scholarly journals Effects of Oxygen Partial Pressure on Wood-Based Activated Carbon Treated with Vacuum Ultraviolet Light

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 411
Author(s):  
Nana Takahashi ◽  
Hiroyuki Kuwae ◽  
Seren Maeda ◽  
Masahiro Kawamura ◽  
Ami Tezuka ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Activated Carbon ◽  
Partial Pressure ◽  
Surface Treatment ◽  
Adsorption Capacity ◽  
Vacuum Ultraviolet ◽  
Aromatic Carbon ◽  
O2 Partial Pressure ◽  
Carbon Bonds ◽  
Edge Defects

This study uses vacuum ultraviolet (VUV) light with a wavelength of 172 nm as a surface treatment to enhance the adsorption capacity of wood-based activated carbon (AC). The AC surface treatment is performed under three O2 partial pressure conditions—5.0 × 104 Pa, where ozone (O3) effects dominate; 6.3 × 10−6 Pa, where VUV effects dominate; and 1.9 × 103 Pa for a balanced condition. For the O3-dominant condition, only graphene edge defects are etched (no aromatic carbon bonds are etched), resulting in increased surface roughness. When the VUV effects dominate, aromatic carbon bonds are cleaved, which then reacted with O2 or water adsorbed inside the pores. This increased both the number and size of the mesopores. Under the balanced conditions, the water adsorption capacity was enhanced by 45.5%, which is higher than that obtained before VUV exposure or with VUV under other conditions. This is because the surface roughness increased, as well as the pore sizes and numbers under the balanced condition. These results indicate that we can control VUV-based AC surface treatments via O2 partial pressure.

scholarly journals RESEARCH ON ION EXCHANGE CAPACITY OF OXIDIZEDACTIVATED CARBON

2018 ◽  
Vol 55 (4C) ◽  
pp. 245
Author(s):  
Pham Thi Hai Thinh
Keyword(s):  
Activated Carbon ◽  
Ion Exchange ◽  
Surface Treatment ◽  
Adsorption Capacity ◽  
Inorganic Compounds ◽  
Exchange Capacity ◽  
Carbon Surface ◽  
Maximum Adsorption Capacity ◽  
Ion Exchange Capacity ◽  
Naoh Solution

Ion exchange capacity of oxidized activated carbon (OAC) by HNO3 and surface treatment by NaOH solution was investigated. The HNO3oxidizedfunctional groups on the activated carbon surface, such as ketone, carboxylic acid and its derivatives, to maximum oxidation state. The OAC surface played the role as cation exchanger for adsorption of inorganic compounds, especially metallic cations. The adsorption capacity of OAC was investigated in batch mode with three representative ions with different valence from +1 to +3 (NH4+, Ca2+, Cr3+). The adsorption process was demonstrated by Langmuir and Freundlich isothermal model, and the maximum adsorption capacity according to Langmuir isothrermal equation was 20.4 mg/g for NH4+, 43.5 mg/g for Ca2+ and 38.5 mg/g for Cr3+. The results showed the OAC modified by HNO3 and surface treatment by NaOH solution improved adsorption capacity of AC for cations in solution to a higher level. 

Analisis Variasi Temperatur Aktivasi Terhadap Daya Serap Arang Aktif Tandan Aren (Arenga Pinnata Merr) Dengan Agen Aktivasi Potassium Silicate(K2SiO3)

2020 ◽  
Vol 5 (3) ◽  
pp. 221
Author(s):  
Muhammad Azam ◽  
Muhammad Anas ◽  
Erniwati Erniwati
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Temperature Variation ◽  
Chemical Activation ◽  
Weight Ratio ◽  
Potassium Silicate ◽  
Physical Activation ◽  
Activation Temperature ◽  
Pyrolysis Reactor

This study aims to determine the effect of variation of activation temperature of activated carbon from sugar palm bunches of chemically activatied with the activation agent of potassium silicate (K2SiO3) on the adsorption capacity of iodine and methylene blue. Activated carbon from bunches of sugar palmacquired in four steps: preparationsteps, carbonizationstepsusing the pyrolysis reactor with temperature of 300 oC - 400 oC for 8 hours and chemical activation using of potassium silicate (K2SiO3) activator in weight ratio of 2: 1 and physical activation using the electric furnace for 30 minutes with temperature variation of600 oC, 650 oC, 700 oC, 750 oC and 800 oC. The iodine and methyleneblue adsorption testedby Titrimetric method and Spectrophotometry methodrespectively. The results of the adsorption of iodine and methylene blue activated carbon from sugar palm bunches increased from 240.55 mg/g and 63.14 mg/g at a temperature of 600 oC to achieve the highest adsorption capacity of 325.80 mg/g and 73.59 mg/g at temperature of 700 oC and decreased by 257.54 mg/g and 52.03 mg/g at a temperature of 800 oCrespectively.However, it does not meet to Indonesia standard (Standard Nasional Indonesia/SNI), which is 750 mg/g and 120 mg/g respectively.

scholarly journals Electroadsorption of Bromide from Natural Water in Granular Activated Carbon

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 598
Author(s):  
David Ribes ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós ◽  
Francisco Osorio ◽  
María J. García-Ruiz
Keyword(s):  
Activated Carbon ◽  
Electric Field ◽  
Adsorption Capacity ◽  
Natural Water ◽  
Granular Activated Carbon ◽  
Open Circuit ◽  
Filter Press ◽  
Anodic Treatment ◽  
Positive Polarization ◽  
Two Stages

The adsorption and electroadsorption of bromide from natural water has been studied in a filter-press electrochemical cell using a commercial granular activated carbon as the adsorbent. During electroadsorption experiments, different voltages were applied (2 V, 3 V and 4 V) under anodic conditions. The presence of the electric field improves the adsorption capacity of the activated carbon. The decrease in bromide concentration observed at high potentials (3 V or 4 V) may be due to the electrochemical transformation of bromide to Br2. The anodic treatment produces a higher decrease in the concentration of bromide in the case of cathodic electroadsorption. Moreover, in this anodic electroadsorption, if the system is again put under open circuit conditions, no desorption of the bromide is produced. In the case of anodic treatment in the following adsorption process after 24 h of treatment at 3 V, a new decrease in the bromide concentration is observed as a consequence of the decrease in bromide concentration after the electrochemical stage. It can be concluded that the electroadsorption process is effective against the elimination of bromide and total bromine in water, with a content of 345 and 470 µg L−1, respectively, reaching elimination values of 46% in a single-stage electroadsorption process in bromide and total bromine. The application of the electric field to the activated carbon with a positive polarization (anodic electroadsorption) increases the adsorption capacity of the activated carbon significantly, achieving a reduction of up to 220 µg L−1 after 1 h of contact with water. The two stage process in which a previous electrochemical oxidation is incorporated before the electroadsorption stage significantly increased the efficiency from 46% in a single electroadsorption step at 3 V, to 59% in two stages.

Separation of carotid body chemoreceptor responses to O2 and CO2 by oligomycin and by antimycin A

1982 ◽  
Vol 242 (3) ◽  
pp. C200-C206 ◽  
Author(s):  
E. Mulligan ◽  
S. Lahiri
Keyword(s):  
Steady State ◽  
Carbonic Anhydrase ◽  
Partial Pressure ◽  
Carotid Body ◽  
Body Tissue ◽  
Antimycin A ◽  
Tissue Ph ◽  
Co2 Partial Pressure ◽  
O2 Partial Pressure ◽  
Metabolic Hypothesis

The cat carotid chemoreceptor O2 and CO2 responses can be separated by oligomycin and by antimycin A. Both of these agents greatly diminish or abolish the chemoreceptor O2 response but not the nicotine or CO2 responses. After either oligomycin or antimycin, the responses to increases and decreases in arterial CO2 partial pressure (PaCO2) consisted of increases and decreases in activity characterized respectively by exaggerated overshoots and undershoots. These were eliminated by the carbonic anhydrase inhibitor, acetazolamide, suggesting that they resulted from changes in carotid body tissue pH. The steady-state PaCO2 response remaining after oligomycin was no longer dependent on arterial O2 partial pressure (PaO2). All effects of antimycin were readily reversible in about 20 min. The separation of the responses to O2 and CO2 indicates that there may be at least partially separate pathways of chemoreception for these two stimuli. The similarity of the oligomycin and antimycin results supports the metabolic hypothesis of chemoreception.

Interaction of hypoxia and hypercapnia on cerebral hemodynamics and brain electrical activity in dogs

1987 ◽  
Vol 253 (4) ◽  
pp. H890-H897 ◽  
Author(s):  
R. W. McPherson ◽  
D. Eimerl ◽  
R. J. Traystman
Keyword(s):  
Partial Pressure ◽  
Elevated Level ◽  
Severe Hypoxia ◽  
O2 Uptake ◽  
Animal Group ◽  
Moderate Hypoxia ◽  
Co2 Partial Pressure ◽  
Arterial Blood ◽  
O2 Partial Pressure ◽  
O2 Delivery

The interaction of hypoxic hypoxia, hypercapnia, and mean arterial blood pressure (MABP) was studied in 15 pentobarbital-anesthetized ventilated dogs. In one group of animals (n = 5) hypercapnia [arterial CO2 partial pressure (PaCO2) approximately 50 Torr] was added to both moderate hypoxia and severe hypoxia. Moderate hypoxia [arterial O2 partial pressure (PaO2) = 36 mmHg] increased MABP and cerebral blood flow (CBF) without changes in cerebral O2 uptake (CMRO2). Superimposed hypercapnia increased CBF and MABP further with no change in CMRO2. In another group of animals (n = 5), a MABP increase of approximately 40 mmHg during moderate hypoxia without hypercapnia did not further increase CBF, suggesting intact autoregulation. Thus, during moderate hypoxia, hypercapnia is capable of increasing CBF. Severe hypoxia (PaO2 = 22 mmHg) increased CBF, but MABP and CMRO2 declined. Superimposed hypercapnia further decreased MABP and decreased CBF from its elevated level and further decreased CMRO2. Raising MABP under these circumstances in another animal group (n = 5) increased CBF above the level present during severe hypoxia alone and increased CMRO2. The change in CBF and CMRO2 during severe hypoxia plus hypercapnia with MABP elevation were not different from that severe hypoxia alone. We conclude that, during hypoxia sufficiently severe to impair CMRO2, superimposed hypercapnia has a detrimental influence due to decreased MABP, which causes a decrease in CBF and cerebral O2 delivery.

Study of the Porous Structure and High Adsorption Capacity of Biomass-Based Activated Carbon Prepared from Aspen Wood by Ferric Nitrate III Activation

2021 ◽  
Vol 15 (2) ◽  
pp. 131-144
Author(s):  
Chunjiang Jin ◽  
Huimin Chen ◽  
Luyuan Wang ◽  
Xingxing Cheng ◽  
Donghai An ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Mass Ratio ◽  
Aspen Wood ◽  
Surface Functional Groups ◽  
Wood Sawdust

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.

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