Photoproducts of carminic acid formed by a composite from Manihot dulcis waste.

Cynthia M Antonio-Cisneros, Martín M Dávila-Jiménez, María P Elizalde-González, Esmeralda García-Díaz

Index: Food Chem. 173 , 725-32, (2014)

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Abstract

Carbon-TiO2 composites were obtained from carbonised Manihot dulcis waste and TiO2 using glycerol as an additive and thermally treating the composites at 800 °C. Furthermore, carbon was obtained from manihot to study the adsorption, desorption and photocatalysis of carminic acid on these materials. Carminic acid, a natural dye extracted from cochineal insects, is a pollutant produced by the food industry and handicrafts. Its photocatalysis was observed under different atmospheres, and kinetic curves were measured by both UV-Vis and HPLC for comparison, yielding interesting differences. The composite was capable of decomposing approximately 50% of the carminic acid under various conditions. The reaction was monitored by UV-Vis spectroscopy and LC-ESI-(Qq)-TOF-MS-DAD, enabling the identification of some intermediate species. The deleterious compound anthracene-9,10-dione was detected both in N2 and air atmospheres.Copyright © 2014 Elsevier Ltd. All rights reserved.