Self-powered Pb(II) removal driven by Zn-air batteries using N, P-doped active straw carbon as cathode

Electrochemical systems have been widely applied in heavy-metal ions (HMIs) pollution control, while their applications are greatly restricted by excessive energy consumption. Self-powered environmental remediation systems (SERSs) can shed the energy reliance to achieve HMIs decontamination and simultaneous electricity output through electrokinetic migration. In this work, SERSs based on Zn-air batteries (ZABs) were achieved to remove bivalent lead (Pb(II)) by circulating effluent as electrolyte. Straw biomass derived N, P functional active nanocarbon (NP-ASC) with hierarchical porosity and electron modulation effect was designed for achieving high oxygen reduction reaction (ORR) activity and efficient Pb(II) uptake. SERSs with electrode active area of 1 cm2 realize outstanding Pb(II) removal efficiency (98.1 %) and electricity generation (67.5 mWh∙cm−2) in simulated sewage. ZABs assembled with NP-ASC delivered specific capacity of 795 mAh∙g−1 and cycling stability for 340 h. This study provides a guide for designing a novel SERS using functionalized biomass nanocarbon.