scholarly journals Feasibility of Carbonaceous Nanomaterial-Assisted Photocatalysts Calcined at Different Temperatures for Indoor Air Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Wan-Kuen Jo ◽  
Kun-Hwan Kim
Keyword(s):  
Calcination Temperature ◽  
Indoor Air ◽  
Low Temperatures ◽  
Photocatalytic Decomposition ◽  
Ethyl Benzene ◽  
Multiwall Carbon Nanotube ◽  
Different Temperatures ◽  
Benzene Toluene ◽  
Uv Lamp ◽  
Carbonaceous Nanomaterial

This study examined the characteristics and photocatalytic activity of multiwall carbon nanotube-assisted TiO2(MWNT-TiO2) nanocomposites calcined at different temperatures to assess their potential indoor air applications. It was confirmed that the composites calcined at low temperatures (300 and 400°C) contained TiO2nanoparticles bound intimately to the MWNT networks. Meanwhile, almost no MWNTs were observed when the calcination temperature was increased to 500 and 600°C. The MWNT-TiO2composites calcined at low temperatures showed higher photocatalytic decomposition efficiencies for aromatic hydrocarbons at indoor concentrations than those calcined at high temperatures. The mean efficiencies for benzene, toluene, ethyl benzene, and o-xylene (BTEX) by the composite calcined at 300°C were 32, 70, 79, and 79%, respectively, whereas they were 33, 71, 78, and 78% for the composite calcined at 400°C, respectively. In contrast, the efficiencies decreased to close to zero when the calcination temperature was increased to 600°C. Moreover, the MWNT-TiO2exhibited superior photocatalytic performance for the decomposition efficiencies compared to TiO2under conventional UV-lamp irradiations. Consequently, these carbonaceous nanomaterial-assisted photocatalysts can be applied effectively to indoor air applications depending upon the calcination temperature.

Indoor Contaminants in Chemical Laboratories: Characteristics of BTEX by Environmental and Biological Monitoring

2017 ◽  
Vol 9 (02) ◽  
Author(s):  
Reza Ahmadkhaniha ◽  
Noushin Rastkari
Keyword(s):  
Indoor Air ◽  
Mean Value ◽  
Ethyl Benzene ◽  
Breathing Zone ◽  
Mean Values ◽  
Work Shift ◽  
Biomarkers Of Exposure ◽  
Indoor Contaminants ◽  
Benzene Toluene ◽  
The Mean

BTEX (benzene, toluene, ethyl benzene and xylenes) are the most important categories of VOCs that occur in the indoor air and often used in chemical laboratories. In the present study the excretion of urinary BTEX were evaluated as biomarkers of exposure to these compounds. The mean value of benzene in breathing zone and the total benzene uptake during the work shift of the two groups of technicians and students in chemical laboratories were 32.11and 46.82 µg m-3 and 14.55 and 34.11ngL-1 , respectively, which were significantly greater than the occupationally non exposed groups. Good correlations (0.839 ≤ r ≤ 0.946) between the mean values of BTEX in breathing zone and the urinary concentrations were observed.

scholarly journals A Comparative Electrochemical and Morphological Investigation on the Behavior of NiCr and CoCr Dental Alloys at Various Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 256
Author(s):  
Florentina Golgovici ◽  
Mariana Prodana ◽  
Florentina Gina Ionascu ◽  
Ioana Demetrescu
Keyword(s):  
Low Temperatures ◽  
Artificial Saliva ◽  
Electrochemical Stability ◽  
Morphological Investigation ◽  
Dental Alloys ◽  
Ion Release ◽  
Icp Ms ◽  
Different Temperatures ◽  
Good Concordance ◽  
Increasing Temperature

The purpose of our study is to compare the behavior of two reprocessed dental alloys (NiCr and CoCr) at different temperatures considering the idea that food and drinks in the oral cavity create various compositions at different pH levels; the novelty is the investigation of temperature effect on corrosion parameters and ion release of dental alloys. Electrochemical stability was studied together with morphology, elemental composition and ions release determination. The results obtained are in good concordance: electrochemistry studies reveal that the corrosion rate is increasing by increasing the temperature. From SEM coupled with EDS, the oxide film formed on the surface of the alloys is stable at low temperatures and a trend to break after 310K. ICP-MS results evidence that in accordance with increasing temperature, the quantities of ions released from the alloys immersed in artificial saliva also increase, though they still remain small, less than 20 ppm.

Preparation and Photocatalysis of a Glass Coated With Nanometer TiO2 Codoped With N, F and Fe Elements

2016 ◽  
Author(s):  
Cong Ding ◽  
Yufei Zhang ◽  
Chen Chuan ◽  
Yanhua Liu
Keyword(s):  
Heat Treatment ◽  
Methylene Blue ◽  
Visible Light ◽  
Calcination Temperature ◽  
Indoor Air ◽  
Heat Treatment Temperature ◽  
Indoor Air Pollution ◽  
Treatment Temperature ◽  
Human Beings ◽  
Glass Plates

Indoor air pollution seriously threats the life and health of human beings. The improvement of indoor air quality has become a focus that people pay more and more attentions to. The photocatalytic of pollutants based on TiO2 is a promising air purification technology. In order to overcome the disadvantages of nanometer powder TiO2 catalyst and to enhance the photocatalytic activity of TiO2, series of glass plates covered with doped-TiO2 were prepared and the photocatalysis them were studied. The glass plates covered with TiO2 which was doped in advance with N, F, or/and Fe were prepared by a sol-gel method. The doping content of N, F, Fe and heat treatment temperature were determined using the orthogonal array of the Taguchi quality design. The prepared gel was coated on the glass by spin-coating method. The effects of doping level of N, F and Fe and heat treatment temperature on the photocatalytic capabilities were investigated. The photocatalytic capabilities of prepared glass plates were investigated by degrading the solution of methylene blue (MB,C16H18ClN3S). The results show that appropriate addition of N, F and Fe and temperaturae are effective for improving the photocatalytic activities of TiO2 under visible light. The optimal TiO2 was prepared under the condition that the doping amount of F element was 9at %, that of N is 7at %, and none of Fe under 400 °C calcination temperature. The degradation rate of the sample for methylene blue solution reaches 23.49% under visible light irradiation for 5 hours. The influence order of the factors was the calcination temperature > F > N > Fe.

scholarly journals Using Diaper Waste to Prepare Magnetic Catalyst for the Synthesis of Glycerol Carbonate

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jincan Wang ◽  
Yong Liang ◽  
Song Wang ◽  
Patrick U. Okoye ◽  
Hongxu Chen ◽  
...  
Keyword(s):  
Magnetic Property ◽  
Calcination Temperature ◽  
Separation Process ◽  
Nickel Nitrate ◽  
Glycerol Carbonate ◽  
Magnetic Catalyst ◽  
Catalyst Separation ◽  
Different Temperatures

Diaper waste was calcined above 400°C after impregnated in the solution of nickel nitrate. The as-prepared diaper waste-derived materials were used as magnetic catalysts for the synthesis of glycerol carbonate (GC). Structure and catalytic ability investigations on the catalysts calcined at different temperatures indicated that calcination temperature was an important factor affecting the property of catalysts. It was found that the catalyst obtained at the calcination temperature of 700°C (named DW-Ni-700) showed the best performance. When DW-Ni-700 was used in the synthesis of GC, GC yield reached 93.2%, and the magnetic property of DW-Ni-700 facilitated the catalyst separation process. Meanwhile, DW-Ni-700 showed high reusability in the reaction. After four times reuse of DW-Ni-700, GC yield decreased less than 4%.

scholarly journals Conditions chimiques contrôlant l'atténuation naturelle des BTEX et solvants chlorés : un état des connaissances

2005 ◽  
Vol 14 (4) ◽  
pp. 419-444 ◽  
Author(s):  
O. Atteia ◽  
M. Franceschi
Keyword(s):  
Cette Technique ◽  
Ethyl Benzene ◽  
Benzene Toluene

L'atténuation naturelle des BTEX (Benzène, Toluène, Ethyl-benzène, Xylène) et des solvants chlorés est de plus en plus étudiée en raison des potentialités offertes par cette technique de gestion. Cet article, après avoir présenté les aspects abiotiques de l'atténuation détaille les conditions chimiques nécessaires à la réalisation des réactions de biodégradation des polluants organiques. Les aspects thermodynamiques sont abordés afin de décliner les réactions possibles et celles qui ne le sont pas selon les environnements chimiques. La dégradation des BTEX est focalisée sur le benzène, produit le plus toxique et le moins dégradable sur la plupart des sites. Les détails de la dégradation du benzène sur le terrain sont analysés dans la littérature et leur comparaison permet de décrire les mécanismes responsables de celle-ci. Dans le cas des solvants chlorés, l'attention est portée sur le TCE (Trichloréthylène), produit le plus couramment rencontré sur les sites pollués. Une mise en parallèle des évolutions de teneurs observées et des conditions chimiques locales permet de mettre en évidence les conditions nécessaires à la dégradation du TCE, et de ses congénères, ainsi que les cinétiques de dégradation dans différentes conditions. La mise en évidence du rôle prépondérant des conditions chimiques conduit à remettre en cause l'utilisation répandue des constantes de dégradation du premier ordre et donne des pistes pour les modèles nécessaires à une prédiction plus fine de l'atténuation naturelle.

scholarly journals The effects of environmental temperature on the properties of myofibrillar adenosine triphosphatase from various species of fish

1973 ◽  
Vol 133 (4) ◽  
pp. 735-738 ◽  
Author(s):  
Ian A. Johnston ◽  
Neil Frearson ◽  
Geoffrey Goldspink
Keyword(s):  
Low Temperatures ◽  
Half Life ◽  
Adenosine Triphosphatase ◽  
Environmental Temperature ◽  
Cold Water ◽  
Warm Water ◽  
Adenosine Triphosphatase Activity ◽  
Water Fish ◽  
Different Temperatures ◽  
Myotomal Muscle

1. Myofibrillar adenosine triphosphatase (ATPase) activities were measured for white myotomal muscle of 19 species of fish. 2. The activity was measured at different temperatures and after periods of preincubation at 37°C. 3. The inactivation half-life at 37°C depended on environmental temperature, increasing as the temperature increased. 4. Cold-water fish had higher myofibrillar adenosine triphosphatase activity at low temperatures than had warm-water fish. 5. The significance of these results is discussed.

scholarly journals CONSEQUENCES OF PRESOWING INFLUENCE OF LOW AND VARIABLE TEMPERATURES ON CARROT AND RADISH SEEDS

2019 ◽  
pp. 62-64
Author(s):  
S. R. Gasanov ◽  
S. A. Mammadova
Keyword(s):  
Low Temperatures ◽  
Raphanus Sativus ◽  
Seed Treatment ◽  
Growth And Yield ◽  
Average Weight ◽  
Vegetable Crops ◽  
Root Crops ◽  
Different Temperatures ◽  
Sowing Seed ◽  
The Impact

The study of the dynamics of plant growth and yield of vegetable crops (carrot variety Absheron winter (Daucus carota subsp. sativus (Hoffm.) Schьbl.) and radish variety Virovsky white (Raphanus sativus var.radicula Pers.)) was conducted in the field conditions after presowing exposure to different temperatures: I option – sowing of seeds exposed to low temperatures (for 15 days the swollen for 24 hours seeds were kept at a temperature of 0±1°С); Option II - sowing of seeds exposed to variable temperatures (for 5 days, the swollen for 24 hours seeds were exposed to variable temperatures of + 20°C (8 hours) and 0±1°C (16 hours) and then 10 days at a temperature of 0±1°C; K1 – sowing dry seeds; K2 – sowing soaked seeds. The impact on the seeds of low and variable temperatures caused an increase in growth processes, both in radish and carrot. Both studied crops showed a tendency to increase the yield to a greater extent when exposed to swollen seeds with variable temperatures. Thus, the average weight of radish crops exceeded the control variant by 47.1% and carrots by 27.6%. The yield of root crops per m2increased by 36.4% for radish and 30.0% for carrot. To increase the productivity of vegetable crops, we recommend using the studied methods of pre-sowing seed treatment in practice.

Effect of calcination temperature on the morphology and catalytic properties of ZnO nanostructures fabricated from a chiral precursor for photodegradation of both cationic and anionic dyes

2022 ◽  
Author(s):  
Shradha Gandhi ◽  
Rupinder Kaur ◽  
Vandana Sharma ◽  
Sanjay Mandal
Keyword(s):  
Calcination Temperature ◽  
Catalytic Properties ◽  
Zno Nanostructures ◽  
Anionic Dyes ◽  
Different Temperatures

Diverse ZnO nanostructures (ZnO_1 to ZnO_3) were synthesized by direct calcination of a chiral MOF precursor {[Zn4(µ3-OH)2(D-2,4-cbs)2(H2O)4].5H2O}n (Zn-CBS) at three different temperatures 600, 700 and 800 oC, respectively. On the...

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