Design of Cu-Doped Goethite for Fenton-like Degradation of Tetracycline: An Integrative Undergraduate Laboratory Module in Wastewater Remediation

To bridge the gap between theoretical courses and practical application, this laboratory module engages upper-level undergraduates in the rational design of Fenton-like systems. Herein, students synthesized Cu-doped goethite (Cu-FeOOH) cocatalyst using a simple coprecipitation method and evaluated its performance in activating hydrogen peroxide (H 2 O 2 ) for tetracycline degradation. Integrated characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) enabled students to link microscopic catalytic structures with macroscopic degradation performance. The optimized 10Cu-FeOOH/H 2 O 2 system achieved 99% tetracycline removal within 60 min, representing a nearly 3.1-fold enhancement in the rate constant (k = 0.0277 min –1 ) over the undoped α-FeOOH/H 2 O 2 system (k = 0.0089 min –1 ). Mechanistic exploration via electron paramagnetic resonance (EPR) spectroscopy and thermodynamic evaluations elucidated the synergistic Cu–Fe redox relay, demonstrating that Cu doping overcomes the kinetic bottlenecks of traditional iron cycles. By treating real wastewater containing tetracycline, students explored complex matrix disturbances, effectively linking materials science with practical environmental applications. This 16-h experiment aims to develop technical competencies, critical thinking, and environmental awareness, preparing students for professional challenges in the field of sustainable water purification.