Ultrasound activation of PS/H2O2 dual oxidants synergistically enhances porosity and wettability of poplar wood

Abstract

Inherent extractive occlusion and underdeveloped pore networks severely restrict the permeability and high-value utilization of fast-growing poplar wood. This study aimed to achieve precise pore structure regulation by constructing an ultrasound-activated persulfate-hydrogen peroxide (PS/H₂O₂) dual oxidant system. The effects of PS/H₂O₂ molar ratios (9:1, 7:3, 5:5) and ultrasonic power levels (100–400 W) on the porosity, specific surface area, wettability, and microstructure of poplar wood were systematically investigated. Characterization was performed using mercury intrusion porosimetry (MIP), Brunauer-Emmett-Teller (BET) analysis, contact angle measurements, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Results showed that the synergistic effect of ultrasonic cavitation and dual radicals (SO₄·^–and ·OH) achieved optimal pore modification under the conditions of PS: H₂O₂ molar ratio 7:3 and ultrasonic power 400 W. The cumulative pore volume of poplar wood reached 2.82 mL/g, representing a 102% increase compared with the untreated sample, accompanied by a specific surface area of 1.2784 m²/g and a median pore diameter of 0.8262 nm. Meanwhile, the contact angle decreased from 96° to 74.9°, indicating significantly enhanced surface wettability. FT-IR and XRD analyses confirmed that the treatment only caused slight degradation of the main wood components, effectively maintaining the structural integrity of the cell wall. This study demonstrates that the ultrasound-activated PS/H₂O₂ dual oxidant system provides a mild and efficient technical approach for improving the pore structure of fast-growing wood, which is expected to promote its application in functional modification and bio-based material fields.