Utilization of textile-related wastes is investigated for the growth of substance-circulating society and the establishment of recycling technology is important. In this work, it was studied that the activated carbons were prepared from polyester sliver and that those were utilized as an adsorbent for environmental purification. The activated carbons prepared from polyester sliver, whose properties and adsorption performances were equal or superior to ordinary activated carbons on the market, were obtained by the control of activation conditions. Activated carbon with more than 1500 m²/g of specific surface area was obtained in the case of steam activation. However the specific surface area of the activated carbons by CO₂-activation was smaller than those by steam activation. It was possible that the pore size of the activated carbons by CO₂-activation was larger relatively from results of porosities analyzed. Adsorption isotherms of 4-nonylphenol (4NP) in water, which was recognized as one of endocrine-disrupting chemicals, were measured by using the activated carbons prepared from polyester sliver. It was found out that the activated carbons were available effectively for adsorptive removal of 4NP in environmental water and that adsorption performance for 4NP could be improved by controlling the conditions for preparation of the activated carbon.

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Adsorptive removal can be an option for the further removal of sulfur from refining oil so as to be available treatment at ambient temperatures and pressures. Benzothiophene (BT) found in petroleum kerosene was used as a model sulfur compound in the study, and commercially purchased activated carbon and those introduced oxygen functional groups on the surface were examined as adsorbents. The adsorption isotherms of BT were presented by these carbons with n-hexane (non-polar) and methanol (polar) solvent. These isotherms showed that two adsorption sites, Cπ sites adsorbing non-polar compounds and C-O complex (COC) sites taking polar compounds, are presented on activated carbon. From bi-Langmuir isotherm equation assuming two types of adsorption sites, equilibrium constants for each site were estimated, revealing that the adsorption affinities of BT are similar between on Cπ and on COC sites. On the Cπ sites, not only BT but also other non-polar compounds as aromatics co-existing in the fuel oil are adsorbed. In contrast, on the COC sites BT is selectively adsorbed but the non-polar compounds are not strongly adsorbed. The results suggested that oxidized activated carbons containing many COC sites can adsorb BT effectively without the inhibition by aromatics.

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Cup-stacked carbon nanotubes (Cup-CNTs) consist of truncated conical graphene layers which exhibit open edges on the tube outer surface. Therefore, when used as filler, Cup-CNTs are expected to have many contact points with the matrix. Acrylonitrile butadiene rubber (NBR) composites containing Cup-CNTs were prepared by mixing the chloroform solutions of Cup-CNTs and NBR polymer followed by the evaporation of the solvent. Using this method Cup-CNTs were dispersed homogeneously in the NBR matrix. Cup-CNTs with different lengths (short- and middle-types) were used and the dependences of the mechanical properties on the length were investigated. The middle-type Cup-CNTs showed better reinforcing effects in terms of tensile strength, Young's modulus and hardness.

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Hydrothermally synthesized glucose-borate complexes (mole ratio 1/1 and 1/2) were carbonized at 800–1200℃ for 1 h in argon, followed by boiling in water to remove borate byproducts. Formed boron-containing carbons (B-carbons) contained 1–3.4 mass% boron and, by XPS, boron was present mainly as a form of C-B-O bonding and not as the substituted boron. The specific surface area by N₂ adsorption, S_BET, was 850–1360 m² g⁻¹, and decreased with raising heat treatment temperature. The 1/2 complex provided larger S_BET than the 1/1 complex. Pore width was less than 3 nm except for the products at 1200℃. The cyclic voltammograms (CVs) at 2 mV s⁻¹ in 1 mol dm⁻³ Na₂SO₄ were rectangular and the specific capacitance normalized by S_BET, C_A, was 0.05–0.1 F m⁻², indicating the electric double layer capacitance. In 1 mol dm⁻³ H₂SO₄, CVs showed broad redox peaks in a potential range of 0–0.6 V vs. SCE and C_A was 0.13–0.2 F m⁻²:the pseudocapacitance is attributed to more than two types of oxygen-containing functional groups and one of them might be =B-OH type. The electrode capacitance, C_M in F g⁻¹, in the H₂SO₄ solution was more than twice of the C_M in the Na₂SO₄ solution. It may be mainly due to the difference between Na⁺ and H⁺ ions, though a certain level of pseudo-capacitance is contributing to C_M. Carbons derived from a mixture of poly (vinyl alcohol) and boric acid were S_BET<50 m² g⁻¹, suggesting that the large S_BET of B-carbon is owing to the thermal decomposition behavior of glucose-borate complexes, which is different from the pore formation mechanism of the MgO template method reported.

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A pellet of as-grown multi-walled carbon nanotubes (MWNTs) prepared by compression was heat-treated at 3000℃ for 30 min to eliminate metal impurities and a piece of the 3000℃-treated pellet was boron doped with a diffusion method. Electron energy loss (EEL) spectrum measurements for an individual boron-doped MWNT (B-MWNT) selected from the boron doped pellet were taken along the central line of the high resolution transmission electron microscope image, i.e. the line of the MWNT axis of the individual B-MWNT. Along the central line, a K-shell excitation EEL spectrum composed of two spectra, a weak boron K-shell excitation EEL spectrum and a strong carbon K-shell excitation EEL spectrum, was obtained at some positions, while at other positions only a carbon K-shell excitation EEL spectrum was recorded. Semi quantitative analysis of the energy loss near the edge structure of the boron K-edge revealed that boron doping had taken place quite locally in the individual B-MWNT.

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Wood carbon prepared by nickel-catalyzed carbonization at 900℃ followed by washing with acid for removal of the metal was oxidized in a muffle furnace at 480℃. This eliminated the amorphous region selectively, and the residual carbon became superior to a commercial electro-conductive carbon, Denka black, in the performance. Observations by scanning electron microscopy and transmission electron microscopy disclosed that the crystallite region in the original wood carbon had a novel graphitic nanostructure. It is noted that such a uniquely morphological graphitic carbon can be inexpensively and easily produced from woody biomass.

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We examined the optical features of double-walled carbon nanotubes (DWNTs). It is found that the semiconducting inner tubes within DWNTs show bright and stable photoluminescence that cannot be found in single-walled carbon nanotubues (SWNTs) having same chirality (n, m), even though both samples were prepared in the same condition. In another finding, optical absorption and photoluminescence signal were observed for the inner tubes within the fluorinated DWNTs as well as CdSe quantum dot-decorated fluorinated DWNTs. Fluorine atoms on the outer tubes of DWNTs are also effective for nucleating and growing CdSe nanoparticles. These optical activities of inner tubes of DWNTs show the shielding effect of the outer tubes. We believe that present finding of intrinsic optical abilities of carbon nanotubes can contribute to improvement of biomedical and optoelectrical applications.

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