Cobalt oxide, sulfide and phosphide-decorated carbon felt for the capacitive deionization of lead ions

Remediation and recovery of highly toxic lead ions are highly important for water purification. In this study, a simple two-step method is developed to obtain the cobalt phosphide-decorated active carbon felt (ACF-CoP) materials for capacitive deionization of dilute Pb2+ (50 mg/L). The as-prepared ACF-CoP materials exhibit higher capacitance of 182.4 F/g than the corresponding ones of pristine ACF, ACF-CoS and ACF-Co3O4, which is possibly due to the surface Co3+ groups and abundant defect sites. Therefore, the Pb2+ ions were successfully recovered with an effective capacity of 90 mg/g at low voltage of -0.6 V. Furthermore, great charge/discharge stability and large voltage application range were also achieved in the as-fabricated ACF-CoP materials.