scholarly journals Preparation of Red Phosphor Sr2Si5N8: Eu2+ by Pellet Method and Its Optical Characteristics

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 283
Author(s):  
Yuemei Lan ◽  
Dong Wang ◽  
Dongliang Xie ◽  
Junhao Tan ◽  
Bowen Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Red Light ◽  
Preparation Condition ◽  
Luminous Efficiency ◽  
Ion Concentration ◽  
Carbon Powder ◽  
Photoluminescence Properties ◽  
Red Phosphor ◽  
Effective Synthesis ◽  
Red Leds

Red Sr2Si5N8: Eu2+ phosphor with excellent properties was successfully synthesized by pellet method, an effective synthesis technology presented in this work. The influence of reactive conditions such as pellet pressure, position of samples in carbon powder, and Eu2+ ion concentration on the properties of crystallinity, particle size, and the photoluminescence properties of Sr2Si5N8: Eu2+ phosphor were studied in detail. Our results show that the optimum preparation condition is 1500, 5 MPa pellet pressure, and the middle position in carbon powder. The phosphor has improved its efficiency under excitation of near UV and blue LEDs, and it emits red light at around 620 nm. In addition, red LEDs were successfully prepared by using Sr2Si5N8: Eu2+ phosphor combined with UV-chips with maximum luminous efficiency at 9.443 lm/W, when the molar concentration of Eu2+ ion reached 0.001.

Enhanced Photoluminescence of YInGe2O7:Eu3+,Li+ Phosphor Prepared Using the Solid-State Method

2013 ◽  
Vol 684 ◽  
pp. 274-278
Author(s):  
Huang Yu Chen ◽  
Ru Yuan Yang ◽  
Shoou Jinn Chang
Keyword(s):  
Solid State ◽  
Red Light ◽  
Broad Band ◽  
Lithium Carbonate ◽  
Ion Concentration ◽  
Photoluminescence Intensity ◽  
Photoluminescence Properties ◽  
Solid State Method ◽  
Enhanced Photoluminescence ◽  
Transfer State

A Eu3+ activated YInGe2O7phosphor was synthesized by solid-state reaction and lithium carbonate was added to change the morphology and photoluminescence properties. Scanning electron microscopy showed large particle size and necking shape were obtained as the concentrations of Li+ ions increase. In the PL studies, the excitation spectrum of YInGe2O7:Eu3+ phosphors exhibited a broad band in the UV region centered at about 272 nm attributed to charge transfer state (CTS) band, which has a little shift after Li+ ion was added. As the Li+ ion concentration increased, the photoluminescence intensity of the red emission at 620 nm of Eu3+ ions was enhanced, and the optimized concentration of of added Li+ ion is 0.05. The results showed that addition of Li+ ion allows YInGe2O7:Eu3+ phosphors emitting relatively pure red light.

scholarly journals The Study of Carbon Recovery from Electrolysis Aluminum Carbon Dust by Froth Flotation

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 145
Author(s):  
Hesong Li ◽  
Jiaoru Wang ◽  
Wenyuan Hou ◽  
Mao Li ◽  
Benjun Cheng ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mixing Time ◽  
Froth Flotation ◽  
Aluminum Electrolysis ◽  
Carbon Powder ◽  
Molten Salt Electrolysis ◽  
Carbon Recovery ◽  
Aluminum Smelting

A large amount of carbon dust is generated in the process of aluminum smelting by molten salt electrolysis. The carbon dust is solid hazardous waste but contains a large quantity of recyclable components such as carbon and fluoride. How to recycle carbon dust more effectively is a challenge in the aluminum electrolysis field. In this study, X-ray diffraction, scanning electron microscope, and other methods were used to analyze the phase composition of electrolytic aluminum carbon dust. The effects of particle size distribution of carbon dust, impeller speed, reagent addition, mixing time, and flotation time on the flotation recovery of carbon dust were studied. The optimal flotation conditions were obtained and the flotation products were analyzed. The results show that the optimal particle size distribution is 70% of particles below 200 mesh, corresponding to a grinding time of 11 min. The optimum speed of the flotation machine was to be between 1600 and 1800 r/min with the best slurry concentration of 20–30% and 5 min mixing time, and the collector kerosene was suitable for adding in batches. Under the above conditions, the recovered carbon powder with a carbon content of 75.6% was obtained, and the carbon recovery rate was 86.9%.

scholarly journals Ricinus CommunisPericarp Activated Carbon Used as an Adsorbent for the Removal of Ni(II) From Aqueous Solution

2008 ◽  
Vol 5 (4) ◽  
pp. 761-769 ◽  
Author(s):  
S. Madhavakrishnan ◽  
K. Manickavasagam ◽  
K. Rasappan ◽  
P. S. Syed Shabudeen ◽  
R. Venkatesh ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Activated Carbon ◽  
Contact Time ◽  
Metal Ion ◽  
Ricinus Communis ◽  
Ion Concentration ◽  
Batch Mode ◽  
Adsorption Data ◽  
Initial Ph

Activated carbon prepared from Ricinus communis Pericarp was used to remove Ni(II) from aqueous solution by adsorption. Batch mode adsorption experiments are carried out by varying contact time, metal-ion concentration, carbon concentration and pH to assess kinetic and equilibrium parameters. The adsorption data were modeled by using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity (Qo) calculated from the Langmuir isotherm was 31.15 mg/g of activated carbon at initial pH of 5.0±0.2 for the particle size 125-250 µm.

Environmentally benign and cost-effective synthesis of water soluble red light emissive gold nanoclusters: selective and ultra-sensitive detection of mercuric ions

2019 ◽  
Vol 43 (2) ◽  
pp. 900-906 ◽  
Author(s):  
Aniruddha Kundu ◽  
Byeongho Park ◽  
Chaiti Ray ◽  
Juyeong Oh ◽  
Seong Chan Jun
Keyword(s):  
Red Light ◽  
Gold Nanoclusters ◽  
Cost Effective ◽  
Water Soluble ◽  
Environmentally Benign ◽  
Sensitive Detection ◽  
Green Approach ◽  
Effective Synthesis ◽  
Mercuric Ions

A green approach to synthesize red emissive gold nanoclusters for nano-molar detection of mercuric ions.

scholarly journals Synthesis and Characterization of the CaTiO3:Eu3+ Red Phosphor by an Optimized Microwave-Assisted Sintering Process

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 874
Author(s):  
Haifeng Wang ◽  
Jianwei Lu ◽  
Ruoxuan Wang ◽  
Yungu Dong ◽  
Linfeng Ding
Keyword(s):  
Red Light ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Sintering Process ◽  
Time Saving ◽  
Red Phosphor ◽  
Microwave Assisted ◽  
Furnace Sintering ◽  
Co Precipitation

The synthesis process has a significant influence on the properties of Ca1-xTiO3:Eu3+x phosphors; thus, an optimized process will lead to a better performance of the Ca1-xTiO3:Eu3+x phosphors. In this work, the feasibility of synthesizing the Ca1-xTiO3:Eu3+x phosphor with a good luminescent performance by combining the chemical co-precipitation method and microwave-assisted sintering was studied. The precursor of Ca1-xTiO3:Eu3+x phosphors were prepared by the chemical co-precipitation method. To find an optimized process, we applied both of the traditional (furnace) sintering and the microwave-assisted sintering to synthesize the Ca1-xTiO3:Eu3+x phosphors. We found out that a sintering power of 528 W for 50 min (temperature around 950 °C) by a microwave oven resulted in similar emission intensity results compared to traditional furnace sintering at 900 °C for 2.5 h. The synthesized Ca1-xTiO3:Eu3+x phosphors has an emission peak at 617 nm (5D0→7F2), which corresponds to the red light band. This new synthesized method is an energy efficient, time saving, and environmentally friendly means for the preparation of Ca1-xTiO3:Eu3+x red phosphor with good luminescent performance.

scholarly journals Studies on Removal of Cr (VI) from Aqueous Solutions Using Powder of Mosambi Fruit Peelings (PMFP) As a Low Cost Sorbent

2012 ◽  
Vol 9 (3) ◽  
pp. 1389-1399 ◽  
Author(s):  
R. Hema Krishna ◽  
A. V. V. S. Swamy
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Metal Ion ◽  
Low Cost ◽  
Ion Concentration ◽  
Isotherm Models ◽  
Batch Tests ◽  
Freundlich Adsorption Isotherm ◽  
Equilibrium Data ◽  
Agitation Time

The powder of mosambi fruit peelings (PMFP) was used as an adsorbent for the removal of heavy metal like Cr (VI) from aqueous solutions was studied using batch tests. The influence of physico-chemical key parameters such as the initial metal ion concentration, pH, agitation time, adsorbent dosage, and the particle size of adsorbent has been considered in batch tests. Sorbent ability to adsorb Cr (VI) ions was examined and the mechanism involved in the process investigated. The optimum results were determined at an initial metal ion concentration was 10 mg/lit, pH=2, agitation time – 60 min, an adsorbent dose (150 mg/50 ml) and the particle size (0.6 mm). The % adsorption, Langmuir constants [Q0=7.51(mg/g) and b=1.69(mg/lit)] Freundlich constant(Kf=2.94), Lagergren rate constants (Kad(min-1)=5.75 x 10-2) for [Cr(VI)] 10 mg/lit were determined for the adsorption system as a function of sorbate concentration. The equilibrium data obtained were tested using Langmuir, Freundlich adsorption isotherm models, and the kinetic data obtained were fitted to pseudo first order model.

Synthesis and photoluminescence properties of novel Sr3LiSbO6:Mn4+ red phosphor for indoor plant growth

2019 ◽  
Vol 89 ◽  
pp. 609-614 ◽  
Author(s):  
Lei Shi ◽  
Ya-jie Han ◽  
Ying Zhao ◽  
Mao Li ◽  
Xiao-yu Geng ◽  
...  
Keyword(s):  
Plant Growth ◽  
Photoluminescence Properties ◽  
Red Phosphor
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