Environmental Resources Engineering Department, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
Department of Chemical Engineering, School of Engineering, University of Mississippi, MS 38677-1848, USA.
J Environ Sci (China). 2021 Jan;99:267-273. doi: 10.1016/j.jes.2020.06.030. Epub 2020 Jul 17.
Generation of hydroxyl radicals (⋅OH) is the basis of advanced oxidation process (AOP). This study investigates the catalytic activity of microporous carbonaceous structure for in-situ generation of ⋅OH radicals. Biochar (BC) was selected as a representative of carbon materials with a graphitic structure. The work aims at assessing the impact of BC structure on the activation of HO, the reinforcement of the persistent free radicals (PFRs) in BC using heavy metal complexes, and the subsequent AOP. Accordingly, three different biochars (raw, chemically- and physiochemically-activated BCs) were used for adsorption of two metal ions (nickel and lead) and the degradation of phenol (100 mg/L) through AOP. The results demonstrated four outcomes: (1) The structure of carbon material, the identity and the quantity of the metal complexes in the structure play the key roles in the AOP process. (2) the quantity of PFRs on BC significantly increased (by 200%) with structural activation and metal loading. (3) Though the Pb-loaded BC contained a larger quantity of PFRs, Ni-loaded BC exhibited a higher catalytic activity. (4) The degradation efficiency values for phenol by modified biochar in the presence of HO was 80.3%, while the removal efficiency was found to be 17% and 22% in the two control tests, with HO (no BC) and with BC (no HO), respectively. Overall, the work proposes a new approach for dual applications of carbonaceous structures; adsorption of metal ions and treatment of organic contaminants through in-situ chemical oxidation (ISCO).
羟基自由基（·OH）的生成是高级氧化工艺（AOP）的基础。本研究考察了微孔碳质结构对原位生成·OH 自由基的催化活性。生物炭（BC）被选为具有石墨结构的碳材料的代表。这项工作旨在评估 BC 结构对 HO 活化的影响、重金属配合物增强 BC 中持久自由基（PFR）的作用，以及随后的 AOP。因此，使用三种不同的生物炭（原始、化学和物理化学活化的生物炭）通过 AOP 吸附两种金属离子（镍和铅）和降解苯酚（100mg/L）。结果表明有四个结果：（1）碳材料的结构、金属配合物的种类和数量在 AOP 过程中起着关键作用。（2）结构活化和金属负载后，BC 上的 PFR 数量显著增加（增加了 200%）。（3）尽管载 Pb 的 BC 含有更多的 PFR，但载 Ni 的 BC 表现出更高的催化活性。（4）在 HO 存在下，改性生物炭对苯酚的降解效率值为 80.3%，而在 HO（无 BC）和 BC（无 HO）两个对照试验中，去除效率分别为 17%和 22%。总的来说，这项工作提出了一种新的方法，用于碳质结构的双重应用；通过原位化学氧化（ISCO）吸附金属离子和处理有机污染物。
