Navegando por Autor "Penido, Jussara Alves"
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Item How does the use of surfactants in polymer-salt based aqueous twophase systems affect the annatto dye (Bixa orellana L.) partitioning?(2018) Junqueira, Cristina Mazzeu; Cabral, Deliane da Silva; Penido, Jussara Alves; Mageste, Aparecida Barbosa; Virtuoso, Luciano SindraIn this work, the partitioning of natural annatto pigments in aqueous two-phase systems formed by poly(ethylene) glycol polymers (1500 or 4000 or 6000 g mol−1) or triblock copolymer L35 (2000 g mol−1) + sodium citrate + water was studied in the presence of cetyltrimethylammonium bromide. The hypothesis investigated was that the use of surfactants as additives in traditional two-phase aqueous systems could improve the solubility of the annatto extract in the phases of these systems through a mechanism of mixed micelle formation. This would make it possible to implement the use of these systems in the annatto dye extraction process. For this, several experiments were conducted. The annatto extract partition coefficient was determined as a function of pH, surfactant concentration, molar mass and hydrophobicity of the polymer, tie-line length, and the nature of the electrolyte. These results showed the potential of surfactant as a modulation agent for dyes transfer between the aqueous two-phase systems phases. The effect of surfactant was attributed to its interaction with norbixin from annatto, which was studied by means of surface tension and spectrophotometric measurements. The driving force governing annatto extract partitioning was dependent on the system composition and the temperature. Lower partition constants values for annatto extract obtained in the presence of surfactant demonstrated the potential of the aqueous two-phase systems for the extraction or purification of annatto.Item A method for dye extraction using an aqueous two-phase system : effect of co-occurrence of contaminants in textile industry wastewater.(2016) Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; Lemos, Leandro Rodrigues de; Mageste, Aparecida Barbosa; Rodrigues, Guilherme DiasThis paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (% R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K ¼ 4.10 104, %R ¼ 0.0069%) was obtained with the ATPS: PEO 1500 þ Na2C4H4O6 (TLL ¼ 50.21% (w/w), pH ¼ 6.00). For MB, the maximum extraction (K ¼ 559.9, %R ¼ 0.258%) was achieved with the ATPS: PEO 400 þ Na2SO4 (TLL ¼ 50.31% (w/w), pH ¼ 1.00). Finally for RR, the method that presented the best results (K ¼ 3.75 104, %R ¼ 0.237%) was the ATPS: PEO 400 þ Na2SO4 (TLL ¼ 50.31% (w/w), pH ¼ 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 104, 724.1, and 3.98 104 for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5e97.95%) from the textile effluent.Item Modulando a partição de corantes em sistemas aquosos bifásicos por meio de interações surfactante catiônico-corante.(2019) Penido, Jussara Alves; Mageste, Aparecida Barbosa; Ferreira, Gabriel Max Dias; Silva, Luís Henrique Mendes da; Ferreira, Guilherme Max Dias; Ferreira, Gabriel Max Dias; Mageste, Aparecida BarbosaNesse trabalho, sistemas aquosos bifásicos (SABs) foram empregados para separar dois corantes modelo, amarelo ouro remazol (AR) e azul de metileno (AM), usando o surfactante brometo de hexadeciltrimetilamônio (C16TAB) como modulador seletivo na partição. Experimentos envolvendo a partição individual e simultânea dos corantes foram realizados na presença e ausência de C16TAB em SABs formados por misturas de poli(etileno glicol) (PEG), poli(propileno glicol) (PPG) ou copolímero tribloco poli(etileno glicol)11- poli(propileno glicol)16- poli(etileno glicol)11 (L35), mais sal ((NH4)2SO4, MgSO4, Na2SO4 ou Li2SO4) e água. Em experimentos de partição individual, os corantes AR e AM foram transferidos para a fase superior dos SABs formados por PEG na ausência de C16TAB. No entanto, na presença de certas concentrações de surfactante, o AM permaneceu na fase superior, enquanto o AR foi transferido para a fase inferior. O mesmo resultado foi obtido em experimentos de partição simultânea. Isso foi atribuído a uma interação específica entre C16TAB e AR, que promoveu a formação de agregados AR-C16TAB que foram estabilizados na fase inferior do SAB. A quantidade de AR transferido para a fase inferior na presença de C16TAB foi dependente da massa molar do polímero e da estrutura do sal e do polímero. Curiosamente, o surfactante não promoveu a transferência de AR para a fase inferior em SABs formados por PPG ou L35, devido à competição entre o polímero e o corante AR pelos monômeros de C16TAB. O melhor fator de separação entre os corantes foi de 271,2 em SAB formado por PEG com massa molar de 1500 g mol-1, MgSO4 e água, demonstrando o potencial desse SAB para a separação entre os corantes. A interação entre AR e C16TAB foi avaliada em água pelas técnicas de tensiometria, condutimetria, calorimetria de titulação isotérmica e turbidimetria, em diferentes razões molares surfactante:corante. Além disso, o efeito da cauda hidrofóbica do surfactante e a concentração de corante sobre esta interação também foram avaliados. O agregado sólido formado a partir da mistura de soluções de corante e surfactante em razões molares específicas foi analisado por termogravimetria e espectroscopia no infravermelho. A entalpia de interação aparente entre AR e C16TAB foi estimada e apresentou valores iguais a -27 kJ mol-1 na região da formação do agregado sólido. A interação entre os dois componentes foi dirigida por um balanço entre interações eletrostáticas e hidrofóbicas, sendo que a formação dos agregados corante-surfactante foi favorecida para surfactantes de maior cadeia hidrofóbica.Item Thermodynamic investigation of the aqueous two-phase systems formed by PEG 400 + water + either sodium carbonate or potassium carbonate at different temperatures : experimental and correlational approaches.(2019) Carvalho, Roberta de Almeida; Penido, Jussara Alves; Lobo, Fabiana Aparecida; Machado, Poliana Aparecida Lopes; Lemes, Nelson Henrique Teixeira; Virtuoso, Luciano Sindra; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Mageste, Aparecida BarbosaSystems composed of poly(ethylene)glycol (PEG 400) + water + either potassium carbonate or sodium carbonate were studied at 283.15, 298.15, and 313.15 K. The effects of temperature and the electrolyte on phase segregation were evaluated. The phase segregation process was endothermic and entropically driven. The efficacy of the cations in inducing phase formation with PEG 400 followed the order K2CO3 < Na2CO3. The binodal curves were successfully described using the empirical equation suggested by Merchuk and modified to include the effect of temperature. Tie-line compositions were correlated using the Othmer–Tobias, Bancroft, and Hand equations. The experimental tie-line data for PEG 400 + K2CO3 + water and PEG 400 + Na2CO3 + water were also correlated using the nonrandom two liquid model. The use of this thermodynamic model resulted in reliable data for the system while reducing the number of experiments needed. All of the correlations indicated satisfactory fits between the calculated and experimental data.Item Use of aqueous two-phase PEG-salt systems for the removal of anionic surfactant from effluents.(2017) Murari, Gabriella Frade; Penido, Jussara Alves; Silva, Heriveltom Morais da; Baeta, Bruno Eduardo Lobo; Aquino, Sergio Francisco de; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Mageste, Aparecida BarbosaLinear alkylbenzene sulfonates (LAS) are synthetic anionic surfactants that are extensively used in many industries. As a result, large volumes of effluents containing high levels of these compounds are discharged into water bodies, causing risks to aquatic flora and fauna. Then, there is a need for environmentally safe and economically viable technologies for the removal of LAS from aqueous matrices. The present work evaluates the use of aqueous two-phase systems (ATPS) composed of PEG and sulfate salts for this purpose, considering the effects of tie line length (TLL), molar mass of polymer, and type of cation-forming salt on the partitioning behavior of LAS. All the LAS partition coefficient (KLAS) values were greater than unity, and the LAS extraction efficiencies (%ELAS) were higher than 97%. The system consisting of PEG 1500 þ (NH4)2SO4 þ H2O provided the highest KLAS (1083.34) and %ELAS (99.9%), indicating that the method provided good extraction of LAS to the top phase. This system was applied using a real effluent sample in laboratory-scale experiments as well as in bench-scale batch trials. The results obtained at the laboratory scale showed %ELAS values greater than 98%, while the best KLAS value obtained in the batch experiments was 8.50 (±1.75) (%ELAS ¼ 78.17%). These values demonstrated the potential of ATPS for the removal of LAS from industrial effluents.