Spectrophotometry and spectrofluorimetry to analyze the destruction of pharmaceuticals during wastewater treatment by enhanced oxidation

Abstract

The work is devoted to the treatment of wastewater from pharmaceuticals by enhanced oxidation. Some studies have shown the high degree and speed of pharmaceutical degradation under the action of a hydroxyl radical formed by the combined action of UV and H2O2 (enhanced oxidation, which was fully confirmed by a decrease in absorption in the UV spectrum. This paper shows that, unlike spectrophotometry, the spectrofluorimetry method can be used in the analyzing the process of destruction of hard-to-degrade pharmaceuticals. The object of the study was synthetic alkaloid vinpocetine, which has an indole core. Vinpocetine solutions were irradiated in a laboratory setup which included a TUV 30w / GTV low-pressure argon-mercury lamp (Philips) for 5–15 min, and also irradiated for 1-10 minutes after adding hydrogen peroxide at a concentration of 100 mg / L). The spectrophotometry method showed an increase (instead of a decrease) in the absorption spectra with an increase in the duration of UV irradiation. Under the same conditions, the spectrofluorimetry method recorded a decrease in the signal intensity in the registration and excitation spectra, and under enhanced oxidation, the appearance of new bands characteristic of the phenolic group.