Fabrication of Porous Metallic Bismuth-Based Blocks via 3D Printing and Their Performance in Chloride Removal

• • At pH 0.1, Bi-PM achieved 53.6% chloride removal in dark and 69.3% under light, demonstrating a 15.7 percentage-point enhancement from photoactivation, critical for acidic industrial effluents. • • At pH 0.5, dark removal was 31.0% rising to 38.1% under light; this pH was selected as optimal for balancing efficiency and shape retention, preventing Bi layer detachment. • • Over five cycles at pH 0.5, average removal efficiency was 25% (dark) versus 41.2% (light), with the fifth cycle maintaining ~40% under light, indicating superior operational stability and reduced Bi loss. • • Radical trapping experiments ranked active species as h+ > Cl· > O2·− > ·OH, with holes being the dominant contributor, guiding mechanistic understanding for process optimization.