Cr^(3+)-activated far-red and near-infrared phosphors have drawn considerable attention owing to their adjustable emission wavelengths and wide applications.Herein,we reported a series of Cr^(3+)-doped phosphors with...Cr^(3+)-activated far-red and near-infrared phosphors have drawn considerable attention owing to their adjustable emission wavelengths and wide applications.Herein,we reported a series of Cr^(3+)-doped phosphors withβ-Ca_(3)(PO_(4))_(2)-type structure,of which Ca_(9)Ga(PO_(4))_(7):Cr^(3+) possessed the highest far-red emission intensity.At an excitation of 440 nm,the Ca_(9)Ga(PO_(4))_(7):Cr^(3+) phosphors exhibited a broad emission band ranging from 650 to 850 nm and peaking at 735 nm,and the broadband superimposed two sharp lines centering at 690 and 698 nm.The optimal sample Ca_(9)Ga_(0.97)(PO_(4))_(7):0.03 Cr^(3+) had an internal quantum efficiency of 55.7%.The luminescence intensity of the Ca_(9)Ga_(0.97)(PO_(4))_(7):0.03 Cr^(3+) phosphor obtained at 423 K could maintain 68.5%of that at room temperature,demonstrating its outstanding luminescence thermal stability.A phosphor-conversion light-emitting diode was fabricated,indicating that the Ca_(9)Ga(PO_(4))_(7):Cr^(3+) phosphor has potential applications in indoor plant cultivation.展开更多
This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy d...This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved the successful synthesis of the adsorbent. The adsorption of Cr(III) on the SDS material was investigated by varying experimental conditions such as pH, contact time and adsorbent dosage. The maximum adsorption capacity of SDS-chitosan for Cr(III) was estimated to be 3.42 mg?g<sup>-1</sup>. The results of adsorption kinetics and isothermal models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating that the adsorption is single-layer chemical adsorption. Thermodynamic analyses indicate that the adsorption of Cr(III) is an endothermic reaction. These results show that the new adsorbent has obvious application prospect to eliminate Cr(III).展开更多
A new fluorescent probe, NPQ-C, was synthesized. NPQ-C was based on the naphthalimide derivatives and exhibited high selectivity and sensitivity for Cr3＋ ions. As a Cr3＋-amplified fluorescent probe, Its fluorescence...A new fluorescent probe, NPQ-C, was synthesized. NPQ-C was based on the naphthalimide derivatives and exhibited high selectivity and sensitivity for Cr3＋ ions. As a Cr3＋-amplified fluorescent probe, Its fluorescence spectrum showed 5.5-fold enhancement in the intensity of the signal at 500 nm on binding with the Cr3＋. Based on the fluorescence titration spectra and Job＇s-plot analysis, binding mode of NPQ-C with Cr3＋ was proposed. Fluorescence intensity was linear with concentration of Cr3＋ cation in a range from 0 to 10 μmol·L-1. NPQ-C was also sensitive for Cr3＋. The detection limit was calculated to be 0.20 pmol.L-1 which indicated that NPQ-C was sensitive to Cr3＋.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51972020)。
文摘Cr^(3+)-activated far-red and near-infrared phosphors have drawn considerable attention owing to their adjustable emission wavelengths and wide applications.Herein,we reported a series of Cr^(3+)-doped phosphors withβ-Ca_(3)(PO_(4))_(2)-type structure,of which Ca_(9)Ga(PO_(4))_(7):Cr^(3+) possessed the highest far-red emission intensity.At an excitation of 440 nm,the Ca_(9)Ga(PO_(4))_(7):Cr^(3+) phosphors exhibited a broad emission band ranging from 650 to 850 nm and peaking at 735 nm,and the broadband superimposed two sharp lines centering at 690 and 698 nm.The optimal sample Ca_(9)Ga_(0.97)(PO_(4))_(7):0.03 Cr^(3+) had an internal quantum efficiency of 55.7%.The luminescence intensity of the Ca_(9)Ga_(0.97)(PO_(4))_(7):0.03 Cr^(3+) phosphor obtained at 423 K could maintain 68.5%of that at room temperature,demonstrating its outstanding luminescence thermal stability.A phosphor-conversion light-emitting diode was fabricated,indicating that the Ca_(9)Ga(PO_(4))_(7):Cr^(3+) phosphor has potential applications in indoor plant cultivation.
文摘This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved the successful synthesis of the adsorbent. The adsorption of Cr(III) on the SDS material was investigated by varying experimental conditions such as pH, contact time and adsorbent dosage. The maximum adsorption capacity of SDS-chitosan for Cr(III) was estimated to be 3.42 mg?g<sup>-1</sup>. The results of adsorption kinetics and isothermal models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating that the adsorption is single-layer chemical adsorption. Thermodynamic analyses indicate that the adsorption of Cr(III) is an endothermic reaction. These results show that the new adsorbent has obvious application prospect to eliminate Cr(III).
基金The authors gratefully acknowledge the National Nature Science Foundation of China，the support from the Fundamental Research Funds for the Central Universities,the Opening Foundation of Zhejiang Provincial Top Key Discipline,and Baihehua Group
文摘A new fluorescent probe, NPQ-C, was synthesized. NPQ-C was based on the naphthalimide derivatives and exhibited high selectivity and sensitivity for Cr3＋ ions. As a Cr3＋-amplified fluorescent probe, Its fluorescence spectrum showed 5.5-fold enhancement in the intensity of the signal at 500 nm on binding with the Cr3＋. Based on the fluorescence titration spectra and Job＇s-plot analysis, binding mode of NPQ-C with Cr3＋ was proposed. Fluorescence intensity was linear with concentration of Cr3＋ cation in a range from 0 to 10 μmol·L-1. NPQ-C was also sensitive for Cr3＋. The detection limit was calculated to be 0.20 pmol.L-1 which indicated that NPQ-C was sensitive to Cr3＋.
