Colloid chemistry state

J.H. SLUYTERS Van t Hoff Laboratory of Physical and Colloid Chemistry, State University Utrecht, 3584 CH Utrecht, The Netherlands... 

Problems which arise with certain precipitates include the coagulation or flocculation of a colloidal dispersion of a finely divided solid to permit its filtration and to prevent its re-peptisation upon washing the precipitate. It is therefore desirable to understand the basic principles of the colloid chemistry of precipitates, for which an appropriate textbook should be consulted (see the Bibliography, Section 11.80). However, some aspects of the colloidal state relevant to quantitative analysis are indicated below. 

With foams, one is dealing with a gaseous state or phase of matter in a highly dispersed condition. There is a definite relationship between the practical application of foams and colloidal chemistry. Bancroft (4) states that adopting the very flexible definition that a phase is colloidal when it is sufficiently finely divided, colloid chemistry is the chemistry of bubbles, drops, grains, filaments, and films, because in each of these cases at least one dimension of the phase is very small. This is not a truly scientific classification because a bubble has a film round it, and a film may be considered as made up of coalescing drops or grains. ... 

Among the purely physical properties of their materials, to which the chemist and the biologist have been compelled to pay an increasing amount of attention during recent years, surface tension undoubtedly occupies the first place. In a great measure this is due to the development of colloidal chemistry, which deals with matter in a state of extreme sub-division, and therefore with a great development of surface for a given mass, so that the properties of surfaces become important, and sometimes decisive, factors in the behaviour of such systems. 

In fact, the state obtained by mixing oil and water is an important example of interfacial behavior of lic]iLid lic iiid2. Emulsions of oil-water systems are useful in many aspects of daily life, such as milk, foods, paint, oil recovery, pharmaceutical, and cosmetics. The colloidal chemistry of milk makes it the most complicated naturally made product. 

The aim of this book is to introduce to the principles and applications of a branch of chemistry called surface and colloid chemistry. Most science students are taught physicochemical principles pertaining to gases, liquids, and solids. The matter around us is recognized to be made of these three states of matter. However, in university chemistry textbooks, seldom more than a chapter is devoted to the science of surface and colloid chemistry. At technical schools worldwide, the same is the case, in general. However, in the realm of applications of physico-chemical technology, the science of surface and colloid chemistry is one of the most important. Common examples of the principles at work in this field are ... 

Professor K. S. Birdi received his BSc (Hons) in chemistry from Delhi University in 1952, and then later traveled to the United States for further studies, majoring in chemistry at the University of California at Berkeley. After graduation in 1957, he went to Standard Oil of California, Richmond. Dr. Birdi moved to Copenhagen, Denmark, in 1959, where he joined the Lever Brothers Development Laboratory in 1959 as chief chemist. During this period, he became interested in surface and colloid chemistry and joined the Institute of Physical Chemistry (founded by Professor... 

The essential differences between the properties of matter when in bulk and in the colloidal state were first described by Thomas Graham. The study of colloid chemistry involves a consideration of the form and behaviour of a new phase, the interfacial phase, possessiug unique properties. In many systems reactions both physical and chemical are observed which may be attributed to both bulk and interfacial phases. Thus for a proper understanding of colloidal behaviour a knowledge of the properties of surfaces and reactions at interfaces is evidently desirable. 

This theory, as originated from the early work of Smoluchowski [20], nowadays has numerous applications in several branches of chemistry, such as colloidal chemistry, aerosol dynamics, catalysis and the physical chemistry of solutions as well as in the physics and chemistry of the condensed state [21-24]. Until recently, its branch called standard chemical kinetics [12, 15, 16] based on the law of mass action seemed to be quite a complete and universal theory. However, because of their entirely phenomenological character, theories of this kind always operate with the reaction rates K which are postulated to be time-independent parameters. 

Weiser (2) states that a colloidal system is a heterogeneous or dispersed system of at least two phases, one of which, a finely divided or dispersed phase, is more or less uniformly distributed in a continuous phase. Colloidal chemistry constitutes a study of the "colloidal system. ... 

Aluminosilicate zeolites are normally synthesized under basic conditions. The introduction of OH- ions to the synthetic system will necessarily lead to the introduction of correlated cations. These positively charged cations play an important role in the polymerization of polysilicates and aluminates by affecting the polymeric state and their distribution, and have an important effect on the colloidal chemistry of aluminosilicate as well. In addition, cations existing in the synthetic system also have important effects on the formation of the framework structure of zeolites. For example, plenty of synthetic data indicated that a tight correlation between the formation of the SBU cages of zeolites and the charge and size of the cations existed, and this was named the templating effect of cations by R.M. Barrer.[191... 

Besides these important relations between PZC and ion adsorption by soils, the physical properties of soils may also be sensitive to the PZC. It is a general principle of colloid chemistry that colloidal particles dispersed in water tend to maintain their dispersed state if the particles possess relatively high surface charge, either positive or negative. Conversely, aggregation of these individual particles (i.e., flocculation) is most favored when the surface charge is low. This leads to the rule that ... 

Department of Colloid Chemistry St.Petersburg State University Universitetskij pr. 26 198504 St.Petersburg - Petrodvorez Russia... 

St. Petersburg State University, Department of Colloid Chemistry,... 

Tall oils are obtained in large quantity from the pulping of soft -woods to make paper. Hoyt and Goheen ( l) state that in 196U the yield of fatty and rosin acids exceeded 1 00,000 tons. Tall oil contains about 9b% total acids and 6% alcohols. The fatty acid fraction contains oleic v 2k% and linoleic v 23%, of which V b°fo is conjugated linoleic of the tall oil. The rosin acid fraction contains abietic acid lk%> and related acids 33 of the total (,2). An extensive literature on general aspects of the colloidal chemistry of compounds in this class is available (see, for example, references 3, 5, and 6 ). 

The state of the art of silica colloid chemistry in the late 1970s is extensively covered by Iler s classic book The Chemistry of Silica (3), Unger s Porous Silica (2), and in the specific case of silica powders by Barby s monograph (19). 

This book covers major areas of modern Colloid and Surface Science (in some countries also referred to as Colloid Chemistry) which is a broad area at the intersection of Chemistry, Physics, Biology and Material Science investigating the disperse state of matter and surface phenomena in disperse systems. The book arises of and summarizes the progress made at the Colloid Chemistry Division of the Chemistry Department of Lomonosov Moscow State University (MSU) over many years of scientific, pedagogical and methodological work. 

The development of colloid science at Moscow State University and elsewhere in Russia was greatly influenced by the fundamental contributions to its major areas ([1-4] in the General Introduction) made by Professor Peter Aleksandrovich Rehbinder (1898 - 1972), Academician of the USSR Academy of Sciences, who chaired and led the Colloid Chemistry Division for more than 30 years. Rehbinder was a great enthusiast of colloid science and an excellent lecturer. The synopsis of his lecture course (published by Moscow State University in 1950) was for a long time used as a textbook by generations of students and still now serves as an example of the most clear, logical and broad coverage of the subject. 

Colloid Chemistry or, alternatively, Colloid and Surface Science, are the established and traditionally used names of the field of science devoted to the investigation of substances in dispersed state with particular attention to the phenomena taking place at interfaces. Peter A. Rehbinder defined colloid chemistry as the chemistry, physics, and physical chemistry of disperse systems and interfacial phenomena [1-6]. 

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