Abstract

MOGOLLON, L. I et al. FRACCIONAMIENTO Y DESMETALIZACIÓN BIOCATALÍTICA DE ASFALTENOS DE CRUDO CASTILLA. C.T.F Cienc. Tecnol. Futuro [online]. 1997, vol.1, n.3, pp.109-121. ISSN 0122-5383.

Asphalte nes obtained from a crude oil rich in heavy metals (Castilla crude oil) were fractioned by adsorption chromatography. These asphaltenes were partially characterized in orderto determine Ni and Vcontent by High pressure liquid chromatography (HPLC), UV-visible spectroscopy and atomic absorption . Petroporphyrin contents and molecular weigth in the fractions were also determined. The results indicated that Ni and V were not uniformely distributed in asphaltene fractions. Biocatalytic modifications by chloroperoxidase (CPO) of these petroporphyrins were evaluated in both aqueous buffer and organic solvents. The reactions were carried out in both aqueous buffers and ternary systems of toluene: isopropanol: water with petroporphyrins as substrate. The petroporphyrins were more soluble in the ternary system than in the aqueous buffer systems. CPO-mediated reactions were effective in eliminating the Soret peak in both aqueous and organic solvent systems. The effect of CPO-mediated reaction on the release of the metals complexed with the porphyrins and asphaltenes was determined. Chloroperoxidase was able to modify components in the heavy fractions of petroleum and remove 57 % of total heavy metals (Ni and V) and 23 % of asphaltenes from petroporphyrin-rich fractions .

Keywords : asphaltenes; chloroperoxidase; Biocatalytic modifications; organic solvent; plating.

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