2014, Vol.15, No.2

Carbon Letters 2023 KCI Impact Factor : 1.35 KCI-WoS Impact Factor : 4.82

pISSN : 1976-4251 / eISSN : 2233-4998
https://journal.kci.go.kr/carbon

Double walled carbon nanotubes (DWCNTs) are considered an ideal model for studyingthe coupling interactions between different concentric shells in multi-walled CNTs. Dueto their intrinsic coaxial structures they are mechanically, thermally, and structurally morestable than single walled CNTs. Geometrically, owing to the buffer-like function of the outertubes in DWCNTs, the inner tubes exhibit exciting transport and optical properties that lendthem promise in the fabrication of field-effect transistors, stable field emitters, and lithiumion batteries. In addition, by utilizing the outer tube chemistry, DWCNTs can be usefulfor anchoring semiconducting quantum dots and also as effective multifunctional fillers inproducing tough, conductive transparent polymer films. The inner tubes meanwhile preservetheir excitonic transitions. This article reviews the synthesis of DWCNTs, their electronicstructure, transport, and mechanical properties, and their potential uses.

Materials with appropriate surface roughness and low surface energy can form superhydrophobicsurfaces, displaying water contact angles greater than 150°. Superhydrophobiccarbon-based materials are particularly interesting due to their exceptional physicochemicalproperties. This review discusses the various techniques used to produce superhydrophobiccarbon-based materials such as carbon fibers, carbon nanotubes, graphene, amorphous carbons,etc. Recent advances in emerging fields such as energy, environmental remediation,and thermal management in relation to these materials are also discussed.

Wastewater from textile industries is a major cause of water pollution in most developingcountries. In order to address the issues of water pollution and high cost for treatment processes,the use of an inexpensive and environmentally benign adsorbents has been studied. The objective was to find a better alternative to the conventional methods. Lemon grasswaste (ash) collected from a lemon grass stream distillation subunit in Bhutan was tested fordye removal from aqueous solutions. The study investigated the removal of methylene blueusing the following operational parameters: initial concentration (100-600 mg/L), contacttime, adsorbent dose (0.1- 0.55 gm/100 mL), and pH (3-10). It was found that the percentageremoval of dye increased with a decrease of the initial concentration and increased contacttime and dose of adsorbent. The basic pH solution of dye showed better adsorption capacityas compared to the acidic dye solution. Langmuir and Freundlich adsorption isothermswere fitted to the data well. Data fitted better to Lagergren pseudo 2nd order kinetics thana 1st order kinetic model. Surface morphology was also examined via scanning electronmicroscopy. An elemental analysis was also carried out and the chemical composition andfunctional groups were analyzed using energy dispersive X-ray spectroscopy and Fouriertransform infrared spectroscopy techniques, respectively. The obtained results indicate thatlemon grass ash could be employed as a low cost alternative to commercial activated carbonin wastewater treatment for the removal of dyes.