Experimental Investigation of the Effect of Ultrasound on the Integrity of Monoethanolamine (MEA) and Piperazine (PZ)

ABSTRACT This study examined the integrity of 30 wt% monoethanolamine (MEA) and 20 wt% piperazine (PZ) solvents after conventional heating (CH) and prolonged sonication (75 h) at different frequencies. CH raised temperatures to 108.3°C for MEA (2 h) and 106.9°C for PZ (5 h), causing noticeable colour changes; the sonicated samples displayed a 52–61.6°C maximum temperature without significant colour change. The carbon loading of 360 kHz sonicated MEA (7.13 mol/kg) was similar to the virgin sample (7.89 mol/kg), whereas PZ showed comparable results (5.81 mol/kg sonicated at 25 kHz vs. 5.9 mol/kg virgin). Sonicated MEA and PZ showed minimal reduction in absorption capacity, with pH drop, absorption rates and physical properties similar to those of virgin samples. The hourly solvent loss of the sonicated samples was negligible at 0.004%–0.03%, and the hourly diffusivity loss ranged from 0.01% to 0.06%. The Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy results were promising enough, and bench‐scale trials with circulation absorption and stripping processes are highly recommended. 2025 Society of Chemical Industry and John Wiley & Sons, Ltd.