyanides, extremely poisonous, being necessary its constant monitoring by sensitive and reliable methods. According to CONAMA, through the Resolution 357 of 2005, the allowed maximum concentration of cyanide in effluents is 0.2 mg.L-1. The objective of this work was to develop a method to quantify the metallic cyanocomplexes found in the refinery streams for control of corrosion in the cracking reactors. The developed chromatographic method was simple and fast, appropriate for routine analysis, that allowed to separate and quantify Fe(CN)6 4-, Ni(CN)4 2- and Co(CN)6 3- in refinery streams, using ion chromatography in reverse phase mode with ion pair and conductivity suppression. After optimization of the chemical and physical variables, using an ion chromatograph of DIONEX model ICS 2500, column Ion Pac NS1 10 µm, precolumn Ion Pac NG1 10 µm and supressor ASRS 4 mm, the ideal mobile phase is composed of 1mM Na2CO3, 2 mM TBAOH, 0,1 M NaCN and acetonitrile (77:23 v/v) and flow rate of 0.7 mL.min-1 . The quantification of the analytes of interest was obtained both by the method of analytical curve and standard addition. The results found in the analysis of the samples of refinery streams didn't present differences, significant statistically, when it was compared the two quantification methods. The method of the analytical curve presented better precision (RSD 3.1% for Fe(CN)6 4-, 2.5% for Ni(CN)4 2- and 2,8% Co(CN)6 3-). The proposed method showed sensitive for analysis of refinery streams, with detection limits for Fe(CN)6 4-, Ni(CN)4 2- and Co(CN)6 3- of 0.002, 0.001 and 0,003 mg.L-1 respectively.