Removal of 2,4-dichlorophenoxyacetic acid from aqueous solutions by modified magnetic nanoparticles with amino functional groups

The present study was performed on the adsorption of 2,4-Dichlorophenoxyacetic acid from aqueous solutions by aminemodified magnetic nanoparticles. The adsorbent was synthesized by the coprecipitation method. The adsorbent properties of Fe3O4@SiO2-NH2 were investigated using XRD, FTIR, TGA, VSM and TEM. Adsorbent efficacy was studied by investigating the effect of pH, initial concentration of pollutants, and adsorbent dose, and times. Finally, kinetics equations and isotherms models were used to describe the data. The results showed that the highest removal percentage was observed at pH 6 and the initial concentration 20 mg/l of 2,4-Dichlorophenoxyacetic acid. Adsorption capacity was increased by 65.3% bypassing the time from the beginning of the process to 60 min. The results from the study of isotherms and adsorption kinetics presented that the sorption procedure follows the pseudosecondorder kinetics and the Langmuir isotherm with R2 99. The maximum adsorption capacity of Fe3O4@SiO2-NH2 is 116.3 mg/g. Besides, thermodynamic studies have shown that the adsorption process in the present study is endothermic and spontaneous. The experiments showed that Fe3O4@SiO2-NH2 synthesized nanoparticles could be an excellent method to remove 2,4- Dichlorophenoxyacetic acid contaminants from the aqueous solutions due to the high efficiency, simplicity, and lack of secondary contamination in the solution.