Analytical, toxicological and kinetic investigation of decomposition of the drug diclofenac in waters and wastes using gamma radiation

Abstract

The radiolytic decomposition of the drug diclofenac (DCF), and in limited extent, also two other widely used drugs, ibuprofen and carbamazepine, was examined using liquid chromatography (LC) methods. The efficiency of DCF decomposition was examined in function of the absorbed dose of gamma radiation, and also in the presence of selected scavengers of radicals, which are commonly present in natural waters and wastes. Three different tests were employed for the monitoring of toxicity changes in the irradiated DCF solutions. The LC/mass spectrometry (MS) was used for the determination of products of DCF radiolysis. Using pulse-radiolysis method with the spectrophotometric detection, the rate constant values were determined for reactions of DCF with the main products of water radiolysis: hydroxyl radicals (1.24 ± 0.02) × 1010 M−1 s−1 and hydrated electrons (3.1 ± 0.2) × 109 M−1 s−1. Their values indicate that both oxidative and reductive processes in radiolytic decomposition of DCF can take place in irradiated diluted aqueous solutions of DCF. The possibility of decomposition of all examined analytes was investigated in samples of river water and hospital waste. Compared to the previous studies, the conducted measurements in real samples were carried out at the concentration levels, which are close to those reported earlier in environmental samples.Graphical abstractᅟ

Contaminants of Emerging Concern Removal by High-Energy Oxidation-Reduction Processes: State of the Art

“…A 100-Gy dose allowed 90% CBZ decomposition in the latter, but only by 37% in hospital effluents. For DCF, complete decomposition in river waters was obtained at 100-Gy, while in hospital effluents 250 Gy were needed [34].…”

“…Table 6. Specific EEO values for different AOPs applied to some contaminants of interest on the same water matrix (spiked Lake Mead surface water, kWh m −3 order −1 ) (data from [34]). Table 7 reports EEO values determined for different AOPs [37].…”

Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)

“…This has been successfully exploited for laboratory transformations of otherwise inert substrates [1][2][3] as well as remediations of industrial pollutants, [4][5][6][7] with particular emphasis on recalcitrant halogenated waste. This has been successfully exploited for laboratory transformations of otherwise inert substrates [1][2][3] as well as remediations of industrial pollutants, [4][5][6][7] with particular emphasis on recalcitrant halogenated waste.…”

First Micelle‐Free Photoredox Catalytic Access to Hydrated Electrons for Syntheses and Remediations with a Visible LED or even Sunlight

“…The NSAID diclofenac e , which is so widely prescribed as to cause problems in wastewater treatment, furnishes an example of the first category. In homogeneous solution, we found that its ‐induced dehalogenation with [Ru(dcob) 3 ] 4− /HUr 2− quickly comes to a halt because a turbidity develops such that the LED light is efficiently blocked.…”