Adsorption of methylparaben from aquatic solutions by CoFe2O4: isotherm, kinetic, thermodynamic, and equilibrium studies

Abstract

Methylparaben (MePB) as an emerging contaminant (ECs) is most widely used in the ingredient of the industrial products due to its accessibility, high antimicrobial effects, and cost-effectiveness. Exposure to this pollutant via drinking water can disrupt the endocrine system. This study aimed to investigate the efficiency of CoFe2O4 for the adsorption of the MePB from aquatic solutions. CoFe2O4 was synthesized by the sol-gel method and characterized using FESEM, FTIR, XRD, and BET. The maximum removal efficiency of MePB was 99.03, achieved under optimized conditions (pH = 5, CoFe2O4 = 0.3 g/L, MePB = 30 mu g/L, and contact time = 55 min). The adsorption mechanisms mainly involved strong electrostatic and chemical interactions, with functional groups such as phenolic-OH and ester C--O actively participating in binding to the metal active sites on the mesoporous CoFe2O4 surface. The adsorption isotherm and kinetics were best described by the Langmuir and pseudo-secondorder models, respectively. In the present study, the maximum adsorption capacity was 142.19 mg/g. Thermodynamic analysis revealed that the adsorption of MePB onto CoFe2O4 was spontaneous and endothermic.