Degradation of Tetramethylammonium Hydroxide through the Coupling of Ozonation with Other Advanced Oxidation Processes

ABSTRACT

In this study, ozonation is coupled with other approaches for the degradation of tetramethylammonium hydroxide (TMAH) to increase the degradation efficiency and reduce the toxicity. A degradation of 70.9% was reached after the reaction of TMAH with ozone for 120 min at pH 11 with the ozone dosage of 16 g O₃ per gram TMAH per hour (16 g O₃ g⁻¹ TMAH h⁻¹). A mineralization of 47.6% was achieved and the cell viability increased from 60.6% (before treatment) to 83.8% (after treatment). When ozone was combined with H₂O₂ and ultraviolet (UV) irradiation, the reaction stimulated by UV light did not facilitate TMAH degradation, whereas the addition of H₂O₂ increased the production of ·OH, thereby increasing the TMAH degradation. The use of ultrafine bubble-enhanced ozonation reduced the required ozone dosage to 1/10 of that used for microbubble ozonation, but similar treatment efficiencies were achieved. The O₃/H₂O₂ approach is favorable for TMAH degradation; under optimal conditions, a degradation of 82.3% and mineralization of 53.5% can be achieved.

KEYWORDS:

• Cell viability
• mineralization
• ozonation
• TMAH
• ultrafine bubble-enhanced ozonation

Acknowledgments

The financial support from the National Science Council, Republic of China [Grant No. 101-2221-E-264-005], and Ministry of Science and Technology, Republic of China [Grant Nos 101-2221-E-264-005 and 103-2221-E-264-001-MY2] is gratefully acknowledged.