Nitrogen (N)-doped ordered mesoporous carbons (OMCs) with a dual transition metal system were synthesized as non-Pt catalysts for the ORR. The highly nitrogen doped OMCs were prepared by the precursor of ionic liquid (3-methyl-1-butylpyridine dicyanamide) for N/C species and a mesoporous silica template for the physical structure. Mostly, N-doped carbons are promoted by a single transition metal to improve catalytic activity for ORR in PEMFCs. In this study, our N-doped mesoporous carbons were promoted by the dual transition metals of iron and cobalt (Fe, Co), which were incorporated into the N-doped carbons lattice by subsequently heat treatments. All the prepared carbons were characterized by via transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). To evaluate the activities of synthesized doped carbons, linear sweep was recorded in an acidic solution to compare the ORR catalytic activities values for the use in the PEMFC system. The dual transition metal promotion improved the ORR activity compared with the single transition metal promotion, due to the increase in the quaternary nitrogen species from the structural change by the dual metals. The effect of different ratio of the dual metals into the N doped carbon were examined to evaluate the activities of the oxygen reduction reaction.
In this research work, a new type of absorbent material was obtained using kaolin which is produced by clay of the "Tsogt-Ovoo" deposit in Umnogovi province. The kaolin was produced by removing its mechanical impurities from clay and treating it to acid and heat treatment. When producing a chitosan based new absorbent bead, pure chitosan and mixtures of chitosan and kaolin (8:1, 8:2 and 8:3) with certain ratios were subjected to chemical processing. It was determined that the absorption capacity of chromium ion (Cr(VI)) was the highest when chitosan and kaolin mass ratio was 8:2. The adsorption activity of Cr(VI)in chitosan-based adsorbent was studied depending on the pH of the solution, time, temperature, initial concentration of chromium ion solution and mass of adsorbent material. The degree of absorption was the highest (80.25%) when initial concentration of thechromium ion solution is 50 mg/l, temperature is 250C, contact time is 3h and the mass of the adsorbent material is 0.1 g. It shows that this chitosan based adsorbent bead can be used for the separation of chromium (Cr(VI)) from aqueous solutions.
Читосан суурьтай шинэ материалын +6 валенттай хром шингээх идэвхийн судалгаа
Хураангуй: Тус судалгааны ажлын хүрээнд Өмнөговь аймгийн нутагт орших “Цогт-Овоо” ордын шаврын дээжийг механик хольцоос салган, хүчлийн ба дулааны боловсруулалтад оруулж бэлтгэсэн каолиныг ашиглан шинэ төрлийн шингээгч материал гарган авав. Читосан суурьтай, үрэл хэлбэрийн шинэ төрлийн шингээгч материалыг гарган авахдаа цэвэр читосан болон тодорхой харьцаа бүхий читосан ба каолины (8:1, 8:2 ба 8:3) хольцыг химийн боловсруулалтад оруулж гарган авсан. Туршилтаар 8:2 массын харьцаа бүхий читосан ба каолинын хольцыг ашиглан гарган авсан үрэл хэлбэрийн шингээгч материалын +6 валенттай хром (Cr(VI)) шингээх шингээлтийн багтаамж хамгийн өндөр болохыг тогтоов. Читосан суурьтай шинэ төрлийн шингээгч материалын усан уусмалаас Cr(VI) шингээх идэвхийг уусмалын рН, хугацаа, температур, хромын уусмалын анхны концентраци ба шингээгч материалын массаас хамааруулан судалж үзэхэд уусмалын орчин pH 3, шингээлтийн хугацаа 3 цаг, шингээлтийн температур T= 25℃, хромын уусмалын анхны концентраци 50 мг/л, шингээгч материалын масс 0.1 г байх нөхцөлд шингээлтийн зэрэг хамгийн өндөр буюу 80.25% байна. Энэхүү шинэ материалыг усан уусмалаас хромыг (Cr(VI)) ялгахад ашиглах боломжтой гэж үзэж байна.
Түлхүүр үг: адбсорбент, металлын ион, усан орчин, шингээлтийн багтаамж
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