Navegando por Autor "Costa, C. C."

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Effects of different structure-directing agents (SDA) in MCM-41 on the adsorption of CO2
(Journal of Porous Materials, 2014) Melo, Marcus Antonio de Freitas; Costa, C. C.; Melo, Dulce Maria de Araújo; Mendoza, M. E.; Nascimento, J. C.; Andrade, J. M.; Barros, J. M. F.
CO2 capturing technologies have attracted significant attention in order to limit emissions and reduce their negative effect on the environment. Mesoporous silica materials (MCM-41) are easily recyclable, affordable, and thermally and mechanically stable, providing added benefits in CO2 capture. However, further studies are necessary to characterize the effects of MCM-41 pore size, adsorption temperature and surface silylation on CO2 adsorption efficiency. In this work, mesoporous silica is synthesized using alkyltrimethylammonium bromide with different chain lengths (CnH2n ? 1 N(CH3)3Br, n = 14, 16 and 18) as structure-directing agents, and the adsorption capacity of CO2 on TTMCM-41 (C17H38NBr), CTMCM-41 (C19H42 NBr), DTMCM-41(C21H46NBr) samples was measured gravimetrically at room temperature and pressure up to 40 bar. The silica structures were characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy (TEM). The XRD, N2 adsorption– desorption and TEM measurements indicated the presence of a well-ordered hexagonal array with uniform mesostructures. The mesoporous silica obtained, denoted as TTMCM-41, CTMCM-41 and DTMCM-41, had distinct physical properties, such as BET surface area, hexagonal unit cell, pore volume, pore diameter and pore wall thickness. CTMCM-41 exhibited an adsorption capacity (0.58 g CO2/g adsorbent) of more than DTMCM-41 (0.48 g CO2/g adsorbent) and TTMCM-41 (0.42 g CO2/g adsorbent). The results suggest that CTMCM-41 can be a better mesoporous adsorbent for CO2 adsorption.
Selection, isolation and growth kinetic study of a bacterial consortium obtained from the potengi mangrove in the presence of crude
(Brazilian Journal of Petroleum and Gas, 2011) Santos, Everaldo Silvino dos; Costa, C. C.; Costa, J. G. da; Vaz, Michelle Rossana Ferreira; Macedo, Gorete Ribeiro de
The selection, isolation and kinetic study of a bacterial consortium obtained from a sample of soil from the Potengi mangrove, located in the city of Natal, Rio Grande do Norte, Brazil, has been carried out using the enrichment culture technique to observe aspects such as the evaluation of main growth parameters. The kinetic study used a rotary incubator shaker at 150rpm, under 30°C. The bacterial consortium isolated from the estuary of the Potengi River showed a good acclimation in minimum mineral medium with 1% (v/v) of oil. The cell concentration reached 2.55 g/L at 16h of cultivation and surface tension dropped. The maximum productivity in cells obtained was of 0.3 g/L.h, the specific velocity of growth was of 0.075h-1, with a generation time (tg) of 9.24h. This study seeks to demonstrate that the consortium can be used as inoculants in biological treatments, capable of reducing the waste’s degradation time

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Navegando por Autor "Costa, C. C."