Supercritical adsorption of buriti oil (Mauritia flexuosa Mart.) in 纬-alumina: A methodology for the enriching of anti-oxidants

详细信息	查看全文 | 推荐本文 |

• 作者：M.A.E. Cunha^a ; R.F. Neves^a ; J.N.S. Souza^b ; L.F. Franç ; a^b ; M.E. Araú ; jo^a ; G. Brunner^c ; N.T. Machado^a ; ^{machado@ufpa.br}
• 关键词：Adsorption ; Buriti oil ; Langmuir isotherm ; Supercritical CO2
• 刊名：The Journal of Supercritical Fluids
• 出版年：2012
• 期刊代码：60_08968446
• 类别：ce
• 出版时间：June, 2012
• 卷：66
• 期：Complete
• 页码：181-191
• 文件大小：1039 K

摘要

In this work, enriching of anti-oxidants has been systematically investigated by supercritical adsorption process. The adsorption of buriti oil (Mauritia flexuosa Mart.) has been determined experimentally by the method of frontal analysis in columns packed with 纬-alumina at 15, 20, and 25 MPa, 333 K, and solvent flow rate of , using an assemble of coupled columns of 81 cm³, adopted to be used as an adsorption cell. The oil of buriti has been physical-chemically characterized according to AOCS official methods in terms of acid, saponification, peroxide and iodine values, refraction index, density and viscosity. Chemical composition of buriti oil in terms of fatty acid esters has been performed by GC and anti-oxidants activity by the method of free radical capture (DPPH). The adsorbent was characterized by X-ray fluorescence, X-ray powder diffraction, electron scanning microscopy, particle and pore size distribution, particle porosity and specific area. A material balance has been performed on the adsorption column to compute the cumulative mass of adsorbing species in 纬-alumina on supercritical adsorption process by applying a pseudo-first order kinetic model as well as an integral kinetic model. The influence of pressure on the supercritical adsorption has been investigated by analyzing the mass transfer performance. A Langmuir type isotherm has been used to model the experimental adsorption data.

The results show that adsorbent capacity increases with pressure, showing a maximum of 99.486 mg_Oil/g_纬-alumina at 25 MPa. In addition, the concentration of anti-oxidant shows a tendency to increase during the curse of supercritical adsorption and with increasing system pressure. Fractions rich in anti-oxidants could be obtained at adsorption column outlet, showing a 2.0 fold enriching by 20 MPa and a 6.5 fold enriching by 25 MPa approximately, corroborating to assert this methodology as feasible to concentrate anti-oxidants from buriti oil. The supercritical adsorption of buriti oil fat soluble compounds in 纬-alumina using carbon dioxide as solvent may be applied as an alternative method for the enriching of anti-oxidants.