| Electro-oxidation of methanol by multi-metal catalysts supported on carbon nanotubes | |
| Cheerapradit R., Chailapakul O., Vanalabhpatana P. | |
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| Abstract | |
| Synthesized by polyol process, platinum (Pt)-based di- and trimetallic nanoparticles supported on multi-walled carbon nanotubes (MWCNTs) were developed as electrocatalysts for the oxidation of methanol. Structural information of the metal nanoparticles supported on MWCNTs was confirmed by X-ray diffraction (XRD) analysis whereas the electrocatalytic properties of the Pt/MWCNT, Pt-based dimetal/MWCNT, and PtRuMo/MWCNT catalysts were investigated by means of cyclic voltammetry. Our results illustrated that the PtRu/MWCNT modified electrodes exhibited higher anodic currents for methanol oxidation than the Pt/MWCNT electrode. Among all of the PtRu/MWCNTs with various Pt-to-Ru molar ratios, the Pt2Ru1.5/MWCNT was the best electrocatalyst. Furthermore, the addition of Mo, the third metal, on dimetallic PtRu/MWCNT catalyst significantly promoted the catalytic activity. Pt2Ru 1.5-xMox/MWCNT showed the best electrocatalytic performance with the anodic current of 138.3 A/g catalyst for 2.0 M methanol containing 0.5 M sulfuric acid. ©The Electrochemical Society. | |
| keywords | |
| Anodic currents; Catalytic activity; Electrocatalytic performance; Electrocatalytic properties; Metal nanoparticles; Methanol Oxidation; Modified electrodes; Molar ratio; Multi-metals; Oxidation of methanol; Polyol process; Structural information; Trimetallic; Anodic oxidation; Catalyst activity; Cyclic voltammetry; Electrocatalysts; Energy storage; Flywheels; Methanol; Molybdenum; Multiwalled carbon nanotubes (MWCN); Nanoparticles; Nanostructured materials; Platinum; Sulfuric acid; X ray diffraction; X ray diffraction analysis; Catalyst supports | |
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| Comparison of an ion exchanger and an in-house electrodialysis unit for recovery of L-lactic acid from fungal fermentation broth | |
| Boonkong W., Sangvanich P., Petsom A., Thongchul N. | |
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| Abstract | |
| Lactic acid has long been widely used in many applications. Currently, the worldwide market is increasing due to the discovery of biodegradable polylactic acid. In this work, L-lactic acid separations from filamentous fungal fermentation broth using ion-exchange chromatography and in-house electrodialysis, were studied and compared. Dowex Marathon WBA was used for the lactic acid separation. The adsorption equilibrium followed a Langmuir isotherm. The optimal conditions for lactic acid adsorption in a fixed-bed column were at pH 6.0, and 0.8 mL/min and elution by a mixture of 1.0 M sulfuric acid and 1.0 M phosphoric acid in a ratio of 30:70 at 0.3 mL/min. The final lactic acid recovery was 76% with 90% purity. A laboratory scale in-house electrodialysis apparatus was constructed with an effective membrane area of 2.925 · 10-3 m2. The effects of feeding solution concentration, flow rate, pH of the fermentation broth, and applicable voltage were studied. Under the optimal conditions, lactic acid recovery was 92% with 100% purity and a specific energy consumption of 0.6122 kWh/kg. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. | |
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| Fungal fermentation broth; In-house electrodialysis; Ion exchange chromatography; L-Lactic acid; Purity; Adsorption; Adsorption isotherms; Body fluids; Chromatographic analysis; Chromatography; Electrodialysis; Fermentation; Houses; Ion chromatography; Ion exchange; Ion exchangers; Ions; Lactic acid; Organic acids; pH effects; Phosphoric acid; Sulfuric acid | |
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| Alternative method for measurement of albumin/creatinine ratio using spectrophotometric sequential injection analysis | |
| Siangproh W., Teshima N., Sakai T., Katoh S., Chailapakul O. | |
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| A simple, automatic and practical system for successive determination of albumin and creatinine has been developed by combining sequential injection analysis (SIA) and highly sensitive dye-binding assays. Albumin detection was based on the increase in the absorbance due to complex formation between albumin and eosin Y in acidic media. The absorbance of the complex was monitored at 547 nm. For the creatinine assay, the concentration of creatinine was measured by reaction with alkaline picrate to form a colored product which absorbs at 500 nm. The influences of experimental variables such as effects of pH, reagent concentration, standard/sample volume and interferences were investigated. Under optimal conditions, the automated method showed linearity up to 20 mg L-1 for albumin and 100 mg L-1 for creatinine. The 3σ detection limits were 0.6 and 3.5 mg L-1 for albumin and creatinine, respectively, and the relative standard deviations (n = 10) were 2.49% for 20 mg L-1 albumin, and 3.14% for 20 mg L-1 creatinine. Application of the proposed method to the direct analysis of urinary samples yielded results which agreed with those obtained from the Bradford protein assay and a creatinine enzymatic assay according to a paired t-test. The results obtained should be a step towards developing a fully automated and reliable analytical system for clinical research, which requires direct determination of albumin and creatinine and/or its ratios. © 2009 Elsevier B.V. All rights reserved. | |
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| Alkalinity; Clinical research; Spectrophotometry; Albumin; Albumin/creatinine ratio (ACR); Creatinine; Sequential injection; Urinary; Assays | |
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| A porphyrin derivative from cardanol as a diesel fluorescent marker | |
| Puangmalee S., Petsom A., Thamyongkit P. | |
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| A novel porphyrin fluorescent marker from a naturally occurring substance, cardanol, is presented. Synthetic routes were investigated to obtain an aldehyde precursor derived from cardanol and the target porphyrin; the conditions for porphyrin formation, choice of acid and reaction time were optimized. The resulting meso-tetrakis(2-methoxy-4-pentadecylphenyl)porphyrin exhibits high solubility in diesel fuel and its strong fluorescence was observed as two characteristic signals; the porphyrin marker was stable in diesel for at least 3 months. The physical properties of the diesel were unaffected by the presence of the porphyrinic marker at a concentration of 2 ppm. © 2008 Elsevier Ltd. All rights reserved. | |
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| Aldehydes; Diesel fuels; Fluorescence; Aldehyde precursors; Cardanol; Characteristic signals; Concentration of; Diesel marker; Fluorescent marker; High solubilities; Marker; Methoxy; Porphyrin derivatives; Reaction time; Synthetic routes; Tetrakis; Porphyrins; fluorescence; optimization; organic compound; physical property | |
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