Comparing the performance of cement and smectite in heavy metals removal from lead contaminated soils
Subject Areas : Heavy metalAmir reza Goodarzi 1 , Hamid reza Akbari 2
1 - Associated Professor, Faculty of Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran. *(Corresponding Author)
2 - MSc, Faculty of Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
Keywords: Lead, Remediation of Contaminated So, Smectite, Cement, Engineering Parameters,
Abstract :
Background and Objective: The continuous accumulation of toxic materials such as heavy metals in soil due to interaction with industrial and domestic wastes has contributed to an extensive health hazards. Therefore, the aims of this study are to evaluate the ability of cement (as a chemical adsorbent) in remediation of contaminated soil and to compre the obtained results by the physical adsorption method through the addition of active smectite clay mineral. Method: To achieve the mentioned objectives, kaolinite soil in the laboratory conditions was contaminated with solutions containing 0 to 1 M concentration of Pb (NO3)2 in 1:10 ratio. Adding different percentages of cement and smectite to each sample, and after equilibrating, changes in pH and concentrations were determined. Tests of hydraulic conductivity (permeability), unconfined compression strength (UCS), toxicity characteristic leaching procedure (TCLP) and SEM were also performed to evaluate the impact of adsorbent type on reduction of the of pollution transportation potential. Findings: The results indicate that at low concentrations of contaminants (up to 50 cmol/kg.soil), the type of absorbent does not have much influence on the heavy metals removal from contaminated soils. It was found that with the increase of the pollutant concentration and due to the buffering capacity reduction and the restructed clay mineral, the possibility of soil remediation through the physical absorption method is greatly decreased. Unlike the smectite limitation encountering with contaminated soil containing the heavy metals, the cement has a high adsorption capacity to adsorbe heavy metals. In the same content of adsorbent and with the increase of the Pb concentration, the amount of its reduction in the presence of cement is 15 times more than what observed in the presence of smectite. In addition, it can be seen that the particles solidification in the samples containing cement improves the engineering properties of materials, causes to trap the pollutants within the soil mass and consequently reduces the leaching and emission capability of pollutants as compared to the physical attraction method. Conclusion: According to the results, using the physical adsorption to remove the heavy metals from contaminated soils (particularly at high concentrations of contaminant) is not recommended. Unlike the smectite limitation encountering with contaminated soil, application of cement is very effective to remove contaminants from the soil due to the combination of two mechanisms of stabilization and solidification. In appropriate remediation condition and with respect to EPA criteria, application of 0.1% of cement per 1 cmol/kg.soil contamination leads to safe remediation of the heavy metals from in contaminated soils.
1- Li, Z., Ma, Z., Kuijp, T.J.V., Zengwei Yuana, Z., Huang, L., 2014. A review of soil heavy metal pollution from mines in China: Pollution and health risk assessment. Science of the Total Environment, Vol. 468-469, pp. 843-853.
2- Huang, Z., Pan, X.D. Wu, P.G. Han, J.L., Chen, Q., 2014. Heavy metals in vegetables and the health risk to population in Zhejiang. China, Food Control, Vol. 36, pp. 248-252.
3- EPA, United States Environmental Protection Agency, 2010. Municipal solid waste generation, recycling and disposal in the United States: Facts and figures.
4- Voglar, G.E., Lestan, D., 2013. Equilibrium leaching of toxic elements from cement stabilized soil. Journal of Hazardous Materials, Vol. 246-247, pp. 18-25.
5- Hekal, E.E., Hegazi, W.S., Kishar, E.A., Mohamed, M.R., 2011. Solidification/stabilization of Ni (II) by various cement pastes. Construction and Building Materials, Vol. 25, pp 109-114.
6- Choi, W.H., Lee, S.R., Park, J.Y., 2009. Cement based solidification/stabilization of arsenic-contaminated mine tailings. Waste Management, Vol. 29, pp. 1766-1771.
7- Zhu, Z., Gao, C., Wu, Y., Sun, L, Huang, X, Ran, W, Shen, Q., 2013. Removal of heavy metals from aqueous solution by lipopeptides and lipopeptides modified Na-montmorillonite. Journal of Bioresource Technology, Vol. 147, pp. 378-386.
8- Fernández-Nava, Y., Ulmanu, M., Anger, I., Marañón, E., Castrillón, L., 2011. Use of granular bentonite in the removal of Mercury (II), Cadmium (II) and Lead (II) from aqueous solutions. Water Air Soil Pollut, Vol. 215, pp. 239-249.
9- Addy, M., Losey, B., Mohseni, R., Zlotnikov, E., Vasiliev, A., 2012. Adsorption of heavy metal ions on mesoporous silica-modified montmorillonite containing a grafted chelate ligand. Applied Clay Science, Vol. 59-60, pp. 115-120.
10- Zha, F.S. Xu, L. Cui, K.R., 2012. Strength characteristics of heavy metal contaminated soils stabilized/solidified by cement. Rock and Soil Mechanics, Vol. 33, pp. 652-664.
11- Cui, Y. Du, X. Weng, L. Willem, H. and Riemsdijk, V., 2010. Assessment of In-Situ immobilization of lead (Pb) and arsenic (As) in contaminated soils with phosphate and iron: solubility and bioaccessibility. Water Air Soil Pollut, Vol. 213, pp. 95-104.
12- Kogbara, R.B., Al-Tabbaa, A., 2011. Mechanical and leaching behaviour of slag-cement and lime-ctivated slag stabilised/solidified contaminated soil. Science of the Total Environment, Vol. 409, pp. 2325-2335.
13- Salem, A., Akbari Sene, R., 2011. Removal of lead from solution by combination of natural zeolite-kaolin-bentonite as a new low-cost adsorbent. Chemical Engineering Journal, Vol. 174, pp. 619-628.
14- Ouhadi, V.R., Yong, R.N., Rafiee, F., Goodarzi, A.R., 2011. Impact of carbonate and heavy metals on microstructural variations of clayey soils. Applied Clay Science, Vol. 52, pp. 228-234.
15- Tantawy, M.A. El-Roudi, A.M. Salem, A.A. 2012. Immobilization of Cr (VI) in bagasse ash blended cement pastes. Construction and Building Materials, Vol. 30, pp. 218-223.
16- Wei, M.L. Du, Y.J. Zhang, F., 2011. Fundamental properties of strength and deformation of cement solidified/stabilized zinc contaminated soils. Rock and Soil Mechanics. Vol 32, pp 306-312.
17- Moon, D.H., Wazne, M., Yoon, I.H., Grubb, D.G., 2008. Assessment of cement kiln dust (CKD) for stabilization/solidification of arsenic contaminated soils. Journal of Hazardous Materials, Vol. 159, pp. 512-518.
18- Antemir, A., Hills, C.D., Carey, P.J., Gardner, K.H, Bates, E.R., Crumbie, A.K., 2010. Long-term performance of aged waste forms treated by stabilization/solidification. Journal of Hazardous Materials, Vol., 181, pp. 65-73.
19- ASTM, 2006. Annual Book of ASTM Standard. American Society for Testing and Materials. Philadelphia; 4.08.
20- EPA, 1983. Process design manual: land application of municipal sludge, Res. Lab. EPA-625/1-83-016.
21- EPA 1311, 2003. Toxicity Characteristic Leaching Procedure, Test Method for Evaluation of Solid Wastes. Physical, Chemical Methods, SW846.
22- Elliott, H.A., Liberati, M.R., and Huang, C.P., 1986. Competitive adsorption of heavy metals by soils. J. Environ. Qual., Vol. 15, pp. 214-219.
23- Yong, R.N., Ouhadi, V.R., Goodarzi, A.R., 2009. Effect of Cu2+ Ions and Buffering capacity on Smectite Microstructure and Performance. Journal of Geotechnical and Geoenvironmental Engineering ASCE, Vol. 135, pp. 1981-1985.
24- Malviya, R., Chaudhary, R., 2006. Factors affecting hazardous waste solidification/Stabilization: Review. J.Hazardous Material, Vol. 137, pp. 267-276.
25- Sánchez-Jiménez, N., Gismera, M.J., Sevilla, M.T., 2012. Clayey materials as geologic barrier in urban landfills: Comprehensive study of the interaction of selected quarry materials with heavy metals. Applied Clay Science, Vol. 56, pp. 23-29.
26- Malamis, S., Katsou, E., 2013. A review on zinc and nickel adsorption on natural and modified zeolite, bentonite and vermiculite: Examination of process parameters, kinetics and isotherms. Journal of Hazardous Materials, Vol. 252-253, pp. 428-461.
