Sintese, caracterização e aplicações analiticas do oxido de zirconio (IV) altamente disperso sobre a superficie da silica gel

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

Silica gel having a specific surface area of 430 m.g and particle size betweem 0.063-0.200 mm, was chemically modified with zirconium(IV) oxide according to the reactions: nSiOH + ZrCl4 --->(SiO)nZrCl(4-n) + nHCI (SiO)nZrCl(4-n) + (4-n) H2O --->(SiO)nZr(OH)(4-n) + (4-n)HCl 2SiOH + ZrOCl2 + H2O --->(SiO)2Zr(OH)2 + 2HCl The modified silica, denoted as SiZr, was characterized and used to sorb chromium(VI) and hydrogen peroxide. Since SiZr was able to sorb chromium(VI) from an acid solution and desorb at basic solution, the material was used to preconcentrate the metal in a column. A flow injection analysis (FIA) system was connected to a microcolumn packed with SiZr to carry out on line preconcentration and selective determination of chromium(VI) at trace leveI. A greater interference was observed for SO4 and PO4 ions in the study of interferents. The system was tested for natural water dopped with chromium(VI). The results, compared with those obtained by the spectrophotometric method using diphenylcarbazide reagent, were shown to be in good agreement. Hydrogen peroxide sorbed on SiZr showed a relative high stability and the redox property tested for conversion of iodide (I) to iodine (I2).

ASSUNTO(S)

silica gel oxido de zirconio

ACESSO AO ARTIGO

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