Journal of the Brazilian Chemical Society
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Item Development of a Disposable Pipette Extraction Method Using Coffee Silverskin as an Adsorbent for Chromium Determination in Wastewater Samples by Solid Phase Extraction(Sociedade Brasileira de Química, 2022-05-02) Silva, Weida R.; Costa, Bruno E. S.; Batista, Alex D.; Alves, Vanessa N.; Coelho, Nivia M. M.A procedure using disposable pipette tips adapted for solid-phase extraction, known as DPX SPE, was used as an alternative way for the chromium determination in wastewater samples. DPX-SPE consists of a device which allows a dynamic contact between the sample and the solid-phase. A residue obtained from the processing of coffee beans, denominate coffee silverskin, was used as a new adsorbent. Characterization techniques revealed properties of lignocellulosic materials with potential application for chromium adsorption. The parameters including adsorbent mass (25.00 mg), elution solvent (0.1 mol L-1 HCl, 200 μL) and pH (2.0) were optimized. Thus, 1.00 mL of deionized water for conditioning, 4.00 mL of sample, 2 extraction cycles and 1 elution cycle were the employed conditions. Enrichment factor of 12, limit of detection of 6.00 µg L-1 and relative standard deviation (RSD) 1.3% (n = 3) were obtained. The method proved to be fast, cheap, environmentally friendly, and simple, providing good recoveries (104-113%), and it was satisfactorily applied in real samples.Item Application of carbon composite adsorbents prepared from coffee waste and clay for the removal of reactive dyes from aqueous solutions(Sociedade Brasileira de Química, 2015) Santos, Davis C. dos; Adebayo, Matthew A.; Lima, Eder C.; Pereira, Simone F. P.; Cataluña, Renato; Sauier, Caroline; Thue, Pascal S.; Machado, Fernando M.A novel carbon composite was prepared from a mixture of coffee waste and clay with inorganic:organic ratio of 1.3 (CC-1.3). The mixture was pyrolysed at 700 °C. Considering the application of this adsorbent for removal of anionic dyes, the CC-1.3 was treated with a 6 mol L−1 HCl for 24 h to obtain ACC-1.3. Fourier transform infrared (FTIR), N2 adsorption/desorption curves, scanning electron microscope (SEM) and powder X-ray diffractometry (XRD) were used for characterisation of CC-1.3 and ACC-1.3 carbon adsorbents. The adsorbents were effectively utilised for removal of reactive blue 19 (RB-19) and reactive violet 5 (RV-5) textile dyes from aqueous solutions. The maximum amounts of RB-19 dye adsorbed at 25 °C are 63.59 (CC-1.3) and 110.6 mg g−1 (ACC-1.3), and 54.34 (CC-1.3) and 94.32 mg g−1 (ACC-1.3) for RV-5 dye. Four simulated dye-house effluents were used to test the application of the adsorbents for treatment of effluents.Item Production and characterization of the bio-oil obtained by the fast pyrolysis of spent coffee grounds of the soluble coffee industry(Sociedade Brasileira de Química, 2019) Krause, Maurício C.; Moitinho, Adriana C.; Ferreira, Luiz Fernando R.; Souza, Ranyere L. de; Krause, Laiza C.; Caramão, Elina B.Agro-industrial wastes are abundant and low-cost sources of energy and chemicals. Biomass account for 14% of the world’s energy production. Industrial residues of production of soluble coffee (spent coffee grounds - SCG) have great potential due to its large-scale production and can be transformed by pyrolysis, in liquid, solid and gaseous products with applications from energy to chemicals. This work has the objective of producing bio-oil from the pyrolysis of industrial SCG, characterize it by chromatography and indicate its possible applications. As SGC contains a large amount of glycerides, they were extracted from SGC before the pyrolysis, aiming to obtain a better bio-oil from the residue. The yield in vegetable oil was 5.2% and its analyses showed that 50% are saturated acids (mainly palmitic 27.6%) and other 50% are unsaturated ones (mainly linoleic acid 35.3%). This composition qualifies this oil for biodiesel purposes. The residue (SGC after extraction) was submitted to pyrolysis, yielding 30% in liquid products, being 6% bio-oil. The bio-oil was analyzed by gas chromatography being identified free fatty acids, hydrocarbons, phenols and N-compounds. The heteroatomic compounds limit the use as biofuel but can be interesting for the pharmaceutical, agrochemical and fine chemicals industries.