Permeable Reactive Concrete For Enhanced Heavy Metal Removal With Optimization Of Individual Components

Catastrophic release of heavy metals in Colorado, U.S or Minas Gerais, Brazil exposed the importance heavy metal contamination have on the surrounding peoples and environment. Permeable reactive barriers (PRBs) are an effective method of remediation the use a reactive media to passively remove contaminates. This research primarily investigated the use of permeable reactive concrete (PRC), a new category of PRBs. In the initial phase, PRCs were made with high carbon or high sulfur fly ashes to ascertain the capabilities and determine a preliminary capacity for removal of lead, cadmium, and zinc. Secondly, aggregate sources for PRC were further studied to evaluate bulk compositional influences on removal, and indirectly, explore some fundamental mechanisms driving removal. Batch reactor testing was conducted to measure removal and leachability of metals over the range of typical field concentrations. Removal ranged from 30-100% and leach testing confirmed a high level of permanency for metals removed by the PRC matrix. Scanning electron microscopy was performed to inspect and qualitatively measure precipitates from solution and on the surface of fractured concrete pieces. A variety of multimodal, simultaneous, processes appear to cause removal of metals from solution. Cementitious materials play a large role in removal, especially fly ash with high carbon or sulfur, while aggregate does not. However, calcareous-sourced aggregate was shown to improve removal and increases permanency. Freundlich adsorption isotherms were generated for each mixture and indicated favorable sorption mechanisms for all PRC mixtures tested. An example remediation scenario, using these isotherms, was conducted on a historical mine tailings waste site in Joplin, Missouri. In this scenario high carbon and sulfur fly ash had the most economical removal, followed by aggregate alone, and lastly traditional portland cement PRC. These results suggest permeable reactive concrete to be a novel and effective remediation technique, especially when considering potential valorization of high sulfur or high carbon fly ash.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Civil Engineering (UMKC)

Grantor dc:publisher

University of Missouri--Kansas City

Year dc:date.issued

2016

Author dc:creator

• Holmes, Ryan Rodrick

Advisor dc:contributor.advisor

• Hart, Megan Leanore, 1976-

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10355/61360

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/61360