Graduation Year

2025

Document Type

Thesis

Degree

M.S.C.H.

Degree Name

MS in Chemical Engineering (M.S.C.H.)

Degree Granting Department

Chemical, Biological and Materials Engineering

Major Professor

Venkat R. Bhethanabotla, Ph.D.

Co-Major Professor

John N. Kuhn, Ph.D.

Committee Member

Marimuthu Andiappan, Ph.D.

Keywords

SAWs, Dye, Free radicals, Hydrogen peroxide, Degradability

Abstract

This study investigates the degradation behavior of methylene blue (MB) under surface acoustic wave (SAW) excitation, focusing on the effects of power, frequency, hydrogen peroxide (H2O2) concentration, and the use of perovskite oxide catalysts (LFO and LSF). Initial experiments showed that MB concentrations remained stable under SAW at ~10 MHz and ~30 MHz with power levels of 1–3 W in the absence of H2O2, though solution temperatures increased. Upon introducing 1 M H2O2, MB degradation followed a second-order rate constant, with degradation rates increasing with power and significantly higher at ~30 MHz, suggesting that both frequency and power enhance free radical formation and dye breakdown. Further analysis revealed a strong dependence on H2O2 concentration, with degradation rates rising up to 4 M H2O2, underscoring the importance of radical availability. Catalyst studies indicated that LFO and LSF alone did not degrade MB. Still, when combined with H2O2 and applied in thicker layers, slight degradation occurred, implying a piezoelectric catalytic effect requiring sufficient catalyst thickness to enable charge separation under SAW. While LFO and LSF improved degradation at lower power levels, their performance plateaued or declined at higher powers, indicating potential for material optimization. These findings collectively underscore the critical roles of frequency, power, radical concentration, and catalyst properties in SAW-based degradation systems.

Download

Share

COinS