Work

Quantifying Radical Pathways in a 425 kHz Sonoreactor: Coupled Calorimetric–Multidosimetric Assessment and Process Variable Impacts in Sunset Yellow FCF Degradation

Year: 2025

Type: article

Abstract: This study quantifies radical pathways and the influence of process variables in a 425 kHz sonoreactor through a coupled calorimetric and multidosimetric approach during Sunset Yellow FCF degradation. Reactive oxygen species were mapped with four complementary dosimeters. Potassium iodide (KI) tracked interfacial hydroxyl radicals (•OH). KI with ammonium heptamolybdate (AHM) captured •OH radicals together with hydrogen peroxide (H2O2). Bulk H2O2 accumulation integrated the recombination branch. Hydroxylation of 4-nitrophenol to 4-nitrocatechol acted as a selective near-interface •OH probe. Calorimetry showed that acoustic power density increased with set power and decreased with liquid height. All four dosimeters rose coherently with this variable, indicating that stronger driving elevated •OH generation while channeling a larger fraction into H2O2 through recombination. Process studies linked energy delivery to performance across operating conditions. Higher power accelerated pseudo-first order dye decay. Increasing initial dye concentration reduced fractional removal at fixed power, consistent with a radical-limited regime. Acidic media enhanced degradation by maintaining a stronger hydroxyl radical to water redox couple and by improving H2O2 persistence. Near neutral and alkaline media exhibited carbonate and bicarbonate scavenging of hydroxyl radicals and faster peroxide loss. Dissolved gas identity strongly modulated activity. Oxygen and argon outperformed air and carbon dioxide due to the combined thermophysical and chemical roles of the bubble gas. The calorimetry anchored and multidosimetric protocol provides a general route to compare reactors, optimize conditions, and support scale-up based on delivered energy density. Ultrasonication-driven degradation is a robust, practical technology for advanced treatment of dye-laden waters.

Source: Processes

DOI: 10.3390/pr13123827

Authors: Abdulmajeed Baker, Oualid Hamdaoui, Lahssen El Blidi, Mohamed K. Hadj-Kali, Abdulaziz Alghyamah

Institution: King Saud University

Language: English

Topic: Ultrasound and Cavitation Phenomena

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funders: King Abdulaziz City for Science and Technology, National Plan for Science, Technology and Innovation