Evaluación multivariada de un fotocatalizador dopado con nanopartículas de plata para la degradación de compuestos orgánicos en una muestra de agua residual.

Abstract

The photocatalytic activity of a photocatalyst doped with silver nanoparticles was evaluated to degrade organic compounds in aqueous solution. Preparing three photocatalysts by the “sol-gel” method using titanium tetrabutoxide (Ti (O-But)4 ) as base, isopropyl alcohol as solvent, nitric acid (HNO3 ) as catalyst and silver nitrate (AgNO3) at different concentrations of 10, 20 and 50% of silver as the dopant solution. The photocatalytic activity was evaluated in triplicate in a target of methylene blue with solutions 0.01520 mg/mL which were subjected to light intensities of 344, 220, 206 lux provided by ultraviolet light (UVc) lamps of 40, 20 and 10W respectively, with continuous stirring by aeration in 24 hours, concentration change measurements were measured by UV-Visible spectrophotometry. It was found that the optimum silver concentration in the photocatalyst was 20% and the adequate light intensity was 344 lux, with this the photocatalytic activity was measured in a residual water sample of the Chibunga river, an initial analysis was performed, then the changes were evaluated after 24 hours of exposure, obtaining as final results the decrease in the concentration of some parameters in the sample of residual water such as oils and fats from 78.0 mg / L to 1.0 mg / L, Nitrates from 22.33 mg / L to 5.30 mg / L and the removal of total coliforms from 4.8x106 to 0 UFC / 100mL. It was determined that photocatalytic activity of the photocatalyst had a value of k = 0.017 min-1 in the sample, light intensity, residence time and optimum silver concentration were identified at which organic compounds could be degraded in aqueous solution. It is recommended to perform this test on water samples contaminated with heavy metals, polycyclic aromatic hydrocarbons (PAHs) to increase information regarding contaminant degradation by this method.