RAPID: Investigating changes to metal oxide nanoparticle stability in a contaminated stream during the initial period of remediation

RAPID：研究修复初期污染流中金属氧化物纳米粒子稳定性的变化

• 批准号: 1736102
• 负责人: James Ranville
• 金额: $ 5万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736102&HistoricalAwards=false
• 关键词: RAPID; Investigating; changes; metal; oxide

There are known impacts to streams in the United States as a result of pollution from abandoned mines. Even after the impact of the acidic mine effluents are removed by treatment, the streambeds themselves will continue to release metals that are toxic to aquatic species. The metal-containing sediments must be naturally removed in order for the stream to recover and allow both restoration of aquatic life and beneficial use by society. The sediments consist primarily of very small nanoparticles of iron oxide that can contain As, Cd, Cu, Pb, and Zn. These small particles, which have stuck to the streambed, may be more quickly removed if they become more stable in water due to changes in the chemistry of their surfaces. A treatment plant that removes the metals and acid from the mine effluents has just begun operation. The treatment process also alters the composition of the stream water in such a way that the particles may become more stable in water and, thus, removed more quickly. This study will provide data that will lead to better estimates of how quickly other streams will recover if similar mine waste treatment is performed. Incidental nanoparticulate iron oxides (NP-FeOx) are formed in streams receiving acidic mine waters. NP-FeOx is capable of transporting contaminant metals such as Cu, Zn, and As. In early 2017 a lime treatment plant will go online in the North Fork of Clear Creek (NFCC), which will dramatically alter the water chemistry of the stream. The colloidal stability of NP-FeOX is dependent on solution composition (ionic strength, divalent cations, pH, DOC) and is thus likely to be affected. The project goal is to understand how the removal of metals will be influenced by changes in the stability of the NP-FeOx. In order to determine the immediate impact of the water treatment plant (WTP) on NP-FeOx stability in the water column, the dispersion of existing NP-FeOx contained in the streambed will be studied using spICP-MS, DLS, zeta potential, and ICP-OES. It is expected that preexisting NP-FeOX will disperse from the creek bed into the water during early WTP operation, which may result in a temporary increase in toxic metal concentrations. This will be of long-term benefit, as this process may accelerate the restoration of the streambed. This is the first time that nanoparticle stability under variable water chemistry conditions has been examined in an actual stream setting. Additionally, the manipulation of pH and hardness in laboratory experiments will allow us to understand the effects of isolated water chemistry variables on particle dispersion in an AMD system. A summer field session aimed at local high school students and college seniors at the Colorado School of Mines will participate in a field session at the study site. In addition, a partnership with the Upper Clear Creek Watershed Foundation will be forged to involve community volunteers on the proposed project.

由于废弃矿山的污染，美国对流的溪流产生了已知影响。 即使通过治疗去除酸性矿物废物的影响，溪流床本身也将继续释放对水生物种有毒的金属。 必须自然去除含金属的沉积物，以使流恢复并恢复水生生物和社会的有益用途。 沉积物主要由非常小的氧化铁纳米颗粒组成，可以含有Cd，Cu，Pb和Zn。这些粘在流床上的小颗粒，如果由于表面的化学变化而在水中变得更稳定，则可能会更快地去除它们。 从矿山废水中去除金属和酸的处理厂刚刚开始运行。 处理过程还改变了溪流的组成，使颗粒可能在水中变得更稳定，因此更快地去除了颗粒。这项研究将提供数据，从而更好地估计，如果执行类似的矿山废物处理，其他流的速度将如何恢复。 偶然的纳米氧化铁（NP-FEOX）在接收酸性矿水的溪流中形成。 NP-Feox能够运输污染物，例如Cu，Zn和As。 2017年初，石灰处理厂将在Clear Creek（NFCC）的北叉上网，该厂将极大地改变溪流的水化学。 NP-FEOX的胶体稳定性取决于溶液组成（离子强度，二价阳离子，pH，DOC），因此可能受到影响。 项目目标是了解如何将金属的去除受到NP-FEOX稳定性的变化的影响。 为了确定水柱中水处理厂（WTP）对NP-FEOX稳定性的直接影响，将使用SPICP-MS，DLS，ZETA电位和ICP-OES研究流床中现有的NP-FEOX的分散。可以预期，在WTP早期运行期间，先前存在的NP-Feox将从小溪床分散到水中，这可能导致有毒金属浓度暂时增加。 这将是长期的好处，因为此过程可能会加速流床的恢复。 这是在可变水化学条件下首次在实际流环境中检查纳米颗粒稳定性。 此外，在实验室实验中对pH值和硬度的操纵将使我们能够理解孤立的水化学变量对AMD系统中颗粒分散的影响。 针对科罗拉多州矿业学院的当地高中生和大学生的夏季野外课程将参加研究地点的一次野外课程。此外，与上级溪流流域基金会建立合作伙伴关系将使社区志愿者参与拟议项目。