Effect of adsorbate structure on adsorption from solutions

Abstract

Adsorption of benzene derivatives of various chemical properties from dilute aqueous solutions on the Norit activated carbons is investigated. The experimental systems are analyzed in terms of adsorption theory on energetically heterogeneous solids. The relations between the optimization isotherm parameters, i.e. equilibrium constants and heterogeneity parameters, and the solute properties, e.g. number, character and position of functional groups are discussed. #

Organic dye adsorption on mesoporous hybrid gels

“…The porous structure of a solid, its energetic heterogeneity, and surface chemical properties (functional groups, surface charge, hydrophilic and hydrophobic nature) are the main factors influencing adsorption equilibria [19]. For a given adsorbent, the adsorption of different adsorbates is a function of solubility, polarity, structure, mass, and size of the molecules.…”

Adsorption of phenols from aqueous solutions: Equilibria, calorimetry and kinetics of adsorption

“…Use of Gaussian-like function in the Condensation Approximation (CA) and suitable local isotherm results in an isotherm equations which very well describe phenols adsorption. Such isotherm is Langmuir-Freundlich (Sips) [5,6,8,16,22,23,51] assuming lack of lateral interactions between molecules. The isotherm which takes into account lateral interactions is e.g.…”

“…Considering that adsorption of phenols on activated carbons (ACs) is one of the most important applications of ACs, a large number of studies have been carried out to examine this issue [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. There are two most common physical forms, in which AC is used, i.e.…”

Influence of differences in porous structure within granules of activated carbon on adsorption of aromatics from aqueous solutions

“…5, left) that nitrobenzene is adsorbed very strongly, 4-nitrophenol, 4-chlorophenol adsorb weaker and phenol adsorption is the weakest. For a given solid these differences in adsorption uptakes for all studied adsorbates result from complex interplay of various effects: the differences in their solubility (c s;nitrobenzene ¼ 0:015 mol/l, c s;p-nitrophenol ¼ 0:087 mol/l, c s;p-chlorophenol ¼ 0:21 mol/l, c s;phenol ¼ 0:871 mol/l), the effect of adsorbate functional groups (the presence of acidic functional groups may weaken the adsorption), the specific interactions with active sites on carbon surface (especially intramolecular or intermolecular hydrogen bonding), the possible sieving effects (bifunctional derivatives possessing two functional groups may be excluded from narrower micropores) [20,21]. Regarding the complexity of studied adsorption systems it is very difficult to estimate the shares of separate effects on adsorption equilibria.…”