Integrated optimization, kinetic modeling, and ecotoxicological evaluation of methylene blue degradation via ozonation: toward sustainable advanced oxidation processes

Hala Naseer Abdelkareem; Younis Swadi Tlaiaa; Mais A. Abdulkarem; Stella Robert Jameel; Mohammed Ali Abulrehman; Ali M. Flayyih; Hala Naseer Abdelkareem; Younis Swadi Tlaiaa; Mais A. Abdulkarem; Stella Robert Jameel; Mohammed Ali Abulrehman; Ali M. Flayyih

doi:10.3934/environsci.2026020

AIMS Environmental Science

2026, Volume 13, Issue 3: 487-507. doi: 10.3934/environsci.2026020

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Research article

Integrated optimization, kinetic modeling, and ecotoxicological evaluation of methylene blue degradation via ozonation: toward sustainable advanced oxidation processes

1.
Department of Civil Engineering, University of Baghdad, 10001 Baghdad, Iraq
2.
Department of Environmental Engineering, Mustansiriyah University, 10045 Baghdad, Iraq
3.
Department of Materials Engineering, Mustansiriyah University, 10045 Baghdad, Iraq
4.
Department of Civil Engineering, Al-Mustafa University, 10045 Baghdad, Iraq

Received: 22 April 2026 Revised: 12 June 2026 Accepted: 25 June 2026 Published: 30 June 2026

Synthetic dyes contained in industrial wastewater have become major sources of pollution for the environment and human health owing to their persistence and difficulty in degradation through traditional wastewater treatment processes. In this study, ozonation was studied as a method for the oxidation of methylene blue (MB) dye in water as an advanced oxidation process (AOP). This research is a combination of process optimization, kinetic modeling, energy requirement assessment, and ecotoxicological evaluation. To determine the optimal conditions (effect of O₃ dose, pH, and contact time) for MB removal, mineralization (chemical oxygen demand-COD; total organic carbon-TOC), residual ozone level, and toxicity toward Daphnia magna and Vibrio fischeri, a Taguchi L9 (3³) experimental design was utilized. Optimal conditions for MB removal achieved 98%, COD removal 88%, TOC removal 82%, a minimal level of residual ozone (0.32 mg L^-1), and low ecotoxicological risk. Kinetic analysis confirmed the pseudo-first-order reaction rate with k = 0.112 min^-1 (R² = 0.987). The energy cost of ozonation (electrical energy per order (EEO)) was 7.06 kWh m^-3 order^-1, which made it energy-efficient among AOPs. According to the results obtained, the key parameters for optimizing the direct ozone oxidation and OH-radical oxidation pathways included the contact time and O ₃ dose under neutral pH values.
- ozonation,
- Methylene Blue,
- pseudo-first-order kinetics,
- Daphnia magna,
- wastewater treatment
Citation: Hala Naseer Abdelkareem, Younis Swadi Tlaiaa, Mais A. Abdulkarem, Stella Robert Jameel, Mohammed Ali Abulrehman, Ali M. Flayyih. Integrated optimization, kinetic modeling, and ecotoxicological evaluation of methylene blue degradation via ozonation: toward sustainable advanced oxidation processes[J]. AIMS Environmental Science, 2026, 13(3): 487-507. doi: 10.3934/environsci.2026020

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Abstract

Synthetic dyes contained in industrial wastewater have become major sources of pollution for the environment and human health owing to their persistence and difficulty in degradation through traditional wastewater treatment processes. In this study, ozonation was studied as a method for the oxidation of methylene blue (MB) dye in water as an advanced oxidation process (AOP). This research is a combination of process optimization, kinetic modeling, energy requirement assessment, and ecotoxicological evaluation. To determine the optimal conditions (effect of O₃ dose, pH, and contact time) for MB removal, mineralization (chemical oxygen demand-COD; total organic carbon-TOC), residual ozone level, and toxicity toward Daphnia magna and Vibrio fischeri, a Taguchi L9 (3³) experimental design was utilized. Optimal conditions for MB removal achieved 98%, COD removal 88%, TOC removal 82%, a minimal level of residual ozone (0.32 mg L^-1), and low ecotoxicological risk. Kinetic analysis confirmed the pseudo-first-order reaction rate with k = 0.112 min^-1 (R² = 0.987). The energy cost of ozonation (electrical energy per order (EEO)) was 7.06 kWh m^-3 order^-1, which made it energy-efficient among AOPs. According to the results obtained, the key parameters for optimizing the direct ozone oxidation and OH-radical oxidation pathways included the contact time and O ₃ dose under neutral pH values.

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