# sepfactor: Calculates separation factors between two transported species In transmem: Treatment of Membrane-Transport Data

## Description

Given the transport data frames of two species, the function calculates the separation factors of the main species A against a secondary species B for each sample taken. If the dataset of secondary species is smaller than that of the main species (e.g. if secondary species were determined in only half the aliquots), the transport profile is completed using fixSecondary function and a message will be printed.

## Usage

 1 sepfactor(main, secon, order = 2, mode = "batch", plot = TRUE) 

## Arguments

 main Main species transport data. Must be a data frame generated using conc2frac, data normalization is indifferent. secon Undesired species transport data. Must be a data frame generated using conc2frac, data normalization is indifferent. order Gives the polinomia order to be used if the secondary species information needs to be corrected due to missing data. mode Operation mode of the membranse system. Only 'batch' and 'continuous' allowed. For semicontinuous systems the separation factor is calculated as for continuous systems. plot Logical. If TRUE, the default, the plot is printed in the current graphical device.

## Details

Separation factor for batch systems at any time different from zero is defined as

SF_{A/B}(t)=\frac{C_a/C_b}{C_a^0/C_b^0}

where C_a and C_b are the concentrations of A and B, respectively, in the strip solution at a time t, and C_a^0 and C_b^0 are the concentrations of A and B, respectively, in the feed phase at t=0 (Chen et al., 2018).

For continuous or semicontinuous systems, the separation factor is calculated according to the equation

SF_{A/B}(t)\frac{C_{a,~s}/C_{b,~s}}{C_{a,~f}/C_{b,~f}}

where C_{a,~s}, C_{b,~s} are A and B concentrations in the strip phase at a time t and C_{a,~f}, C_{b,~f} are the concentrations of A and B in the feed solution at a time t (Koros and Shimidzu, 1996). Separation factor at t=0 equals 1 indicating that no species separation has occurred yet.

## Value

Data frame with two variables: Time in the same units as provided data and SF with the separation factors at each time.

## Author(s)

Cristhian Paredes, craparedesca@unal.edu.co

Eduardo Rodriguez de San Miguel, erdsmg@unam.mx

## References

Q. B. Chen, Z. Y. Ji, J. Liu, Y. Y. Zhao, S. Z. Wang, J. S. Yuan, Development of recovering lithium from brines by selective-electrodialysis: Effect of coexisting cations on the migration of lithium, Journal of Membrane Science 548 (2018) 408-420. doi:10.1016/j.memsci.2017.11.040.505

J. Koros, H. Ma, T. Shimidzu, Terminology for membranes and membrane processes (iupac recommendations 1996), Pure and Applied Chemistry 68 (7) (1996) 1479-1489. doi:10.1351/pac199668071479.

## Examples

 1 2 3 4 5  data(seawaterLiNaK) sepfactor(main = seawaterLiNaK$Lithium.1, secon = seawaterLiNaK$Sodium.1) sepfactor(main = seawaterLiNaK$Lithium.1, secon = seawaterLiNaK$Potassium.1) 

transmem documentation built on July 1, 2020, 10:38 p.m.