Hydrodynamic cavitation effects over complex organic mixtures

Hydrodynamic cavitation (HC) is a promising technology for the intensification of chemical and physical processes, with applications in wastewater treatment, extraction from suspended solids, and disinfection. In this study, the effects of HC on different model compounds for dissolved organic matter (DOM) were investigated. These compounds, such as lignin, humic acids, and protein-like compounds, are commonly present in organic wastewaters and were studied under various conditions. Specifically, changes in UV-Vis spectra and fluorescence properties resulting from HC treatments were analyzed. Results show that HC had distinct effects on the spectral indices, fluorescence intensity, and peak positions of the model compounds. Changes in humic acid and lignin were attributed to the oxidation and fragmentation of polymers, while changes in tryptone were explained by the polymerization and partial oxidation of its amino acids. Pyrolysis was found to be the dominant mechanism affecting non-polar substances, such as zwitterions in tryptone, whereas radical attack predominantly affects hydrophilic compounds like large, charged molecules like humic acids. Large molecules with both charged and non-charged groups, such as lignin, experienced a mixed effect. Findings in this work provide a comprehensive understanding of HC effects on various DOM model compounds. These results could aid in the development of more efficient HC-based treatment processes for organic pollutants.