Book Reviews
Langmuir, Vol. 1, No. 4,1985 529
Book Reviews Hepatology. Volume 4 (September-October 1984 Supplement). Physical Chemistry of Bile in Health and Disease. Williams & Wilkins, Baltimore. Volume 4,No. 5, of “Hepatology (September-October 1984 Supplement)” is devoted entirely to the physical chemistry of bile. The issue contains papers and discussion from the Kroc Foundation Conference held Dec 5-9, 1983 in’Santa Ynez Valley, CA. The 24 invited participants were well-qualified representatives of the “two cultures” of biomedical scientists and physical scientists, having a common interest in the components of bile. Short papers were given by all of the conferees, on topics as varied as methods of sampling and studying biliary fluid, the formation of bile, bilirubin chemistry, biliary proteins, cholesterol gall stone dissolution, and biliary lipid secretion. Of potential interest to readers of Langmuir are a number of papers on the surface and colloid chemistry of aqueous solutions of the bile acids and their salts. A report on the self-association of bile salts and their capacity for solubilizingorganics emphasizes the difference in characteristics of bile salt micelles as compared with micelles of the common flexible-chain surfactants. One report describes the ionization behavior of fatty acids and bile acids in micelles and membranes; another summarizes results of NMR and crystallographic studies of bile salt micelles. Bile salt association is discussed in relation to surface tension-composition diagrams, and a critical review provides information about the current state of knowledge of the size and aggregation numbers of bile salt micelles. A discussion of self-diffusion studies sketches a general picture of amphiphile self-associationin surfactant and bile salt systems. The counterion binding of Ca2+to micelles of glycine and taurine bile acid conjugates has been inferred from Ca2+-specificelectrode measurements, and the rate of dissolution of lecithin by bile salts has been investigated with turbidity measurements. A report is given of an elaborate NMR study of the molecular organization of lecithin-cholate-water phases. In one paper, X-ray scattering differential scanning calorimetry and ESR results are described for bile salt-lecithin mixed micelles; structural information obtained by light scattering and other techniques is given for similar systems in other reports. A description of the phase behavior of cholesterol-lecithin-bile salt systems and general comments on the use of phase diagrams are included in several of the papers and in the discussions. The printed discussions following many of the papers, the general discussions, and the focused discussion of research needs all provide the reader with valuable insight into research problems that are current in bile chemistry. Although the papers are somewhat uneven in quality and depth, as might be expected considering the wide range of topics covered, any scientist anticipating doing research on the components of bile should find this issue of “Hepatology” quite useful. Sherril D. Christian, The University of Oklahoma Principles of Adsorption and Adsorption Processes. By D. M. Ruthven. Wiley-Interscience, New York. 1984. 433 pages. $49.50. Separation and purification of gas and liquid mixtures by adsorption has become an important unit operation in the chemical industry and a very large volume of literature on different aspects of the technology is available. Yet there was no book that
covered the basic principles of adsorption and their applications in a comprehensive fashion. Professor Ruthven’s book is the first of its kind to fill that gap. It is an exceptional blend of the key practical topics in adsorption such as the adsorbent (Chapter l), the equilibrium and thermodynamics of adsorption (Chapters 2-4), the kinetics of adsorption (Chapters 5, 6),the dynamics of adsorption in columns (Chapters 7-9), and the adsorptive separation processes (Chapters 10-12). A large portion of this book is based on the author’s own research and experience. The first chapter describes the characteristics of various microporous adsorbents (silica gels, aluminas, activated carbons, and zeolites) of practical interest and includes some valuable information on the adsorbent regeneration and deactivation. An undue emphasis is, however, given to the structures of zeolites which can be found in other excellent monographs. The sections on the equilibrium and thermodynamics of adsorption provide an excellent review of the classical theories of gas-solid molecular interactions and the models for adsorption isotherms such as Langmuir, BET, virial, Kelvin, etc. A comparative evaluation of different models such as the ideal adsorbed solution theory, the vacancy solution theory, and the statistical thermodynamic approach to predict mixed gas isotherms is also given. This can be very useful to design engineers. The section on the thermodynamics of adsorption is, however, rather brief and developed in terms of the specific amounts adsorbed instead of the Gibbsian surface excesses. The useful thermodynamic consistency tests are omitted. A serious criticism of these chapters is the lack of a significant discussion on the adsorbent heterogeneity and adsorption from liquid mixtures. A voluminous literature exists on these topics and they are subjects of many current research efforts. The chapters on the kinetics of adsorption outline various experimental techniques and describe different possible mechanisms for adsorbate mass transfer into porous adsorbents. Both isothermal and nonisothermal adsorption kinetics are described at length by using mathematical models for various mechanisms. Gas adsorption kinetics into zeolite crystals is presented in detail. The sections on the column dynamics provide a comprehensive survey of many mathematical models to describe isothermal or adiabatic column adsorption of single or multicomponent gaseous adsorbates with linear or nonlinear isotherms. Formation of various patterns of mass- and heat-transfer waves in the column is discussed in detail. The local equilibrium theory of adsorption in columns is presented at great length along with several numerical solutions of the conservation equations for nonequilibrium adsorption. This excellent treatise should be very valuable for process design. Again, a weakness is the omission of the kinetics and dynamics of adsorption from liquid mixtures. The last three chapters of the book describe the concepts of the chromatographic, the pressure, and the thermal swing adsorption processes and discuss the factors influencing them. Commercial processes such as drying of gases, air separation by pressure swing adsorption, the hypersorption process, and the separation of bulk liquid mixtures by simulated continuous countercurrent operation are described at some length. Simplied mathematical models for the processes are included. In general, the book provides a clear, thoughtful, and unified presentation of many practical aspects of a very complex subject. It will serve as a valuable reference manual for scientists and engineers working in the field of adsorption. Shivaji Sircar, Air Products and Chemicals, Znc.
