R/LangmuirParameters.R

In devalc/Sorption: Predicts Sorption Processes Using Empirical Models

#' Estimate Parameters of Langmuir model
#'
#' This function estimates langmuir isotherm model parameters using the linear form of langmuir equation.
#' @param Ce equilibrium solution concentrations in mg/l
#' @param Qe retention by solid (adsorption) in mg/kg
#' @param  output_fname file name/path to which the parameters will be exported (e.g: "analysis/langmuir.csv" )
#' @return A csv file containing the estimated parameters
#' @export



LangmuirParameters <- function(Ce, Qe, output_fname)
{
    x <- Ce
    y <- Ce/Qe
    fit <- lm(y ~ x)
    c <- fit$coefficients[[1]]
    slp<- fit$coefficients[[2]]
    qmax <- 1/slp
    KL<- 1/(qmax*c)
    Par_names_header<-paste0("parameters_",sub(pattern = "(.*)\\..*$", replacement = "\\1", basename (output_fname)))
    Par_names<- c("intercept","slope(1/qmax(mg/Kg))", "qmax(mg/Kg)", "KL")
    Par_values_header <- paste0("par_Values_",sub(pattern = "(.*)\\..*$", replacement = "\\1", basename (output_fname)))
    Par_values<- c(c,slp,qmax,KL)
    out_df <- data.frame(Par_names, Par_values)
    write.table(out_df, output_fname,sep = ",", row.names = FALSE, col.names = c(Par_names_header,  Par_values_header))
}