Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.

http://science.sciencemag.org/content/sci/297/5582/787.full.pdf

Carbon Nanotubes--the Route Toward Applications

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

The relationship between soil structure and the ability of soil to stabilize soil organic matter (SOM) is a key element in soil C dynamics that has either been overlooked or treated in a cursory fashion when developing SOM models. The purpose of this paper is to review current knowledge of SOM dynamics within the framework of a newly proposed soil C saturation concept. Initially, we distinguish SOM that is protected against decomposition by various mechanisms from that which is not protected from decomposition. Methods of quantification and characteristics of three SOM pools defined as protected are discussed. Soil organic matter can be: (1) physically stabilized, or protected from decomposition, through microaggregation, or (2) intimate association with silt and clay particles, and (3) can be biochemically stabilized through the formation of recalcitrant SOM compounds. In addition to behavior of each SOM pool, we discuss implications of changes in land management on processes by which SOM compounds undergo protection and release. The characteristics and responses to changes in land use or land management are described for the light fraction (LF) and particulate organic matter (POM). We defined the LF and POM not occluded within microaggregates (53–250 μm sized aggregates as unprotected. Our conclusions are illustrated in a new conceptual SOM model that differs from most SOM models in that the model state variables are measurable SOM pools. We suggest that physicochemical characteristics inherent to soils define the maximum protective capacity of these pools, which limits increases in SOM (i.e. C sequestration) with increased organic residue inputs.

Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils

Application of low-cost adsorbents for dye removal – A review

Summary
Mechanisms for C stabilization in soils have received much interest recently due to their relevance in the global C cycle. Here we review the mechanisms that are currently, but often contradictorily or inconsistently, considered to contribute to organic matter (OM) protection against decomposition in temperate soils: (i) selective preservation due to recalcitrance of OM, including plant litter, rhizodeposits, microbial products, humic polymers, and charred OM; (ii) spatial inaccessibility of OM against decomposer organisms due to occlusion, intercalation, hydrophobicity and encapsulation; and (iii) stabilization by interaction with mineral surfaces (Fe-, Al-, Mn-oxides, phyllosilicates) and metal ions. Our goal is to assess the relevance of these mechanisms to the formation of soil OM during different stages of decomposition and under different soil conditions. The view that OM stabilization is dominated by the selective preservation of recalcitrant organic components that accumulate in proportion to their chemical properties can no longer be accepted. In contrast, our analysis of mechanisms shows that: (i) the soil biotic community is able to disintegrate any OM of natural origin; (ii) molecular recalcitrance of OM is relative, rather than absolute; (iii) recalcitrance is only important during early decomposition and in active surface soils; while (iv) during late decomposition and in the subsoil, the relevance of spatial inaccessibility and organo-mineral interactions for SOM stabilization increases. We conclude that major difficulties in the understanding and prediction of SOM dynamics originate from the simultaneous operation of several mechanisms. We discuss knowledge gaps and promising directions of future research.

Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions – a review

Solid-state cross-polarisation/magic-angle-spinning3C nuclear magnetic resonance (CP/MAS13C NMR) spectroscopy was used to characterise semi-quantitatively the organic materials contained in particle size and density fractions isolated from five different mineral soils: two Mollisols, two Oxisols and an Andosol The acquired spectra were analysed to determine the relative proportion of carboxyl, aromatic, O-alkyl and alkyl carbon contained in each fraction Although similar types of carbon were present in all of the fractions analysed, an influence of both soil type and particle size was evident The chemical structure of the organic materials contained in the particle size fractions isolated from the Andosol was similar; however, for the Mollisols and Oxisols, the content of O-alkyl, aromatic and alkyl carbon was greatest in the coarse, intermediate and fine fractions, respectively The compositional differences noted in progressing from the coarser to finer particle size fractions in the Mollisols and Oxisols were consistent with the changes noted in other studies where CP/MAS13C NMR was used to monitor the decomposition of natural organic materials Changes in the C:N ratio of the particle size fractions supported the proposal that the extent of decomposition of the organic materials contained in the fine fractions was greater than that contained in the coarse fractions The increased content of aromatic and alkyl carbon in the intermediate size fractions could be explained completely by a selective preservation mechanism; however, the further accumulation of alkyl carbon in the clay fractions appeared to result from both a selective preservation and anin situ synthesis The largest compositional differences noted for the entire organic fraction of the five soils were observed between soil orders The differences within orders were smaller The Mollisols and the Andosol were both dominated by O-alkyl carbon but the Andosol had a lower alkyl carbon content The Oxisols were dominated by both O-alkyl and alkyl carbon A model describing the oxidative decomposition of plant materials in mineral soils is proposed and used to explain the influence of soil order and particle size on the chemical composition of soil organic matter in terms of its extent of decomposition and bioavailability

Aspects of the chemical structure of soil organic materials as revealed by solid-state 13C NMR spectroscopy

BACKGROUND TO NANOTECHNOLOGY Scientific Revolutions Types of Nanotechnology and Nanomachines The Periodic Table Atomic Structure Molecules and Phases Energy Molecular and Atomic Size Surfaces and Dimensional Space Top Down and Bottom Up MOLECULAR NANOTECHNOLOGY Atoms by Inference Electron Microscopes Scanning Electron Microscope Modern Transmission Electron Microscope Scanning Probe Microscopy - Atomic Force Microscope Scanning Tunnelling Microscope Nanomanipulator Nanotweezers Atom Manipulation Nanodots Self Assembly Dip Pen Nanolithography NANOPOWDERS AND NANOMATERIALS What Are Nanomaterials? Preparation Plasma Arcing Chemical Vapour Deposition Sol-Gels THE CARBON AGE New Forms of Carbon Types of Nanotubes Formation of Nanotubes Assemblies Purification of Carbon Nanotubes The Properties of Nanotubes Uses of Nanotubes MOLECULAR MIMICS Catenanes and Rotaxanes Molecular Switches The Electron Driven Molecular Shuttle Switch The pH Driven Molecular Shuttle Switch The Light Driven Molecular Shuttle Switch Synthesis of Rotaxanes and Catenanes Rotaxanes and Molecular Computers Chemical Rotors Prodders Flippers Atom Shuttles Actuators Contacts NANOBIOMIMETICS Introduction Lipids as Nano-Bricks and Mortar Same but Different: Self-Assembled Nanolayers The Bits that Do Things - Proteins Structure is Information - DNA A Biological Nanotechnological Future OPTICS, PHOTONICS AND SOLAR ENERGY Properties of Light and Nanotechnology Interaction of Light and Nanotechnology Nanoholes and Photons Imaging New low Cost Energy Efficient Windows and Solar Absorbers Based On Nanoparticles Photonic Crystals, Surface Wave Guides and Control of Light Paths NANOELECTRONICS Introduction What Will Nanoelectronics Do for Us? The Birth of Electronics The Tools of Micro- and Nanofabrication From Classical to Quantum Physics Quantum Electronic Devices Quantum Information and Quantum Computers Experimental Implementations of Quantum Computers FUTURE APPLICATIONS Micro-Electromechanical Machines Robots - How Small Can They Go? Ageless Materials Invisible Mending of Atomic Dislocations Inside Damaged Materials Nanomechanics and Nanoelasticity Nanoparticle Coatings - Special New Effects Nanoelectronic and Magnetic Devices and New Computing Systems Optoelectronic Devices Environmental Applications INTO THE REALMS OF IMAGINATION Introduction Communication Manufacturing Nanomedicine Society and Ethics Religion and Making Everything from Everything Else Thanks for All the Fish REFERENCES INDEX Each chapter also contains References and Exercises

Nanotechnology: Basic Science and Emerging Technologies

Colored wastewater poses a challenge to the conventional wastewater treatment techniques. Solid−liquid phase adsorption has been found to be effective for the removal of dyes from effluent. In this paper, the ability of bentonite as an adsorbent for the removal of a commercial dye, Basic Red 2 (BR2), from an aqueous solution has been investigated under various experimental conditions. The adsorption kinetics was shown to be pseudo-second-order. It was found that bentonite had high adsorption capacity for BR2 due to cation exchange. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The effect of the experimental parameters, such as temperature, salt, and pH was investigated through a number of batch adsorption experiments. It was found that the removal of dye increased with the increase in solution pH. However, the change of temperature (15−45 °C) and the addition of sodium chloride were found to have little effect on the adsorption process. The results show that...

Michael A. Wilson

Papers

Aspects of the chemical structure of soil organic materials as revealed by solid-state 13C NMR spectroscopy

Nanotechnology: Basic Science and Emerging Technologies

Adsorption Study for Removal of Basic Red Dye Using Bentonite

Catalytic upgrading of biorefinery oil from micro-algae

Nanomaterials in soils