Navegando por Palavras-chave "Coffee straw"

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Estudo comparativo da palha de café, bagaço da cana-de-açúcar e quitosana comercial para remoção de metais, como ferro e zinco em meio aquoso
    (Universidade Federal de São Paulo, 2017-06-20) Tanikoshi, Mario Bruno Faioli [UNIFESP]; Mercuri, Lucildes Pita [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The present work has as main objective the accomplishment of a comparative study between three different biomasses, the coffee straw (PC), the sugarcane bagasse (BC) and the commercial chitosan (QTS-C) applied as adsorbents to act in the removal of iron and zinc. The adsorption tests were performed on a fixed bed column. The process consisted of three steps: (1st) conditioning the bed with 10 mL of Milli-Q water; (2nd) adsorption, where 10 mL of the solution was added with known metal concentration and (3rd) washing with the addition of another 10 mL of Milli-Q water in the column. The process was repeated for four different concentrations of iron (0, 0.15, 0.30 and 0.50 ppm) and zinc (0, 2.5, 5.0 and 7.5 ppm). At all stages, metal concentrations were quantified using the flame atomic absorption spectrometry (FAAS) technique. The biomass samples used in the tests were characterized using the following techniques: thermogravimetry/thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), elemental analysis (AE), Fourier transform infrared absorption spectroscopy (FTIR) And X-ray diffractometry. In all samples quantified by FAAS, it was observed that, even with the increase of the initial concentrations of the solutions, the final concentrations after passage through the biomass did not increase, indicating the removal of the metal ion by biomass. Concentration change tests showed that PC could adsorb a value of 0.84 mg.g-1 iron and QTS-C 0.92 mg.g-1 zinc. The TG/DTG techniques helped to confirm the residual percentages present in each sample. This showed that, with increasing initial concentrations, higher residual percentages were observed. Faced with this observation. It can be reported that the biomasses were effective for the retention of these metal ions present in the solution.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Thermoanalytical study of inner and outer residue of coffee harvest
    (Springer, 2011-12-01) Orsini, Rosely dos Reis; Moscardini Filho, Elder [UNIFESP]; Mercuri, Lucildes Pita [UNIFESP]; Matos, Jivaldo do Rosario; Sequeira de Carvalho, Fatima Maria; IPEN CNEN SP; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    The better use of agricultural residues is expected, when they are mostly disposed of improperly and it is often burned in the natural environment. This study of the thermal decomposition of residues was performed from the coffee crop for energy purposes and in this case was used thermal analysis techniques for such assessment. the TG/DTG and DSC curves showed that the thermal decomposition occurs in four consecutive events and it is predominantly exothermic. the first mass loss evidenced in TG/DTG curves has an endothermic peak in DSC curve, which it can be associated with the water liberation of the material. This first thermal event also can be related to the liberation of volatile compounds present in the sample, which is also corroborated by the endothermic peak. the other events of mass loss are related with the thermal decomposition of the material. This decomposition has an exothermic behavior, which is positively applied to the main aim of this scientific research: the coffee straw use like biomass energy font. the thermoanalytical techniques were satisfactory in the characterization of this material.