Novel iminodiacetic acid functionalized basalt fiber for adsorption of Cu (II) ions in batch experiments

Abstract

A novel composite adsorbent was prepared by polydopamine (PDA) coating, amination, and carboxylation modification using basalt fiber (BF) as the carrier material for the removal of Cu²⁺ from water. The resulting adsorbent, BF/PDA-iminodiacetic acid (IDA), was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The effects of pH, ionic strength, temperature, and duration on the adsorption properties of BF/PDA-IDA were investigated by batch experiments. The maximum uptake capacity for Cu²⁺ was 22.96 mg/g at 303 K. The adsorption process conformed to pseudo-second-order kinetics and the equilibrium can be reached within two hours. The Langmuir isotherm equation fitted well to the adsorption isotherm experimental data. Thermodynamic analysis showed that the adsorption process was spontaneous and exothermal. Furthermore, BF/PDA-IDA can be easily recovered by 0.1 mol/L Na₂EDTA and about 90% adsorption capacity remained after four successive regeneration cycles. The adsorption mechanism could be a combination of chelation and electrostatic interactions. This study demonstrated that the adsorbent prepared from BF skeleton has great potential to remove Cu²⁺ from water.

Graphical Abstract

Highlights

• BF/PDA-IDA was prepared by grafting amine and carboxyl groups onto basalt fiber.

• The adsorption performance of BF/PDA-IDA for Cu²⁺ was investigated.

• The desorption rate of BF/PDA-IDA reached more than 99%.

• The adsorption mechanism of Cu²⁺ is the result of coordination and electrostatic interactions.

Keywords:

• Heavy metal
• separation
• basalt fiber
• dopamine
• surface modification

Additional information

Funding

This work was supported by the National Key R & D Program of China (2017YFC0504505).