P 掺杂生物炭调控 nZVI 纳米裂纹形成以实现超高效过硫酸盐活化。
P-doped biochar regulates nZVI nanocracks formation for superefficient persulfate activation.
机构信息
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Engineering Center of Environmental Diagnosis and Contamination Remediation, Tianjin 300350, China.
出版信息
J Hazard Mater. 2023 May 15;450:130999. doi: 10.1016/j.jhazmat.2023.130999. Epub 2023 Feb 13.
In this study, a novel P-doped biochar loaded with nano zero-valent iron (nZVI) composite (nZVI@P-BC), with abundant nanocracks from inside to outside in nZVI particles, was designed for ultra-efficient persulfate (PS) activation and gamma-hexachlorocyclohexane (γ-HCH) degradation. Results showed that P-doping treatment significantly enhanced specific surface area, hydrophobicity and adsorption capacity of biochar. Systematic characterizations revealed that the additional electrostatic stress and continuously generated multiple new nucleation sites of P-doped biochar were the main mechanism for the formation of nanocracked structure. nZVI@P-BC with KHPO as P precursor showed superefficient PS activation and γ-HCH degradation, by which 92.6 % of 10 mg/L γ-HCH was removed within 10 min using 1.25 g/L catalyst and 4 mM PS, being 10.5-fold greater than that of without P-doping. Electron spin resonance and radical quenching test showed that •OH and O were the dominant active species, and further revealed that the unique nanocracked nZVI, high adsorption capacity and abundant P sites in nZVI@P-BC enhanced their generation and mediated extra direct surface electron transfer. nZVI@P-BC also exhibited high tolerance to different anions, humic acid and wide pH conditions. This work provides a new strategy and mechanism insight for the rational design of nZVI and diversified application of biochar.
在这项研究中，设计了一种新型的 P 掺杂负载纳米零价铁（nZVI）的生物炭复合材料（nZVI@P-BC），其内部到外部的 nZVI 颗粒中具有丰富的纳米裂纹，用于超高效过硫酸盐（PS）活化和六氯环己烷（γ-HCH）降解。结果表明，P 掺杂处理显著提高了生物炭的比表面积、疏水性和吸附能力。系统的表征揭示了 P 掺杂生物炭额外的静电应力和不断产生的多个新成核点是形成纳米裂纹结构的主要机制。以 KHPO 为 P 前驱体的 nZVI@P-BC 表现出超高效的 PS 活化和 γ-HCH 降解性能，在 1.25 g/L 催化剂和 4 mM PS 条件下，10 mg/L γ-HCH 在 10 min 内去除了 92.6%，比未掺杂 P 时提高了 10.5 倍。电子自旋共振和自由基猝灭试验表明，•OH 和 O 是主要的活性物质，进一步表明独特的纳米裂纹 nZVI、高吸附能力和丰富的 P 位在 nZVI@P-BC 中增强了它们的生成，并介导了额外的直接表面电子转移。nZVI@P-BC 还表现出对不同阴离子、腐殖酸和宽 pH 条件的高耐受性。这项工作为 nZVI 的合理设计和生物炭的多样化应用提供了一种新的策略和机制见解。
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