Solid wetting measurement

Flow nozzles are particularly suited for measurement of steam flow and other high-velocity fluids, fluids with some solids, wet gases, and similar materials. Because an exact contour is not critical, the flow nozzle can be expected to retain good calibration for a long time even under erosion or other hostile conditions. 

The shapes of these isotherms are controlled by surface heterogeneity, and thus provide a means of deducing the various modes of interfacial attraction presented by the substrates. Isotherms of pentane on unsized IM6 before and after plasma treatment are congruent. Pentane interacts only by dispersion force attraction, as does methylene iodide the registry of these isotherms is predicted by the similarity in ft obtained from wetting measurements. Pentane isotherms serve as a reference with which to assess the effect of additional modes of solid/vapor interaction with acidic and basic probes. 

Zettlemoyer, A.C., Chessick, J.J., and HoUabaugh, C.M. (1958). Estimation of the surface polarity of solids from heat of wetting measurements. Phys. Chem., 62, 489-90. Morimoto, T. and Suda, Y. (1985). Heat of immersion of zinc oxide in organic liquids. 1. Effect of surface hydroxyls on the electrostatic field strength. Langmuir, 1, 239—43. 

A quick test by a wet swab dipped in liquor ammonia solution can be done by holding it against the exit gas to detect the presence of unabsorbed HCI gas. Quick check of scrubbing liquor— Eh ovide a sampling line from pump discharge to control room and check by pH papers or universal indicator solutions. This is to check the alkalinity of scmbbing liquor if the pH metre is not working. Solid feed measurement... 

When a drop of liquid is placed on a solid surface, the liquid will either spread across the surface to form a thin, approximately uniform film (Fig. 17.2fl) or spread to a limited extent but remain as a discrete drop on the surface. The final condition of the applied liquid on the surface is taken as an indication of the wettability of the surface by the liquid or the wetting ability of the liquid on the surface, depending on your point of view. The quantitative measure of the wetting process is taken to be the contact angle, 6, which the drop makes with the solid as measured through the liquid in question (Fig. 17.2fi). 

Vignes-Alder, M. and Brenner, H., A micromechanical derivation of the differential equations of interfacial statics. III. line tension, 7. Colloid Interface Sci., 103,11,1985. Vogler, E.A., Practical use of concentration-dependent contact angles as a measure of solid-liquid adsorption. 1. Theoretical aspects, Langmuir, 8, 2005, 1992. Vrbanac, M.D. and Berg, J.C., The use of wetting measurements in the assessment of acid-base interactions at solid-liquid interfaces, J. Adhesion Sci. TechnoL, 4, 255, 1990. 

Contact Angie. The degree to which a liquid wets a solid is measured by the contact angle B (Fig 6). When 6 = 0, the liquid spreads freely over the surface and is said to completely wet it. This occurs when the molecular attraction between the liquid and solid molecules is greater than that between similar liquid molecules (54). Surface tensions are related to the contact angle by an expression from equilibrium considerations (55) ... 

In other cases, the surface may be pre-covered, totally or partially, by a liquid film prior to the heat of wetting measurement. The sample is pre-covered by the vapor of the immersion liquid at different partial pressures, and this sample is immersed in the liquid. At low partial pressures, the vapor adsorbs on high-energy sites, and the enthalpy of immersion will be lower as compared with that obtained with the outgassed solid. The enthalpy of immersion continues to decrease as the coverage becomes complete (this is achieved by increasing the partial pressure of the vapor when the sample is treated). At this point, the immersion enthalpy obtained corresponds to the formation of an adsorbed film-liquid interface. 

A description of the flow phenomena in this type of process is very complicated and is outside the scope of this book (see reviews by Shah 1979, and Shah and Sharma, 1987). Phenomena that have been studied include the various flow regimes, liquid and gas hold-ups, pressure drop, the distribution of liquid and gas flows, effective solids wetting, axial mixing, etc.. However, it is important to remenber that for chemical reactor development one can measure, separately, the mass transfer and the integral performance of the three-phase system on a small scale, using the same solid particles that are going to be used on the larger scale. 

Grundke, K., Bogumil, T., Gietzelt, T., Jacobasch, H. -J., Kwok, D. Y. and Neumann, A. W., Wetting measurements on smooth, rough and porous solid surfaces, Progr. Colloid Polym. Set, 101, 58-68 (1996). 

Obviously, the reversible work of adhesion cannot be estimated because the solid interfacial tensions cannot be deduced explicitly from wetting measurements as outlined at... 

J Panzer. Components of solid surface free energy from wetting measurements. J... 

In Table 3.2, these approaches are applied to our systems methylated solid surfaces and four characteristic nonpolar liquids. The adhesion energy Wvalues are estimated as mentioned above W=Gs + (Jl- F/2. W values are independently obtained data on the work of adhesion for considered nonpolar phases on the basis of contact angle of wetting measurements [20, 34] as W = 0l(1 + cos i ) 0 evaluations of interfacial energy in these systems as 05 = 0s—<7lCosi3. W a) and W(p), 0sl(A) and 0sl(F) are the estimations calculated for the same systems following Antonov and Fowkes, respectively, with the same 0s and 0l. 

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