Enhancement of Removal of VOCs and Odors from Wood by Microwave-Activated Persulfate

Since traditional methods for removing volatile organic compounds (VOCs) from wood consume large amounts of energy and generate environmental pollution, it is desired to develop a convenient and green treatment method. Oxidation by microwave-activated persulfate (MW-PS) is a promising alternative method that has been used to eliminate VOCs from wood. The penetration of microwave energy can destroy the wood pit membranes and increase VOC emissions. The VOCs are further degraded by ·OH and SO4•–, which are generated via the activation of microwaves. This phenomenon can be detected by the electron paramagnetic resonance spectrometry. The 35 types of main VOCs of natural wood were determined, including alkanes/terpenes, alcohols/ethers, esters, aldehydes/ketones, and others. In the MW-PS system, 23 compounds were removed with an efficiency of 100%. Specifically, as one of the major compounds, the content of alkanes/terpenes was sharply decreased, and no alcohols/ethers and esters were detected. It was found that the optimal conditions of the MW-PS system for the minimum release of VOCs from wood were the microwave power of 462 W, irradiation time of 30 min, and PS dosage of 0.5 mmol/L.