Yes / The deactivation of the oxidative desulfurization (ODS) catalysts is a challenge and is a major concern in industrial catalytic processes. In this work, an activated carbon (AC) was prepared from agricultural waste and modified to withstand the ODS activity loss over time. The AC was impregnated with manganese and coated with aluminum oxide to prolong the activity lifetime. The catalysts were characterized by nitrogen adsorption-desorption, scanning electron microscope, energy dispersive X-ray, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and transition electron microscope (TEM). The BET surface areas of the examined AC materials were 814.48 m2/g, 784.76 m2/g, and 755.03 m2/g for the AC, Mn/AC, and coated Mn/AC catalysts, respectively with a dominance of microporous pore size. The TGA showed that the coating layer retards the degradation of the active metal and suppresses phase transitions. XRD showed no change in the structure of the catalyst with a coating layer, and from the TEM analysis, the coating layer thickness was 3.6 nm. The kinetics of the ODS catalysts were investigated. It was shown that the ODS reaction follows the first-order kinetics and is not influenced by the coating layer. The activity decay was also investigated. It is found that the activation energy of the deactivation reaction over the coated catalyst was higher than the uncoated catalyst.

Made available in DSpace on 2017-07-21T20:42:38Z (GMT). No. of bitstreams: 1 Juliana Schultz.pdf: 2166644 bytes, checksum: abe9199d57a29d6f3d6f49ca3e41ce72 (MD5) Previous issue date: 2012-07-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / There is great concern for society as a whole with the waste generation without proper treatment, knowing that can cause disorders. The Brazil is a major producer of agro-industrial, and this waste generation is very large and often and this material doesn’t have an appropriate destination. This work uses an agro-industrial residue very common in the Brazil, for the production of activated carbon, a material that is widely used as adsorbent in the industry. As a precursor, was used the sugar cane bagasse and activation, the chemical reagent ZnCl2 (proportion 1:2). The mean time was 14 hours impregnation and carbonization, was used a heating rate of 3°C/min until the temperature of 250C, with a level of 30 minutes at this temperature, then the temperature was increased to 600C at a rate of 5C/min level this heating for 1 hour at that temperature. The samples were characterized by MEV and BET. They had an average specific surface area mean of 1.501,3 m2/g and an average pore size of 2.6 nm. Tests for adsorption of the antibiotic amoxicillin were performed by two different methods, namely, with magnetic stirrer and column. The two methods showed very satisfactory results, reducing the concentration of antibiotic 10% (1.37,10-3 mol/L) to about 9.95,10-8 mol/L test with magnetic stirrer and 3.53,10-8 mol/L column test, i.e. the concentration of antibiotic in water, after adsorption was reduced by five orders of magnitude, confirmed the efficiency of the nanostructured material of carbon developed here for the removal of residual antibiotic environment. / Há uma grande preocupação por parte da sociedade como um todo com a geração de resíduos sem um tratamento adequado, por saber dos transtornos que podem ocasionar. O Brasil é um grande produtor agroindustrial, com isso a geração de resíduos é muito grande e, muitas vezes, esse material não tem destino adequado. Este trabalho utiliza um resíduo agroindustrial muito comum no Brasil, para a produção de carvão ativado, material que tem muita utilização como adsorvente na indústria. Como precursor, utilizou-se o bagaço de cana e para a ativação, o reagente químico ZnCl2 (proporção 1:2). O tempo médio de impregnação foi de 14 horas e para carbonização, utilizou-se uma taxa de aquecimento de 3C/min até a temperatura de 250C, com patamar de 30 minutos nessa temperatura, logo, a temperatura foi aumentada até 600oC a uma taxa de aquecimento de 5C/min com patamar de 1 hora nessa temperatura. As amostras foram caracterizadas por MEV e BET. Apresentaram uma área superficial específica média de 1501,3 m2/g e tamanho médio de poros de 2,6 nm. Os testes de adsorção do antibiótico amoxicilina foram realizados por dois métodos diferentes, a saber: com agitador magnético e em coluna. Os dois métodos apresentaram resultados muito satisfatórios, reduzindo a concentração do antibiótico de 10% (1,37.10-3 mol/L) para em torno de 9,95.10-8 mol/L no teste com agitador magnético e 3,53.10-8 mol/L no teste em coluna, ou seja a concentração do antibiótico em água, após a adsorção, foi reduzida em cinco ordens de magnitude, comprovado a eficiência do material nanoestruturado de carbono desenvolvido neste trabalho na remoção de antibiótico residual do meio ambiente.

Energy is one of the biggest costs of production in industries and Small scale industries in Uganda are faced with a big burden due to the high energy costs they incur in their operations. Due to the high costs associated with electricity and fossil fuels, biomass energy continues to supply the bulk (81%) of industrial energy demands. However unsustainable harvesting of tradition biomass fuels (firewood and charcoal) is leading to depletion and causing a hike in prices of this important energy source. This study determined current thermal loads for 4 small scale industries, the costs of the fuels used, possible agro waste replacement options and economic comparisons of gasification using these fuel alternatives. Questionnaires, interviews and quantitative measurements of the various parameters were undertaken to establish current fuel usage and costs. Economic and emission reductions analysis were conducted using RETScreen energy planning tool. Results of indicated that the current combustion and heat transfer devices are very inefficient leading to intensive energy demands. Proposed gasifier systems of the range of 30 kW to 100kW fuel power, would cost between US$ 6,156.35 and US$20,371.20. It was further established that installing gasifiers and incorporating agro wastes in the fuel mix (60%) would greatly reduce expenditure on fuels with pay back periods ranging from 0.4 – 3 years. Risk analysis further showed that fuel costs and operations and maintenance would attract the highest risk to the net present value of each proposed gasifier installation. From these results, it was recommended that gasification coupled with use of agro wastes provides viable cheap alternative for small scale industrial thermal energy needs

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