Optimized degradation of emerging contaminants in hospital wastewater using novel Ti4O7 coated graphite anode in an electrochemical advanced oxidation process

Removing low-concentration emerging contaminants from wastewater is crucial, especially for hospital effluents. Electrochemical oxidation (EO), a sustainable advanced oxidation process (AOP), offers a promising solution. However, finding cost-effective anodic materials with high oxygen evolution potential (OEP) remains a significant challenge. This study explores the use of Ti 4 O 7 -coated graphite plates (Ti 4 O 7 @Gr) as anodes for EO in treating hospital wastewater (HWW). Ti 4 O 7 , known for its superior OEP and simple preparation, was synthesized by reducing a Ti and TiO 2 mixture in a tube furnace and then coating it onto graphite plates via wet chemistry. XRD confirmed the formation of the Magnéli phase of TiO 2 , with SEM images showing a compact Ti 4 O 7 coating on the graphite plate. Performance was tested using a 3-level central composite design (CCD), and the results confirmed a well-fit quadratic model with p-values < 0.0001 and high correlation coefficients (R 2 > 0.99) for all the responses. The EO reactor achieved 99.39% removal of pharmaceuticals like ciprofloxacin (CIP), levofloxacin (LFX), ofloxacin (OFX), ampicillin (AMP), and sulfamethoxazole (SMX) at an optimized pH value of 6.87, 64.85 mM electrolyte concentration, and 7.23 mA cm -2 current density after 2 h. Mineralization efficiencies were 81.27% for total organic carbon (TOC) and 66.39% for chemical oxygen demand (COD). Radical scavenging experiments were conducted to determine the dominant reactive species, and the proposed mechanisms were elucidated. Applying this system to real HWW showed a slight decrease in removal efficiencies, but Ti 4 O 7 @Gr anode demonstrated high stability and effectiveness, making it a robust benchmark for efficient and sustainable HWW treatment. • EO effectively removes emerging contaminants from hospital wastewater (HWW). • Synthesis of high-performance Magnéli phase Ti 4 O 7 through a wet chemistry approach. • Achieved enhanced treatment efficiency with optimal conditions using RSM. • Followed pseudo-first-order kinetics with 99.4% PCs removal and 81.3% mineralization. • Demonstrated superior performance and robust stability in treating actual HWW.