Characterization and use of functionalized carbon nanotubes for the adsorption of heavy metal anions

2880

CARBON

4 9 ( 2 0 1 1 ) 2 8 7 8 –2 8 8 1

electrical conductivity up to 527 S/m after the thermal treatment

Characterization and use of functionalized carbon nanotubes for

at temperatures from 130 to 200 °C. This environmentally friendly

the adsorption of heavy metal anions

and easy approach is promising for the large scale preparation of

Yi-jun Xu, Rosa Arrigo, Xi Liu, Dang-sheng Su

graphene oxide films with no need of hydrazine and other toxic chemicals. [New Carbon Materials 2011, 26(1):41-45]

Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany Carbon nanotubes (CNTs) have been chemically functionalized

doi:10.1016/j.carbon.2011.02.038

with various oxygen-containing surface groups. The feature of abundant oxygen-containing surface functional groups on the functionalized CNTs is characterized by X-ray photoelectron specEffect of vacancies and Si-dopant on In adsorption on graphene

troscopy and temperature-programmed desorption analyslis.

Xian-qi Dai, Yong-can Sun, Jian-hua Zhao, Shu-yi Wei

Results indicate that the functionalized CNTs have a superior

College of Physics and Information Engineering, Henan Normal Univer-

adsorption capacity toward anionic chromate CrO24 , a typical toxic

sity, Xinxiang 453007, China First-principles calculations were carried out to study the effect of vacancies and Si-dopant on indium (In) adsorption on graphene. It is demonstrated that a vacancy or a Si-dopant strengthens In adsorption on graphene. The effect of the vacancy is greater at low In coverage than that of Si impurity, owing to the fact that the vacancy provides more dangling bonds for In adsorption, which strengthens the interaction between the In atom and

heavy metal ion in waste water, as compared with the unmodified ones. The excellent adsorption ability of CrO24 is attributed to the interaction of CrO24

with the surface oxygen-containing func-

tional groups on the modified CNTs. The functionalized CNTs can be potentially used as an alternatively viable and promising adsorbent for the removal of heavy metal anions in waste water. [New Carbon Materials 2011, 26(1):57-62] doi:10.1016/j.carbon.2011.02.041

graphene. However, the Si impurity affects In adsorption on graphene stronger than that the vacancy does at high In coverage (i.e. 1/6).

Carbon-coated TiO2 composites for the photocatalytic degrada-

[New Carbon Materials 2011, 26(1):46-51]

tion of low concentration benzene Jiang Zhanga, Zheng-hong Huanga, Yong Xub, Fei-yu Kanga

doi:10.1016/j.carbon.2011.02.039

a

Laboratory of Advanced Materials, Department of Materials Science

and Engineering, Tsinghua University, Beijing 100084, China b

Beijing Tongfang Puri-tech Co., ltd, Beijing 100083, China

Synthesis and field emission property of carbon nanotubes with sharp tips

Carbon-coated TiO2 was synthesized by mixing TiO2 powders

Yan-li Zhanga, Li-li Zhanga, Peng-xiang Houa, Hua Jiangb,

and polyethylene glycol, followed by heat treatment in nitrogen

Chang Liua, Hui-ming Chenga

atmosphere. All samples were characterized by powder X-ray dif-

a

Shenyang National Laboratory for Materials Science, Institute of Metal

Research, Chinese Academy of Sciences, Shenyang 110016, China b

Department of Applied Physics and Center for New Materials, Aalto

University, P.O. Box 15100, Puumiehenkuja 2, FIN-02150 Espoo, Finland

fraction, UV diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, and nitrogen adsorption. The photocatalytic activity of carbon-coated TiO2 for benzene degradation was investigated with a benzene concentration of 1.2  10 5. Results showed that the residual carbon content was influenced greatly by heat treatment temperature (HTT)

Carbon nanotubes (CNTs) with sharp tips were synthesized

and the amount of PEG, which decreased and increased with

by a hydrogen arc discharge method. Three unusual morpholo-

increasing the temperature and the amount of PEG, respectively.

gies, i.e., a cone-shaped tip, a suddenly-shrinking tip, and a pen-

The crystallinity of TiO2 was improved when the HTT increased.

cil point-like tip were observed. These novel tip structures are

However, the carbon residue had an inhibition effect on the crys-

considered to be related to the addition of a small amount of sil-

tal growth of TiO2. The carbon-coated anatase samples were

icon powder in the raw material, which may introduce struc-

shown to exhibit higher photocatalytic activities than the pristine

tural defects in the CNTs. The field emission property of the

TiO2 because of the adsorption enrichment of benzene by carbon

sharp-tip CNTs was investigated, and a low threshold electric

around the anatase particles and of the effective charge separa-

field of 3.75 V/m, a high field emission current density of

tion due to the electronic conduction of carbon. Another impor-

1.6  105 A/cm2, and a good emission stability were demon-

tant factor affecting photocatalytic activity was the crystallinity

strated. The superior field emission performance of the CNTs

of the anatase phase. High photocatalytic activity for benzene

can be attributed to their good crystallinity and unique tip

requires a balance between the carbon content and the anatase

structures.

crystalline structure.

[New Carbon Materials 2011, 26(1):52-56]

[New Carbon Materials 2011, 26(1):63-70]

doi:10.1016/j.carbon.2011.02.040

doi:10.1016/j.carbon.2011.02.042