| dc.description.abstract | Capacitive deionization (CDI) is an emerging water treatment technology with many
advantages, including low energy consumption, high efficiency, low cost, green and pollution free electrode regeneration. However, the electrode material is the main controlling factor for
achieving high CDI performance. For a long time, activated carbon (AC) has been a preferred
electrode material for CDI due to its availability, ease of preparation, low cost, and tunable
textural properties. However, the pristine AC lacks selectivity towards the targeted ions,
resulting in unnecessary energy consumption for treating polluted water and decreasing the
removal efficiency (RE) of the targeted pollutant. To improve ion selectivity, in this study,
composites of AC with metal oxides have been synthesized through a simple and one-step co precipitation method at ambient temperature (23-27°C) for defluoridation and removing
paraquat (PQ) from water. The composite properties were characterized by X-ray diffraction,
scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X ray spectroscopy, and Brunauer-Emmett-Teller analysis. In competitive fluoride (Fˉ) removal
CDI experiments, AC–Al4Fe2.5Ti4 composite reduced the Fˉ concentration from 5.15 to 1.18
mg/L, below the allowable limit of 1.5 mg/L set by the World Health Organization while
pristine AC reduced the Fˉ concentration to 4.5 mg/L. Also, AC–Al4Fe2.5Ti4 composite
demonstrated a high RE of 79% and excellent regeneration performance after continuous
electric adsorption–desorption cycles. Furthermore, CDI batch experiments compared the
electrosorption of paraquat (PQ) herbicide by the composite electrodes (AC-Al2O3: 1:1) and
pristine AC. The performance of the composite electrodes showed that PQ RE and
electrosorption capacity (EC) depend on aluminium content loading, applied potential, flow
rate, and charging time. At 1.2 V, a flow rate of 15 mL/min, and a charging time of 3 h, the
composite electrode demonstrated a RE, EC, and energy consumption of 95.5%, 1.27 mg/g,
and 0.055 kWh/m3
, respectively, compared to 62%, 0.83 mg/g, and 0.11 kWh/m3
for the
pristine AC. The presence of other ions/pollutants was found to have negligible interference on
PQ pesticide removal as the RE of the AC/Al2O3-1:1 composite in both artificial and natural
water were 95.5 and 87.5% while EC was 1.27 and 1.17 mg/g, respectively. Therefore, the
modified AC-metal oxides electrodes are promising and efficient materials for removing
inorganic pollutants from water, such as Fˉ and organic pollutants, including PQ pesticides for
CDI technology | en_US |
