Study and construction of a sustainable solar photocatalytic reactor: indigo carmine blue food dye degradation

The disposal of effluents from food industries into surface waters represents a serious environmental problem, mainly due to the presence of dyes in their composition, which alters the photosynthetic capacity of aquatic plants. In addition, many of the by-products generated by their degradation can be toxic and non-biodegradable. In this research, a photocatalytic reactor constructed from quartz tubes was designed and built to be applied in an advanced oxidation processes (UV/TiO2), for the degradation of indigo carmine blue food dye, in an aqueous solution. A factorial design 23 was performed, where three variables were studied: the dye concentration (20 and 30 mg/L); the pH of the solution (4 and 10), and the TiO2 dosage (20 and 30 mg/L). The aqueous solution was subjected to constant circulation, inside the quartz tubes in order to carry out the experiments. The results showed that pH is the parameter with the greatest impact on degradation efficiency, which showed that at basic pH (10) a degradation rate of 99.91% was achieved, against 34.95% at acidic pH (4). It was concluded that the photo reactor using solar energy, presented itself as a strategic alternative for the removal of contaminants, including recalcitrant, such as synthetic dyes, which contribute to agro-industrial sustainability.