Influence Factors of Exfoliation Synthesis Exfoliated Graphite from Vietnamese Natural Graphite Flakes Using Microwave Irradiation

2018 ◽  
Vol 279 ◽  
pp. 230-234 ◽  
Author(s):  
Pham Van Thinh ◽  
Nguyen Duy Trinh ◽  
Nguyen Thi Thuong ◽  
Van Thi Thanh Ho ◽  
Bui Thi Phuong Quynh ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Ph Value ◽  
Influence Factors ◽  
Exfoliated Graphite ◽  
Oxidizing Agent ◽  
Natural Graphite ◽  
Microwave Assisted

In this study, we prepared the exfoliated graphite (EG) using microwave-assisted exfoliation synthesis exfoliated graphite from the inexpensive natural Vietnamese graphite flakes as the precursors. The exfoliation of graphite was conducted employing intercalation method using H2O2 as oxidizing agent and H2SO4 as intercalating agent. The influent of the precursors (VH2O2/VH2SO4) (1.0/20 – 2.0/20), pH value of EG (1-6), time intercalation (70-120 min), microwave power (180-720 W), and time microwave (10-60 second) in the exfoliation volume of EG was investigated.

Microwave-Assisted Leaching Vanadium from Stone Coal

2011 ◽  
Vol 189-193 ◽  
pp. 3916-3919 ◽  
Author(s):  
Hong Zhou Ma ◽  
Xin Zhe Lan ◽  
Yao Ning Wang ◽  
Yu Hong Tian
Keyword(s):  
Sulfuric Acid ◽  
Microwave Power ◽  
Orthogonal Design ◽  
Chemical Constituents ◽  
Influence Factors ◽  
Sulfate Solution ◽  
Leaching Rate ◽  
Stone Coal ◽  
Microwave Assisted ◽  
Design Experiments

Technological process of microwave-assisted leaching of vanadium with sulfate solution has been defined on the base of phase and chemical constituents of stone coal. The influence factors such as content of sulfuric acid, microwave power, and leaching time were studied on leaching rate of vanadium from the stone coal. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. The experimental results showed that the leaching rate of vanadium was improved by the change of influence factors at some range. The single leaching rate of vanadium reached 80.9% under the optimal conditions of sulfuric acid content of 12%, microwave power 539w,leaching time of 2h.

Microwave Assisted Synthesis of Schiff Bases: A Green Approach

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Mousumi Chakraborty ◽  
Sanjay Baweja ◽  
Sunita Bhagat ◽  
TejpalSingh Chundawat
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Mass Spectra ◽  
Molar Ratio ◽  
Microwave Assisted Synthesis ◽  
Schiff’S Bases ◽  
Microwave Assisted ◽  
Green Approach ◽  
Schiff's Bases ◽  
Effects Of Temperature

Abstract In the present study Schiff’s bases are synthesized by the conventional as well as by microwave irradiation. Excellent yield within short reaction time is obtained using microwave irradiation along with other advantages like mild reaction condition, non-hazardous and safer environmental conditions. The effects of temperature, reactant molar ratio, and microwave power variation on yield are observed. Mathematical model has been developed using matlab software to obtain the yield as a function of microwave power. Kinetic study of the reaction has also been attempted. Schiff’s bases structures are confirmed by IR, 1HNMR, Mass Spectra and elemental analysis.

Meso-mechanics simulation analysis of microwave-assisted mineral liberation

2015 ◽  
Author(s):  
Qin Like ◽  
Dai Jun ◽  
Yuan Liqun
Keyword(s):  
Energy Consumption ◽  
Microwave Irradiation ◽  
Power Density ◽  
Microwave Power ◽  
Mineral Content ◽  
Crystal Size ◽  
Irradiation Time ◽  
Mineral Crystal ◽  
Microwave Assisted ◽  
Time And Energy

Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value.

Preparation of Exfoliated Graphite by Microwave Using Natural Graphite with Different Particle Sizes

2010 ◽  
Vol 163-167 ◽  
pp. 2333-2336 ◽  
Author(s):  
Kun Yu
Keyword(s):  
Particle Size ◽  
Microwave Irradiation ◽  
Small Particle ◽  
Graphite Particle ◽  
Microwave Oven ◽  
Raw Material ◽  
Exfoliated Graphite ◽  
Particle Sizes ◽  
Natural Graphite ◽  
Graphite Intercalation

Three natural graphite flakes (35, 50 and 80 mesh) were used as raw material. Exfoliated graphite (EG) was prepared by rapidly heating residue H2SO4-graphite intercalation compounds (RGIC) in a muffle and by irradiating it in a microwave oven, respectively. Results show that the exfoliation volume of EG decreases with decreasing the raw graphite particle size. Compared with muffle heating, microwave irradiation is more helpful for the exfoliation of RGICs, especially for the small particle samples.

Study on the Hydrolysis of Pollen in Pure Water under Microwave Irradiation

2013 ◽  
Vol 683 ◽  
pp. 222-225
Author(s):  
Huan Wang ◽  
Li Li Geng ◽  
Bo Wu ◽  
Na Liu ◽  
Dong Zhang
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Microwave Power ◽  
Orthogonal Experiment ◽  
Pure Water ◽  
Influence Factors ◽  
Weight Ratio ◽  
Pinus Massoniana ◽  
Hydrolysis Reaction ◽  
Microwave Hydrolysis

Pinus massoniana pollen was hydrolyzed by using the method of orthogonal experiment in pure water under microwave irradiation. The main influence factors of pollen microwave hydrolysis reaction was confirmed as temperature, weight ratio of pollen to water, microwave power and the reaction time, and its effects on the pollen microwave hydrolysis reaction was studied in detail. The results showed that the sequence of influence factors was reaction temperature>weight ratio of pollen to water>microwave power>reaction time. The optimal reaction conditions was that the temperature, 120oC; the power, 120W; the reaction time, 150min; the weight ratio of pollen to water, 1:10.

Benefits of Microwave-Assisted Processing Go Beyond Time Savings

2009 ◽  
Vol 17 (5) ◽  
pp. 28-33
Author(s):  
Richard T. Giberson ◽  
Mark A. Sanders
Keyword(s):  
Microwave Irradiation ◽  
Temperature Control ◽  
Microwave Power ◽  
Sample Temperature ◽  
Microwave Cavity ◽  
Processing Methods ◽  
Microwave Assisted ◽  
Time Savings ◽  
And Control ◽  
Improved Technology

Microwave-assisted processing of biological specimens, from its inception, has been a methodology that promised time savings over conventional processing methods [1]. It has taken almost 30 years to define and control the significant variables associated with microwave processing [2]. Recent research combined with improved technology have helped in the identification and control of the experimental variables associated with microwave-assisted processing [2–7]. Stated simply they are: (1) constant sample temperature control in conjunction with continuous microwave irradiation [3–4], (2) control of wattage in the microwave device (the ability to control microwave power in the same manner as a dimmer switch controls a light) [2–5], and (3) energy uniformity in the microwave cavity [3–4].

Effect of Activated Attapulgite on Ammonia-Nitrogen Removal

2012 ◽  
Vol 549 ◽  
pp. 92-95
Author(s):  
Fei Liu ◽  
Tao Hu ◽  
Shi Ying Ren ◽  
Ying Ying Shi
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Microwave Power ◽  
Ph Value ◽  
Influence Factors ◽  
Ammonia Nitrogen ◽  
Heating Time

The removal of ammonia-nitrogen (NH4+–N) in water by activated attapulgite was investigated. The study focuses on the effect of different activated attapulgite. The influence factors include microwave power, heating time and pH value in solution. The results show that heating 4 minutes, microwave power of 89 watts, and pH value of 9 are the best conditions to remove NH4+-N in the wastewater and the removal efficiency can above 80%. The attapulgite activated by microwave and alkali can remove NH4+-N in breeding waste effectively and the removal efficiency can reach 84.15%.

Preparation of Calcium-Deficient Carbonated Hydroxyapatite Nanoparticles by Microwave Process

2008 ◽  
Vol 368-372 ◽  
pp. 1178-1180
Author(s):  
Song Chen ◽  
Jin Gou Ji ◽  
Yi Xu ◽  
Wei Qi Liu ◽  
Ji Da Chen ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Ph Value ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Hydroxyapatite Nanoparticles ◽  
Molar Ratios ◽  
Reaction Solution ◽  
Microwave Process

In this paper, carbonated calcium-deficient hydroxyapatite (d-HA) nanoparticles were synthesized by a chemical precipitation method assisted with microwave irradiation. The important factors which effected on the synthesis process, such as pH value, time and the power of microwave irradiation on the Ca/P molar ratios of d-HA were discussed. The experimental results showed that carbonated d-HA nanoparticles could be quickly synthesized by irradiating the reaction solution for about 1h under moderate microwave power and pH value ranging from 8 to 9.

scholarly journals Microwave-Assisted Noncatalytic Esterification of Fatty Acid for Biodiesel Production: A Kinetic Study

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2167
Author(s):  
Hoang Chinh Nguyen ◽  
Fu-Ming Wang ◽  
Kim Khue Dinh ◽  
Thanh Truc Pham ◽  
Horng-Yi Juan ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Reaction Model ◽  
Biodiesel Production ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Reaction Rate Constants ◽  
Microwave Assisted ◽  
Reaction Conversion ◽  
Biodiesel Synthesis

This study developed a microwave-mediated noncatalytic esterification of oleic acid for producing ethyl biodiesel. The microwave irradiation process outperformed conventional heating methods for the reaction. A highest reaction conversion, 97.62%, was achieved by performing esterification with microwave irradiation at a microwave power of 150 W, 2:1 ethanol:oleic acid molar ratio, reaction time of 6 h, and temperature of 473 K. A second-order reaction model (R2 of up to 0.997) was established to describe esterification. The reaction rate constants were promoted with increasing microwave power and temperature. A strong linear relation of microwave power to pre-exponential factors was also established, and microwave power greatly influenced the reaction due to nonthermal effects. This study suggested that microwave-assisted noncatalytic esterification is an efficient approach for biodiesel synthesis.

Research on Microwave-Assisted Extraction of Baicalin from Scutellaria baicalensis Extractive Drug Residue

2010 ◽  
Vol 113-116 ◽  
pp. 2329-2332
Author(s):  
Wei Yang ◽  
Xiao Jing Zhao ◽  
Li Li Xu ◽  
Hui Zheng ◽  
Jin Yu Lu
Keyword(s):  
Microwave Irradiation ◽  
Output Power ◽  
Microwave Power ◽  
Active Component ◽  
Scutellaria Baicalensis ◽  
Microwave Assisted Extraction ◽  
Drug Residue ◽  
Microwave Assisted ◽  
Assisted Extraction

Microwave-assisted extraction (MAE) is first used to extract baicalin from Scutellaria baicalensis extractive drug residue to study the value of Scutellaria baicalensis extractive drug residue. The content of baicalin in the Scutellaria baiacalensis extractive drug residue was determined by UV. Effects of different granularity sizes of its extractive drug residue, different microwave output power, duration of microwave irradiation and different concentration of ethanol on yield of baicalin were discussed. The results indicated that the microwave power was 500w, granularity of Scutellaria baicalensis extractive drug residue was 0.25mm, 30% ethanol was as solvent, duration of microwave irradiation was 3min.The　yield of baicalin arrived 9~10%.The conclusion is that some active component such as Baicalin is still in Scutellaria baicalensis extractive drug residue, Scutellaria baicalensis extractive drug residue can be reused as resources again.

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