碳包裹纳米零价铁活化过硫酸盐降解土壤中苯并(a)蒽的活性物种及生成途径

Activated species and generation pathways of Benzo(a)anthracene in soil degradation by carbon encapsulated nano zero valent-iron activated persulfate

纳米零价铁(nZVI)用作过硫酸盐(PS)活化剂具有高活性和长持久性等优势,而其易团聚和钝化的问题极大地限制了其在土壤污染治理修复中的应用.本研究采用水热法和碳热还原法制备了一种具有抗氧化特性的碳包裹纳米零价铁复合材料(nZVI@C),并与过硫酸盐联合降解土壤中苯并(a)蒽.结果表明,反应48 h,土壤中苯并(a)蒽的去除率达到88.7%,显著高于nZVI活化过硫酸盐的效果(48.3%).电子顺磁共振谱证实了nZVI@C活化过硫酸盐的过程中同时产生了SO_(4)^(·-)、HO^(·)、O_(2)^(·-)和^(1)O_(2),自由基猝灭实验进一步表明HO^(·)和SO_(4)^(·)-在苯并(a)蒽的降解过程发挥了主要作用.研究结果可为深入理解该技术体系的机制,推动其在土壤修复中的应用与发展提供支撑.

Nano zero valent iron(nZVI)as a persulfate(PS)activator has advantages of high activity and long persistence,but its easy aggregation and passivation greatly limit its application in soil remediation.To tackle these problem,the preparation of carbon encapsulated nano zero-valent iron(nZVI@C)was carried out by hydrothermal and carbon thermal reduction methods,which combines with PS to degrade benzo(a)anthracene(BaA)in soil.The results demonstrated that the removal rate of BaA reached 88.7%,significantly higher than that of nZVI system(48.3%)after 48 hours.Electron paramagnetic resonance spectroscopy confirmed the simultaneous generation of SO_(4)^(·-),HO^(·),O_(2)^(·-)and^(1)O_(2) during the activation of PS by nZVI@C.Free radical quenching experiments further verified that HO^(·)and SO_(4)^(·)−played a major role in the degradation process of BaA.Together,these research results can provide support for a deeper understanding of the mechanism of this technology system and promoting its application and development in soil remediation.