Influence of morphology and composition of fumed oxides on changes in their structural and adsorptive characteristics on hydrothermal treatment in steam phase at different temperatures

2004 ◽  
Vol 269 (2) ◽  
pp. 403-424 ◽  
Author(s):  
V Gun'ko
Keyword(s):  
Hydrothermal Treatment ◽  
Different Temperatures

scholarly journals Titanium Silicates Precipitated on the Rice Husk Biochar as Adsorbents for the Extraction of Cesium and Strontium Radioisotope Ions

2019 ◽  
Vol 3 (1) ◽  
pp. 36 ◽  
Author(s):  
Igor Zhuravlev
Keyword(s):  
Hydrothermal Treatment ◽  
Rice Husk ◽  
Aqueous Media ◽  
Distribution Coefficients ◽  
Water Soluble ◽  
Titanium Sulfate ◽  
Titanium Silicates ◽  
Different Temperatures ◽  
Thermochemical Processing ◽  
Strontium Ions

The aim of the work was the development of cheap and effective adsorbents based on titanium silicates deposited on the products of thermochemical processing of rice husk to extract cesium and strontium radioisotopes from aqueous media. Synthesis of adsorbents was carried out using the cheapest and widely used titanium water-soluble reagent, titanium sulfate (an intermediate product of white rutile pigment production), as feedstock. After treatment with titanium sulfate and neutralization, hydrothermal treatment was carried out in various ways. The traditional method of processing in an autoclave was used, as well as the blowing at different temperatures by steam. The distribution coefficients and the adsorption capacity for cesium and strontium ions on these sorbents were studied. Along with the chemical composition of adsorbents obtained by those ways, the type and the temperature of hydrothermal treatment also affected the adsorption properties. It was found that the adsorbent obtained by hydrothermal treatment in an autoclave has the highest degree of cesium ions extraction (Kd = 27,500). The highest degree of strontium ions extraction (Kd = 2,095,000) has an adsorbent obtained by hydrothermal treatment with water vapor blowing.

Flexural Properties of Bio-Composite Made from Hydrothermally Treated Kenaf (Hibiscus cannabinus) Fibres

2012 ◽  
Vol 535-537 ◽  
pp. 2409-2412 ◽  
Author(s):  
Mohamad Nurul Azman Mohammad Taib ◽  
Mohd Ariff Jamaludin ◽  
Masitah Abu Kassim
Keyword(s):  
Hydrothermal Treatment ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
High Density ◽  
Hibiscus Cannabinus ◽  
Flexural Properties ◽  
High Elasticity ◽  
Different Temperatures ◽  
Kenaf Fibres

This study evaluated the effect on bending strength of hydrothermal treatment on kenaf (Hibiscus cannabinus) fibres of high density fibreboards (HDF) at elevated temperatures. HDF were manufactured from untreated and treated kenaf fibres at three different temperatures that were 100, 130 and 150 °C for 30 minutes in a laboratory autoclave. The bending strength of panel referred to MOE and MOR of sample were analyzed. Bending strength of panel was increased with the increased of temperature. HDF panels made from hydrothermally treated kenaf fibres at 150°C has the higher MOE value and can be used as the building partition or application that needed high elasticity materials.

scholarly journals Hydrothermal pretreatment of oxytetracycline fermentation residue: Removal of oxytetracycline and increasing the potential for anaerobic digestion

2020 ◽  
Vol 26 (4) ◽  
pp. 200258-0
Author(s):  
Mohammed Awad ◽  
Zhe Tian ◽  
Yu Zhang ◽  
Min Yang ◽  
Wenjuan Yin ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Hydrothermal Treatment ◽  
Removal Rate ◽  
Tetracycline Resistance ◽  
Hydrothermal Pretreatment ◽  
Residue Removal ◽  
Different Temperatures ◽  
Methane Potential ◽  
Fermentation Residue ◽  
High Level

The presence of high level of antibiotics in the antibiotic fermentation residue is one of the main reasons that prevent their direct disposal or further use as a resource. In this study, the feasibility of using the hydrothermal pretreatment for removing oxytetracycline (OTC) from its fermentation residue and enhancing anaerobic digestion was evaluated under different temperatures i.e. 110, 130, 150 and 170°C. The results showed that the removal rate of OTC increased as a function of temperature, and hydrothermal treatment at 130°C for 5 min was found sufficient to reduce the concentration of OTC from 3.9 mg/g to less than the detection limit (i.e., 0.25 ng/g). Biochemical methane potential tests showed that the cumulative methane production over 23 d was 73.7, 215.9, 656.8, and 439.0NmL CH4/gVS for the raw residue and the residue treated at 130, 150, and 170°C for 5 min, respectively. At the same time, the abundances of tetracycline resistance genes were reduced by hydrothermal treatments followed by anaerobic digestion. Conclusively, it is suggested that hydrothermal treatment at 150°C for 5 min was found beneficial for OTC fermentation residues ensuring the removal of OTC and further use of the residue for anaerobic digestion.

scholarly journals Physicochemical Characterization of Cattle Dung Fibre Under the Hydrothermal Process

2021 ◽  
Author(s):  
Vinayak Fasake ◽  
Perminder Jit Kaur ◽  
Kavya Dashora
Keyword(s):  
Hydrothermal Treatment ◽  
Incubation Time ◽  
Hydrothermal Process ◽  
Physicochemical Characterization ◽  
Physicochemical Analysis ◽  
Added Value ◽  
Cattle Dung ◽  
Cow Dung ◽  
X Ray Crystallography ◽  
Different Temperatures

Abstract Cattle dung fibre is a lignocellulosic material abundant and sustainable non-wood source of polymeric components, which can be converted into high added-value products. Hydrothermal treatment of the fibre obtained from cow dung was explored using four different temperatures (120, 140, 160 and 180 ◦C) and incubation times (0 and 120 minutes) at a fixed material to water ratio (1:10). The present study resulted in the highest yield of 94% (w/w) that gradually decreased with temperature and incubation time. The physicochemical analysis revealed that hydrothermal treatment resulted in high cellulose, low lignin, and ash content (51.6%, 30.93%, and 6.3%, respectively) at 160◦C for 2 hr incubation time and was appropriate for pulp and paper production. The SEM and X-ray crystallography indicates the treatment resulted in separated fibrils and a porous structure. Both FTIR studies and chemical characterisation techniques were used to optimize the temperature and duration of hydrothermal treatment. Overall, the study presents the first report on the extraction of fibres from cow dung and their hydrothermal treatment. In perspective, it is possible to achieve the properties required for its industrial-scale conversion to eco-friendly papers by heating the fibre under controlled conditions.

scholarly journals The Effect of Hydrothermal Treatment on Silver Nanoparticles Stabilized by Chitosan and Its Possible Application to Produce Mesoporous Silver Powder

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dang Viet Quang ◽  
Nguyen Hoai Chau
Keyword(s):  
Silver Nanoparticles ◽  
Hydrothermal Treatment ◽  
Chemical Reduction ◽  
Silver Powder ◽  
Chitosan Solution ◽  
Aggregation State ◽  
Treatment Conditions ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Different Temperatures

Aggregation state of silver nanoparticles dispersed in an aqueous solution greatly varies with storage and treatment conditions. In this study, silver nanoparticles synthesized in chitosan solution by a chemical reduction method were hydrothermally treated at different temperatures. The variation in the aggregation state of silver nanoparticles in the solution was observed by UV-Vis spectroscopy and field emission transmission electron microscopy. Results indicated that a phase transition occurred while silver nanoparticles were hydrothermally treated for 5 h at 100 and 120∘C; however, they aggregated and completely precipitated at 150∘C. Mesoporous silver powder obtained by hydrothermal treatment at 150∘C was characterized by using X-ray diffraction technique, BET analyzer, and scanning electron spectroscope.

scholarly journals From unavoidable food waste to advanced biomaterials: microfibrilated lignocellulose production by microwave-assisted hydrothermal treatment of cassava peel and almond hull

Cellulose ◽  
2021 ◽  
Author(s):  
Allyn P. Sulaeman ◽  
Yang Gao ◽  
Tom Dugmore ◽  
Javier Remón ◽  
Avtar S. Matharu
Keyword(s):  
Hydrothermal Treatment ◽  
Food Waste ◽  
Structural Changes ◽  
Crystallinity Index ◽  
Processing Temperature ◽  
Microwave Assisted ◽  
Potential Applications ◽  
Different Temperatures ◽  
Alternative Feedstocks ◽  
Cassava Peel

AbstractLignocellulose based nanomaterials are emerging green biosolids commonly obtained from wood pulp. Alternative feedstocks, such as as unavoidable food waste, are interesting resources for nano/microfibers. This research reports the production and characterization of microfibrillated lignocellulose (MFLC) from cassava peel (CP) and almond hull (AH) via acid-free microwave-assisted hydrothermal treatment (MHT) at different temperatures (120–220 °C). During processing, the structural changes were tracked by ATR-IR, TGA, XRD, 13C CPMAS NMR, zeta potential, HPLC, elemental analysis (CHN; carbon, hydrogen and nitrogen), TEM and SEM analyses. The microwave processing temperature and nature of feedstock exerted a significant influence on the yields and properties of the MFLCs produced. The MFLC yields from CP and AH shifted by 15–49% and 31–73%, respectively. Increasing the MHT temperature substantially affected the crystallinity index (13–66% for CP and 36–62% for AH) and thermal stability (300–374 °C for CP and 300–364 °C for AH) of the MFLCs produced. This suggested that the MFLC from CP is more fragile and brittle than that produced from AH. These phenomena influenced the gelation capabilities of the fibers. AH MFLC pretreated with ethanol at low temperature gave better film-forming capabilities, while untreated and heptane pretreated materials formed stable hydrogels at solid concentration (2% w/v). At high processing temperatures, the microfibrils were separated into elementary fibers, regardless of pretreatment or feedstock type. Given these data, this work demonstrates that the acid-free MHT processing of CP and AH is a facile method for producing MFLC with potential applications, including adsorption, packaging and the production of nanocomposites and personal care rheology modifiers. Graphic abstract

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Sign in / Sign up

Export Citation Format

Share Document