Inorganic surfaces adsorption

Adsorption and Surface Chemical Grafting. As with siHca and many other siHcate minerals, the surface of asbestos fibers exhibit a significant chemical reactivity. In particular, the highly polar surface of chrysotile fibers promotes adsorption (physi- or chemisorption) of various types of organic or inorganic substances (22). Moreover, specific chemical reactions can be performed with the surface functional groups (OH groups from bmcite or exposed siHca). 

In this communication a study of the catalytic behavior of the immobilized Rhizomucor miehei lipase in the transesterification reaction to biodiesel production has been reported. The main drawbacks associated to the current biodiesel production by basic homogeneous catalysis could be overcome by using immobilized lipases. Immobilization by adsorption and entrapment have been used as methods to prepare the heterogeneous biocatalyst. Zeolites and related materials have been used as inorganic lipase supports. To promote the enzyme adsorption, the surface of the supports have been functionalized by synthesis procedures or by post-treatments. While, the enzyme entrapping procedure has been carried out by sol-gel method in order to obtain the biocatalyst protected by a mesoporous matrix and to reduce its leaching after several catalytic uses. 

Adsorption on Inorganic Surfaces. McCarty et al. (55) and Karickhoff (1 ) proposed a two-phase model for sorption onto mineral surfaces and organic matter partitioning. This model hypothesizes that sorption to inorganic surfaces may occur simultaneously with the accepted partitioning into the organic matter. Assuming additivity of these two contributions, Kj can be estimated from... 

Adsorption of Nonionic Organic Compounds to Inorganic Surfaces... 

Give five examples of environmentally relevant situations in which adsorption of organic vapors on inorganic surfaces is important. 

For what kind of compounds and in which environmentally relevant cases is adsorption of organic chemicals to inorganic surfaces in water important Give five examples. 

Mills, A. C., and J. W. Biggar, Adsorption of 1,2,3,4,5,6-hexachlorocyclohexane from solution The differential heat of adsorption applied to adsorption from dilute solutions on organic and inorganic surfaces , J. Coll. Int. Sci., 29, 720-731 (1969b). 

The surface chemical and morphological characteristics of inorganic sorbents such as silicas, aluminas, talc, micas define both their chemical and physical adsorption potentials (surface energy). But the existence of mineral and organic surface pollutants will indeed strongly influence those properties. 

Murray, J. P. and Laband, S. J. "Degradation of pxjliovirus by adsorption on inorganic surfaces" Appl. Environ. Microbiol. 1979. 37 480-486. 

Murray, J. P. "Physical chemistry of virus adsorption and degradation on inorganic surfaces" U.S. Environmental Protection Agency, Cincinnati, Ohio. 1980. 

The test of the models is then twofold (1) Do the differences in DLVO potentials account for the observed differences in free energy for all solids (2) Are the values selected for characteristic distances realistic, considering what is understood about the atomic structure of solid-liquid interfaces, for example, 0.1 to 1 nm If these conditions are met we have evidence that the DLVO theory explains virus adsorption to various inorganic surfaces, provided that equally convincing evidence is not obtained when considering other types of interaction. 

MandeFs conformational bimodality is predicted to be of critical importance in regard to virus adsorption to inorganic surfaces in the environment. Gerba et al. (68) recently observed that echovirus type 1 adsorbed on sandy soil to a much lesser extent than poliovirus type 1, strain LSc. This corresponds to the low value of the A state conformation of echovirus type 1 presented in Table X compared to that of poliovirus. Since this bimodality of virus lEP s is intrinsically coupled to solution pH, we will expand the discussion of its importance in the section concerned with the eflFects of pH on adsorption. 

The DLVO-Lifshitz theory should be regarded as a principal mechanism governing the adsorption of viruses on various inorganic surfaces. This finding has direct application to problems concerning transport of viruses in aquatic systems and soils. It is possible that it could lead to the design and optimization of adsorption-filtration processes for removing viruses and other particulates from contaminated water. 

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