Morphological and Microstructural Study of Heavy Metal Contaminant Retention in Dispersive Soils

Subject Areas : environmental management

Vahidreza Ouhadi ¹ (Prof., Faculty of Engineering, Bu-Ali Sina University; Adjunct Prof., School of Civil Engineering, University of Tehran, Iran)
Mohammad Amiri ² (Assistant Professor, Faculty of Engineering, Hormozgan University, Bandar Abbas, Iran. * (Corresponding Author))
Morteza Diranlou ³ (Instructor, Faculty of Engineering, Esfarayen University of Technology, Esfarayen, Iran.)

Received: 2014-12-11 Accepted : 2015-11-07 Published : 2017-03-21

Keywords: Heavy metal, Dispersive Soils, XRD, SEM, EDX,

Abstract :

Background and Objective: Various adsorbents have been used for retention of heavy metal contaminants. However, natural dispersive soils and soil morphology have received little attention. The dispersive natural soil used in this study is a clayey soil with micro and nano-scale particles. Accordingly, the main objective of the present study is to investigate retention of heavy metal contaminants and the changes in the structure and morphology of dispersive soils exposed to environmental contaminants. Method: To achieve this objective, environmental and geotechnical tests were performed to investigate and to compare the interaction of natural dispersive soil, bentonite and kaolinite clay samples with lead and zinc. The retention of heavy metals by dispersive soil was investigated by X-ray diffraction, scanning electron microscope (SEM) images and energy dispersion spectroscopy (EDX) experiments. Conclusion: According to the results, the retention capacity of natural dispersive soil is higher than that of bentonite and kaolinite, because of its morphology, dispersive structure and high percentage of carbonate. Although cation exchange capacity (CEC) of the natural dispersive soil is approximately 50% less than that of bentonite, retention of the heavy metal contaminant in this sample is more than 20% as compared with that of bentonite at high concentrations of heavy metals. Furthermore, the retention capacity of the natural dispersive soil is 2.3 times more than that of kaolinite sample. According to the results obtained in this paper, the orientation and structure of clay platelets strongly influence the retention of contaminant by clay samples.

References:

1-      Sevim, I. F. and Güner, G. (2005). “Investigation of rheological and collodial properties of bentonitic clay dispersion in the presence of a cationic surfactant”. Progress in Organic Coatings. Vol. 54, 1, 28-33.

2-      Kónya1, J., Nagy, N. M., Földvári, M.,  (2005). “The Formation and Production of Nano and Micro Particles on Clays under Environmental-Like Conditions”, Journal of Thermal Analysis and Calorimetry, Vol. 79, 537–543.

3-      Ouhadi. V.R., Yong. R.N., (2003), “The role of clay fractions of marly soils on their post Stabilization failure”, Engineering Geology 70, pp 365–375.

4-      Ouhadi, V.R., and Amiri, M., (2011), "Geo-environmental Behaviour of Nanoclays in Interaction with Heavy Metals Contaminant", Amirkabir J, Civil, 42, 3, pp 29-36

5-      Yong, R. N. and Mohamed, A.M.O and Warketin, B. P., (1992), “Principles of contaminant transport in soils”, Elsevier, Holland.

6-      Yong, R. N. & Warkentin, B. P. (1975). Soil properties and behaviour. Elsevier Scientific Publishing Company

7-      Elliott, H. A., Liberati, M. R., Huang, C. P., (1986). “Competitive adsorption of heavy metals by soils.” Journal of Environmental Quality 15, pp. 214–219.

8-      Lumsdon, D.G., Evans, L.J., Bolton, K.A., (1995). “The influence of pH and chloride on the retention of cadmium, lead, mercury and zinc by soils”. Journal of Soil Contamination 4, 137–150.

9-      Ouhadi, V.R., and Amiri, M., Goodarzi, A.R. (2012). "The Special Potential of Nano-Clays for Heavy Metal Contaminant Retention in Geo-Environmental Projects", Journal of Civil and Surveying Engineering, Vol: 45, Issue: 6, pp. 631-642.

10-  Ouhadi, V. R. & Goodarzi, R. V., (2006), "Assessment of the stability of a dispersive soil treated by alum", Engineering Geology Vol. 85: 91-101.

11-  Mitchell, I. V., (2005)."Pillared Layered Structures: Current Trends and Applications". Elsevier Applied Science.

12-  Yong, R. N., Sethi, A. J., Ludwig, H. P. & Jorgensen, M. A. (1978). Physical chemistry of dispersive clay particle interaction. American Society of Civil Engineers, Chicago, 1-21

13-  Sherard, J. I., Dunnigan, L. P. & Decher, R. S., (1977). "Some engineering problems with dispersive soils", ASTM, STP, No. 623: 3-12.

14-  Yong, R. N. and Phadangchewit, Y., (1993), “pH Influence on selectivity and retention of heavy metals in some clay soils”, Can. Geotech. J., 30, 821-833.

15-  American Society for Testing and Materials, (1992). "ASTM, 1992 American Society for Testing and Materials, ASTM, Annual Book of ASTM Standards", P.A., Philadelphia V.4, 08.

16-  EPA, (1983), “Process design manual, land application of municipal sludge, Municipal Environmental Research Laboratory”, EPA-625/1-83-016, U.S. Government Printing Offices, New York.

17-  Hesse, P. R., (1971), “A textbook of soil chemical analysis”, William Clowes and Sons, 519p.

18-  Eltantawy and Arnold, I.N. Eltantawy and Arnold, P.W., (1973), “Reappraisal of ethylene glycol mono-ethyl ether (EGME) method for surface area estimation of clays”, Soil Sci. 24, pp. 232–238.

19-  Handershot, W. H., and Duquette, M., (1986), “A simple barium chloride method for determining cation exchange capacity and exchangeable cations”, Soil Sci. Soc. Am. J. 50, pp. 605–608.

20-  Ouhadi. V.R., Yong. R.N., (2003). “Experimental and theoretical evaluation of impact of clay microstructure on the quantitative mineral evaluation by XRD analysis”. Elsevier Appl. Clay Sci. J. 23. pp 141-148.