Clay minerals, adsorption

Key words Clay minerals — adsorption — ionic surfactants — heat of wetting — surface hydrophobicity — humic acids — rheology — SAXS experiments... 

Surface heterogeneity may be inferred from emission studies such as those studies by de Schrijver and co-workers on P and on R adsorbed on clay minerals [197,198]. In the case of adsorbed pyrene and its derivatives, there is considerable evidence for surface mobility (on clays, metal oxides, sulfides), as from the work of Thomas [199], de Mayo and co-workers [200], Singer [201] and Stahlberg et al. [202]. There has also been evidence for ground-state bimolecular association of adsorbed pyrene [66,203]. The sensitivity of pyrene to the polarity of its environment allows its use as a probe of surface polarity [204,205]. Pyrene or ofter emitters may be used as probes to study the structure of an adsorbate film, as in the case of Triton X-100 on silica [206], sodium dodecyl sulfate at the alumina surface [207] and hexadecyltrimethylammonium chloride adsorbed onto silver electrodes from water and dimethylformamide [208]. In all cases progressive structural changes were concluded to occur with increasing surfactant adsorption. 

Effect on Oxide—Water Interfaces. The adsorption (qv) of ions at clay mineral and rock surfaces is an important step in natural and industrial processes. SiUcates are adsorbed on oxides to a far greater extent than would be predicted from their concentrations (66). This adsorption maximum at a given pH value is independent of ionic strength, and maximum adsorption occurs at a pH value near the piC of orthosiUcate. The pH values of maximum adsorption of weak acid anions and the piC values of their conjugate acids are correlated. This indicates that the presence of both the acid and its conjugate base is required for adsorption. The adsorption of sihcate species is far greater at lower pH than simple acid—base equihbria would predict. 

The clay mineral bentonite (sodium montmorillonite) has an excellent ion exchange and adsorption capacity. Films can be applied to electrode surfaces from colloidal clay solutions by simple dip or spin coating that become electroactive after incorporation of electroactive cations or metal particles 136-143)... 

Hermosin MC, Martin P, Cornejo J (1993) Adsorption mechanisms of monobutyltin in clay minerals. Environmental Science and Technology, 27(12) 2606-2611. 

Shikazono and Shimizu (1987) concluded that Ag contents of gold precipitated from low-salinity fluids is higher than that prediction and the relationship between NAg of gold and salinity of fluid inclusions estimated from freezing temperature data. Therefore, another interpretation is that NAg of gold from shale-hosted deposits is lower than that from sandstone-hosted deposits, because shale is expected to be richer in Cl mainly due to adsorption by clay minerals included in shale than sandstone. 

T. Austad, P. A. Bjorkum, T. A. Rolfsvag, and K. B. Oysaed. Adsorption Pt 3 Nonequilibrium adsorption of surfactants onto reservoir cores from the North Sea The effects of oil and clay minerals. J Petrol SciEng, 6(2) 137-148, 1991. 

Adsorption (including both physical adsorption and ion exchange) by clay minerals and silicates... 

High adsorption loss observed in the present work in both dynamic and static tests indicates a possibility of multilayer adsorption. However, the long times required to achieve adsorption equilibrium may indicate interlayer adsorption in the clay minerals. 

More than 50 years ago, the English physical chemist J. D. Bernal (1901-1971) suggested that clay minerals may have played a key role in synthetic processes taking place on the primordial Earth he was referring to the adsorption and concentration of organic substances at the surface of such minerals. 

Exchangeable ions (EXC), sometimes including ions nonspecifically adsorbed and specifically absorbed on the surface of various soil components, such as carbonate, organic matter, Fe, Mn, Si, and Al oxides, and clay minerals. This part is controlled by adsorption-desorption processes. 

Frost R.R., Griffin R.A. Effect of pH on adsorption of arsenic and selenium from landfill leachate by clay minerals. Soil Sci Soc Am J 1977 41 53-57. 

Goldberg S., Forster H.S., Heick E.L. Boron adsorption mechanisms on oxides, clay minerals and soils inferred from ionic strength effects. Soil Sci Soc Am J 1993 57 704-708. 

Clay minerals or phyllosilicates are lamellar natural and synthetic materials with high surface area, cation exchange and swelling properties, exfoliation ability, variable surface charge density and hydrophobic/hydrophilic character [85], They are good host structures for intercalation or adsorption of organic molecules and macromolecules, particularly proteins. On the basis of the natural adsorption of proteins by clay minerals and various clay complexes that occurs in soils, many authors have investigated the use of clay and clay-derived materials as matrices for the immobilization of enzymes, either for environmental chemistry purpose or in the chemical and material industries. 

The entrapment of various enzymes and proteins by clay minerals proceeds by weak interactions including electrostatic interactions, hydrogen and van der Waals bonding. Additivity of these various attractive forces renders the adsorption irreversible in some cases, but usually a leaching of enzyme is observed under working conditions. In order to fix the enzyme irreversibly at the surface of the clay layers different processes have been tried. In order to fix invertase on bentonite, Monsan and Durand [90] previously treated the clay mineral with a coupling agent,... 

Frost RR, Griffin RA (1977) Effect of pH on adsorption of As and selenium from land fill leachate by clay minerals. Soil Sci Soc Am J 41 53—57 Goh K-H, Lym TT (2005) Arsenic fractionation in a fine soil fraction and influence of various anions on its mobility in the sub surface environment. Appl Geochem 20 229-239... 

Manning BA, Goldberg S (1997a) Adsorption and stability of arsenic (III) at the clay mineral-water interface. Environ Sci Technol 31 2005-2011 Manning BA, Goldberg S (1997b) Arsenic(III) and arsenic(V) adsorption on three California soils. Soil Sci 162 886-895... 

Carrizosa MJ, Hermosin MC, Koskinen WC, Cornejo J (2004) Interactions of two sulfonylurea herbicides with organoclays. Clays Clay Miner 52 643-649 Celis R, Hermosin MC, Cornejo J (2000) Heavy metal adsorption by functionalized clays. Environ Sci Technol 34 4593-4599 Chappell MA, Laird DA, Thompson ML, Li H, Teppen BJ, Johnston CT, Boyd SA (2005) Influence of smectite hydration and swelling on atrazine sorption behavior. Environ. Sci Technol 39 3150-3156 Chiou CT (1989) Theoretical considerations of the partition uptake of nonionic organic compounds by soil organic matter. In Sawhney BL, Brown K (eds) Reactions and movement of organic chemicals in soils. Soil Science Society of America, Madison, WI, pp 1-29... 

Cowan CT, White D (1962) Adsorption by organo-clay complexes. Clays Clay Miner 9 459-467... 

Haderlein SB, Weissmahr KW, Schwarzenbach RP (1996) Specific adsorption of nitroaromatic explosives and pesticides to clay minerals. Environ Sci Technol... 

Jaynes WF, Boyd SA (1991b). Hydrophobicity of siloxane surfaces in smectites as revealed by aromatic hydrocarbon adsorption from water. Clays Clay Miner 39 428-436... 

Kowalska M, Gtiler H, Cocke DL (1994) Interactions of clay minerals with organic pollutants. Sci Total Environ 141 223-240 Kukkadapu RK, Boyd SA (1995) Tetramethylphosphonium-smectite and tetramethylammonium-smectite as adsorbents of aromatic and chlorinated hydrocarbons - effect of water on adsorption efficiency. Clays Clay Miner 43 318-323... 

Theng BKG, Greenland DJ, Quirk JP (1967) Adsorption of alkylammonium cations by montmorillonite. Clay Miner 7 1-17... 

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