Acceleration of photo-reduction and oxidation capabilities of Bi4O5I2/SPION@calcium alginate by metallic Ag: Wide spectral removal of nitrate and azithromycin.

[Display omitted] • Integrating calcium alginate and Ag@Bi 4 O 5 I 2 /SPION- Wide-spectral response. • Faster and selective photocatalytic reduction of NO 3 – into N 2. • Ag and Fe greatly enhance N 2 selectivity-under visible, NIR and solar light. • High performance degradation of azithromycin-●O 2 – active species-ESR probe. • In Built I 3 -/I- and Fe3+/Fe2+ redox and high CAlg adsorption potential. Wide spectral responsive photocatalysts with improved charge separation and transfer capacity have attracted researchers for various photo-oxidative and reductive applications. This work reports Vis-NIR active photocatalyst Ag@Bi 4 O 5 I 2 /SPION@calcium alginate (here in designated as ABSA) prepared by hydrothermal impregnation for high performance degradation of azithromycin (AZY) and selective reduction of NO 3 – into N 2. The composite catalyst ABSA shows 98.4% AZY degradation in 90 min with visible light. Surprisingly, the apparent rate constant for ABSA catalyst (0.08321 min−1) is ~ 8 times higher than bare Bi 4 O 5 I 2. The photocatalyst is capable of selectively reducing NO 3 – into N 2 with formic acid at a wide range of pH especially in acidic conditions with ~ 100% photo-reduction and 97.6% N 2 selectivity. The high performance is manifested in the excellent photoreduction and oxidative capabilities under UV, visible, NIR and sunlight. SPIONs and Ag improve the visible activity, I 3 -/I- redox mediates better charge flow and Ag provides "hot electrons" via SPR effect. ●O 2– radicals are the active species during AZY degradation as confirmed by ESR probe. ●CO 3 – plays immensely important role in selective NO 3 – reduction into N 2. This work reports a relatively simple photocatalytic system with more bio-benevolence utilizing Bi 4 O 5 I 2 and Calg and modifying with Fe 3 O 4 and Ag as dopants for a wide spectral photo-redox capability. The hybrid wide spectrum responsive material integrates environmental friendliness, robust structure, full recycling and stability with sturdy improvement in photocatalytic efficiency. [ABSTRACT FROM AUTHOR]