State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, P. R. China.
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China.
Environ Sci Technol. 2021 Jun 1;55(11):7690-7701. doi: 10.1021/acs.est.1c01882. Epub 2021 May 17.
Persulfate (PS) activation on biochar (BC) is a promising technology for degrading the aqueous organic contaminants. However, the complexity of activation mechanisms and components in biomass that used to produce BC makes it difficult to predict the performance of PS activation. In this study, we employed eight sludges as the representative biomass that contained absolutely different organic or inorganic components. Results showed that the elemental composition, surface properties, and structures of the sludge-derived BCs (SBCs) clearly depended on the inherent components in the sludges. The intensities of persistent free radicals (PFRs) in the electron paramagnetic resonance (EPR) correlated positively with N-containing content of sludges as electron shuttle, but negatively with the metal content as electron acceptor. Linking with PFRs as crucial sites of triggering a radical reaction, a poly-parameter relationship of predicting PS activation for organic degradation using the sludge components was established ( = 0.004 × + 0.16 × -0.118). However, for the PS activation on those SBCs without PFRs, this redox process only relied on the sorption or conductivity-related characteristics, not correlating with the content of intrinsic components in biomass but with pyrolysis temperatures. This study provided insightful information of predicting the remediation efficiency of PS activation on BCs and further understanding the fate of contaminants and stoichiometric efficiency of oxidants in a field application.
过硫酸盐（PS）在生物炭（BC）上的活化是降解水中有机污染物的一种很有前途的技术。然而，用于生产 BC 的生物质中的活化机制和成分的复杂性使得很难预测 PS 活化的性能。在这项研究中，我们使用了八种污泥作为代表性生物质，它们含有完全不同的有机或无机成分。结果表明，污泥衍生生物炭（SBC）的元素组成、表面性质和结构明显取决于污泥中的固有成分。电子顺磁共振（EPR）中持久自由基（PFRs）的强度与作为电子穿梭体的污泥中的含氮含量呈正相关，与作为电子受体的金属含量呈负相关。与 PFRs 作为引发自由基反应的关键位点相关联，建立了使用污泥成分预测 PS 用于有机降解的活化的多参数关系（ = 0.004 × + 0.16 × -0.118）。然而，对于那些没有 PFRs 的 SBC 上的 PS 活化，这个氧化还原过程仅依赖于吸附或导电性相关的特性，与生物质中的固有成分含量无关，而与热解温度有关。本研究为预测 PS 在 BC 上的修复效率提供了有见地的信息，并进一步了解了污染物的命运和氧化剂在野外应用中的化学计量效率。
