ISSN 1000-3665 CN 11-2202/P

    硫磺强化高氯酸盐衰减的柱试验研究

    Column experiments study on attenuation of perchlorate stimulated by sulfur

    • 摘要: 高氯酸盐(\mathrmClO_4^- )是一种新的持久性污染物,其分子量小、扩散快、稳定性高,普遍存在于环境中,特别是在烟花生产和燃放较为密集的地区检出浓度较高。\mathrmClO_4^- 会干扰人体甲状腺的正常功能,因此其环境污染问题引起了广泛关注,成为了近年来环境科学领域的研究热点。针对硫磺强化\mathrmClO_4^- 衰减的作用机制和影响因素研究不足的问题,选取污染场地的天然河沙为试验介质,通过柱试验对硫磺强化\mathrmClO_4^- 衰减的过程进行研究,考察了铁及铁氧化物、地下水基质、硝酸盐(\mathrmNO_3^- )对硫磺强化\mathrmClO_4^- 衰减过程的影响。结果表明,硫磺具有强化\mathrmClO_4^- 衰减的能力,衰减过程主要由微生物驱动,其限制因素主要为微生物必要的无机盐等营养物质;铁及铁氧化物对体系内pH值的降低起到缓冲作用,但对体系内\mathrmClO_4^- 衰减的促进作用有限;地下水基质显著提升了硫磺强化\mathrmClO_4^- 衰减的能力,提升了微生物的产酸作用;地下水中\mathrmNO_3^- 的降解优先于\mathrmClO_4^- ,当\mathrmNO_3^- 低至10 mg/L以下时,\mathrmClO_4^- 才开始明显的降解。硫磺具备作为渗透反应格栅(PRB)的反应介质原位修复\mathrmClO_4^- 、\mathrmNO_3^- 等污染物的潜力。本研究为环境修复中的实际应用提供理论依据和数据支持。

       

      Abstract: Perchlorate (\mathrmClO_4^- ) is a new persistent pollutant with small molecular weight, rapid diffusion, and high stability. It is widely found in the environment, especially in the areas where fireworks are produced and set off intensively. Perchlorate impacts the normal function of thyroid gland; its environmental pollution attracted wide attention and has become a research hotspot in the field of environmental science in recent years. Column experiments using river sand from polluted site as the experiment material were conducted to study on the mechanism and influencing factors of the attenuation of perchlorate stimulated by sulfur. The effects of groundwater, iron oxides, and nitrate (\mathrmNO_3^- ) were investigated in this study. The results show that sulfur is able to stimulate \mathrmClO_4^- attenuation, which mainly depends on microbial degradation, and it is limited by the lack of essential inorganic salts and other nutrients for microorganisms. Iron oxides have a buffering effect on the decrease of pH, but have a limited stimulating effect on the \mathrmClO_4^- attenuation in the column. Groundwater significantly enhanced sulfur-stimulated \mathrmClO_4^- attenuation and microbial acid production. The degradation of nitrate (\mathrmNO_3^- ) in groundwater is preferred to that of \mathrmClO_4^- ; when \mathrmNO_3^- concentration is less than about 10 mg/L, \mathrmClO_4^- begins to be reducted significantly. Sulfur has the potential as the PRB reaction medium for in-situ remediation of pollutants such as \mathrmClO_4^- and \mathrmNO_3^- . This study provides a theoretical basis and data support for the practical application of environmental remediation.

       

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