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...

In chromatographic separations involving elutes with large differences in the molecular size, the adsorption saturation capacities of the elutes may differ because of the differences in the degree of size exclusion. With uneven saturation capacities, isotherm crossovers may occur, which often results in selectivity reversal. In this work, a new multicomponent isotherm has been developed for thi...

14 The mechanisms of sorption of four steroidal hormones – estradiol, estrone, progesterone and 15 testosterone – to electrodialysis (ED) membranes were investigated as a function of solution pH 16 and presence of humic acid (HA). Hormone-membrane partition coefficients (log KAEM/CEM) 17 determined through sorption isotherm experiments suggested that hormone sorption was due to 18 hydrogen bond...

A favorable isotherm open to the right to some extent is better than a linear isotherm to give shorter column height in pressure swing adsorption(PSA). We face to a problem how favorable isotherm is actually favorable in PSA operation. The purpose of this paper is to propose how to construct such a custom made isotherm which optimizes the PSA processes. The PSA mod...

High-speed counter-current chromatography (HSCCC) is a versatile technique in preparative separation and purification of pure compounds from complex matrices. As a preparative chromatography, there is a need to maximize the column production. Based on the plate theory of Van Deemter, the effect of the sample load on the separation was investigated in a preparative HSCCC with a 1000 ml column ca...

Comparison analysis of linear least-square method and non-linear method of three widely used isotherms (Langmuir, Freundlich, and Redlich-Peterson) were examined to experiment with Remazol Red (C.I. 18221) onto pistachio nut shells at a solution temperature of 293 K. All three isotherm equations showed a better fit to the experimental equilibrium data. The results show that the Langmuir model s...

The sorption isotherm is important information for evaluating the ability of an adsorption system to treat the industrial waste water. In this study, eleven datasets from literatures were selected and three two-parameter and threeparameter equations were used to evaluate adsorption systems. Quantitative criteria included six error functions, and the quantitative criterion was residual plots. Is...

Analytical isotherm equations such as Langmuir and Freundlich isotherms are widely used for modeling adsorption data. However, these isotherms are primarily useful for simulating data collected at a fixed pH value and cannot be easily adapted to simulate pH-dependent adsorption effects. Therefore, most adsorption studies currently use numerical surface-complexation models (SCMs), which are more...

A preferential interaction quadratic isotherm model for hydrophobic interaction chromatographic systems is presented in this paper. In this isotherm, the nonlinear effect of salt on the capacity factor is described using the preferential interaction model developed by Perkins et al. [J. Chromatogr. A, 766 (1997) 1]. This is then coupled with a quadratic nonlinear isotherm to describe nonlinear ...

abstract the availability of heavy metals in the soil is related to their partitioning between solution and solid phases and expressed by sorption isotherm. twenty surface soil samples (0-30 cm) belonging to five soil subgroups were taken from agricultural regions of western azerbaijan province. the sorption isotherms of pb were determined by equlibrating the soil with solutions containing 0, 1...