Electrochemical heavy metal removal from water using PVC waste-derived N, S co-doped carbon materials

The removal of heavy metal contaminants has aroused global attention due to water shortage and the lax control on the discharge of heavy metal pollutants. Capacitive deionization (CDI) has emerged as a robust, energy-/cost-efficient technique for water treatment. Herein, we reported the simple synthesis of N, S-co-doped carbon materials (NS-C) derived from PVC plastic wastes as CDI electrode materials for the efficient removal of heavy metal ions (HMIs). The NS-C exhibited a large specific surface area (∼1230 m² g^-1) and contained heavy heteroatom doping (∼4.55 at% N and ∼13.30 at% S). The CDI electrode fabricated using NS-C showed high removal efficiency (94-99%), high capacity (36-62 mg g^-1), and good regeneration capability for the adsorption of various kinds of low-concentration heavy metal ions (including Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Pb²⁺, and Cd²⁺). Moreover, PVC plastic wastes that are heavily accumulated in the environment and extremely hard to be decomposed and recycled were applied as the carbon source in this study for the fabrication of NS-C, which further rendered the importance of our study in practically treating hazardous waste (HMIs) with waste (PVC plastic wastes) in a clean and efficient way.