Obtenção e caracterização de materiais argilosos quimicamente ativados para utilização no descoramento de óleo vegetal

Abstract

A natural bentonite sample from Argentina was activated by sulfuric acid in different concentrations (20 and 40 wt%) and different contact time (120 and 210 min), at the same temperature (90°C) . The ratio of the mass of clay to the volume of acid solution was 1:10 (w/v). These materials were tested to verify its bleaching (decolorization) capacity of soybean oil, which was compared to a standard commercial bleaching material Fulmont Premiere. Differential thermal analysis and thermogravimetric techniques, infrared spectrometry and chemical analysis showed that the acid activation modified the clay material structural properties. Bleaching capacity was found to be dependent on the acid concentration and treatment time used. The activated Argentine material showed superior bleaching performance compared to the commercial clay used by vegetable oil refiners.

Influência do tipo de ácido usado e da sua concentração na ativação de uma argila bentonítica

“…Por isso torna-se importante um conhecimento prévio das propriedades estruturais das bentonitas adquiridas por tratamento químico para um posterior emprego em processos de adsorção. As correlações entre aspectos estruturais de bentonitas ácidas com o poder descorante desenvolvido após o tratamento já foram apresentadas [6,7].…”

Synthesis of aluminophosphate by the ionothermal method using factorial design

“…According to Foletto et al, the mass loss observed around 480°C for the solids obtained in run 9 and 15 can be attributed to a dehydroxylation process [23]. This process is due to framework defects which depend strongly on the pore size of the AlPO 4 as well as the hydration level before dehydroxylation [24].…”

Effect of the Acid Treatment of Montmorillonite Clay in the Oleic Acid Esterification Reaction

“…When the solid precursor is activated at temperatures between 100 -200 °C, bronsted acid sites are formed and under activation above of 200 °C result in a collapse of the structure interlayer of the clay mineral, with this there is a proportionate increase in acidity for Lewis sites. The material, after acid treatment (HCl or H 2 SO 4 ), increases its adsorption ability and is used in bleaching, deodorization and dehydration of vegetable, mineral and animal oils, as also in catalysis [14][15][16][17][18][19][20] . The activation force and the number of acidic sites increase with the acid treatment, however, in excess, decreases the catalytic activity of clays because of the impairment of the octahedral layers.…”