Environmetal Soil Properties and Behaviour

Environmetal Soil Properties and Behaviour


DisciplinaControle e Remediação da Poluição dos Solos5 materiais18 seguidores
Pré-visualização50 páginas
For a successful and accurate presentation of soil fabric, 
it is necessary to obtain a representative sample of the soil in a manner that 
preserves the natural particle arrangement. This can pose severe problems 
since one requires thin sections and flat smooth surfaces. For light micros-
copy, one generally uses specimens with a thickness of 10\u201330 µm obtained 
by microtomes equipped with special steel or diamond knives. Light micros-
copy using special wavelengths and optics can be used for identifying soil 
fabric details with a size down to about 3 µm.
For electron microscopy techniques, the thickness of the section from which 
micrograph pictures are taken is of fundamental importance. The ideal thin 
section is a two-dimensional plane. The thicker the section, the smaller the 
possibility of identifying voids included in the clay matrix. The question of 
what thickness one can accept depends on the required resolution and the 
need for discerning microstructural details. Specimens used in transmission 
electron microscopy (TEM) are generally 20\u2013100 nm thick. It is expected that 
objects with sizes of 1 nm are discernible with this technique. A detailed 
discussion of quantitative analysis of microstructural features can be found 
in Pusch and Yong (2006).
For sample preparation, impregnation of clay samples with a suitable 
well-hardening substance is used to replace the porewater. Impregnation of 
a sample without prior drying can be made by repeated impregnation of 
special water-soluble substances such as Durcupan and Carbowax. This pro-
cedure removes the porewater and replaces it with a substance that becomes 
sufficiently hard for microtomy. In the case of monomers used for impreg-
nation, replacement of the porewater by the monomer without disturbing 
the network during the replacement phase or during polymerization of the 
monomer is a problem that needs to be addressed.
2.10 Concluding Remarks
A recurring question in soil characterization or soil identification is \u201cHow 
detailed should we be in conducting tests for soil characterization/iden-
tification?\u201d There is no simple answer to this simple question, the reason 
being that this depends on several factors as identified in Section 2.9.1. 
The presence of various kinds of clay fractions and their interactions 
are important factors in the evaluation of the surface properties of clays. 
79Nature of Soils
Because of the pH dependency of the surface properties of such fractions 
as organic matter, amorphous materials, and even some clay minerals, 
interactions occurring between various clay fractions will change the 
characteristic SSA and CEC of the clays. We see from the discussion in the 
early part of this chapter that the surface properties of the mineral parti-
cles are more or less dominated by the hydroxyl surface functional groups, 
whereas organic matter possesses a greater variety of surface functional 
groups. We will learn in the next few chapters about the importance of 
surface properties of soils in relation to soil integrity and in regard to 
interactions with contaminants.
The importance of the role of microstructure in the control of the hydraulic 
conductivity and other transmission characteristics of clay, and in the devel-
opment of clay integrity and rheological properties, cannot be overstated. We 
need to emphasize that the microstructural units and groups of microstruc-
tural units are never static, in the sense that restructuring of the microstruc-
tural units and groups of such units will always occur in response to internal 
and external provocative gradients.
The physical properties of soils discussed in this chapter relate directly to 
the status of a soil. In soil and geoenvironmental engineering applications, 
one is generally interested in the initial or natural state of the soil under 
consideration. These include organic matter content, soil density, water 
content, degree of water saturation, and consistency limits. There are some 
that would argue that physical properties should also include inherent soil 
strength and hydraulic conductivity of the soil. We believe otherwise since 
these fall under classifications of mechanical and transmission properties, to 
be discussed in the next few chapters.
References
Asutton, R., and Sposito, G., 2005, Molecular structure in soil humic substances: The 
new view, Envr. Sci. Tecnnol., 39:9009\u20139015.
Birrell, K.S., and Fields, M., 1952, Allophane in volcanic ash soils, J. Soil Sci., 3:156\u2013166.
Bolt, G.H., and Bruggenwert, M.G.M., 1978, Composition of soil, in G.H. Bolt and 
M.G.M. Bruggenwert (Eds.), Soil Chemistry: Basic Elements, Elsevier Scientific 
Publishers, Amsterdam, 281 pp.
Brunauer, S., Emmett, P.H., and Teller, E., 1938, Adsorption of gases in multimolecular 
layers, J. Am. Chem. Soc., 60:309\u2013319.
Carter, D.L., Mortland, M.M., and Kemper, W.D., 1986, Specific surface, in A. 
Klute (Ed.), Methods of Soil Analysis, Part 1: Physical and Mineralogical Methods, 
Monograph 9. Am. Soc. Agron., pp. 413\u2013423.
Dixon, J.B., 1977, Kaolinite and serpentine group minerals, in J.B. Dixon and S.B. Weed 
(Eds.), Minerals in Soil Environment, Soil Sci. Soc. Amer. J., 41:357\u2013403. Madison, 
Wisconsin
80 Environmental Soil Properties and Behaviour
Flaig, W., Beutelspacher, H., and Reitz, E. 1975. Chemical composition and physical 
properties of humic substances, Soil Composition, Geisking, J.E., (Ed), Springer-
Verlag, Berlin, 1:1\u2013219.
Greenland, D.J., and Hayes, M.H.B. (Eds.) 1985, The Chemistry of Soil Constituents, 
John Wiley and Sons, Chichester, 469 pp.
Greenland, D.J., and Mott, C.J.B., 1985, Surfaces of soil particles, in The Chemistry of 
Soil Constituents, 1985. D.J. Greenland, and M.H.B. Hayes. (Eds.), John Wiley & 
Sons, Chichester, pp. 321\u2013354.
Griffith, S.M., and Schnitzer, M., 1975, Analytical characteristics of humic and fulvic 
acids extracted form tropical soils, Soil Sci. Soc. Amer. J., 39:861\u2013869.
Grim, R.E., 1953, Clay Mineralogy, McGraw Hill, New York, 384 pp.
Huang, P.M., and Schnitzer, M., 1986, Interactions of Soil Minerals with Natural Organics 
and Microbes, 3rd. printing, SSSA Special Publ. 17. Madison, Wisconsin.
Hatcher, P.G., Schnitzer, M., Dennis, L.W., and Maciel, G.E., 1981, Aromaticity of 
humic substances in soils, Soil Sci. Soc. Amer. J. 45:1089\u20131094.
Kitagawa, Y., 1971, The \u201cunit particle\u201d of allophone, Amer. Mineral., 56:465\u2013475.
Konishi, Y., Asai, S., and Katoh, H., 1990, Bacterial dissolution of pyrite by Thiobacillus 
ferooxidans, Bioprocess Eng., 5:231\u2013237.
Konishi, Y., Asai, S., and Yoshida, N., 1995. Growth kinetics of Thiobacillus thiooxidans 
on the surface of elemental sulfur. Am. Soc. Microbiology, 61:3617\u20133622.
LaMer, V.K., and Healy, T.W., 1963a, Adsorption\u2013flocculation reactions of macromol-
ecules at the solid\u2013liquid interface, Rev. Pure Appl. Chem., 13:112\u2013133.
LaMer, V.K., and Healy, T.W., 1963b, The role of filtration in investigating flocculation 
and redispersion of colloidal dispersions, J. Phys. Chem., 67:2417.
Lambe, T.W., 1953, The structure of inorganic soil, Proc. ASCE, No. 315.
Lambe, T.W., 1958, The structure of compacted clay, J. Soil Mech. and Found. Div. 
ASCE, 84: SM2, p.34.
Marshall, K.C., 1976, Interfaces in Microbial Ecology, Harvard University Press, 
Cambridge, MA.
Molz, F.J., Widdowson, M.A., Benefield, L.D., 1986. Simulation of microbial growth 
dynamics coupled to nutrient and oxygen transport in porous media, Water 
Resour. Res., 22:1207\u20131216.
Monod, J., 1949, The growth of bacterial culture, Annu. Rev. Microbiol., 3:371.
Mortland, M.M., and Kemper, W.D., 1965, Specific surface, in C.A. Black (Ed.), Methods 
of Soil Analysis: Part 1, Amer. Soc. Agron., pp. 532\u2013544.
Nakano, M., 2010. Personal communication to R.N. Yong on studies by Hamamoto, 
S., Yamaguchi, N., and Nakano, M. on pH influence on adsorption