Preparation of areca residue activated carbon composite and its adsorption performance for uranium (VI) in wastewater

Abstract

In this paper, areca residue was used as a new material to prepare activated carbon by microwave. With the iodine adsorption value of wood activated carbon as the main index, the adsorption capacity of activated carbon to uranium was investigated by static adsorption experiment with the different pH value of uranium solution, initial concentration of uranium solution, dosage of areca residue activated carbon and adsorption time. On this basis, the impact of microwave irradiation time, activator concentration and activator immersion time on the production process of activated carbon was analyzed. The structure of the prepared activated carbon from areca residue before and after adsorption treatment was explored by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy. The results showed that the activated carbon prepared by areca residue had the best adsorption effect when the concentration of activator with NaOH was 20%, the soaking time of activator was 36 h, and the microwave irradiation time with power of 700 W was 2 min. It is found that the best percentage removal of uranium from solution was 92.8% under pH value of 7, the dosage of areca residue activated carbon of 8 g/L and the adsorption time of 7 h. The kinetic data followed the pseudo-second-order model. The hydroxyl, carbonyl, carboxyl and C=C groups on the surface of the prepared activated carbon were responsible for adsorption of uranium. Desorption and regeneration processes showed that the activated carbon material prepared by areca residue had the potential of regeneration and reuse.