Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants
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University of Toledo / OhioLINK
2011
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=toledo1301937693 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-toledo13019376932021-08-03T06:07:48Z Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants Messner, Clint Andrew Civil Engineering Engineering active sediment capping contaminants <p>Contaminated sediment management represents one of the most challenging contaminated site issues facing freshwater and estuarine coastal environments due to the large volumes (several million cubic yards in the US annually), the wide range in contaminants and their concentrations, and the need to minimize exposure pathways. Removal technologies, when applied alone, can be limited by high costs, minimal access to some sites, possible ecological risks posed to aquatic species, and increasingly limited disposal options. In most cases, sediment remediation and restoration is best accomplished using a combination of both removal and in place technologies. This research focuses on sediment capping, an in place technology.</p> <p>Traditionally caps have been mainly composed of granular materials, such as sand, because they are readily available and distinguishable from contaminated sediments. More recently, active capping materials have been selected since sediment contaminants may vary widely and may include heavy metals, persistent organic compounds (e.g., pesticides, PCBs), and nutrients. It is difficult to deliver active materials in sand since the components tend to separate. The main objective of this ongoing research is to do a comparative study of the efficacy of active capping materials (e.g., activated carbon and chemisorptive media) when delivered alone or in combination using clay minerals as a binder.</p> <p>Active capping materials are being synthesized by amending clay minerals (e.g. sodium bentonite and organoclay) with selected active materials (approx 5% by weight) including activated carbon and chemisorptive media. Shake tests were performed at 20°C in the dark for 7 days on a shaker table on sediments contaminated with heavy metals. Approximately 2mg/L of Hg, As, Se, and Pb were spiked into freshwater (laboratory grade water with 0.1%HNO3) and salt water (Instant Ocean® + laboratory grade water + 0.1%HNO3). Treatment efficacy was determined by calculating the sorption affinity (percent removal) and distribution coefficient (Kd) values of the various materials selected for testing alone and in combination with clay minerals. The chemisorptive media performed the best at removing all metals (~100%) except Pb (<30%) and performed almost as well when combined with sodium bentonite. The organoclay alone and in combination with powder activated carbon (PAC) was most effective at sequestering Pb (~40%). Similar experiments were repeated for each amendment to determine their ability to sequester the following polycyclic aromatic hydrocarbons (PAHs): phenanthrene and pyrene (~100 µg/L). Shake tests were performed at 20°C in the dark for 48 hours and the solution was then extracted with Methylene Chloride after centrifugation. PAC performed the best in both the fresh water and salt water environments. PAC had adsorbed a greater amount of phenanthrene and pyrene in the salt water environment.</p> <p>It is imperative that sediment remediation approaches be adaptable and proficient at addressing a wide variety of sediment contaminants. This research will support the development of an active capping material which will target the sequestration or destruction of specific sediment contaminants including heavy metals, nutrients, and pesticides allowing broader application of the product.</p> 2011-05-22 English text University of Toledo / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=toledo1301937693 http://rave.ohiolink.edu/etdc/view?acc_num=toledo1301937693 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Civil Engineering Engineering active sediment capping contaminants |
| spellingShingle |
Civil Engineering Engineering active sediment capping contaminants Messner, Clint Andrew Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| author |
Messner, Clint Andrew |
| author_facet |
Messner, Clint Andrew |
| author_sort |
Messner, Clint Andrew |
| title |
Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| title_short |
Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| title_full |
Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| title_fullStr |
Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| title_full_unstemmed |
Investigating the Performance of Active materials Amended to Clay Minerals for Sequestering Sediment Contaminants |
| title_sort |
investigating the performance of active materials amended to clay minerals for sequestering sediment contaminants |
| publisher |
University of Toledo / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1301937693 |
| work_keys_str_mv |
AT messnerclintandrew investigatingtheperformanceofactivematerialsamendedtoclaymineralsforsequesteringsedimentcontaminants |
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1719431408220372992 |