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In this article, we report the silver orthophosphate (Ag3PO4) photocatalytic inactivation properties on strains Gram-positive Saprophyte B. subtilis, a diploid fungus Candida albicans and Gram-negative Pseudomonas aeruginosa, using as irradiation source white-light-emitting diodes (WLEDs) with luminous flux (Φ v) of 1.3 × 103 Lumens and relative power density of 15 mW m−2. Microorganisms death curves and the kinetic constants (Kd) indicated that the inhibitory effect of the Ag3PO4 under WLEDs irradiation is well pronounced to C. albicans (6.6 × 10–2 min−1) in relation to P. augenosas (4.6 × 10–2 min−1) and B. subitilis (2.5 × 10–2 min−1). Decimal reduction time (Dt) were 34.4 min to C. albicans, 50.1 min P. augenosas and 92.1 min to B.subitilis. The micrographs obtained by scanning electron microscopy with field emission gun (SEM-FEG) demonstrated that there was cell wall permeability and consequently total rupture in the C. albicans, suggesting the lipid peroxidation phenomenon and protein oxidation promoted by the presence of reactive oxygen species (ROS). Furthermore, it was observed the Ag3PO4 when irradiated by WLEDs demonstrates important sporicidal activity in related to B. subtilis, promoting the endospore wall rupture.

This work presents results of synthesis and characterization of Ag3PO4 and Fe3O4 as well as the AgP-Mag1 and AgP-Mag2 composites. The X-ray diffraction (XRD) elucidated the formation of the composites. Ag3PO4 has a body centered cubic structure with high crystallinity. The UV–Vis and Raman spectroscopy analyses indicate that a synergistic interaction occurs between Ag3PO4 and Fe3O4. The vibration sample magnetometry analysis showed the magnetic behavior of the composites through the hysteresis curves. Photocatalytic activities performed at 120 min evidenced significant results for degradation of Rhodamine-B dye (RhB) using Ag3PO4, AgP-Mag1 and AgP-Mag2 composites (98%, 100%, and 100%, respectively). In addition, the catalytic cycles revealed that the photocatalytic efficiency of the composite was preserved over that of the pure semiconductor, and 100% degradation of the dye at 120 min could be obtained in the third catalytic cycle. The toxicity studies demonstrated that photodegradation products did not have genotoxicity, cytotoxicity, and mutagenicity, indicating that RhB was degraded into carbon dioxide and water or into other nontoxic products.

In this article, we report the silver orthophosphate (Ag3PO4) photocatalytic inactivation properties on strains Gram-positive Saprophyte B. subtilis, a diploid fungus Candida albicans and Gram-negative Pseudomonas aeruginosa, using as irradiation source white-light-emitting diodes (WLEDs) with luminous flux (Φ v) of 1.3 x 103 Lumens and relative power density of 15 mW m− 2. Microorganisms death curves and the kinetic constants (Kd) indicated that the inhibitory effect of the Ag3PO4 under WLEDs irradiation is well pronounced to C. albicans (6.6 x 10− 2 min− 1) in relation to P. augenosas (4.6 x 10− 2 min− 1) and B. subitilis (2.5 x 10− 2 min− 1). Decimal reduction time (Dt) were 34.4 min to C. albicans, 50.1 min P. augenosas and 92.1 min to B.subitilis The micrographs obtained by scanning electron microscopy with field emission gun (SEM-FEG) demonstrated that there was cell wall permeability and consequently total rupture in the C. albicans, suggesting the lipid peroxidation phenomenon and protein oxidation promoted by the presence of reactive oxygen species (ROS). Furthermore, it was observed the Ag3PO4 when irradiated by WLEDs demonstrates important sporicidal activity in related to B. subtilis, promoting the endospore wall rupture.

Ciprofloxacin (CIP) is a fluoroquinolone antibiotic sensitive to conventional degradation, which allows for the development of greater environmental bacterial resistance. Thus, CIP degradation was evaluated under polychromatic irradiation over silver phosphate and SBA-15 substrates. X-ray diffraction patterns indicated that Ag3PO4 and mesoporous hexagonal SBA-15 showed good crystallinity. The Rietveld refinement was used to index the Ag3PO4 phase. The active vibrational modes related to the characteristic groups of the photocatalysts were identified using Raman spectroscopy and Fourier-transform infrared spectroscopy. Field-emission scanning electron microscopy images revealed that 498-nm cube-like Ag3PO4 particles were predominant. Ultraviolet–visible diffuse reflectance spectroscopy showed that Ag3PO4 and Ag3PO4/SBA-15(20%) showed bandgap energies of 2.25 and 2.14 eV, respectively. Impregnating Ag3PO4 with SBA-15 reduced the specific surface area from 582.1 (for SBA-15) to 373.3 m2 g−1 (for Ag3PO4/SBA-15(20%)). Photocatalytic tests showed that CIP was 78.5% photodegraded using only Ag3PO4 and was 61.96% photodegraded in the presence of Ag3PO4/SBA-15(20%) when irradiated with polychromatic light for 210 min.

Dichlorophenoxyacetic acid (2,4-D) is an herbicide widely used in extensive agriculture, toxic to humans and other animals, in addition to causing contamination of water resources. The 2.4-D is resistant to conventional degradation processes, in this context, heterogeneous photocatalysis is presented as a promising alternative in the degradation of this type of micropollutant. This work aims to synthesize, characterize and evaluate the catalytic activity of Fe3O4@WO3/SBA-15 in the photodegradation of (2.4-D) under ultraviolet irradiation. The nanomaterials were obtained by the co-precipitation, solvothermal and hydrothermal methods. The XRD patterns showed that the insertion of Fe3O4@WO3 in SBA-15 (5, 10 and 20 %) did not destroy the support mesoporous structure as well as indicated Fe3O4 and WO3 chrystillen phases. The core-shell morphology was confirmed by micrographs (FESEM, TEM and HRTEM) as well as the average size of the particles of WO3 = 35.8 nm and Fe3O4 = 13.3 nm. The energetic gap of nanomaterials were (WO3 = 2.6, Fe3O4 = 2.8, Fe3O4@WO3 = 1.9, Fe3O4@WO3/SBA-15 (5 %). = 2.7, Fe3O4@WO3/SBA-15 (10 %) = 1.7 and Fe3O4 @ WO3/SBA-15 (20 %) = 1.8). The Fe3O4@WO3/SBA-15 (X%) samples showed magnetic properties and photocatalict efficience for 2,4 D photodegradation under UV irradiation. The Fe3O4@WO3/SBA-15 (5 %) sample has promoted 90.73 % of degradation of the herbicede, at 240 min.