A facile and green synthesis of Mn and P functionalized graphitic carbon nitride nanosheets for spintronics devices and enhanced photocatalytic performance under visible-light.

Manganese and phosphorus co-doped, graphitic carbon nitride (g-C3N4) nanosheet (Mn/P-g-C3N4) is prepared by facile and green calcination process of melamine (C3H6N6), manganese chloride tetrahydrate (MnCl2·4H2O), and ammonium dihydrogen phosphate ((NH4)H2PO4). The Mn/P co-doping significantly enhances magnetic values compared to pristine-g-C3N4, phosphorus-doped g-C3N4 (P-g-C3N4), and manganese-doped g-C3N4 (Mn-g-C3N4). We find that Mn/P-g-C3N4 is a half-metallic ferromagnetic material having a magnetic moment and Curie temperature of 4.51 µB and âˆ¼ 800 K, respectively. The ultraviolet-visible (UV-vis) absorption spectrum of Mn/P-g-C3N4 reveals superior absorption in broader wavelength compared to pristine-g-C3N4, P-g-C3N4, and Mn-g-C3N4. The methyl orange degradation efficiency of Mn/P-g-C3N4 photocatalyst is 94 %, which is three times more than that of pristine-g-C3N4 (29 %) and more significant than the P-g-C3N4 (46 %) and Mn-g-C3N4 (58 %). Furthermore, density functional theory (DFT) calculation explains the origin of high magnetic behavior, the boosted photocatalytic efficiency of Mn/P-g-C3N4, and the essential material properties like structure, bandgap, the density of states (DOS), and atomic level interaction. This work may be helpful for reasonably designing ferromagnetic material for spintronics devices and boosting visible-light (VL) photocatalytic performance for environmental remediation.

Synthesis and characterization of titanium-substituted nanocrystalline Co2-Y hexaferrite: magnetically retrievable photocatalyst for treatment of methyl orange contaminated wastewater.

Rapid industrial growth causes considerable environmental havoc, adversely affecting human and aqueous life. It becomes a significant concern to deal with adequate wastewater treatment strategies by converging on water scarcity. This research work explored the synthesis of titanium-substituted Y-type barium hexaferrite (Co2-Y), having a general formula of Ba2Co2Fe12-xTixO22 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5), using a facile nitrate-based sol-gel auto-combustion route and its suitability was investigated as a heterogeneous catalyst within the photo-Fenton-based degradation of methyl orange (MO), one of the significant pollutants generated from textile industries. Developing a thermochemically stable and magnetically separable heterogeneous catalyst for photocatalytic decomposition of nonbiodegradable organic dye from wastewater was also emphasized. The as-prepared nanocrystalline Co2-Y powders were analyzed using XRD, FTIR, DLS, UV-visible spectroscopy, SEM, VSM, and XPS. Furthermore, the photocatalytic degradation performance of pristine and titanium substituted Ba2Co2Fe11.6Ti0.4O22 ferrite, having the lowest bandgap value among all samples, was quantified and compared in terms of apparent rate constant (karc) value and turnover frequency values. The enriched photocatalytic performance was correlated with the existence of multi-valance states of transition metal cations and the availability of oxygen vacancy, confirmed by the surface chemistry using the XPS analysis. The modified (enhanced thermal and chemical stability) hexaferrite catalyst was magnetically separable and reusable without significant losses to its catalytic performance. This promising catalyst may be considered as a replacement for soft ferrite materials to catalyze the degradation of several other nonbiodegradable organic pollutants from wastewater in large-scale industries.

Retinal pigment epithelium tear in vogt-koyanagi-harada disease.

PURPOSE: The purpose of this study was to report a case of Vogt-Koyanagi-Harada disease causing large tears of the retinal pigment epithelium (RPE). METHODS: Case report and literature review. RESULTS: A 41-year-old woman presented with headache, tinnitus, and bilateral panuveitis with multiple serous retinal detachments. She was started on oral prednisone, and the inflammation and serous detachments subsided. However, 2 weeks later, she developed large RPE tears. CONCLUSION: Vogt-Koyanagi-Harada disease is an inflammatory disorder of the choroid; however, irregularities in the RPE have been noted, most recently with the use of spectral domain ophthalmic coherence tomography. The finding of RPE tear with resolution of serous retinal detachment may further implicate involvement of the RPE in the disease process.