CAS Key Laboratory of Mineralogy and Metallogeny, Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (CAS), Guangzhou, 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, 510640, China.
CAS Key Laboratory of Mineralogy and Metallogeny, Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (CAS), Guangzhou, 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Chemosphere. 2022 Jan;287(Pt 1):131933. doi: 10.1016/j.chemosphere.2021.131933. Epub 2021 Aug 19.
As the heterogeneous Fenton reactions are always restricted by the unsatisfied reduction efficiency of Fe(III) and ineffective consumption of HO, many strategies have been developed. In this work, we prepared hydrothermal carbons (HTC) with different graphitization degrees using glucose under different hydrothermal times, and then they were combined with ferrihydrite (Fh). Interestingly, although 30%HTC/Fh has much better BPA degradation efficiency than Fh (26 times larger of calculated degradation rate constants), the decomposition rate of HO in the former system is lower. The generated Fe(II) of HTC/Fh is much higher than that of Fh during the heterogeneous Fenton reactions, and the degradation of BPA is almost unaffected by p-benzoquinone (scavenger of superoxide radicals (O)) while greatly inhibited by isopropanol (scavenger of hydroxyl radicals (HO)). These results indicate that HTC act as electron donors due to the abundant carbon-centered persistent free radicals (PFRs) to directly reduce Fe(III) to Fe(II) and therefore decrease the HO consumption by Fe(III), which subsequently inhibits the generation of less active O and promote the utilization efficiency of HO. HTC with a low graphitization degree contain more PFRs for Fe(III) reducing, significantly enhancing the Fenton catalytic activity of Fh.
由于非均相 Fenton 反应一直受到 Fe(III)还原效率不高和 HO 消耗效果不佳的限制，因此开发了许多策略。在这项工作中，我们使用葡萄糖在不同的水热时间下制备了具有不同石墨化程度的水热碳（HTC），然后将它们与水铁矿（Fh）结合。有趣的是，尽管 30%HTC/Fh 的 BPA 降解效率比 Fh 高得多（计算降解速率常数大 26 倍），但前者体系中 HO 的分解速率较低。在非均相 Fenton 反应中，HTC/Fh 产生的 Fe(II)比 Fh 多得多，BPA 的降解几乎不受对苯醌（超氧自由基 (O) 的清除剂）的影响，但被异丙醇（羟基自由基 (HO) 的清除剂）大大抑制。这些结果表明，由于富含碳中心的持久自由基（PFRs），HTC 充当电子供体，可直接将 Fe(III)还原为 Fe(II)，从而减少 Fe(III)对 HO 的消耗，从而抑制了活性较低的 O 的生成并促进了 HO 的利用效率。石墨化程度较低的 HTC 含有更多的 PFRs 来还原 Fe(III)，显著提高了 Fh 的 Fenton 催化活性。
