Concept of copper mobility and compatibility with lead and cadmium in landfill liners
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：Saleh Kaoser.
- 分类号：a484 ; a875.4
- ISBN：0612982866(ebk.) :
MARC全文
02h0029750 20120628143201.0 cr un||||||||| 120628s2004 xx ||||f|||d||||||||eng | NQ98286 0612982866(ebk.) : CNY371.35 NGL NGL NGL a484 ; a875.4 Kaoser, Saleh. Concept of copper mobility and compatibility with lead and cadmium in landfill liners [electronic resource] / Saleh Kaoser. 2004. 1 v. : digital, PDF file. Adviser: Barrington, Suzelle. Thesis (Ph.D.)--McGill University (Canada), 2004. Despite improved liner design, there are still reported incidences of landfill leachate, rich in heavy metals, percolating through to groundwater and threatening ecosystems. This thesis introduces the concept of segregating municipal solid wastes MSW) according to their major heavy metals and their metals adsorption compatibility. Each segregated portion can be disposed in a different landfill compartment to minimize leaching of these heavy metals with the greatest bioactive impact. The validity of the concept was evaluated by batch and column retention mobility studies using copper Cu) alone or with either lead Pb) or cadmium Cd) in solutions bearing various pHs. This was supported by selective sequential extraction SSE) to determine the affinity to specific liner fractions. The following summarizes the procedure used. Beforehand, a soil column test using sand with 5 and 10% bentonite was conducted to develop an equation predicting liner permeability, k , under simulated field conditions. The column permeability test revealed that a liner with 5% bentonite resulted in a k value which respected the North American criteria of 10-5 m/s. In the batch experiments, solutions with Cu alone or with Cd or Pb, adjusted to pH of 3.7, 5.5 or 7.5, were applied to sand liners with 0%, 5% or 10% bentonite, having CECs of 2.0, 6.4, and 10.8 cmol＋) kg-1 ), respectively. Bentonite, pH and Pb significantly affected Cu adsorption. Cu was adsorbed by the liners at pH <；6.5 whereas Cu precipitated at pH ＞6.5. Cu retention was higher in the presence of Cd than in that of Pb, at all combinations of CEC and pH. Competition between metals was greater in liners with lower CEC and therefore fewer adsorption sites. Limiting Pb in a landfill compartment can improve Cu adsorption at pHs below the precipitating threshold. In the SSE procedure, the liner samples were centrifuged, decanted from their solutions and each adsorption fraction analyzed for Cu content. Results indicated that the carbonate fraction adsorbed more Cu, and that Pb significantly increased the mobility of Cu due to competition for exchangeable sites. In the final soil column test using a sand liner with 5% bentonite, the leachate had an initial pH of 3.7. The leaching test confirmed the compatibility of Cu with Cd. The leaching of Cu was greater in the presence of Pb. Total metals in leachate was greater for the Cu-Cd solutions than for the Cu-Pb, because of Cds relatively high mobility. The sequential extraction results showed again that the carbonate fraction dominated metal adsorption. Total heavy metal leaching followed the order of Cu/Cd ＞ Cu/Pb ＞ Cu alone. Thus, disposing MSW in landfill compartments based on their heavy metal compatibility can minimize migration of heavy metals. Sanitary landfills ; Sanitary landfills ; Heavy metals Linings. ; Leaching. ; Environmental aspects. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=SI%2bnkPjD074%3d NGL Bs1622 rCNY371.35 ; h1 bs1204