Efficient removal of Pb(II) by iminodiacetic acid modified magnetic mesoporous carbon

Abstract

Magnetic mesoporous adsorbent carbon modified with iminodiacetic acid (Fe3O4@mC-IDA), was prepared to remove Pb(II). The magnetic mesoporous carbon (Fe3O4@mC) was first synthesized by in-situ growing carbon layers on the surface of ferrosoferric oxide, which exhibited large specific surface area and mesoporous structure, and the template molecule and carbon source are both from rich and cheap magnesium citrate. Then, iminodiacetic acid (IDA) was attached to Fe3O4@mC by a ring opening reaction. Multiple characterization techniques were applied to demonstrate the synthesis of the adsorbent. The composite could achieve adsorption equilibrium of Pb(II) in 65 min, and had a maximum adsorption capacity of 429.23 mg g−1 for Pb(II). Langmuir isothermal, pseudo-2nd-order kinetics model and Elovich model could be relatively suitable for simulating the adsorption process. In addition, the adsorbent had fine reusability, and the removal rate of Pb (II) reached 90.67% after 5 cycles. The adsorption mechanistic study showed that COO− and tertiary amine formed tridentate chelates with Pb(II), and hydroxyl groups combined with Pb(II) through electrostatic attraction. These results suggested that Fe3O4@mC-IDA was a potential adsorbent for Pb(II) removal with fast adsorption speed, easy separation ability and fine reusability.