scholarly journals Adsorption of methanol and water vapor on modified forms of mordenite–clinoptilolite rock

2018 ◽  
Vol 36 (3-4) ◽  
pp. 927-935 ◽  
Author(s):  
Antonina D Kustovska
Keyword(s):  
Thermal Stability ◽  
Water Vapor ◽  
Adsorption Capacity ◽  
Thermal Activation ◽  
Adsorption Properties ◽  
Microporous Structure ◽  
Adsorption Ability ◽  
Modified Forms ◽  
Thermal Stability Of

The influence of thermal activation, decationation, and dealumination on adsorption properties of rock from Transcarpathian deposit (Lypcha village, Ukraine) containing mordenite and clinoptilolite at the ratio 1:1 was studied in this research. Taking into account the need of preliminary thermal activation of adsorbent, the research of thermal stability of zeolite component of rock was conducted. Parameters of microporous structure of decationated and dealuminated samples were calculated. Obtained results show that decationation of mordenite–clinoptilolite rock leads to insignificant increase and dealumination leads to significant decrease of adsorption capacity for water. Maximal adsorption ability for methanol is about 50% dealumination degree of the sample.

scholarly journals Case Study about the Energy Absorption Capacity of Metal Oxide Varistors with Thermal Coupling

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 536 ◽  
Author(s):  
Flaviu Frigura-Iliasa ◽  
Sorin Musuroi ◽  
Ciprian Sorandaru ◽  
Doru Vatau
Keyword(s):  
Thermal Stability ◽  
Metal Oxide ◽  
Thermal Activation ◽  
Absorption Capacity ◽  
Technical Solution ◽  
Thermal Coupling ◽  
Thermal Exchange ◽  
Surge Arresters ◽  
Thermal Stability Of

Metal oxide varistors are applied today inside modern surge arresters for overvoltage protection for all voltage levels. Their main issue is the thermal activation of their crossing current, which could lead to complete destruction by thermal runaway. This article presents a new technological solution developed in order to increase the thermal stability of metal oxide varistors. It consists in connecting in parallel two or more similar varistors (for dividing their current), having a thermal coupling between them (for equalizing their temperatures and forcing them to act together and simultaneously as much as possible). Starting from a finite element computer model performed for each situation (varistor standalone or parallel), up to real measurements, the thermal stability of the equipment was analyzed in permanent and impulse regime. Experiments were carried out in the same conditions. Experimental data obtain from two disk varistors corresponds very well to simulations, proving that parallel connection of varistors, combined with a thermal exchange between them is an efficient technical solution for thermal stability improvement, even if not apparently economically justified.

scholarly journals Synthesis, Structural, and Adsorption Properties and Thermal Stability of Nanohydroxyapatite/Polysaccharide Composites

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
Ewa Skwarek ◽  
Olena Goncharuk ◽  
Dariusz Sternik ◽  
Wladyslaw Janusz ◽  
Karolina Gdula ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Adsorption Properties ◽  
Thermal Stability Of

Chemical modification results in hyperactivation and thermostabilization ofFusarium solaniglucoamylase

2007 ◽  
Vol 53 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Haq Nawaz Bhatti ◽  
M. Hamid Rashid ◽  
Muhammad Asgher ◽  
Rakhshanda Nawaz ◽  
A.M. Khalid ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Modification ◽  
Soluble Starch ◽  
Water Soluble ◽  
Chemically Modified ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Specificity Constant ◽  
Modified Forms ◽  
Thermal Stability Of

Chemical modification of carboxyl groups of glucoamylase from a mesophilic fungus, Fusarium solani , was carried out using ethylenediamine as nucleophile in the presence of water-soluble 1-ethyl-3(3-dimethylaminopropyl)carbodiimide. Modification brought about a dramatic enhancement of catalytic activity and thermal stability of glucoamylase. Temperature and pH optima of ethylenediamine-coupled glucoamylase (ECG) increased as compared with those of native enzyme. The specificity constant (kcat/Km) of native, ECG-2, ECG-11, and ECG-17 was 136, 173, 225, and 170, respectively, at 55 °C. The enthalpy of activation (ΔH*) and free energy of activation (ΔG*) for soluble starch hydrolysis were lower for the chemically modified forms. All of the modified forms werestable at higher temperatures and possessed high ΔG* against thermal unfolding. The effects of α-chymotrypsin and subtilisin on the modified forms were activating as compared with native. Moreover, denaturation of ECG-2, ECG-11, and ECG-17 in urea at 4 mol·L–1also showed an activation trend. A possible explanation for the thermal denaturation of native and increased thermal stability of ECG-2, ECG-11, and ECG-17 at higher temperatures is also discussed.

THERMAL STABILITY OF LOW DOSE Ga+ ION-IRRADIATED MAGNETIC TUNNEL JUNCTIONS

2010 ◽  
Vol 24 (32) ◽  
pp. 6211-6218
Author(s):  
GUANGHONG ZHOU ◽  
YINGANG WANG ◽  
YIZHONG HUANG ◽  
XIANJIN QI ◽  
JIANKANG CHEN
Keyword(s):  
Thermal Stability ◽  
Exchange Bias ◽  
Thermal Activation ◽  
Room Temperature ◽  
Low Dose ◽  
Magnetic Tunnel Junction ◽  
Experimental Period ◽  
Bias Field ◽  
Absolute Value ◽  
Thermal Stability Of

The thermal stability of low dose Ga + ion-irradiated IrMn/CoFe/AlO x/ CoFe magnetic tunnel junction (MTJ) was investigated using a vibrating sample magnetometer at room temperature and compared with that of the non-irradiated one. The results show that not only does the loop become broad both in the pinned FM layer and in the free FM layer but also there is an obvious larger shift in the pinned FM layer after irradiated at a dose of 1×1013 ions/cm 2 Ga + ions. The training effect becomes more legible after performing a low dose irradiation. In both the non-irradiated and the low dose Ga + irradiated MTJs the thermal activation has been observed and holding the films at negative saturation of the pinned FM layer for up to 28 h results in a decrease of the exchange bias field (H ex ). However, the absolute value of H ex of the irradiated MTJ is always larger than that of the non-irradiated one in the experimental period of time, although the H ex of the irradiated MTJ decreases a little faster.

Research Progress of Adsorption Properties of Hydroxyapatite

2014 ◽  
Vol 1073-1076 ◽  
pp. 28-31
Author(s):  
Hai Lin Fan ◽  
Zhao Xia Hou ◽  
Shao Hong Wang ◽  
Mei Han Wang ◽  
Xiao Dan Hu
Keyword(s):  
Nonferrous Metal ◽  
Adsorption Mechanism ◽  
Research Topic ◽  
Adsorption Properties ◽  
Adsorption Kinetic ◽  
Research Progress ◽  
Microporous Structure ◽  
Treatment Technology ◽  
Adsorption Ability ◽  
Strong Adsorption

Nowadays, serious environmental pollution demands enterprises to dispose waste water, especially for the printing, dyeing and nonferrous metal ones. Wastewater treatment technology is needed to improve urgently. Hydroxyapatite with large specific surface area and more microporous structure becomes a hot research topic in recent years for its strong adsorption ability. In this paper, the pollution situation, adsorption properties, adsorption mechanism, influencing factors and adsorption kinetic of hydroxyapatite are introduced.

scholarly journals Enhanced Adsorption of Carbon Dioxide from Simulated Biogas on PEI/MEA-Functionalized Silica

2020 ◽  
Vol 17 (4) ◽  
pp. 1452
Author(s):  
Yankun Sun ◽  
Wanzhen Liu ◽  
Xinzhong Wang ◽  
Haiyan Yang ◽  
Jun Liu
Keyword(s):  
Thermal Stability ◽  
Adsorption Capacity ◽  
Co2 Adsorption ◽  
Weight Ratio ◽  
Diffusion Resistance ◽  
Impregnation Method ◽  
Adsorption Activity ◽  
Adsorption Performance ◽  
Co2 Adsorption Capacity ◽  
Thermal Stability Of

A series of efficient adsorbents were prepared by a wet-impregnation method for CO2 separation from simulated biogas. A type of commercially available silica, named as FNG-II silica (FS), was selected as supports. FS was modified with a mixture of polyethyleneimine (PEI) and ethanolamine (MEA) to improve the initial CO2 adsorption capacity and thermal stability of the adsorbents. The influence of different adsorbents on CO2 adsorption performance was investigated by breakthrough experiments. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and N2 adsorption–desorption isotherm were used to characterize the silica before and after impregnating amine. Additionally, the thermal stability of adsorbents was measured by differential thermal analysis (TDA). Silica impregnated with mixtures of MEA and PEI showed increased CO2 adsorption performance and high thermal stability compared with those obtained from silica impregnated solely with MEA or PEI. With a simulated biogas flow rate of 100 mL/min at 0.2 MPa and 25 °C, FS-10%MEA-10%PEI exhibited a CO2 adsorption capacity of ca. 64.68 mg/g which increased by 81 % in comparison to FS-20%PEI. The thermal stability of FS-10%MEA-10%PEI was evidently higher than that of FS-20%MEA, and a further improvement of thermal stability was achieved with the increasing value of PEI/MEA weight ratio. It was showed that MEA was able to impose a synergistic effect on the dispersion of PEI in the support, reduce the CO2 diffusion resistance and thus increase CO2 adsorption performance. Additionally, if the total percentage of amine was the same, FS impregnated by different ratios of PEI to MEA did not exhibit an obvious difference in CO2 adsorption performance. FS-15%PEI-5%MEA could be regenerated under mild conditions without obvious loss of CO2 adsorption activity.

scholarly journals Curcumin Incorporated Poly(Butylene Adipate-co-Terephthalate) Film with Improved Water Vapor Barrier and Antioxidant Properties

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4369
Author(s):  
Swarup Roy ◽  
Jong-Whan Rhim
Keyword(s):  
Thermal Stability ◽  
Antimicrobial Activity ◽  
Antioxidant Activity ◽  
Water Vapor ◽  
Antioxidant Properties ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Water Vapor Barrier ◽  
Bright Yellow ◽  
Thermal Stability Of

Curcumin incorporated poly(butylene adipate-co-terephthalate) (PBAT) based film was fabricated. Curcumin has uniformly distributed in the PBAT matrix to form a bright yellow PBAT/curcumin film. The PBAT/curcumin film has slightly reduced tensile strength and flexibility than the neat PBAT film, while the thermal stability of the film has not changed significantly. The blending of curcumin significantly decreased the water vapor permeability of the PBAT film. Additionally, the PBAT/curcumin film showed potent antioxidant activity with some antimicrobial activity. The PBAT/curcumin films with improved water vapor barrier and additional functions can be used for active packaging applications.

scholarly journals Adsorption Properties of Waste Building Sludge for Environmental Protection

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 309
Author(s):  
Barbora Doušová ◽  
Eva Bedrnová ◽  
Pavel Reiterman ◽  
Martin Keppert ◽  
David Koloušek ◽  
...  
Keyword(s):  
Environmental Protection ◽  
Adsorption Capacity ◽  
Environmentally Friendly ◽  
Adsorption Properties ◽  
Langmuir Model ◽  
Adsorption Selectivity ◽  
Laboratory Temperature ◽  
Adsorption Affinity ◽  
Adsorption Data ◽  
Modified Forms

Waste building sludge (WBS) originating in the production of concrete prestressed poles (CSW) and technical stone (TSW) used in original and Fe-modified forms (CSWFe, TSWFe) was tested as an environmentally friendly and cheap sorbent of selected cations (Cd2+, Pb2+, Cs+) and anions (AsO43−, PO43−, CrO42−) from water. The experiments were performed with 0.1 and 0.5 mmol·L−1 model solutions in a batch manner at laboratory temperature. Adsorption data were fitted with the Langmuir model. The adsorption of cations (Pb2+ and Cd2+) ran almost quantitatively (>97%) on both CSW and TSW. Cesium (Cs+) adsorption on TSW reached 80%, while in the case of CSW, it was ineffective. The modification of CSW and TSW with FeII (CSWFe and TSWFe) improved their adsorption selectivity to anions by up to 70%. The adsorption of PO43− and AsO43− ran quantitatively (>98%) on modified CSWFe and TSWFe and also on initial CSW, while CrO42− was effectively adsorbed (≈80%) on TSWFe only. The adsorption affinity of tested ions in terms of adsorption capacity and sorbent consumption declined in order as follows: Pb2+ ≈ Cd2+ >> Cs+ for cations and AsO43− ≈ PO43− > CrO42− for anions.

scholarly journals Immobilization of Radioiodine via an Interzeolite Transformation to Iodosodalite

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2157
Author(s):  
Hyejin An ◽  
Sungjoon Kweon ◽  
Sanggil Park ◽  
Jaeyoung Lee ◽  
Hyung-Ki Min ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Elemental Analysis ◽  
Adsorption Properties ◽  
Zeolite A ◽  
Zeolite X ◽  
Adsorption Ability ◽  
Characterization Methods ◽  
Lta Zeolite ◽  
X Zeolite ◽  
Zeolites A And X

We described a technology for immobilizing radioiodine in the sod-cages by the interzeolite transformation of iodine-containing LTA (zeolite A) and FAU (zeolites X and Y) into a sodalite (SOD) structure. The immobilization of iodine in the sod-cage was confirmed using diverse characterization methods including powder XRD, elemental analysis, SEM–EDS, 127I MAS NMR, and I 3d XPS. Although both zeolites A (Na-A) and X (Na-X) were well converted into SOD structure in the presence of NaI and AgI, the iodide anions were fixed in the sod-cages only when NaI was used. The ability to adsorb methyl iodide (CH3I) was evaluated for zeolites A and X in which Na+ and/or Ag+ ions were exchanged, and Ag+ and zeolite X showed better adsorption properties than Na+ and zeolite A, respectively. However, when both CH3I adsorption ability and the successive immobilization of iodine by interzeolite transformation were considered, Na-X was determined to be the best candidate of adsorbent among the studied zeolites. More than 98% of the iodine was successfully immobilized in the sod-cage in the SOD structure by the interconversion of Na-X following CH3I adsorption, although the Na-X zeolite exhibited half the CH3I adsorption capacity of Ag-X.

Sign in / Sign up

Export Citation Format

Share Document