Ag3PO4 immobilized on hydroxy-metal pillared montmorillonite for the visible light driven degradation of acid red 18

This work reports the facile fabrication of Ag3PO4/Fe-Al/Mt and Ag3PO4/Al/Mt by loading Ag3PO4 on hydroxy-iron-aluminum pillared montmorillonite (Fe-Al/Mt) and hydroxy-aluminum pillared montmorillonite (Al/Mt). The structural characteristics of the resulting materials were studied with XRD, SEM-EDS, XPS, ICP, nitrogen adsorption-desorption isotherms, and UV-vis diffuse reflectance spectra; the photocatalytic activity of the obtained catalysts was tested using acid red 18 (AR18) as a model contaminant under visible light irradiation. The obtained results illustrate that Ag3PO4 of a high dispersity and smaller size was successfully loaded on hydroxy-metal pillared montmorillonite. The photocatalytic activity and structural stability of the three synthesized catalysts were in the order Ag3PO4/Fe-Al/Mt > Ag3PO4/Al/Mt > Ag3PO4. An efficiency of 98.5% was achieved for AR18 degradation by Ag3PO4/Fe-Al/Mt after recycling seven times, while only 54.9% was achieved for Ag3PO4. The superoxide radical anion (O(2)is approximately equal to) was confirmed to be the dominant reactive species in all the three degradation systems, and the Ag3PO4/Fe-Al/Mt system formed the largest amount of O(2)is approximately equal to. Except for the larger specific surface area and smaller particle size, the high removal efficiency of AR18, remarkable O(2)is approximately equal to generation performance, and good stability of Ag3PO4/Fe-Al/Mt could be attributed to the presence of Fe3+ as well, which can act as an electron acceptor for photoinduced electrons from Ag3PO4 during the photocatalytic process and then inhibit the transformation of Ag+ into metallic Ag.