We develop a model for solute transport in porous media, which takes into account equilibrium and non-equilibrium multiple-site adsorption. Binary ion exchange is included. Adsorption rate formulations and their isotherms are reviewed and their mathematical properties investigated. This forms the basis of the study of travelling wave solutions in the second part of the paper.

Equilibrium adsorption of gas phase mixtures of Dand Lalanine (Ala) onto the naturally chiral Cu{3,1,17} surfaces has been studied by both experiment and DFT-based modeling. Isotopically labeled *L-Ala (HO2 CCH(NH2)CH3) and unlabeled D-Ala allow mass spectrometric enantiodifferentiation of the adsorbed species during temperature-programmed decomposition, following equilibrium adsorption. Measur...

Methods of nonlocal density functional theory (NLDFT), proposed recently for predictions of adsorption equilibrium and calculations of pore size distributions in micro- and mesoporous materials, were tested on reference MCM-41 materials. Five newly synthesized MCM-41 adsorbents with presumably uniform pore channels varying from 32 to 45 Å were characterized by X-ray diffraction (XRD), nitrogen ...

background and purpose:the presence of dyes in wastewaters may cause serious problems for the environment because of their high toxicity to aquatic organisms and unfavorable aesthetical impact. in the present study, multi-walled carbon nanotubes (mwcnts) were used for removal of anionic dyes direct blue 106 (db106) and acid green 25 (ag25), from water samples. materials and methods:mwcnts were ...

The equilibrium properties of particle adsorption is investigated theoretically. The model relies on a free-energy formulation which allows us to generalize the Maxwell-Boltzmann description to solutions for which the bulk volume fraction of potentially adsorbed particles is very high. As an application we consider the equilibrium physical adsorption of neutral and charged particles from soluti...

An experimental study has been conducted on the adsorption of Direct red-28 dye using activated carbon prepared from Punica granatum (Pomegranate rind) by chemical activation with sulphuric acid. BET surface area of the activated carbon was determined as 1075.6 m.g and SEM observations showed the amorphous nature of the carbon. Adsorption kinetics, equilibrium and thermodynamics were investigat...

Recently, adsorption process has been introduced as a favorable and effective technique for the removal of metal ions from aqueous solutions. In the present study, bimetallic nanoparticles consisting of zero valent iron and silver were loaded on the activated carbon powder for the preparation of a new adsorbent (PAC-Fe(o)/Ag). The above adsorbent was characterized by using XRD, SEM and TEM tech...

The rate of reaction of trace metals between soils and solutions is important in predicting trace metal behavior as equilibrium may not be attained. Although chemical equilibrium models are commonly used for soil systems, there has been less progress in developing predictive kinetic models. Kinetics of Zn adsorption/desorption have been modeled based on the linear adsorption isotherm assumption...

A new type of thiourea cross-linked chitosan with Fe(III) as template (TCCTS template) was synthesized. The adsorption of Fe(II) and Fe(III) on this TCCTS template was studied. The factors affecting adsorption such as pH and contact time were considered. The results showed that the optimum pH value for adsorption was pH = 5.0 and the adsorption equilibrium time was about 60 min. The adsorption ...

an agricultural waste i.e. rice husk has been used as a cheap adsorbent for the removal ofleadas a harmful heavy metal from contaminated water via adsorption. the adsorption capacity of rice husk was calculated by equilibrium models. the results showed that the adsorption process has the best accordance with langmuir model. the kinetics of the adsorption was also investigated and obtained that ...