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BaLa2ZnO5:Er3+/Yb3+ has been synthesized via a high temperature solid-state method, and the tunable upconversion luminescence and energy transfer process between Yb3+ and Er3+ in this system have been demonstrated. Upon 980 nm laser excitation, the intense green and red emission around 527, 553, and 664 nm were observed for BaLa2ZnO5:Er3+/Yb3+, which can be assigned to the characteristic energy level transitions of 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 of Er3+, respectively. The critical Er3+ quenching concentration (QC) was determined to be about 5 mol%, and the power studies indicated that mixture of 2- and 3-photon process was responsible for the green and red upconversion luminescence. [ABSTRACT FROM AUTHOR]

Alpha, beta, gamma, and delta hydroxyl ferric oxides (FeOOH), as the most common rust layers on iron surface, play different roles in iron preservation. Using modern surface analysis technologies such as X-ray diffraction (XRD), infrared spectra (IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), we studied the interactions between these four types of synthetic FeOOH and phosphoric and tannic acid of different concentrations and proportions. A 3% tannic acid + 10% phosphoric acid + FeOOH was the most suitable formula for rust stabilizer and its reaction products were made up of iron phosphate and chelate of iron and tannin. This research provided technical basis in distinguishing FeOOH and selecting rust layer stabilizer for the preservation of iron, especially iron cultural relics. [ABSTRACT FROM AUTHOR]

The efficiency of ciprofloxacin (CIP) adsorption on synthesized birnessite was systematically studied under varying physicochemical conditions, such as solution pH, contact time, initial CIP concentration, and different average oxidation states (AOS) of Mn in birnessite. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and molecular simulations were employed to investigate the adsorption mechanism of CIP on birnessite. Experimental results showed that surface adsorption instead of cation exchange was responsible for the uptake of CIP on birnessite. The quantum mechanics simulation showed that the final energy of the interaction between CIP and birnessite was smaller under the condition when the AOS of Mn was lower, in comparison to the case when the AOS of Mn was high. The highest CIP adsorption occurred under a weak alkaline condition. [ABSTRACT FROM AUTHOR]