Enhanced Cl- electrosorptive performance of activated carbon fibre via modification by TiO2 and polyaniline

Chloride ions in reclaimed water are the main contributors to corrosion of pipelines. In this study, titanium dioxide (TiO2)-and polyaniline (PANI)-modified activated carbon fibre (ACF) electrodes were prepared using the sol-gel method and in situ polymerisation, and their Cl- electrosorptive performance in simulated reclaimed water was extensively investigated. The prepared materials were characterised using X-ray diffraction, scanning electron microscopy, N2 adsorption, and Fourier-transform infrared spectroscopy. The experimental results indicated that the optimal Cl- removal rate from the ACF/TiO2/PANI electrode reached 85.34% when the calcination temperature of TiO2 was 400 degrees C and the polymerisation concentration of PANI was 0.02 mol center dot L 1. This study demonstrated that the ACF/TiO2/PANI electrode showed an excellent equilibrium adsorption capacity of 17.1 mg center dot g 1, which was 1.4 times that of the parent ACF. The superior performance was attributed to the modification of TiO2 and PANI, which considerably improved the hydrophilicity, conductivity, and physical adsorption capacity of the electrode. Consequently, the electrosorption rate and adsorption capacity were enhanced. In addition, the prepared ACF/TiO2/PANI electrode exhibited a high Cl- removal rate of 80.42% (adsorption capacity of 16.88 mg center dot g 1) in actual reclaimed water. Based on these results, the electrosorption kinetics and mechanism of the prepared ACF/TiO2/PANI electrode were analysed further.