The knowledge of sorption processes of nonelectrolytes in solution by solid adsorbents implies the study of kinetics, equilibrium, and thermodynamic functions. However, quite frequently the equilibrium isotherms are studied by comparing them with those corresponding to the Giles et al. classification (1); these isotherms are also analyzed by fitting them to equations based on thermodynamic or k...

Thermodynamic equations are de®eloped for adsorption of multicomponent gas mixtures in microporous adsorbents based on the principles of solution thermodynamics. The con®entional spreading pressure and surface area ®ariables, which describe 2-D films, must be abandoned for adsorption in micropores, in which spreading pressure cannot be measured experimentally or calculated from intermolecular f...

Dehydration of ethanol via adsorption on 3Å molecular sieves has recently been increasing in application in industry as an alternative to the conventional separation techniques for breaking the ethanol-water azeotrope. Over the past 20 years, Pressure-Vacuum Swing Adsorption (PSA) processes have gained increasing commercial acceptance as an energy-efficient separation technique. A general purpo...

This paper describes a preliminary study of the adsorption of toxic elements from synthetic wastewater in a batch mode. Clay minerals have been highly considered as inexpensive available adsorbents that adapt with the environment due to a special level and a high potential of adsorption. In the present research work, low-cost natural minerals of speiolite from the Iliato mine (located in NE Ir...

A new three-scale model to describe the coupling between pH-dependent flows and transient ion transport, including adsorption phenomena in kaolinite clays, is proposed. The kaolinite is characterized by three separate nano/micro and macroscopic length scales. The pore (micro)-scale is characterized by micro-pores saturated by an aqueous solution containing four monovalent ions and charged solid...

The adsorption at the interface between an aqueous solution of several surface-active agents and another fluid (air or oil) phase is addressed theoretically. We derive the kinetic equations from a variation of the interfacial free energy, solve them numerically, and provide an analytic solution for the simple case of a linear adsorption isotherm. Calculating asymptotic solutions analytically, w...

Syringopicroside is the major constituent in Folium syringae leaves with known pharmacological activities. In this study, a simple method for preparative separation of syringopicroside from F. syringae leaves with macroporous resins was developed. Adsorption characteristics of syringopicroside on six types of macroporous resins, including ADS-8, ADS-17, D141, NKA-9, HPD450, and HPD600, have bee...

Ion transport across weakly charged membranes with surface charge due to ion adsorption is analyzed and particular attention is paid to the caw of Langmuir-type adsorption. Coupling between electrodiffusion of ions and their adsorption to the membrane matrix results ina number of intereating nonlinear phenomena. The steady-state transport equations lead to a firat-order differential equation th...

A new colorimetric method for determining the surface-accessible acidic lignin hydroxyl groups in lignocellulose solid fractions was developed. The method is based on selective adsorption of Azure B, a basic dye, onto acidic hydroxyl groups of lignin. Selectivity of adsorption of Azure B on lignin was demonstrated using lignin and cellulose materials as adsorbents. Adsorption isotherms of Azure...

The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as B...