Effect of micropore and mesopore structure on CO2 adsorption by activated carbons from biomass

Effect of micropore and mesopore structure on CO2 adsorption by activated carbons from biomass

CARBON 93 (2015) 1081– 1084 Pd nanoparticles (Pd-NPs) were deposited on the surface of a 1083 Department of Engineering Materials, Faculty of Manu...

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CARBON 93 (2015) 1081– 1084

Pd nanoparticles (Pd-NPs) were deposited on the surface of

a

1083

Department of Engineering Materials, Faculty of Manufacturing

Vulcan XC-72 carbon black (CB), multi-walled carbon nanotubes

Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah

(MWCNTs) and carbon spheres (CSs) by the spontaneous reduction

Jaya, 76100 Durian Tunggal, Melaka, Malaysia

of PdCl2 with oxygen-functional groups on the carbon surfaces to

b

Department of Telecommunication, Faculty of Electronics and

produce catalysts for the electrochemical oxidation of ethanol.

Computer Engineering, Universiti Teknikal Malaysia Melaka (UTeM),

These carbons were also modified with a cationic surfactant (hex-

Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia

adecyltrimethyl ammonium bromide, CTAB) and subsequently used as supports for the deposition of Pd nanoparticles using the

Activated carbons were prepared from rubber wood sawdust

spontaneous reduction method. SEM, TEM and XRD were used to

by chemical activation using ZnCl2 as an activation agent at

characterize their structures. Pd-NPs with a size of ca. 9 nm were

500 °C for 60 min with ZnCl2/dried rubber wood sawdust mass

obtained on the surface of the CTAB-modified MWCNTs. The

ratios from 1.0 to 2.0. Flat polyurethane (PU) composites filled

amount of Pd-NPs spontaneously deposited on the CTAB-

with the activated carbons were prepared by a chemical foaming

MWCNTs is much larger than that on the MWCNTs, CB or CSs.

method using different loading amounts of the activated carbons

The Pd/CTAB-MWCNTs exhibit a higher anodic peak current den-

to investigate their complex permittivity and the microwave

in cyclic voltammetry, indicating a better elec-

absorption properties for use in electromagnetic interference

trocatalytic activity for ethanol oxidation than the other catalysts.

(EMI) shielding. It was found that the best activated carbon is

[New Carbon Materials 2015, 30(2): 150–155]

obtained at a ratio of 1.5, which has the highest Brunauer–

sity of 44.2 mAcm

2

Emmett–Teller surface area and a micropore volume of 1301 m2/ g and 0.37 cm3/g, respectively. With increasing activated carbon

http://dx.doi.org/10.1016/j.carbon.2015.04.074

content, the dielectric constant (e0 ) and the return loss increase Effect of micropore and mesopore structure on CO2 adsorption by activated carbons from biomass

8 wt% activated carbon has a maximum dielectric constant of 3.0 and its return loss is above 10 dB at the global system mobile

Tao Songa, Jing-ming Liaoa,b, Jun Xiaoa, Lai-hong Shena a

in the frequency range of 1–3 GHz. The composite filled with

phone frequency of 1.8 GHz. Its EMI shielding efficiency is in the

Key Laboratory of Energy Thermal Conversion and Control of Ministry

useful range of approximately 3 dB over a wide frequency range

of Education, Southeast University, Nanjing 210096, China

of 1–2.5 GHz. Compared with conventional materials such as

b

polyethelene and polyester filled with metal additives, this com-

Fujian Electric Power Survey & Design Institute, Fuzhou 350003, China

posite is suitable for microwave absorption and is a potential canActivated carbons (ACs) were produced by a one step process with CO2 as the physical activation agent at 800 °C. The ACs were further activated chemically using KOH, HNO3 or CH3COOH and heat-treated at 300 or 600 °C for 1 or 2 h to modify their proper-

didate for EMI shielding applications. [New Carbon Materials 2015, 30(2): 167–175] http://dx.doi.org/10.1016/j.carbon.2015.04.076

ties. The effect of CO2 concentration, activation time, types of chemical agents and the post heat-treatment conditions on CO2

Rheological properties of mesophase pitch investigated by the

capture were investigated. Results showed that the optimum con-

Giseeler fluidity method

ditions for AC production from corn stalks was at 800 °C for

Ming-lin Jin, Jie-ling Cheng, Lian-xing Wang, Shuang-ling Jin,

30 min with a CO2 concentration of 20% during the physical acti-

Rui Zhang

vation. Chemical agents and further heat-treatment modified the pore structure of the ACs, resulting in a performance improvement for CO2 adsorption. The BET surface area of one sample

School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China

(HNO3 activation + 100 °C water bath 1 h + post heat-treatment at 600 °C for 2 h) was 639. 8 m2/g. The maximum CO2 adsorption

The Giseeler fluidity method was used to investigate the rheo-

capacity of the sample was 7.33 wt%, which is higher than that

logical properties of pitch with and without heat treatment from

of a commercial AC (6.55 wt%). The CO2 adsorption is dominantly

room temperature to 520 °C. Results show that the fluidity has a

dependent on the mesopore volume when the BET surface area is

good repeatability at different temperatures under different heat-

smaller than 500 m2/g while the adsorption is closely associated

ing rates. The fluidity of the raw pitch slowly increases from 253

with micropore area when the BET surface area is larger than

to 282 °C, then increases exponentially from 282 to 311 °C near

500 m2/g.

the softening temperature, and finally remains unchanged from

The

adsorption

kinetics

agreed

well

with

the

Bangham kinetic model.

311 to 498 °C. This changing pattern of fluidity with temperature

[New Carbon Materials 2015, 30(2): 156–166]

has also been found for heat-treated mesophase pitch and can be formulated by the Arrhenius equation, from which the viscous

http://dx.doi.org/10.1016/j.carbon.2015.04.075

flow activation energy can be obtained. The toluene-insoluble fraction increases from 67.3% to 88.7% with heat-treatment time

Preparation of rubber wood sawdust-based activated carbon and its use as a filler of polyurethane matrix composites for microwave absorption a

a

b

Azizah Shaaban , Sian-Meng Se , Imran Mohd Ibrahim , Qumrul Ahsana

and the flow activation energy of the treated mesophase pitch in the Newtonian fluid region at low temperature range is between 203.6 and 294 kJ/mol. [New Carbon Materials 2015, 30(2): 176–180] http://dx.doi.org/10.1016/j.carbon.2015.04.077