This article was downloaded by: 10.3.98.104 On: 23 Sep 2021 Access details: subscription number Publisher: CRC Press Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: 5 Howick Place, London SW1P 1WG, UK Encyclopedia of Surface and Colloid Science, Third Edition P. Somasundaran, Namita Deo, Raymond Farinato, Vicki Grassian, Max Lu, Martin Malmsten, K.L. Mittal, Ramanathan Nagarajan, Patra Partha, Gleb Sukhorukov, Darsh Wasan Acid–Base Behavior of Clay Surfaces in Aqueous Media Publication details https://www.routledgehandbooks.com/doi/10.1081/E-ESCS3-120028031 Marcelo J. Avena Published online on: 27 Aug 2015 How to cite :- Marcelo J. Avena. 27 Aug 2015, Acid–Base Behavior of Clay Surfaces in Aqueous Media from: Encyclopedia of Surface and Colloid Science, Third Edition CRC Press Accessed on: 23 Sep 2021 https://www.routledgehandbooks.com/doi/10.1081/E-ESCS3-120028031 PLEASE SCROLL DOWN FOR DOCUMENT Full terms and conditions of use: https://www.routledgehandbooks.com/legal-notices/terms This Document PDF may be used for research, teaching and private study purposes. Any substantial or systematic reproductions, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The publisher shall not be liable for an loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Acid–Base Behavior of (Polymer) Surfaces: Theory Acid — Claudio Della Volpe Stefano Siboni Absorption Department of Materials Engineering, University of Trento, Trento, Italy Abstract The acid–base paradigm is, probably, the most celebrated concept in chemistry, and its importance and applications are so general that a bulk chemist imagines, with difficulty, the state of chemistry before its introduction. For more than a century this paradigm was able to overcome all cultural crises due to the chemistry development. This entry begins with a historical overview of the interaction forces theory and the acid–base theory, then moves to the mathematical bases of the approach of GVOC theory to the acid–base properties of surfaces, providing several examples of application for further illustration of key concepts. INTRODUCTION should be convinced that these terms are substantially flawed (or, of reduced importance) in the context of sur- Only the chemist can tell, and not always the face physical chemistry. chemist, what will result from compounding fluids At first glance, it can appear a purely lexical problem. or solids. The point is that, in condensed phases, the high (as com- pared to dilute gases) number of nearest neighbors pro- vides conflicting local fields that minimize dipole —Edgar L. Masters, “Spoon River” interactions. Even if the language of intermolecular forces in condensed phase is dominated by the term “polar,” this The acid–base paradigm is, probably, the most cele- kind of force, plays only a very minor role. The lively brated concept in chemistry and its importance and appli- discussions on this subject by the late Prof. Fowkes, by cations are so general that a bulk chemist imagines, with Berg or by Good et al. are highly recommended.[1-4] difficulty, the state of chemistry before its introduction. This is the reason the paradigm of the “polar For more than a century this paradigm was able to over- components,” which was extremely common until 1980s, come all cultural crises due to the chemistry development. was substituted in 1990s by the acid–base theory. How- The original Arrhenius concept, valid only in water ever, even the “bible” of the polar components theory, solution, became the Brnsted–Lowry definition; after written by S. Wu in 1982,[5] indicated the potential the introduction of quantum mechanics, Lewis upgraded importance of acid–base interactions at interfaces, in the the definition of acids and bases, using the concept of section “Ionic Bonding at Interfaces,” dedicated to the accepting or donating electron pairs. Usanovich tried to different kinds of oxide surfaces and their interactions. further generalize it by eliminating the limit of electron To some extent, the use of improper terms, as in the pairs and including the redox reactions. After the Sec- case of the adjective “ionic” cited in the previous sen- ond World War, approaches based on the factorization tence, is well correlated with the numerous attempts to of acid and basic strength were developed by Drago, analyze surface interactions using inadequate theoretical Pearson, and Klopman, who proposed the concept of approaches. hard and soft acids and bases, strongly correlated to the These problems have a “cultural” origin, probably molecular orbital (MO) theory. dependent on the different points of view on this subject In all cases, these new paradigms corresponded to an developed in the cultural domain of physics and of incredible development of the applications and the chemistry, respectively. importance of acid–base theory. The development of the acid–base theory has been The situation is different in the field of surface chem- “parallel” to that of a remarkable achievement in the istry. Due to a long series of cultural and experimental understanding of the attractive forces in gases, initially reasons, the acid–base paradigm is a “young” one in made by van der Waals in 1873. Between 1921 and surface physical chemistry; even today it is common to 1930, Keesom, Debye, and London were able to write a find the terms “polar” or “nonpolar” defining the chemi- general equation to express the interaction potential cal character of a surface; on the contrary, the reader between “pairs” of “polar” molecules. The work of Encyclopedia of Surface and Colloid Science, Third Edition DOI: 10.1081/E-ESCS3-120000910 Copyright Ó 2015 by Taylor & Francis. All rights reserved. 75 Downloaded By: 10.3.98.104 At: 09:41 23 Sep 2021; For: 9781351252386, entry3, 10.1081/E-ESCS3-120028031 76 Acid–Base Behavior of (Polymer) Surfaces: Theory Absorption Table 1 Some historical notes on surface interactions and on Table 1 (Continued) Some historical notes on surface inter- acid–base theory actions and on acid–base theory — Year ○Physics/.Chemistry Year ○Physics/.Chemistry Acid 1805 Young equation gsv = glv cos q + gsl 1953 .Fukui: frontier electron density for nucleophylic or electrophylic attack 1869 Dupre equation Wadh = glv + gsv À gsl ○ 1872–1873 ○van der Waals hypothesized 1955 Lifshitz: a general theory of intermolecular forces to explain vdW molecular interactions applicable the correction term on the pressure to condensed phases of real gases (+a/v2) avoiding the additivity problem . 1887 .Arrhenius theory: acids and bases 1957 Good: correction of Hamaker equation À 2 in water H+ and OHÀ for repulsive forces DG12(1) = A12/16p1 ○ 1903–1908 ○Mie and Gru¨neisen: 1963 McLachlan: a generalized theory of vdW A B forces for the case of dilute gases with a wðrÞ¼ À rn rm more general expression for Hamaker constant, more than a single ionization potential applicable to interactions in 1920–1921 ○Debye: permanent dipole-induced dipole solvent medium 2 2 aiµ þ ajµ 1 Debye ¼ j i Á .Pearson: HSAB theory: hard Fij 6 2 rij and soft acids and bases 1962–1968 .Fowkes: division of surface tension 1921–1922 ○Keesom: permanent dipole-permanent in different components based on dipole separability of K D. and L. forces 2 µ2µ2 1 Keesom ¼ i j Á 1964 .Klopman: a general treatment of Fil 6 3 kT rij chemical reactivity; the perturbation equation reproduces the qualitative features of HSAB and similar . 1923 Br nsted, Lowry: acids donate, bases reactivity indices. accept H+in different solvents 1965 .Drago: the role of molecule polarizability .Lewis: acids accept and bases ÀDH = E E + C C donate eÀ pairs AB A B A B . ○ 1966 Good: concludes that dipole forces are 1928 Lennard–Jones, Dent: repulsive not important in the case of solid component of intermolecular potential; and liquid phases, evaluates the Lennard–Jones or 6–12 potential A B the case of water (1991) wðrÞ¼ À r12 r6 .Gootman: donor and acceptor numbers (revised in 1978) 1930 ○London: induced dipole-induced dipole 1969 .Bolger, Michaels: interactions of liquids 3 2IiIj 1 and solid oxides in terms of dispersive FLondon ¼ a a Á lj i j þ 6 forces and acid–base interactions 4 Ii Ij rij “ ” an additive theory integrating 1978 .Fowkes, Mostafs:qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi acid–base theory of solids forces between independent pairs ¼ LW LW of molecules Wadh 2 glv gsv þ ð A B þ A BÞ 1937 ○Hamaker: energy of interaction between fN E E C C macroscopic systems integrating forces between independent pairs of molecules 1985 .Good, van Oss, Chaudury: acid–base DG (1) = ÀA /12p12 12 12 theory of solids . qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1939 Usanovich: acids accept and bases LW LW À W ¼ 2 g g donate e adh lv sv qffiffiffiffiffiffiffiffiffiffiffi pffiffiffiffiffiffiffiffiffiffiffi 1941 ○Derjaguin, Landau: DLVO theory; vdW þ À þ g gÀ þ g gþ forces and double layer forces in lv sv lv sv colloidal stability (Continued) (Continued) Downloaded By: 10.3.98.104 At: 09:41 23 Sep 2021; For: 9781351252386, entry3, 10.1081/E-ESCS3-120028031 Acid–Base Behavior of (Polymer) Surfaces: Theory 77 Table 1 (Continued) Some historical notes on surface inter- actions and on acid–base theory Acid — Year ○Physics/.Chemistry 1991 .Whitesides: contact angle titrations on Absorption artificially modified surfaces : common origin; .: mainly chemical results; ○: mainly physical results. Many of these quantities are more precisely defined in the text; in the other cases refer to this encyclopedia or a physical chemis- try textbook. gij = interfacial energy at the boundary between i and j phases; q = the Fig.