Phosphate ion adsorption properties of PAN-based activated carbon fibers prepared with K2CO3 activation

Abstract

Adsorbents for phosphate ion removal were prepared with K2CO3 activation and heat treatment at 950 °C from polyacrylonitrile-based carbon fiber (PAN-CF). Comparative tests for specific surface area and pore structures, elemental and nitrogen species analysis, and phosphate ion adsorption experiments demonstrated that K(3)-Δ, which was activated with K2CO3/PAN-CF weight ratio of 3 and then treated at 950 °C, exhibited larger amount of quaternized-nitrogen (0.46 wt%) and equilibrium adsorption amount (0.23 mmol/g) among the prepared adsorbents. The experimental data for phosphate adsorption of K(3)-Δ was well fitted to Langmuir adsorption isotherms and pseudo-second-order kinetic model. As for regeneration performance, K(3)-Δ still remained more than 60% adsorption amount of the fresh adsorbent after rejuvenation treatment.