Made available in DSpace on 2017-05-12T14:47:40Z (GMT). No. of bitstreams: 1 Mariana_ sbizzaro.pdf: 1501907 bytes, checksum: 5610159e30f98d52848320f90146f751 (MD5) Previous issue date: 2016-02-12 / The agricultural sector has great influence in Brazilian economy. Furthermore, agricultural yield has been associated with pesticides application during crop cycle, which atrazine is applied for example, since it can cause environmental contamination when it does not reach its target. Thus, there are some essential and imperative options that can minimize contamination and negative impacts during agricultural practices. So, present study aimed at evaluating the ability of three biochars in atrazine adsorption. Therefore, three biochars produced from bamboo culm were used, whose species is Phyllostachys aurea, and temperature ranged at 350 ºC, 450 ºC and 550 ºC. The three studied biochars were named as BE350, BE450 and BE550. They were characterized based on their physical and chemical properties by elemental analysis, characterization of functional groups (Infrared Spectroscopy Fourier Transform - FTIR), surfaces morphology evaluation (Scanning Electron Microscopy - SEM) as well as specific surface area (ASEBET) and porosity. A kinetic study was carried out to determine the equilibrium period of adsorption process and the kinetic mechanism that controls such process. Langmuir and Freundlich isotherms were also modeled during this trial. Atrazine determination, after the adsorption test, was carried out by High Performance Liquid Chromatography (HPLC). The obtained analyses showed that the adsorption capacity of biochars decreased in the following order: BE 450> BE 350 > BE 550, and such capacity has been associated with the physical and chemical characteristics of biochars. The three studied biochars are well represented by the kinetic model of pseudo-second order. At last, all biochars have shown high affinity to adsorb atrazine; however, the biochar that was produced at 450 ºC has shown the highest adsorption capacity. / O setor agrícola possui grande destaque na economia brasileira, a produção agrícola está associada ao uso de pesticidas durante o ciclo das culturas, como é o caso da atrazina, que pode causar a contaminação do ambiente, quando não atinge seu alvo. Sendo assim, alternativas que minimizem as contaminações e impactos negativos da prática agrícola são essenciais e urgentes. Desta forma, o presente estudo teve por objetivo avaliar a capacidade de três biocarvões, em adsorver o herbicida atrazina. Para tanto, foram utilizados três biocarvões, produzidos a partir do colmo de bambu, da espécie Phyllostachys aurea à 350ºC, 450ºC e 550ºC, nomeados BE350, BE450 e BE550. Os biocarvões foram caracterizados quanto as propriedades físicas e químicas, por meio de análise elementar, caracterização de grupos funcionais (Espectroscopia de Infravermelho com Transformada de Fourier - FTIR), avaliação da morfologia das superfícies (Microscopia Eletrônica de Varredura - MEV), bem como, área superficial específica (ASEBET) e porosidade. Estudo cinético foi realizado, visando determinar o tempo de equilíbrio do processo de adsorção, bem como, o mecanismo cinético que controla o processo. Também foram modeladas isotermas de Langmuir e Freundlich. A determinação da atrazina, após os ensaios de adsorção, foi realizada por Cromatografia Líquida de Alta Performance (CLAE). As análises realizadas apontaram que a capacidade de adsorção dos biocarvões diminuiu na ordem de BE 450 > BE 350 > BE 550, e tal capacidade está associada às características físicas e químicas dos biocarvões. Os três biocarvões são bem representados pelo modelo cinético de pseudo-segunda ordem. Todos biocarvões exibiram elevada afinidade para a adsorção do herbicida atrazina, contudo, o biocarvão produzido à 450 ºC demonstra maior capacidade de adsorção

The results of this study show that novel mesoporous carbons were obtained as inverse replica of SBA-15, HMS and MCM-41 silica templates, with a large pore diameter (2-4 nm), a BET surface area of 1867, 874 and 910 m2g –1 respectively for CA_SBA-15_LPG_105, CA_HMS_LPG_80 and CA_MCM- 41_LPG_80 with bimodal pore size distribution (PSD) in the mesopores range. The results obtained show that mesoporous carbon with graphitic structures can be synthesized via the LPG route.

The results of this study show that novel mesoporous carbons were obtained as inverse replica of SBA-15, HMS and MCM-41 silica templates, with a large pore diameter (2-4 nm), a BET surface area of 1867, 874 and 910 m2g –1 respectively for CA_SBA-15_LPG_105, CA_HMS_LPG_80 and CA_MCM- 41_LPG_80 with bimodal pore size distribution (PSD) in the mesopores range. The results obtained show that mesoporous carbon with graphitic structures can be synthesized via the LPG route.

Philosophiae Doctor - PhD / The results of this study show that novel mesoporous carbons were obtained as inverse replica of SBA-15, HMS and MCM-41 silica templates, with a large pore diameter (2-4 nm), a BET surface area of 1867, 874 and 910 m2g–1 respectively for CA_SBA-15_LPG_105, CA_HMS_LPG_80 and CA_MCM- 41_LPG_80 with bimodal pore size distribution (PSD) in the mesopores range. The results obtained show that mesoporous carbon with graphitic structures can be synthesized via the LPG route. / South Africa

In this research, the adsorptive capacities of kenaf in the forms of chopped whole stalk, chopped core, and bast materials were evaluated for the removal of lead, zinc, and toluene from contaminated synthetic waste streams using traditional adsorption isotherm techniques. The effect of surface oxidation using ozone was observed with respect to the adsorption of metals. Hydraulic conductivity experiments were conducted to evaluate the head loss associated with packing a column with kenaf fibers and to determine the suitability of its use in dynamic packed column systems. B.E.T. surface areas were determined as well. Under increasingly stringent regulatory requirements, even low level organic and inorganic contamination (under 100 ppm) in surface and ground waters must be treated. This study is part of an ongoing multi-year research effort aiming to develop a kenaf-based biosorptive process to improve treatment of contaminated aqueous streams at reduced costs and technical complexity.