Search

The objective of this study was to investigate the photoluminescence properties of Al4B2O9:M (M = Dy3+, Sm3+, and Tb3+). The solution combustion method was employed to prepare Al4B2O9 doped with M ions. The synthesized aluminum borates were subjected to phase analysis using X-ray diffraction, while their photoluminescence properties were evaluated using a spectrofluorometer. Under excitation at 352 nm, Al4B2O9:Dy3+ exhibited emission peaks at 484, 578, and 701 nm. Similarly, when excited at 402 nm, Al4B2O9:Sm3+ emitted light at 563, 599, 645, and 702 nm. Finally, upon excitation at 238 nm, Al4B2O9:Tb3+ emitted light at 489, 544, 588, and 622 nm. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the photoluminescence properties of Bi3+-activated Sr3B2O6. Pure Sr3B2O6 and Bi3+-doped Sr3B2O6 were synthesized by a solution combustion method. The phase and photoluminescence analyses of the borates that were synthesized were determined by using X-ray diffraction and a spectrofluorometer respectively at room temperature. It was observed that the synthesized Bi3+-doped Sr3B2O6 emitted blue light (441 nm) upon excitation with 366 nm. Finally, the Stokes shift of Sr3B2O6:Bi3+ was calculated and found to be 4646 cm–1. [ABSTRACT FROM AUTHOR]

Today, increasing dyes pollution is of great importance for life. Leaving the dyes used in industries such as textiles without being discharged pollutes other water sources. In order to prevent this, different methods are used in the literature. In this study, SrAl2B2O7, a borate metal, was used to remove methyl blue (MB), an anionic dye, by batch adsorption method. Strontium aluminoborate (SrAl2B2O7) was prepared using a solution combustion method at 950 °C for 4 h in air. The prepared adsorbent was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The particle morphology of the adsorbent was investigated using scanning electron microscope (SEM). By using N2 adsorption–desorption, the Brunnauer, Emmet, and Teller (BET) specific surface area was found to be 1.9578 m2 g−1. The surface charge of the dye-adsorbed SrAl2B2O7 was determined based on zeta-potential measurements. Langmuir (R2=0.9897), Freundlich (R2=0.985), Dubinin & Radushkevic (R2=0.976), Scatchard (R2=0.881), Temkin & Pyzhev (R2=0.978) isotherms were calculated in the study. SrAl2B2O7 showed good adsorption performance for methyl blue (MB) with maximum adsorption capacities of 29.069 mg g−1 (Langmuir). Adsorption processes were also studied in detail. Thermodynamic and kinetic models; pseudo-first-order (R2=0.415), pseudo-second-order (R2=0.999), Elovich (R2=0.968) showed that adsorption using SrAl2B2O7 in MB removal is endothermic and pseudo-second order. [ABSTRACT FROM AUTHOR]

Abstract Sr2Mg(BO3)2 was prepared by a solution combustion method at 900 °C for 6 hour in air. The prepared adsorbent was characterized by X-Ray Diffraction (XRD). The XRD pattern of Sr2Mg(BO3)2 is in agreement with the ICDD File No: 01-076-9795. The particle morphology of the adsorbent was investigated by scanning electron microscope (SEM). The average size of particles is about 3–10 µm. The Congo red dye was removed from aqueous solution using Sr2Mg(BO3)2. The effect of time, initial concentration, pH, temperature and dosage on adsorption were investigated. The Freundlich model fitted according to equilibrium data and maximum adsorption capacity is 886.952 mg/g. According to theories of pseudo-second-order kinetics, the removal procedure involves chemical adsorption. According to the thermodynamic data, negative ΔG values indicated that adsorption of Sr2Mg(BO3)2 occurred spontaneously and negative ΔH values, the adsorption process was exothermic. Sr2Mg(BO3)2 is a useable material for Congo red dye removal. [ABSTRACT FROM AUTHOR]

Dy 3+ and Sm 3+ doped Li 4 CaB 2 O 6 materials were prepared by the solid state reaction. The phase analysis of all phosphors were determined using the X- Ray Powder Diffraction Analysis. The photoluminescence (PL) properties of both phosphors were investigated using spectrofluorometer at room temperature. The first luminescent material, Li 4 CaB 2 O 6 : Dy 3+ emits 489, 577 and 674 nm upon excitation with 345 nm. The second luminescent material, Li 4 CaB 2 O 6 : Sm 3+ , emits (565–570), (602–609), 650 and 712 nm upon excitation with 404 nm. Also, the dependence of the emission intensity on the activator ions (Dy 3+ and Sm 3+ ) concentration for the Li 4 CaB 2 O 6 were studied in detail. It was observed that the concentration quenching of Dy 3+ and Sm 3+ in Li 4 CaB 2 O 6 are 0.05 and 0.06 mol, respectively. [ABSTRACT FROM AUTHOR]

MSr 4 (BO 3 ) 3 :Sm 3+ (M = Li, Na) materials were synthesized a solution combustion synthesis method followed by heating of the precursor combustion ash at 800 and 750 °C, respectively. The synthesized phosphors were characterized by using the powder XRD. The excitation and emission spectra of these materials were measured at room temperature with a spectrofluorometer. The photoluminescence properties of MSr 4 (BO 3 ) 3 :Sm 3+ (M = Li, Na) materials with different mol ratios of Sm 3+ were analyzed in detail. Both LiSr 4 (BO 3 ) 3 :Sm 3+ and NaSr 4 (BO 3 ) 3 :Sm 3+ phosphors emit a strong in orange–red region. It was observed that the optimum concentration of Sm 3+ in LiSr 4 (BO 3 ) 3 and NaSr 4 (BO 3 ) 3 are 0.04 and 0.03 mol, respectively. Finally, The relation between the photoluminescence properties of Sm 3+ and host compositions was discussed in detail. [ABSTRACT FROM AUTHOR]

Pb 2+ doped NaSr 4 (BO 3 ) 3 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials was carried out using the powder XRD. The synthesized materials were investigated using spectrofluorometer at room temperature. The excitation and emission bands of NaSr 4 (BO 3 ) 3 : Pb 2+ were observed at 291 and 368 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the NaSr 4 (BO 3 ) 3 was studied in detail. It was observed that the concentration quenching of Pb 2+ in NaSr 4 (BO 3 ) 3 is 0.01 mol. The Stokes shifts of NaSr 4 (BO 3 ) 3 : Pb 2+ phosphor were calculated to be 7190 cm −1 . [ABSTRACT FROM AUTHOR]

Pure, Pb 2+ and Bi 3+ doped Li 4 SrCa(SiO 4 ) 2 materials were prepared by using a conventional solid state reaction. The phase of Li 4 SrCa(SiO 4 ) 2 was determined using the powder XRD. The photoluminescent properties of Pb 2+ and Bi 3+ doped Li 4 SrCa(SiO 4 ) 2 materials were investigated using a spectrofluorometer at room temperature. The emission bands of Li 4 SrCa(SiO 4 ) 2 : Pb 2+ and Li 4 SrCa(SiO 4 ) 2 : Bi 3+ were observed at 290 and 380 nm, respectively. Li 4 SrCa(SiO 4 ) 2 with different Pb 2+ and Bi 3+ doping concentrations were analyzed at room temperature. The Stokes shifts of Li 4 SrCa(SiO 4 ) 2 : Pb 2+ and Li 4 SrCa(SiO 4 ) 2 : Bi 3+ were calculated to be 5678 and 5942 cm −1 , respectively. [ABSTRACT FROM AUTHOR]

Pure and Pb 2+ doped Ba 2 Be 2 B 2 O 7 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials was carried out using the powder XRD. The synthesized phosphors were investigated using spectrofluorometer at room temperature. The excitation and emission bands of Ba 2 Be 2 B 2 O 7 :Pb 2+ were observed at 284 and 396 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the Ba 2 Be 2 B 2 O 7 was studied in detail. It was observed that the concentration quenching of Pb 2+ in Ba 2 Be 2 B 2 O 7 is 0.04 mol. The Stokes shifts of Ba 2 Be 2 B 2 O 7 :Pb 2+ phosphor were calculated to be 9959 cm −1 . [ABSTRACT FROM AUTHOR]

Pure and Pb 2+ doped Li 4 CaB 2 O 6 materials were prepared by the solid state reaction. The phase analysis of all synthesized materials were determined using the powder XRD. The synthesized materials were investigated using spectrofluorometer at room temperature. The excitation and emission bands of Li 4 CaB 2 O 6 :Pb 2+ were observed at 263 and 298 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the Li 4 CaB 2 O 6 were studied in detail. It was observed that the concentration quenching of Pb 2+ in Li 4 CaB 2 O 6 is 0.01 mol. The Stokes shifts of Li 4 CaB 2 O 6 :Pb 2+ phosphor was calculated to be 4466 cm −1 . Also, the photoluminescence properties of Pb 2+ in various lithium calcium borates (LCB) with different structure was discussed. [ABSTRACT FROM AUTHOR]