Multi‐Walled Carbon Nanotubes Loaded with Nickel‐Manganese Bimetallic as Three‐Dimensional Particle Electrodes for the Removal of 2,2′‐bipyridine From Photovoltaic Copper Electroplating Wastewater: Process Preparation, Influencing Factors and Mechanisms

ABSTRACT 2,2′‐Bipyridine (Bpy) serves as an essential cathodic polarization additive in the copper electroplating process of photovoltaic silicon wafers. Its presence significantly inhibits biochemical reactions and exhibits toxic effects, thereby emphasizing the urgent need for an effective removal method. This study introduces the development of multi‐walled carbon nanotubes (MWCNTs)‐supported nickel‐manganese bimetallic particles (Ni‐Mn@MWCNTs) as 3D electrocatalytic agents for Bpy degradation. Fundamental characterization (FTIR, Raman, XRD, BET, XPS) confirms successful loading of Ni‐Mn onto the MWCNTs framework, significantly increasing defect sites and enhancing electrochemical activity. Electrochemical testing indicates optimal performance at a Ni:Mn ratio of 2:1, current density of 4 mA/cm 2 , particle dosage of 4 g/L, and electrode spacing of 2 cm, achieving 88.09% degradation of Bpy from an initial concentration of 0.98 g/L. The system demonstrated efficacy across a broad pH range (1–9), with radical scavenging experiments and Electron Paramagnetic Resonance (EPR) analysis confirming ·OH and ·O 2 − radicals as primary active species. Reusability testing confirmed high stability and recyclability. Liquid Chromatography‐Mass Spectrometry (LC‐MS) and Density Functional Theory (DFT) calculations proposed a plausible Bpy mineralization pathway. Toxicity assessments indicated reduced neurotoxicity to humans and aquatic toxicity for degradation intermediates. Overall, this study provides an innovative, efficient, and environmentally friendly electrochemical solution for removing pyridinium ions from photovoltaic manufacturing wastewater.