Adsorption from solutions, research

Adsorption from solutions, research, 653-654 Adsorption isotherm, 253, 254f Adsorption methods, characterization of silica surface, 170, 175-177/... 

Adsorption from solutions was fully studied by G. C. Schmidt. He first showed that the adsorbed amount reaches a maximum, when the surface is saturated, and does not then increase if the concentration of the solution is increased (1910). He proposed an adsorption formula (1911) taking this into account, which he later modified (1916). Extensive researches carried out from 1906 by Freundlich showed that a thermodynamic theory given by J. W. Gibbs (1877, see p. 742) could be used as a guide. A modification of the adsorption equation (5), viz. xlm=kc f (6), applies to solutions, where adsorbed amount, m=mass of adsorbent, equilibrium concentration of solution, k and n are constants (i/n varies from o i to o-8). It was apparently first used by C. H. D. Bodeker, then by W. Biltz, and Freundlich. 

Adsorption phenomena from solutions onto sohd surfaces have been one of the important subjects in colloid and surface chemistry. Sophisticated application of adsorption has been demonstrated recently in the formation of self-assembhng monolayers and multilayers on various substrates [4,7], However, only a limited number of researchers have been devoted to the study of adsorption in binary hquid systems. The adsorption isotherm and colloidal stabihty measmement have been the main tools for these studies. The molecular level of characterization is needed to elucidate the phenomenon. We have employed the combination of smface forces measmement and Fomier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR) to study the preferential (selective) adsorption of alcohol (methanol, ethanol, and propanol) onto glass surfaces from their binary mixtures with cyclohexane. Om studies have demonstrated the cluster formation of alcohol adsorbed on the surfaces and the long-range attraction associated with such adsorption. We may call these clusters macroclusters, because the thickness of the adsorbed alcohol layer is about 15 mn, which is quite large compared to the size of the alcohol. The following describes the results for the ethanol-cycohexane mixtures [10],... 

Much work has been done on the removal of Pb and Zn from aqueous solution. Removal of these ions has been attempted by several researches employing a wide variety of techniques. Adsorption of removal of Pb and Zn from solution agricultural waste [5], three fern [6], tannin gel [7], removal of Pb sea module [8], tannin gel adsorbent synthesized from condensed tatmin [8] and removal of Zn green macro alga [9], soil [3] have been extensively studied for this purpose. 

Current interest in the multi-faceted role of adsorption in the water and waste water field has been stimulated in large part by research originating within this field. Concomitantly, more and more investigations in the field of surface and colloid chemistry have focused on aqueous systems. The results of these investigations are of considerable significance to the water scientist. The convergence of interests of researchers in these two fields has provided the impetus for this joint symposium on adsorption from aqueous solution. 

The corrosion process also includes acid-base reactions involving solute particles in aqueous solution. As for the acid-base characteristics of corrosion processes, we still have many research issues that remain to be studied, such as the effect of various solutes in aqueous solution on materials corrosion. Novel experimental techniques in the nanometer scale recently developed in electrochemistry and corrosion science will provide, from now on, much information that, we hope, will contribute to elucidating the acid-base characteristics of corrosion processes, particularly the effect of adsorption of solute particles on the corrosion. 

An area of intensive research involves the interfacial aspects of diverse polymer systems. Multidisciplinary programs on the interfacial characteristics of polymers are in progress as various academic institutions e.g., Center for Interfacial Engineering at the University of Minnesota, NSF Center on Interfacial Science at Lehigh University). The projects under investigation involve the nature of interfacial adhesion, interdiffusion of diverse polymer chains, and adsorption of polymers from solution on polymer surfaces. A recent textbook on polymer blends and composites has several chapters dedicated to polymer surfaces and interfaces [Sperling, 1997]. 

Sparks CJ Jr (1980) X-ray fluorescence microprobe for chemical analysis. In Winick H, Doniach S (eds) Synchrotron Radiation Research, Plenum Press, New York, p 459-512 Spngberg D, Hermansson K, Lindqvist-Reis P, Jalilehvand F, Sandstroem M, Persson I (2000) Model extended X-ray absorption fine structure (EXAFS) spectra from molecular dynamics data for Ca2+ and Al3+ aqueous solutions. J Phys Chem 104 10467-10472 Sposito G. (1986) Distinguishing adsorption from surface precipitation. In Geochemical Processes at Mineral Surfaces, Davis JA, Hayes KF (eds) ACS Symposium Series 323, The American Chemical Society, Washington, DC, p 217-228... 

Clearly studies of single proteins and of mixtures in buffer solutions provide useful information as is evident from the above discussion. However, only studies using blood or plasma can give definitive answers regarding blood material interactions. Accordingly much of our research over the past several years has been devoted to studies of protein adsorption from plasma or blood. 

Metal recovery by adsorption from dilute aqueous solutions is an emerging field of interest from the standpoints of both resource conservation and environmental remediation. Many biopolymers derived from microbes and plants are known to bind metals strongly. The use of biopolymers as adsorbents for the recovery or removal of metals from aqueous environments has been a topic of extensive research in recent years [18]. Biopolymers such as cellulosics, alginate carrageenans, lignins, proteins, and chitin derivatives are industrially attractive for a number of reasons. Biopolymers are capable of removing heavy metal ions at parts per... 

---