Isotherm investigation for the sorption of fluoride onto Bio-F: comparison of linear and non-linear regression method

Abstract

A comparison of the linear and non-linear regression method in selecting the optimum isotherm among three most commonly used adsorption isotherms (Langmuir, Freundlich, and Redlich-Peterson) was made to the experimental data of fluoride (F) sorption onto Bio-F at a solution temperature of 30 ± 1°C. The coefficient of correlation (r 2 ) was used to select the best theoretical isotherm among the investigated ones. A total of four Langmuir linear equations were discussed and out of which linear form of most popular Langmuir-1 and Langmuir-2 showed the higher coefficient of determination (0.976 and 0.989) as compared to other Langmuir linear equations. Freundlich and Redlich-Peterson isotherms showed a better fit to the experimental data in linear least-square method, while in non-linear method Redlich-Peterson isotherm equations showed the best fit to the tested data set. The present study showed that the non-linear method could be a better way to obtain the isotherm parameters and represent the most suitable isotherm. Redlich-Peterson isotherm was found to be the best representative (r 2 = 0.999) for this sorption system. It is also observed that the values of b are not close to unity, which means the isotherms are approaching the Freundlich but not the Langmuir isotherm.

Mucin‐Based Composites for Efficient Mercuric Biosorption

“…Adsorption sites are considered homogenous. [ 55 ] Tóht on the other hand, is a three‐parameter model, with the addition of a parameter representing the heterogeneity of the surface, and thus may better reflect the mechanism complexity and the affinity of Hg 2+ to mucin as compared to Langmuir. [ 56 ] Using the adsorption results and Langmuir and Tóht fitting parameters, the mercuric adsorption capacity by mucin reaches 95.2 mg g(1 and 124.94 mg g(1, values of Qmax in Langmuir and Tóht models, respectively.…”

Pb2+ adsorption on functionalized biochar nanoparticles: Insights from nanoparticle characterization and kinetic‐isotherm analysis

“…However, applying linear fitting of models is improper because the distribution of errors may change due to the various linearization techniques. Therefore, using a model in its standard nonlinear form is more reliable in evaluating isotherm parameters (Yadav & Singh, 2017).…”

Properties and the Application of Sludge-Based Biochar in the Removal of Phosphate and Methylene Blue from Water: Effects of Acid Treating

“…The equation becomes linear when the surface coverage is 0, and it is simplified to the Langmuir model when g = 1. It is widely used for versatility. , …”