Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2309
O Mestrado Acadêmico iniciou-se em 1992 e pertence ao Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
Navegar
Navegando Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC por Assunto "Activated carbon"
Agora exibindo 1 - 2 de 2
- Resultados por página
- Opções de Ordenação
Item Acesso aberto (Open Access) Adsorção monocomponente e binária de antiinflamatórios não esteroidais (Ibuprofeno e Diclofenaco) do meio aquoso por carvão ativado de resíduos da castanha-do-Brasil (Bertholletia excelsa H.B.K.)(Universidade Federal do Pará, 2024-09-12) SILVA, João Paulo Sousa da; VIEIRA, Melissa Gurgel Adeodato; http://lattes.cnpq.br/6611289393148830; CARVALHO, Samira Maria Leão de; http://lattes.cnpq.br/6192858937057152Emerging contaminants (ECs) present in low concentrations have caused damage to water bodies. This study investigated the single-component and binary adsorption of sodium ibuprofen (IBU) and diclofenac (DIC) using activated carbon (AC) produced from Brazil nut shells. The single-component adsorption process of IBU and DIC by AC was denoted as (AC_IBU and AC_DIC), and the binary adsorption process was denoted as (AC_IBU+DIC). The AC was synthesized by chemical activation using phosphoric acid (H3PO4) as the activating agent. The AC was characterized through physical, chemical, and textural analyses, including moisture content, ash content, yield, Thermogravimetric Analysis/Differential Thermal Analysis (TGA/DTA), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS), surface pH, point of zero charge (pHPZC), Boehm titration, and nitrogen (N2) adsorption/desorption at 77 K. The AC presented moisture and ash contents of 8.62% and 4.2%, respectively. The XRD analysis confirmed the amorphous nature of the AC, while FT-IR, surface pH, and pHPZC analyses indicated its acidic nature. The specific surface area (SBET) of the AC was 1,383.624 m².g-1 , with a predominance of micropores (VMIC=77.88%). From the analysis of the Central Composite Rotational Design (CCRD), the experimental conditions for the kinetic and equilibrium adsorption tests were defined for single-component adsorption: (i) IBU (pH = 6.1; initial adsorbate concentration, C0 = 50 mg.L-1 ; adsorbent dosage, DA = 0.5 g.L-1 ) and (ii) DIC (pH = 5.5; C0 = 50 mg.L-1 ; DA = 0.5 g.L-1 ). In the single-component adsorption kinetics study, the pseudofirst-order (PFO) and pseudo-second-order (PSO) models resulted in the best fits to the experimental data for the AC_IBU and AC_DIC adsorption processes, respectively, and external mass transfer was the rate-controlling step of the processes. In the singlecomponent adsorption equilibrium study, the Langmuir, Freundlich, Sips, DubininRadushkevich, and Redlich-Peterson isotherms were investigated. The Sips and Freundlich models showed the best correlations for AC_IBU and AC_DIC, respectively. The thermodynamic parameters calculated from the adsorption isotherms showed that the AC_IBU and AC_DIC processes are spontaneous, favorable, and exothermic. The CCRD, the experimental conditions for the binary adsorption kinetics and equilibrium tests were defined: (i) AC_IBU+DIC (C0IBU = 50 mg.L -1 ; C0DIC = 50 mg.L-1 ; DA= 0.5 g.L-1 ). Binary adsorption indicated, through the calculation of the separation factor parameter, that the adsorption preference order by the adsorbent is IBU > DIC, and the interaction between the adsorbates was antagonistic. In the binary adsorption process, the PSO model was well fitted to the experimental kinetics data of IBU and DIC; the intraparticle diffusion (IPD) kinetic models and the Boyd equation were correlated with the experimental data, and external mass transfer was the rate-controlling step of the adsorption processes. The isotherms of binary adsorption (AC_IBU+DIC) at different temperatures (26 ºC, 45 ºC, and 55 ºC) showed inflection points, and after these inflection points, there was an increase in the adsorption capacity values of AC (qe). The qe values of binary adsorption (AC_IBU+DIC) were lower than the qe values of the singlecomponent adsorption processes of the adsorbates IBU and DIC. The reduction percentages of the qe values were approximately 35% to 48% for IBU and about 52% to 53% for DIC.Item Acesso aberto (Open Access) Aproveitamento de resíduos sólidos da mandiocaba (Manihot esculenta Crantz) para o desenvolvimento de bioadsorventes(Universidade Federal do Pará, 2023-07-10) DIAS, Rafael Silva; MARTELLI, Marlice Cruz; http://lattes.cnpq.br/1213009262936026; BRASIL, Davi do Socorro Barros; http://lattes.cnpq.br/0931007460545219; https://orcid.org/0000-0002-1461-7306The chemical contamination of water by dyes resulting from the disposal of industrial effluents triggered the need to develop technologies to remove such pollutants. Occurring naturally in the Amazon region, cassava differs from other cassava varieties in that it has high humidity and low starch yield. As part of a project on cassava technologies, this study analyzed the best conditions for the production of activated carbon from cassava solid waste for the adsorption of methylene blue dye. The Box-Behnken experimental design was used to determine the optimal production conditions. First, a physical-chemical analysis of the precursors was carried out, then 30 coal samples were produced according to the experimental plan. The maximum adsorbed amount and percentage of removal were determined under finite bath conditions, at a concentration of 120 mg/L and with 0.01 g of coal sample. The best conditions of temperature, acid concentration and heat contact time were observed at 600 ºC, 25 % and 3 h for peel and 600 ºC, 10.2 % and 3 h for pulp. These samples were subjected to physical-chemical and morphological characterization analyzes using scanning electron microscopy and Fourier transform infrared. For the adsorption kinetics tests, the models that best fitted the experimental data were intraparticle diffusion for shell and pulp coals, and for the adsorption equilibrium tests, the Freundlich and Langmuir models best fitted the experimental data for shell and pulp, respectively. Analysis of the adsorbents reveals a lower concentration of functional groups, however, in the pulp adsorbent, the loss of functional groups related to groups containing oxygen can be observed, which may help explain the lower adsorption capacity observed for pulp adsorbents. The activated carbons produced from the solid residues of cassava roots (pulp and peel) showed that, under the conditions used in this work, they can be applied as effective bioadsorbents in the removal of methylene blue in aqueous solution.