The plasma assisted preparation of Fe-MOFs with high adsorption capacity

Abstract

Fe-MOFs were successfully synthesized via a dielectric barrier discharge (DBD) plasma method and applied to methyl orange adsorption. Fe-MOFs were characterized via XRD, SEM, FT-IR, BET and zeta potential analysis. A systematic study was carried out to optimize the synthesis conditions, taking into account the adsorption capacity of the Fe-MOFs. The optimum conditions were determined to be: a discharge time of 80 min; a discharge voltage of 18 kV; a reactant concentration of 10 mg mL⁻¹; and a mass ratio of terephthalic acid to ferric chloride hexahydrate of 1 : 1. Fe-MOFs synthesized under the optimum conditions exhibited an adsorption capacity of 750 mg g⁻¹, at a methyl orange concentration of 100 mg L⁻¹ and with an Fe-MOF dosage of 0.1 g L⁻¹. The kinetic adsorption data showed a good fit to the pseudo-second-order kinetics equation, while the isotherm data were well modeled using the Langmuir equation. Plasma preparation was shown to be an effective method for the preparation of MOFs.