MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing, 100083, China; Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, Beijing, 100083, China; Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
Chemosphere. 2022 Mar;291(Pt 2):132882. doi: 10.1016/j.chemosphere.2021.132882. Epub 2021 Nov 12.
Wood is rich in extractives and volatile oils that emit unpleasant odors and some harmful volatile organic compounds (VOCs). Chemical oxidation technologies processes high efficiency on the destruction of aqueous organic components via oxidation by radicals, however, wood block treatment scenarios suffer from the low availability of radicals in aqueous conditions owing to the special structure of the wood blocks, limitations of mass transfer and the short life of free radicals. Herein, ethylenediaminetetraacetic acid (EDTA) is selected as a chelating agent to synthesize EDTA-Fe chelate, thus introducing Fe into the wood by vacuum impregnation. The Fe is evenly distributed and immobilized in the wood to form a chemical oxidation system via in-situ activation of the dual oxidant (HO-PS), which truncates the contact distance between free radicals and extractives/volatile oils thus enhancing the removal efficiency. Various controlling factors, including EDTA/Fe molar ratio, Fedosage, PS/HO molar ratio, and persulfate (PS) dosage are evaluated. The degradation products of VOCs by headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) indicate that the wood VOC removal rate is ∼80%. The Electron paramagnetic resonance (EPR) analysis further reveals that SO· and ·OH are the primary reactive species. The characterization of wood properties illustrates that the process has no destructive effect. The results of this work may provide a theoretical basis for feasibility of the practical application of the EDTA-Fe/HO-PS system.
木材富含抽提物和挥发性油，会散发出难闻的气味和一些有害的挥发性有机化合物 (VOCs)。化学氧化技术通过自由基氧化对水相有机成分的破坏具有高效率，然而，由于木材块的特殊结构、传质限制和自由基的短寿命，木材块处理方案中自由基的可用性较低。在此，选择乙二胺四乙酸 (EDTA) 作为螯合剂来合成 EDTA-Fe 配合物，从而通过真空浸渍将 Fe 引入木材中。Fe 均匀分布并固定在木材中，通过原位激活双氧化剂 (HO-PS) 形成化学氧化体系，从而缩短自由基与抽提物/挥发性油之间的接触距离，提高去除效率。评估了各种控制因素，包括 EDTA/Fe 摩尔比、Fedosage、PS/HO 摩尔比和过硫酸盐 (PS) 用量。通过顶空固相微萃取结合气相色谱-质谱法 (HS-SPME/GC-MS) 对 VOCs 的降解产物进行分析，表明木材 VOC 去除率约为 80%。电子顺磁共振 (EPR) 分析进一步表明，SO·和·OH 是主要的反应性物质。木材性能的表征表明该工艺没有破坏性影响。这项工作的结果可能为 EDTA-Fe/HO-PS 系统实际应用的可行性提供理论依据。
