Pharmaceutical Transformation Products Formed by Ozonation—Does Degradation Occur?

Abstract

The efficiency of an advanced oxidation process (AOP) using direct and indirect ozonation for the removal of pharmaceutical residues from deliberately spiked deionized water was examined. Both direct and indirect ozonation demonstrated 34% to 100% removal of the parent compounds. However, based on the products’ chemical structure and toxicity, we suggest that despite using accepted and affordable ozone and radical concentrations, the six parent compounds were not fully degraded, but merely transformed into 25 new intermediate products. The transformation products (TPs) differed slightly in structure but were mostly similar to their parent compounds in their persistence, stability and toxicity; a few of the TPs were found to be even more toxic than their parent compounds. Therefore, an additional treatment is required to improve and upgrade the traditional AOP toward degradation and removal of both parent compounds and their TPs for safer release into the environment.

Performance of a Pilot-Scale Continuous Flow Ozone-Based Hospital Wastewater Treatment System

“…Levofloxacin is considered the primary antimicrobial agent that causes clinical problems with ARB [97]. Previous studies have reported that ozone and/or UV treatment reduces ecotoxicological effects to approximately 1/10-1/20,000 compared to untreated compounds [47,[98][99][100]. On the other hand, some researchers pointed out that the toxicity increases approximately 2-100 fold in some cases [99,100].…”

“…Previous studies have reported that ozone and/or UV treatment reduces ecotoxicological effects to approximately 1/10-1/20,000 compared to untreated compounds [47,[98][99][100]. On the other hand, some researchers pointed out that the toxicity increases approximately 2-100 fold in some cases [99,100]. It is known that differences in susceptibility to these toxic effects occur in different target species, and that under conditions where multiple compounds coexist, weakening or strengthening effects would occur compared to exposure to a single substance [101,102].…”

Application of advanced oxidation processes for domestic and industrial wastewater treatment

“…Nevertheless, the advanced oxidation process, indirect ozonation, according to the information gathered, is inefficient for removing persistent pollutants (e.g., some emerging pollutants) [63].…”

A Review of Ozone Decomposition by a Copper-Based Catalyst

“…Its advantage is its swift reactivity with organic compounds, which does not require selection. It readily reacts with organic compounds at various positions in the gas phase, producing easily oxidizable intermediates [80].…”