Guo Liu, Nie Ziqiu, Wen Lijia, Chen Bohan, Tang Jie, Gao Man, Chen Jiajing, Liu Jingjing
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & Water Pollution, Chengdu University of Technology, Chengdu 610059, China; College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.
College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.
Sci Total Environ. 2023 Dec 1;902:165883. doi: 10.1016/j.scitotenv.2023.165883. Epub 2023 Jul 28.
In-situ chemical oxidation based on sodium percarbonate (SPC) has received much attention for remediation of groundwater contaminated with organic pollutants due to the high efficiency, stable reaction, and sustainability of SPC. Currently, metal ions and their composite materials, are mainly employed for the activation of SPC. However, due to its narrow pH range, slow Fe/Fe circulation, and generation of refractory sludge, its application in groundwater is limited. In this study, SPC was activated with natural pyrite (FeS) to remove tetracycline, which was selected as the target pollutant. FeS exhibited excellent catalytic activity and stability towards the degradation of tetracycline. The tetracycline degradation efficiency of SPC/FeS system reached 70 % within 10 min, and nearly half of the tetracycline was degraded in the first 5 min of the reaction. The optimum SPC dosage for the tetracycline removal was 8 mM, with FeS dosage of 0.5 g/L. The tetracycline removal efficiency remained above 60 % after 4 cycles, indicating its good recycling efficiency of the system. SPC/FeS system was not significantly affected by the initial pH or the presence of Cl, SO, NO while, HCO, Ca, Mg, and humid acid suppressed the reaction. The electron paramagnetic resonance spectroscopy and quenching experiments demonstrated that OH and O played a dominant role in tetracycline removal by the system. S, as an electron donor, was able to participate in the Fe/Fe cycle. In addition, the 13 transformation products were determined by liquid chromatography-mass spectrometry predicted that the degradation pathway of tetracycline consisted of hydroxylation, demethylation, and decarbonylation reactions. Finally, the dynamic simulation experiments of SPC/FeS sand column showed that FeS effectively activated SPC and significantly reduced the toxicity in groundwater after the packed column treatment. This study reveals that FeS can efficiently activate SPC and has good prospects for tetracycline-contaminated groundwater remediation applications.
基于过碳酸钠（SPC）的原位化学氧化法因其高效、反应稳定和可持续性，在修复受有机污染物污染的地下水方面备受关注。目前，金属离子及其复合材料主要用于活化SPC。然而，由于其pH范围窄、铁/铁循环缓慢以及产生难处理的污泥，其在地下水中的应用受到限制。在本研究中，天然黄铁矿（FeS）被用于活化SPC以去除四环素，四环素被选为目标污染物。FeS对四环素的降解表现出优异的催化活性和稳定性。SPC/FeS体系对四环素的降解效率在10分钟内达到70%，且在反应的前5分钟内近一半的四环素被降解。去除四环素的最佳SPC用量为8 mM，FeS用量为0.5 g/L。经过4个循环后，四环素去除效率仍保持在60%以上，表明该体系具有良好的循环利用效率。SPC/FeS体系不受初始pH值或Cl、SO、NO的存在的显著影响，而HCO、Ca、Mg和腐殖酸会抑制反应。电子顺磁共振光谱和猝灭实验表明，·OH和O在该体系去除四环素过程中起主导作用。S作为电子供体，能够参与铁/铁循环。此外，通过液相色谱-质谱法确定了13种转化产物，预测四环素的降解途径包括羟基化、脱甲基化和脱羰基反应。最后，SPC/FeS砂柱的动态模拟实验表明，FeS有效地活化了SPC，并且在填充柱处理后显著降低了地下水中的毒性。本研究表明，FeS能够高效活化SPC，在修复受四环素污染的地下水方面具有良好的应用前景。
