Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Antibiotics in the aquatic environment - A review - Part II

https://opus.lib.uts.edu.au/bitstream/10453/33344/4/A%20review%20on%20the%20occurrence%20of%20micropollutants%20in%20the%20aquatic%20environment%20and%20their%20fate%20and%20removal%20during%20wastewater%20treatment.pdf

A review on the occurrence of micropollutants in the aquatic environment and their fate and removal during wastewater treatment

Single-walled carbon nanotubes (SWNTs) are molecular wires that exhibit interesting structural, mechanical, electrical, and electromechanical properties. 1-3 A SWNT is unique among solidstate materials in that every atom is on the surface. Surface chemistry could therefore be critical to the physical properties of SWNTs and their applications. 3-10 SWNT sidewall functionalization is important to soluble nanotubes, 4-6 self-assembly on surfaces, and chemical sensors. 8-10 For these purposes, it is imperative to functionalize the sidewalls of SWNTs in noncovalent ways to preserve the sp 2 nanotube structure and thus their electronic characteristics. Immobilization of biomolecules on carbon nanotubes has been pursued in the past, motivated by the prospects of using nanotubes as new types of biosensor materials. 11-15 The electronic properties of nanotubes coupled with the specific recognition properties of the immobilized biosystems would indeed make for an ideal miniaturized sensor. A prerequisite for research in this area is the development of chemical methods to immobilize biological molecules onto carbon nanotubes in a reliable manner. Thus far, only limited work has been carried out with multiwalled carbon nanotubes (MWNTs). 11-15 Metallothionein proteins were trapped inside and placed onto the outer surfaces of open-ended MWNTs.11-14 Streptavidin was found to adsorb on MWNTs presumably via hydrophobic interactions between the nanotubes and hydrophobic domains of the proteins. 15 DNA molecules adsorbed on MWNTs via nonspecific interactions were also observed. 12-14

Noncovalent Sidewall Functionalization of Single-Walled Carbon Nanotubes for Protein Immobilization

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

Occurrence of antibiotics in hospital, residential, and dairy effluent, municipal wastewater, and the Rio Grande in New Mexico.

Single-walled nanotubes (SWNTs) are an interesting new molecular form of carbon in the fullerene family, first reported by Iijima in 1991.1 Intense research activity is now focused on these molecules2 and many applications are envisioned.2 It is necessary to understand the chemical processes and functionalization of SWNTs in order to pursue these applications. FTIR is one of the powerful techniques available to researchers to study these surface properties.3 For example, we have recently used transmission FTIR to study the thermal decomposition of carboxyl and quinone functional groups formed by acidic cutting of the SWNTs.4 These groups, located at the ends and at surface defect sites on the nanotubes,2,5-8 block the entry ports for Xe adsorption on the interior of the SWNTs.9 We report here FTIR spectroscopic studies of the oxidation and etching of SWNTs using ozone at 298 K, and the subsequent thermal stability of the oxygenated groups. It has been shown through microscopy that reactions appear to begin at the end caps or kink sites of the SWNTs, followed by reaction at the rim sites that remain after the end caps and kink sites are etched away.6,7,10 The enhanced reactivity of the end caps and kink sites, compared to the reactivity of the walls, can be understood by the increased strain at these sites causing a partial loss of conjugation.8 In fact, forming a hole at the end cap by oxidation has been calculated to be much more energetically favorable (9 eV) than formation of holes on the walls.11 Ozonolysis is a common way to oxidatively break carboncarbon double bonds at low temperatures.12-14 Studies of the reaction of ozone with C60 and C70 have been reported in detail (see for example refs 15-17). However, the reaction of ozone with carbon nanotubes has been mentioned only briefly,16,17 and no spectroscopic studies have been carried out. The SWNTs used in this study have a distribution of diameters near that of a (10,10) tube (13.6 Å).18 The final sample consists of a mixture of open and closed-end SWNTs.19 The samples were deposited via the drop/dry technique from a methanol suspension onto CaF2 pressed into a tungsten grid clamped between electrical leads. This sample and a bare CaF2 blank were then mounted in a stainless steel FTIR cell20 used previously for transmission studies of powders and dispersed opaque materials.21 The sample was heated to 373 K overnight in a vacuum (1 × 10-6 Torr after 16 h) to remove the solvent, followed by heating to 1073 K in a vacuum to remove most of the oxygen-containing functional groups on the original SWNT sample.4 This heating revealed the IR-active phonon mode of SWNTs near 1580 cm-1.4 The ozone was prepared at an initial purity of 97% (3% O2) in a corona discharge-based trapping and purification system described elsewhere22 and O3(g) was transferred directly to the FTIR cell. The initial ozone purity in the FTIR system was determined to be ∼70% O3 (g) due to decomposition on the stainless steel walls of the apparatus. Figure 1 presents the IR spectral changes of the SWNT sample caused by O3 exposure at 298 K. The spectral bands that develop at 1739, 1200, and 1040 cm-1 are indicative of the production of ester groups. The band at 1650 cm-1 is assigned to the CdO stretching mode of quinone groups, while the band at 1581 cm-1 is assigned to CdC double bonds located near the newly formed oxygenated groups.23,24 The origin of the bands at 1380 and 925 (1) Iijima, S. Nature 1991, 354, 56. (2) Dresselhaus, M. S.; Dresselhaus, G.; Eklund, P. C. Science of Fullerenes and Carbon Nanotubes; Academic Press: San Diego, 1996. (3) Vibrational Spectroscopy of Molecules on Surfaces Yates; J. T., Jr., Madey, T. E., Eds.; (Plenum: New York, 1987). (4) Kuznetsova, A.; Mawhinney, D. B.; Naumenko, V.; Yates, J. T., Jr.; Liu, J.; Smalley, R. E. Chem. Phys. Lett., in press. (5) Liu, J.; Rinzler, A. G.; Dai, H.; Hafner, J. H.; Bradley, R. K.; Boul, P. J.; Lu, A.; Iverson, T.; Shelimov, K.; Huffman, C. B.; Rodriguez-Macias, F.; Shon, Y. S.; Lee, T. R.; Colbert, D. T.; Smalley, R. E. Science 1998, 280, 1253. (6) Tsang, S. C.; Harris, P. J. F.; Green, M. L. H. Nature 1993 362, 520. (7) Ajayan, P. M.; Ebbesen, T. W.; Ichihashi, T.; Iijima, S.; Tanigaki, K.; Hiura, H. Nature 1993, 362, 522. (8) Srivastava, D.; Brenner, D. W.; Schall, J. D.; Ausman, K. D.; Yu, M. F.; Ruoff, R. S. J. Phys. Chem. B 1999, 103, 4330. (9) Kuznetsova, A.; Yates, J. T., Jr.; Liu, J.; Smalley, R. E. J. Chem. Phys., in press. (10) Ajayan, P. M.; Iijima, S. Nature 1993, 361, 333. (11) Mazzoni, M. S. C.; Chacham, H.; Ordejon, P.; Sanchez-Portal, D.; Soler, J. M.; Artacho, E. Phys. ReV. B 1999, 60, R2208. (12) Morrison, R. T.; Boyd, R. N. Organic Chemistry, 4th ed.; Allyn and Bacon: Boston, 1983. (13) Neeb, P.; Horie, O.; Moortgat, G. K. J. Phys. Chem. A 1998, 102, 6778. (14) Manoilova, O. V.; Lavalley, J. C.; Tsyganenko, N. M.; Tsyganenko, A. A. Langmuir 1998, 14, 5813. (15) Malhotra, R.; Kumar, S.; Satyam, A. J. Chem. Soc., Chem. Commun. 1994, 1339. (16) Deng, J. P.; Mou, C. Y.; Han, C. C. Fullerene Sci. Technol. 1997, 5, 1033. (17) Deng, J. P.; Mou, C. Y.; Han, C. C. Fullerene Sci. Technol. 1997, 5, 1325. (18) Rinzler, A. G.; Liu, J.; Dai, H.; Nikolaev, P.; Huffman, C. B.; Rodrı́guez-Macı́as, F. J.; Boul, P. J.; Lu, A. H.; Heymann, D.; Colbert, D. T.; Lee, R. S.; Fischer, J. E.; Rao, A. M.; Eklund, P. C.; Smalley, R. E. Appl. Phys. A. 1998, 67, 29. (19) Smalley, R. E., personal communication. (20) Basu, P.; Ballinger, T. H.; Yates, J. T., Jr. ReV. Sci. Instrum. 1988, 59, 1321. (21) Mawhinney, D. B.; Rossin, J. A.; Gerhart, K. Yates, J. T., Jr. Langmuir 1999, 15, 5, 4617. (22) (a) Yates, J. T., Jr. Experimental InnoVations in Surface Science; AIP/ Springer-Verlag, New York, 1998; p 702. (b) Zhukov, V.; Popova, I.; Yates, J. T., Jr. J. Vac. Sci. Technol. A, accepted for publication. (23) Socrates, G. Infrared Characteristic Group Frequencies; John Wiley & Sons: New York, 1980. (24) Fanning, P. E.; Vannice, M. A. Carbon 1993, 31, 721. Figure 1. Infrared modes resulting from the ozonation of SWNTs. The background spectrum of the nanotubes before ozone exposure has been subtracted so that the changes can be more clearly observed. Both CO2(g) and CO(g) are formed as well. 2383 J. Am. Chem. Soc. 2000, 122, 2383-2384

Infrared Spectral Evidence for the Etching of Carbon Nanotubes: Ozone Oxidation at 298 K

Enhancement of adsorption inside of single-walled nanotubes: opening the entry ports

Surface defect site density on single walled carbon nanotubes by titration

The oxidation of hydrogen-terminated porous silicon surfaces produced by electrochemical etching has been studied using transmission FTIR spectroscopy. The surface is passivated to oxidation by surface hydrogen below about 523 K. Above this temperature as hydrogen depletion occurs by H2 evolution, Si surface dangling bond sites, capable of O2 dissociation, are involved in initiating the first stage of oxidation. Two reactions are observed. The first, O insertion into Si−Si back-bonds, leads to −OySiHx surface species which exhibit frequency shifts to the blue compared to parent SiHx stretching modes. In addition, Si−O−Si modes are also observed to form. The second reaction involves oxygen atom insertion into Si−H bonds to produce isolated Si−OH surface species.

Douglas B. Mawhinney

Papers

Occurrence of antibiotics in hospital, residential, and dairy effluent, municipal wastewater, and the Rio Grande in New Mexico.

Infrared Spectral Evidence for the Etching of Carbon Nanotubes: Ozone Oxidation at 298 K

Enhancement of adsorption inside of single-walled nanotubes: opening the entry ports

Surface defect site density on single walled carbon nanotubes by titration

FTIR Study of the Oxidation of Porous Silicon