Adsorption of humic acid from aqueous solutions on organo Mg-Fe-SDS

Abstract

In this study, Organophilic LDH was prepared by interposing a surfactant (sodium dodecylsulfate, SDS 0.1 M) and applied for the removal of humic acid from solutions in batch system, the synthesized adsorbent (Mg-Fe-SDS) was characterized by FTIR, X-ray diffraction, and BET. Several adsorption kinetics models (pseudo-first order, pseudo-second order, n^th-order and intraparticule diffusion) were tested against the experimental results. The calculation of the corresponding parameters show that results are best fitted with n^th-order (n €R⁺), n≠1model with a determination coefficient close to 1 and a relatively small root mean square error. Among the available mathematical models used to describe the isotherms experimental results (Langmuir, Freundlich and many-parameters models). The three models that are proposed show a better performance than Freundlich, Langmuir. The calculation of the parameters of the different adsorption models was performed on MATLAB using genetic algorithms. Thermodynamic analysis of sorption isotherms suggest that sorption process of humic acid is spontaneous (ΔG°<0), with a positive enthalpy variation, characteristic of an endothermic process.