Eco-Friendly Anionic Surfactant for the Removal of Methyl Red from Aqueous Matrices

This study aimed to evaluate the methyl red (MR) removal efficiency from aqueous matrices using an eco-friendly anionic surfactant (a calcium surfactant, or CaSF), obtained frying oil residue. Data by infrared spectroscopy revealed several functional groups that favor capture of dye chemisorption forming hydrogen bonds and covalent interactions. The kinetic testing results fit pseudo-second order model, reaching equilibrium in 30 min. Adsorption was greatly influenced temperature. Langmuir isotherm one best fitting process at 20 °C, while Dubinin–Radushkevich fitted it better higher temperatures. Under optimized conditions, maximal MR adsorption capacity CaSF reached 53.59 mg·g?1 rate 95.15%), proving adsorbent hand can be excellent alternative for undesirable levels present matrices.