Kinetic modeling of adsorption of di-2-pyridylketone salicyloylhydrazone on silica gel

An anionic resin modified by di-2-pyridyl ketone salicyloylhydrazone as a new solid preconcentration phase for copper determination in ethanol fuel samples

“…DPKSH was adsorbed onto silica gel and Amberlite resins (XAD-2 and XAD-7), and the adsorption was investigated using kinetic and isotherm models. [13][14][15] In ethanolic/aqueous solution, DPKSH is in tautomeric equilibrium with the (I) ketonic and (II) enolic form, Scheme 1.…”

Adsorption of 5.5’-Disulfonicindigotin (5.5’-DI) onto Green Coconut Fiber (<i>Cocos nucifera</i> L.): Kinetic and Isotherms

“…After determining the best conditions for the adsorption study, experimental data were obtained by varying the initial adsorbate by keeping a constant time of contact between the fiber and 5.5'-DI adsorbate. Isotherms show the relationship between adsorbate concentration in solution and the amount of adsorbate adsorbed onto a specific sorbent at a constant temperature [36] [37]. To understand the adsorption equilibrium, three commonly used mathematical models were compared with experimental data: the Langmuir [18], Freundlich [19] and DubininRadushkevich [20] isotherms.…”

“…To understand the adsorption equilibrium, three commonly used mathematical models were compared with experimental data: the Langmuir [18], Freundlich [19] and DubininRadushkevich [20] isotherms. The Langmuir model [37] was originally developed to represent chemisorption on a set of well-defined andlocalized adsorption sites with the same adsorption energy, irrespective of the surface coverage and with no interaction between adsorbed molecules. Maximum sorption is defined when the adsorbent surface is covered with a monolayer of adsorbate, and each site is responsible for the adsorption of a single molecule of dye and no further adsorption may therefore occur [38] [39].…”

“…The higher the value of n, the more energetically heterogeneous the adsorption sites. The Freundlich adsorption isotherm does not predict any saturation of the solid adsorbent surface, therefore the infinite coverage is predicted mathematically [37]. Adsorption on fiber shows a K F value (136.5 g•g −1 at 298 K) higher than the corresponding K F values (30.6 g•g −1 at 283 K) and (22.1 g•g −1 at 313 K) which represents a stronger interaction between 5.5'-DI and coconut fiber at 298 K.…”

“…According to Antonio et al [37], if the surface is heterogeneous and a Langmuir isotherm approximation is chosen as a local isotherm for all energetically equivalent sites then the quantity B 1/2 can be related to the mean sorption energy (E) according to:…”