1：Experimental Design and Method Selection:

The study employed a hydrothermal synthesis method to prepare g-C3N4/CdWO4 composites, chosen for its ability to form well-crystallized materials with controlled morphology. Theoretical models included the use of XRD for phase analysis, SEM and TEM for morphology, FTIR for chemical bonding, UV-Vis for optical properties, and PL for charge recombination analysis. The photocatalytic degradation followed pseudo-first-order kinetics.

2：Sample Selection and Data Sources:

Samples included pure g-C3N4, pure CdWO4, and g-C3N4/CdWO4 composites with mass ratios of

3：

1,

4：

1,

5：

1, and

6：

1. Minocycline antibiotic (20 ppm concentration) was used as the pollutant in aqueous solution.

7：Minocycline antibiotic (20 ppm concentration) was used as the pollutant in aqueous solution. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a tube furnace for g-C3N4 synthesis, autoclave for hydrothermal treatment, magnetic stirrer, hot plate, ultrasonic disperser, electric oven, XRD (Philips X’Pert Pro MPD), FESEM and EDS (Hitachi S-3500), FTIR (Nicolet Avatar-370), UV-Vis-NIR spectrophotometer (Hitachi-4100), PL spectrometer (Hitachi FL-4500), centrifuge, and UV-Visible spectrophotometer. Materials were melamine, cadmium acetate dihydrate, acetic acid, sodium tungstate dihydrate, minocycline, ethanol, and distilled water.

8：Experimental Procedures and Operational Workflow:

g-C3N4 was synthesized by heating melamine at 520°C. CdWO4 was prepared by mixing cadmium nitrate and sodium tungstate solutions, followed by hydrothermal treatment at 180°C. Composites were made by mixing g-C3N4 and CdWO4 in ethanol, ultrasonic dispersion, hydrothermal treatment at 180°C, washing, drying, and annealing at 465°C. Photocatalytic tests involved adding photocatalyst to MC solution, shaking in dark for adsorption-desorption equilibrium, irradiating with a 250 W xenon lamp (420 nm), sampling hourly, centrifuging, and measuring UV absorption.

9：Data Analysis Methods:

Data were analyzed using XRD for crystallinity, SEM and EDS for morphology and composition, FTIR for functional groups, UV-Vis for band gap calculation via Tauc plot, PL for recombination rates, and kinetic analysis using the pseudo-first-order model for degradation rates.