College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
J Hazard Mater. 2023 Mar 5;445:130589. doi: 10.1016/j.jhazmat.2022.130589. Epub 2022 Dec 14.
Over 3000 mercury (Hg)-contaminated sites worldwide contain liquid metallic Hg [Hg(0)] representing a continuous source of elemental Hg(0) in the environment through volatilization and solubilization in water. Currently, there are few effective treatment technologies available to remove or sequester Hg(0) in situ. We investigated sonochemical treatments coupled with complexing agents, polysulfide and sulfide, in oxidizing Hg(0) and stabilizing Hg in water, soil and quartz sand. Results indicate that sonication is highly effective in breaking up and oxidizing liquid Hg(0) beads via acoustic cavitation, particularly in the presence of polysulfide. Without complexing agents, sonication caused only minor oxidation of Hg(0) but increased headspace gaseous Hg(0) and dissolved Hg(0) in water. However, the presence of polysulfide essentially stopped Hg(0) volatilization and solubilization. As a charged polymer, polysulfide was more effective than sulfide in oxidizing Hg(0) and subsequently stabilizing the precipitated metacinnabar (β-HgS) nanocrystals. Sonochemical treatments with sulfide yielded incomplete oxidation of Hg(0), likely resulting from the formation of HgS coatings on the dispersed µm-size Hg(0) bead surfaces. Sonication with polysulfide also resulted in rapid oxidation of Hg(0) and precipitation of HgS in quartz sand and in the Hg(0)-contaminated soil. This research indicates that sonochemical treatment with polysulfide could be an effective means in rapidly converting Hg(0) to insoluble HgS precipitates in water and sediments, thereby preventing its further emission and release to the environment. We suggest that future studies are performed to confirm its technical feasibility and treatment efficacy for remediation applications.
全世界有超过 3000 个受汞（Hg）污染的地点，其中含有液态金属汞 [Hg(0)]，通过挥发和在水中溶解而成为环境中元素汞（Hg(0)）的连续来源。目前，可用的去除或固定原位 Hg(0)的有效处理技术很少。我们研究了超声化学处理与络合剂、多硫化物和硫化物结合，以氧化水中、土壤中和石英砂中的 Hg(0)并稳定 Hg。结果表明，通过声空化，超声处理非常有效地打破和氧化液态 Hg(0)珠，特别是在多硫化物存在的情况下。没有络合剂时，超声处理仅导致 Hg(0)的轻微氧化，但增加了气相中 Hg(0)和水中溶解的 Hg(0)。然而，多硫化物的存在基本上阻止了 Hg(0)的挥发和溶解。作为一种带电聚合物，多硫化物比硫化物更有效地氧化 Hg(0)，并随后稳定沉淀的辰砂（β-HgS）纳米晶体。用硫化物进行超声化学处理导致 Hg(0)不完全氧化，这可能是由于分散的 µm 尺寸 Hg(0)珠表面上形成了 HgS 涂层所致。用多硫化物进行超声处理也导致 Hg(0)在石英砂和 Hg(0)污染的土壤中迅速氧化和 HgS 的沉淀。这项研究表明，用多硫化物进行超声化学处理可能是一种有效手段，可以迅速将 Hg(0)转化为水中和沉积物中的不溶性 HgS 沉淀物，从而防止其进一步排放和释放到环境中。我们建议进行未来的研究，以确认其在修复应用中的技术可行性和处理效果。
