State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
J Hazard Mater. 2021 Apr 15;408:124454. doi: 10.1016/j.jhazmat.2020.124454. Epub 2020 Nov 2.
Sludge-derived biochar (SDBC) has been regarded as persulfate (PS) activator during the remediation of organic contamination. However, the complexity of sludge composition makes it difficult to predict the activity of SDBC and the efficacy of PS. To improve the understanding of how the composition of sludge regulated activity of its parent SDBC towards PS activation, we used two SDBCs derived from different sludges with significantly different organic compositions and metals. Results indicated the higher content of organic and nitrogen content in sludge led to higher polymerization and condensation of carbon layer and more moieties in SDBC1, whereas more Fe species (e.g. Fe-O, Fe and Fe) formed in SDBC2. According to the results of phenol (PN) degradation in SDBC/PS, the apparent rate constants (k) of SDBC2-700 (0.0037 min) was 2 folds higher than that of SDBC1-700 (0.0016 min), whereas the SDBC1-500 (6.0 ×10 min) exhibited higher k than that of SDBC2-500 (4.9 ×10 min). The difference of PS activation by different SDBCs mainly relied on generated reactive oxygen species (ROS). The persistent free radicals (PFRs) and Fe species acted as redox sites for generated ROS, which were depended on the organic compositions and involved metals in used sludges.
污泥衍生生物炭 (SDBC) 在有机污染修复中被视为过硫酸盐 (PS) 的活化剂。然而，污泥组成的复杂性使得难以预测 SDBC 的活性和 PS 的功效。为了提高对污泥组成如何调节其母体 SDBC 对 PS 活化活性的理解，我们使用了两种源自具有明显不同有机成分和金属的污泥的 SDBC。结果表明，污泥中较高的有机和氮含量导致 SDBC1 中碳层的聚合和缩合以及更多基团的形成，而 SDBC2 中则形成了更多的 Fe 物种（例如 Fe-O、Fe 和 Fe）。根据 SDBC/PS 中苯酚 (PN) 的降解结果，SDBC2-700（0.0037 min）的表观速率常数（k）比 SDBC1-700（0.0016 min）高 2 倍，而 SDBC1-500（6.0×10 min）的 k 比 SDBC2-500（4.9×10 min）高。不同 SDBC 对 PS 的活化差异主要依赖于生成的活性氧物种 (ROS)。持久自由基 (PFR) 和 Fe 物种作为生成 ROS 的氧化还原位点，这取决于所用污泥中的有机成分和涉及的金属。
