To mineral surfaces

Conceivably, many compounds of inorganic elements have chemical reactivity that could contribute to improved adhesion to mineral surfaces. A fairly wide range of compounds, not restricted to any particular group in the periodic table, have been proposed as coupling agents as is shown in the following list ... 

Improve adhesion of dissimilar materials such as polymers to inorganic substrates. Also called primers. Primers generally contain a multifunctional chemically reactive species capable of acting as a chemical bridge. In theory, any polar functional group in a compound may contribute to improved bonding to mineral surfaces. However, only a few organofunc-tional silanes have the balance of characteristics required... 

Even if the solubility limit of relevant solid phases is not exceeded, a large fraction of trace metals in natural waters often occurs bound to particles of various size ranges (nanometres to millimetres). An important process for binding of metals to particles is adsorption to mineral surfaces (often oxides or hydroxides) [29]. 

Many mass balance studies which report weathering rates as a function of unit area of landscape surface do not permit comparison of those rates with laboratory dissolution rates, and cannot, therefore, contribute to the objectives of this paper. Only two published studies have thus far attempted to renormalize such calculated rates to mineral surface area. Discussion of these studies therefore forms the basis for comparisons of laboratory rates with natural weathering rates. 

Haderlein, S.B. and Schwarzenbach, R.P. Adsorption of substituted nitrobenzenes and nitrophenols to mineral surfaces. 

Mader, B.T., Uwe-Goss, K., and Eisenreich, S.J. Sorption of nonionic, hydrophobic organic chemicals to mineral surfaces. 

Humic substances. Analogous to the reactions described above, humic substances (the polymeric pigments from soil (humus) and marine sediments) can be formed by both enzymatic and non-enzymatic browning. High concentrations of free calcium and phosphate ions and supersaturation with respect to hydroxyapatite can sustain in soil, because adsorption of humic acids to mineral surfaces inhibits crystal growth (Inskeep and Silvertooth, 1988). A similar adsorption to tooth mineral in a caries lesion can be anticipated for polycarboxylic polymers from either the Maillard reaction or enzymatic browning. 

Aside from the Maillard reaction, other covalent modifications of amino acids and proteins are possible within the caries lesion, which merit future investigation. For example, certain oral microorganisms excrete y-glutamyl transferases. These enzymes catalyse the formation of cross-links between glutamic acid and lysine residues of proteins. In addition, N-acyl amino acids are present in plaque, which adsorb to mineral surfaces. 

Cadmium is found naturally deep in the subsurface in zinc, lead, and copper ores, in coal, shales, and other fossil fuels it also is released during volcanic activity. These deposits can serve as sources to ground and surface waters, especially when in contact with soft, acidic waters. Chloride, nitrate, and sulfate salts of cadmium are soluble, and sorption to soils is pH-dependent (increasing with alkalinity). Cadmium found in association with carbonate minerals, precipitated as stable solid compounds, or coprecipitated with hydrous iron oxides is less likely to be mobilized by resuspension of sediments or biological activity. Cadmium absorbed to mineral surfaces (e.g., clay) or organic materials is more easily bioaccumulated or released in a dissolved state when sediments are disturbed, such as during flooding. 

Kaiser K. G. Guggenberger (2000) The role of DOM sorption to mineral surfaces in the preservation of organic matter in soils. Org. Geo-chem. 31 711-725... 

Murphy, E.M. Zachara, J.M. Smith, S.C. Phillips, J.L. (1992) The sorption of humic acids to mineral surfaces and their role in contaminant binding. Sci. Total Environ. 117/ 118 413-423... 

This paper contributes to the literature by quantifying anionic polymer adsorption onto the clay minerals kaolinite, feldspar, mica and quartz by X-ray photoelectron spectroscopy (XPS). XPS measures the sorbed amount directly rather than by a subtraction technique. This enables an insight into how effective selective flocculation is for obtaining kaolinite from a mineral mixture. Atomic force microscopy (AFM) is also used to image polymer adsorption onto mineral surfaces and the effectiveness of this technique applied to mineral surfaces is discussed here. 

Adsorption to mineral surfaces such as Fe and Al (hydr)oxides has long been known to be an important process that limits the mobility of heavy metals and metalloid species in aqueous systems (e.g., Stumm 1992). The sorption of ionic species in MSWI bottom ash has been recently studied in detail by Meima Comans (1998, 1999). These authors used a sequence of selective chemical extractions to determine sorbent concentration, namely Fe and Al (hydr)oxides. Their model calculations suggested that Zn(II) and M0O4 sorbed to Fe (hydr)oxides, while Pb(II) and Cu(II) appeared to have a greater affinity for Fe (hydr)oxides. The sorption of Cd(Il) was found to be very weak. The interpretation of... 

Using the limited empirical observations of the magnitudes of Kimin values, one may examine the question of when nonpolar chemical sorption to mineral surfaces from... 

In sum, we do not yet know how to predict sorption of apolar and monopolar organic compounds to mineral surfaces submerged in water. If empirical results are available from structurally related compounds, parameters quantifying sorbate hydropho-bic-ity may help us anticipate the intensity of surface associations for new com-pounds in the same compound classes (i.e., interpolating data such as that shown in Fig. 11.7). 

Romanowski,G., Lorenz, M. G. Wackernagel, W. (1991). Adsorption of plasmid DNA to mineral surfaces and protection against DNasel. Applied and Environmental Microbiology, 57, 1057-61. 

The problems in bonding polymers to hydrophilic mineral surfaces were discussed and a theory of adhesion in which silane coupling agents provide a bond at the interphase was proposed by Plueddemann in 1974 [3]. However, silane coupling agents specifically designed to impart hydrophilicity to mineral surfaces have been proposed only recently [34], A trimethoxysilyl-terminated poly( /V-... 

Reduction of nitro aromatic compounds often appears to be a two-step process, in which a mediator is required for facile transfer of electrons from a bulk reductant to the contaminant. A well documented example is the coupling of organic matter oxidation by iron reducing bacteria to "abiotic" nitro reduction by biogenic Fe(II) that is adsorbed to mineral surfaces in a column containing aquifer material (36, 39, 76). 

Proteins contain a variety of functional groups that can bind them to mineral surfaces carbonyl, alcoholic, carboxylic acid, and amine. Studies have shown that protein adsorption to clays is rapid at a pH below the isoelectric point of the protein (e.g., McLaren, 1954 Armstrong and Chesters, 1964). Conversely, then, protein should be extracted by a solvent system with a pH above the protein s isoelectric point. There are also hydrophobic regions on some proteins that create the possibility for hydrophobic interactions between the sorbed protein and the mineral surface (Quiquampoix, 2000). 

NMR can provide detail regarding the types of NOM structures that are preferentially sorbed to mineral surfaces in soils and sediments. Simpson et al. (2006b) used H liquid-state and HR-MAS NMR methods to study the sorption of model compound mixtures to calcium-saturated montmorillonite. The model compound mixture included one representative compound from each of the following structural classes sugars, lignin, peptides, and long-chain aliphatics. After sorption, the supernatant was analyzed by liquid-state NMR and the organo-mineral complex... 

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