In this study, SnS 2 nanocrystals with controlled morphology were successfully synthesized by a simple hydrothermal method using thiosemicarbazide both as a sulfur source and as a capping agent.The X-ray powder diffraction analysis confirmed the hexagonal phase of these as-prepared SnS 2 nanocrystals.Morphological features were studied by field-emission scanning electron microscopy, indicating that the as-prepared SnS 2 crystals were nanoparticles.The optical property was studied by ultravioletvisible diffused reflectance spectroscopy, indicating that the bandgap of SnS 2 samples is ~2.2 eV.Under white LED light irradiation (λ = 450 nm), the as-prepared SnS 2 nanocrystals exhibited a high photocatalytic activity for degrading 2,4,6-trichlorophenol solution.This work suggests that SnS 2 nanocrystal is a potential photocatalyst for detoxification.
Organosilane-modified (island-type) electrodes of 5 and 10 μm were fabricated and used to detect trace amounts of metal ions using atomic force microscopy. The smaller electrode had a lower limit of detection due to the enhancement in electron tunneling through metal ions that are adsorbed between the conductive-tip (mobile) and the surface (fixed) electrode. To simulate the detection of metal ions at concentrations below 10-3 mM, a sectional adsorption mechanism is proposed, which satisfactorily explains the adsorption of Cu(II) and Hg(II) to the amine and thiol moieties of the 5-μm-sized electrode.
This study evaluated the concentration(OU/m3) of a complex odor being discharged from tire, feedstuff, bakery, paper, casting and painting manufacturing process, correlation between odor concentration(OU/m3) and the odor sensor was investigated. 4 type(A, B, C, D) gas sensors of metal oxide compounds are used in this study. Each odor sample of manufacturing process is diluted with odorless air and diluted odor samples were prepared for five different concentrations. Correlation results(R) of odor sample of tire, feedstuff, bakery, paper manufacturing process ware 0.86~0.99, and odor sample of casting, painting manufacturing process ware more than 0.93. Thus the odor concentration(OU/m3) evaluation by odor sensor was to determine the possible. In particular odor sensor B and D are likely to be effective for evaluation of odor concentration. However, odor samples before evaluation is needed the calibration process depending on the field odor sample to field apply.
Abstract Linear, branched, and grafted polyamine flocculants were synthesized and applied for dye wastewater treatment. The effect of polyamines on color removal was investigated by comparing two treatments: (i) alum alone and (ii) alum/polyamine in combination. Compared to alum alone treatment, the use of polyamine flocculants in combination with alum was highly efficient in color and turbidity removal. Addition of a small amount of polyamine (40 mg/L) reduced alum dosage by 50% while improving color removal efficiency by 20%. Branched polyamines were more efficient than grafted polyamines presumably because branched polyamine has higher charge density than grafted polyamine. Our results indicate that the use of alum/polyamine system is beneficial in dye wastewater treatment. The effects of polyamine flocculants on total organic carbon removal and zeta potential were also discussed. Keywords: Dye wastewaterColor removalPolyamineAlumFlocculant Acknowledgment The authors would like to thank the G7 Project from the Ministry of Environment of Korea for the financial support of this research.
This study was carried out to elucidate the partial substitutability of SB latex with environmental-friendly coating binders for coated paper. Starch-based biobinder, ethylene vinyl acetate and acryl-based binder were evaluated for this purpose. Several combinations of above binders were applied to top layer coating, and properties of coating colors and printability were evaluated. When 20% and 30% of SB latex were substituted by acryl-based synthetic binder, ethylene vinyl acetate and biobinder, the brightness, whiteness and opacity of coated paper were similar to those obtained from SB latex. Ink set and stiffness of coated paper manufactured through 20% and 30% substitution of SB latex by biobinder and EVAc were improved, but dry- and wet-pick strength were decreased. The research works on the improvement of dry- and we-pick strength, mechanical stability and rheological properties at high shear condition should be continued for the commercial application of biobinder, EVAc and acryl-based binder.
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