scholarly journals Studies of Dormancy in the Seeds of Subterranean Clover (Trifolium Subterraneum l.) I. Breaking of Dormancy by Carbon Dioxide and by Activated Carbon

1958 ◽  
Vol 11 (3) ◽  
pp. 246 ◽  
Author(s):  
LAT Ballard
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Low Concentration ◽  
New Methods

Two new methods for breaking the dormancy of subterranean clover (Trifolium subterraneum L.) seeds are described, viz. treatment of imbibed seeds with a low concentration of carbon dioxide, and with activated carbons.

scholarly journals Studies of Dormancy in the Seeds of Subterranean Clover (Trifolium Subterraneum L.) II. The Interaction of Time, Temperature, and Carbon Dioxide During Passage Out of Dormancy

1961 ◽  
Vol 14 (2) ◽  
pp. 173 ◽  
Author(s):  
LAT Ballard
Keyword(s):  
Carbon Dioxide ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dormancy Breaking ◽  
Temperature Dependent

The dormancy-breaking action of C02 on imbibed seeds of subterranean clover ('1'rijolium 8ubterraneum L.) is temperature dependent, the efficiency falling off sharrlly above 25�C and approaching zero at 30�C. Within the effective temp. erature range the action is rapid, exposure of seeds to CO2 for 6 hr having signifiC!,fit effect.

scholarly journals Effects of Gasifying Agents on the Characterization of Nut Shell-derived Activated Carbon

1995 ◽  
Vol 12 (3) ◽  
pp. 247-258 ◽  
Author(s):  
C. Nguyen ◽  
A. Ahmadpour ◽  
D.D. Do
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Benzene Adsorption ◽  
Surface Areas ◽  
Activating Agent ◽  
Micropore Size ◽  
Adsorptive Properties ◽  
Insight Into

Activated carbon was prepared from nut shells using a conventional two-stage method: carbonization followed by activation. Activation with steam or carbon dioxide as activating agent produced a range of chars of different burn-off. These were characterized for their total and micropore surface areas, and benzene adsorption capacity. Benzene adsorption measurement provided an insight into the effect of porosity development on the adsorptive properties of the adsorbent. It was found that activated carbon products from nut shells were comparable, in terms of adsorption characteristics, with activated carbons from other lignocellulosic precursors. The evolution of porosity of the resulting carbons shows that carbon dioxide is the preferable agent for the production of activated carbon with a narrow micropore size distribution.

scholarly journals CO2 and CH4 Adsorption Behavior of Biomass-Based Activated Carbons

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3136 ◽  
Author(s):  
Deneb Peredo-Mancilla ◽  
Imen Ghouma ◽  
Cecile Hort ◽  
Camelia Matei Ghimbeu ◽  
Mejdi Jeguirim ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Textural Properties ◽  
Micropore Volume ◽  
Activation Method ◽  
Physical Activation

The aim of the present work is to study the effect of different activation methods for the production of a biomass-based activated carbon on the CO 2 and CH 4 adsorption. The influence of the activation method on the adsorption uptake was studied using three activated carbons obtained by different activation methods (H 3 PO 4 chemical activation and H 2 O and CO 2 physical activation) of olive stones. Methane and carbon dioxide pure gas adsorption experiments were carried out at two working temperatures (303.15 and 323.15 K). The influence of the activation method on the adsorption uptake was studied in terms of both textural properties and surface chemistry. For the three adsorbents, the CO 2 adsorption was more important than that of CH 4 . The chemically-activated carbon presented a higher specific surface area and micropore volume, which led to a higher adsorption capacity of both CO 2 and CH 4 . For methane adsorption, the presence of mesopores facilitated the diffusion of the gas molecules into the micropores. In the case of carbon dioxide adsorption, the presence of more oxygen groups on the water vapor-activated carbon enhanced its adsorption capacity.

scholarly journals Activated Carbons Tailored to Remove Different Pollutants from Gas Streams and from Solution

1997 ◽  
Vol 15 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Th. El-Nabarawy ◽  
M.R. Mostafa ◽  
A.M. Youssef
Keyword(s):  
Carbon Dioxide ◽  
Methylene Blue ◽  
Activated Carbon ◽  
Organic Pollutants ◽  
Zinc Chloride ◽  
Activated Carbons ◽  
Carbon Surface ◽  
Gas Streams ◽  
Surface Areas ◽  
Flow Techniques

Non-activated carbon ‘A’, physically-activated carbons P1–P4, zinc chloride-activated carbons Z1–Z4 and potassium sulphide-activated carbons K1–K4 were prepared from Maghara coal (Sinai, Egypt). The surface areas of these carbons were determined by investigating the adsorption of carbon dioxide at 298 K and of nitrogen at 77 K. The decolourization powers of the carbons were determined from methylene blue adsorption at 308 K. The adsorption of methanol, benzene, n-hexane, n-octane and α-pinene at 308 K was also determined using equilibrium and flow techniques. The removal of ammonia and phenol from water was investigated on some selected samples. The activated carbons showed high capacities towards the removal of organic pollutants from water and from gas streams via adsorption. Their capacity towards a particular pollutant depends on the method of activation and is related to the textural and/or the chemistry of the carbon surface.

scholarly journals Utilization of spent dregs for the production of activated carbon for CO2 adsorption

2017 ◽  
Vol 19 (2) ◽  
pp. 44-50 ◽  
Author(s):  
Jarosław Serafin
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Density Functional ◽  
Activated Carbons ◽  
Density Functional Theory Method ◽  
Textural Properties ◽  
Carbon Dioxide Adsorption ◽  
Functional Theory ◽  
Surface Areas ◽  
Adsorption Desorption

Abstract The objective of this work was preparation of activated carbon from spent dregs for carbon dioxide adsorption. A saturated solution of KOH was used as an activating agent. Samples were carbonized in the furnace at the temperature of 550°C. Textural properties of activated carbons were obtained based on the adsorption-desorption isotherms of nitrogen at −196°C and carbon dioxide at 0°C. The specific surface areas of activated carbons were calculated by the Brunauer – Emmett – Teller equation. The volumes of micropores were obtained by density functional theory method. The highest CO2 adsorption was 9.54 mmol/cm3 at 0°C – and 8.50 mmol/cm3 at 25°C.

scholarly journals Activated Carbons from Crosslinked Novolac Resin

2005 ◽  
Vol 23 (5) ◽  
pp. 381-386
Author(s):  
Janusz Pajak ◽  
Grzegorz Labojko ◽  
Andrzej Lachowski
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Active Carbon ◽  
Pore Volume ◽  
Activated Carbons ◽  
Novolac Resin ◽  
Carbon Dioxide Activation

Activated carbons were prepared from well-characterized Novolac resin cured with various amounts of hexamethylenetetramine (HMTA). The process consisted of curing the resin with HMTA at 200°C, carbonization in nitrogen at 600°C and gasifying the char in carbon dioxide or in steam at 900°C. The influence of the amount of HMTA used for curing on the yield and the characteristics of the activated carbon was investigated. The pore volume attained a maximum for Novolac initially cured with ca. 2 wt% HMTA. Further increase in the amount of HMTA used for curing resulted in an increase in the yield of active carbon, but the susceptibility to carbon dioxide activation decreased. Relative to carbon dioxide, the use of steam generated a narrower, but more extensive, microporosity in the char obtained from cured Novolac resin.

scholarly journals Studies of Dormancy in the Seeds of Subterranean Clover (Trifolium Subterraneum L.)

1969 ◽  
Vol 22 (2) ◽  
pp. 279 ◽  
Author(s):  
LAT Ballard ◽  
AE Grant Lipp
Keyword(s):  
Carbon Dioxide ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Second Phase ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Breaking Dormancy ◽  
Low Concentrations ◽  
Stimulation Of ◽  
Oxygen Concentrations

When imbibed dormant subterranean clover seeds were exposed to low concentrations of oxygen for up to 6 days, and then transferred to either air or 100% oxygen atmospheres, germination was markedly increased above that of seeds held only in air. Stimulation of germination was similar whether the atmosphere of the second phase was air or 100% oxygen; it was maximal when that of the first phase contained no oxygen, and became insignificant above concentrations in the region of 5% oxygen. The additional germination was roughly proportional to the duration of exposure to low oxygen concentrations, and the effects of two separated exposures to low oxygen were additive. These effects could be produced only in those dormant samples whose seeds or embryos could also be made germinable by exposure to 2�5% carbon dioxide. At higher temperatures, anaerobic conditions were less effective in breaking dormancy, paralleling the reduced efficacy of carbon dioxide at these temperatures.

The germinability of soft seed of a number of strains of subterranean clover

1970 ◽  
Vol 10 (44) ◽  
pp. 293 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Carbon Dioxide ◽  
High Temperatures ◽  
Seed Treatment ◽  
Laboratory Tests ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dormant Seed ◽  
Seed Treatments ◽  
Embryo Dormancy

The effect of several seed treatments on germination of 13 strains of subterranean clover (Trifolium subterraneum) seed was examined at two constant temperatures in the laboratory. Tests were conducted on soft seed obtained after scarification of seed sampled on three occasions during the summer and autumn. Germinability varied between strains, but always increased with time after harvest ripeness. Leaching with water promoted some germination in even the most dormant seed. Treatment with carbon dioxide was effective in promoting germination at 20�C, but was less effective than leaching at 30�C. The results suggest that protection against germination by embryo dormancy is likely to be confined to conditions of comparatively high temperatures (>20�C) when associated with summer rains having little or no leaching effect.

scholarly journals Breakthrough adsorption study using activated carbon and molecular sieve for CO2 capture

2021 ◽  
Author(s):  
Mohd Danish ◽  
Vijay Parthasarthy ◽  
Mohammed K. Al Mesfer
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Molecular Sieve ◽  
Activated Carbons ◽  
Fixed Bed ◽  
Morphological Characteristics ◽  
Operating Conditions ◽  
Co2 Uptake ◽  
Utilization Factor ◽  
Adsorption Study

Abstract The increased levels of carbon dioxide in the environment have incited the search of breakthrough technologies to lessen their impact on climate. The fixed bed CO2 adsorption study has been carried out using two-grades of adsorbents from CO2/N2 feed. The molecular sieve 3Å and porous carbon prepared from low-cost date stone were used for the adsorption study. BET analyser and a scanning electron microscope were used to analyze the surface and morphological characteristics of activated carbons. The result of temperature, flow rate, initial carbon dioxide concentration levels in feed on breakthrough behaviour was analysed. The adsorption response was explored in terms of breakthrough and saturation points, CO2 uptake, temperature profiles, effective column efficiency, usable bed height, utilization factor and length of mass transfer zone. The vastly steep breakthrough curves produced under different operating conditions reveals satisfactory utilisation of adsorbent capacity at breakthrough condition. The CO2 uptake of 73.08 mg/g was attained having high effective column capacity of 0.938 at 298 K for synthesized activated carbon. The activated carbon AC-SY performs better with lessen LMTZ of 1.20 cm and improved utilization factor of 0.97 at Co=5 % and 298 K. The findings of study suggest that activated carbon developed from date stone is highly encouraging to capture CO2 from CO2/N2 mixture using continuous fixed bed column

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