纳米N-C/ZrO2活化过硫酸盐降解苯酚的机理研究

锆基纳米材料具有很好的物理化学稳定性及较高的比表面积，适用于解决传统过渡金属基催化剂活化过硫酸盐时金属浸出等问题.本研究将氯化锆-尿素络合物通过热解法合成了一种氮掺杂碳/氧化锆复合材料（N-C/ZrO₂），用于活化过硫酸盐降解水中苯酚，并采用SEM、XRD、XPS和FTIR技术对N-C/ZrO₂进行表征.结果表明，N-C/ZrO₂催化材料是直径小于50 nm的纳米颗粒，且氮掺杂量为3.6%~4.9%；在pH=6~7的硼酸缓冲体系中，N-C/ZrO₂催化过硫酸盐可在30 min内使水中苯酚（20 mg·L^-1）的降解率达99%，且催化剂具有良好的化学稳定性和可重复利用性.淬灭和电子顺磁共振（EPR）结果表明，在N-C/ZrO₂/PMS体系中，苯酚的降解是以¹O₂为主要氧化物质的非自由基氧化过程.本研究为Zr基纳米材料在活化过硫酸盐降解污染物领域的应用提供了理论基础.

The mechanism on activation of peroxymonosulfate using nano N-C/ZrO2 for phenol degradation

Zirconium-based nanomaterials with high physical and chemical stability and surface area, have emerged as catalyst for persulfate activation with less extraction than that of traditional transition metal catalyst. A nano nitride-doped carbon-zirconia (N-C/ZrO₂) was fabricated via a facile thermal pyrolysis method using zirconium chloride (ZrCl₄) and urea as a zirconia precursor and nitride-carbon source, respectively. The N-C/ZrO₂ was used to catalyze persulfate activation for phenol degradation and its physicochemical properties were exanimated by Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR). The result showed that the as-fabricated N-C/ZrO₂ catalyst with 3.6%~4.9% N-doping and a particle size of <50 nm revealed an excellent catalytic capability with almost removal (99%) of 20 mg·L^-1 phenol in 30 min in borate buffer solution (pH=6~7). Moreover, the N-C/ZrO₂ catalyst exhibited good chemical stability after five successive degradation cycles. The singlet oxygen (¹O₂) as the dominant reactive species in phenol degradation was confirmed by electron paramagnetic resonance spectroscopy (EPR) and scavenger experiments. This study demonstrated that the N-doped Zr-based nanomaterials in activating persulfate can be considered as a promising technology for the removal of aqueous organic contaminant.