Navegando por Autor "Rodrigues, Guilherme Dias"

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Adsorption of organic and inorganic arsenic from aqueous solutions using MgAl-LDH with incorporated nitroprusside.
(2020) Borges, Gabriella Alexandre; Ferreira, Gabriel Max Dias; Siqueira, Kisla Prislen Félix; Dias, Anderson; Najera Navarro, Keirom Osmany; Silva, Sílvia Juliana Barros e; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa
An evaluation was made of the use of MgAl-LDH with incorporated nitroprusside as an adsorbent to remove inorganic arsenic (As(III) and As(V)) and organic arsenic (DMA) from aqueous matrices. The material was synthesized by the co-precipitation method at constant pH and was characterized by Raman spectroscopy, infrared spectroscopy, thermogravimetry, X-ray diffraction, and high-resolution transmission electron microscopy, before and after use in the adsorption process. The effects on adsorption of contact time, initial metalloid concentration, and pH were investigated. For an initial concentration of 10 mg L1 and pH 2.00, the MgAl-LDH with incorporated nitroprusside was only able to adsorb the DMA and As (V) species, with removal percentages of 25.10 and 103.8%, respectively. At pH 6.02 and 12.00, only the inorganic species were adsorbed, with removal percentages of 22.93% and 60.07%, respectively, for As(III), and 89.81% and 71.64%, respectively, for As(V). Application of the Langmuir and Freundlich isotherm models indicated that the features of the adsorption process depended on the pH of the medium and the arsenic species. The results showed that the use of MgAl-LDH with incorporated nitroprusside has potential for the development of techniques for the speciation of arsenic species.
Application of aqueous two-phase system for selective extraction and clean-up of emerging contaminants from aqueous matrices.
(2021) Assis, Roberta Condé de; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues de; Orlando, Ricardo Mathias; Rodrigues, Guilherme Dias
This review approaches how aqueous two-phase systems (ATPS), in their various compositions (e.g., polymer + salt, copolymer + salt, ionic liquid + salt, acetonitrile + salt), can be efficiently used for extraction, pre concentration, and clean-up of analytes in aqueous samples to determine the compounds classified as emerging contaminants (ECs). In the literature, there are some studies using ATPS applied to ECs, like pesticides, pharmaceuticals, illicit drugs, personal care products, alkaloids, and hormones, even when in trace concentrations. The ATPS is an alternative to the conventional liquid-liquid extraction technique. However, it is predominantly composed of water and do not generally use organic solvents and, therefore, is based on the principles of green chemistry. An ATPS approach has a unique advantage because it can extract neutral, anionic, cationic, polar, and nonpolar compounds, even when present simultaneously in the same sample. This review covers how this simple and low environmental impact technique has been employed for the analysis of different classes of emerging contaminants.
Application of aqueous two-phase systems for the extraction of pharmaceutical compounds from water samples.
(2020) Assis, Roberta Condé de; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues de; Orlando, Ricardo Mathias; Rodrigues, Guilherme Dias
In this study, the proposal was to use aqueous two-phase systems (ATPS) as a sample preparation technique for the determination of five pharmaceuticals, classified as emerging contaminants (EC): ibuprofen, paracetamol, ciprofloxacin, norfloxacin and amoxicillin. The evaluation of this study was performed through the partition co efficient (K) of each pharmaceutical by varying some parameters of the system, such as the pH value of the me dium, the nature of the ATPS-forming electrolyte and polymer, the tie-line length (TLL), the system temperature and the mass ratio between the top and bottom phases of the ATPS. Values of K between 9.30 and 1150 were ob tained for the five pharmaceuticals during the system optimization. The ATPS also proved to be efficient as a sam ple preparation technique in the partition of the studied pharmaceuticals when applied to water samples, including drinking water, surface water and filtered water from a water treatment plant. The values of the parti tion coefficients found in these complex samples ranged from 2.49 to 74.2.
Aqueous three-phase systems formed by poly(vinylpyrrolidone) + poly(ethyleneglycol) + lithium sulfate + water : phase behavior and partition data.
(2022) Abreu, Christian Silva; Neves, Dilaine Suellen Caires; Gomes, Vinícius Azevedo; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de
Aqueous three-phase systems (A3PSs) have been used to extract and separate several strategic analytes; however, there are several gaps in the characterization and theoretical principles of this technique. Therefore, an A3PS made up of 10,000 g‧mol−1 of polyvinylpyrrolidone (PVP), 10,000 g‧mol−1 of polyethylene glycol (PEG), lithium sulfate (Li2SO4), and water was characterized in this study. The results revealed that PEG, PVP, and Li2SO4 were concentrated in the top, middle, and bottom phases, respectively, whereas water was the main component in all phases. The three-dimensional coordinates of the phase composition points generated a plane with an area that increased as the difference in the phase compositions increased. The tie-plane area (TPA) decreased as the global composition and temperature decreased, indicating a strong temperature effect. Moreover, at relatively low overall concentrations, a phase inversion behavior between the electrolyte-rich phase and the PVP-rich phase was observed at 308.15 K. HE-4R dye molecules preferentially partitioned to the PVP-rich phase, and this trend increased as the TPA and temperature increased. A similar partition behavior was observed for Cu(II) ions, but they preferred to concentrate in the salt-rich phase. At relatively low overall concentrations, the Cu(II) ions promoted phase inversion at 298.15 K, a phenomenon similar to that observed in the temperature study. Thus, the phase diagram for a new A3PS was obtained, and as far as we know, this is the first work that quantitatively describes the TPA.
Aqueous two-phase systems formed by different phase-forming components : equilibrium diagrams and dye partitioning study.
(2020) Silva, Keycianne da Cruz; Abreu, Christian Silva; Vieira, Alício Wagner; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de
The present work aimed to characterize new aqueous two-phase system (ATPS) formed by Triton X-100 þ Li2SO4 þ H2O, polyvinylpyrrolidone Mw ¼ 10,000 g mol -1 (PVP10k) þ Li2SO4 þ H2O, and Triton X-100 þ PVP10k þ H2O, evaluating the effect of temperature and the nature of ATPS-forming components on the biphasic region. ATPSs formed by Li2SO4 showed greater efficiency in phase segregation compared to ATPSs formed by polymer/surfactant, with the biphasic area of ATPSs formed by Triton X-100 greater than that formed by PVP10k. For all ATPSs studied, temperature had a small effect on the biphasic region. The data were fitted with good correlation using the Merchuk equation for the binodal curves and OthmereTobias and Bancroft equations for the tie-lines. The partitioning studies show that there is an uneven distribution of Reactive Yellow HE-4R dye between the phases for all ATPSs and, with a tie-line length increase, there is an increase in the tendency of the dye to partition to the phase in which it interacts most strongly. For ATPSs formed by Li2SO4, the dye is preferentially transferred to the macromolecule-rich phase (top phase), whereas for the system formed by polymer/surfactant, the dye is partitioned to the PVP10k enriched phase (bottom phase). The present work aimed to characterize new aqueous two-phase system (ATPS) formed by Triton X -100 þ Li2SO4 þ H2O, polyvinylpyrrolidone Mw ¼ 10,000 g mol 1 (PVP10k) þ Li2SO4 þ H2O, and Triton X 100 þ PVP10k þ H2O, evaluating the effect of temperature and the nature of ATPS-forming components on the biphasic region. ATPSs formed by Li2SO4 showed greater efficiency in phase segregation compared to ATPSs formed by polymer/surfactant, with the biphasic area of ATPSs formed by Triton X-100 greater than that formed by PVP10k. For all ATPSs studied, temperature had a small effect on the biphasic region. The data were fitted with good correlation using the Merchuk equation for the binodal curves and OthmereTobias and Bancroft equations for the tie-lines. The partitioning studies show that there is an uneven distribution of Reactive Yellow HE-4R dye between the phases for all ATPSs and, with a tie-line length increase, there is an increase in the tendency of the dye to partition to the phase in which it interacts most strongly. For ATPSs formed by Li2SO4, the dye is preferentially transferred to the macromolecule-rich phase (top phase), whereas for the system formed by polymer/surfactant, the dye is partitioned to the PVP10k enriched phase (bottom phase).
Bixin as a new class of biosorbent for Hg2+ removal from aqueous solutions.
(2021) Vieira, Júlia Condé; Diniz, Mariana Cristine Coelho; Mendes, Louise Aparecida; Sinisterra Millán, Ruben Dario; Rodrigues, Guilherme Dias; Orlando, Ricardo Mathias; Windmoller, Cláudia Carvalhinho
In this study, the apocarotenoid bixin was investigated as a potential biosorbent for Hg2+ in aqueous solutions. Bixin was used to form a thin film on an inert support using the drop-coating technique. This film was char- acterised using ATR-FTIR, SEM, and TGA-DTG techniques. Parameters that influence adsorption, such as pH, temperature, NaCl concentration, salt type, bixin mass, and supports for the bixin film, were evaluated. Using 0.112 mg of a bixin covering on a cellulose filter, the sorbent material was able to remove 75 % of Hg2+ from a 2.0 mL, 0.3 mg g− 1 , pH 6.00, 25 ◦C solution after 180 min of contact. Kinetics studies were carried out between 5 and 1440 min, and the pseudo-first-order adsorption model was applied. Equilibrium isotherm data were ana- lysed, and the best fit was for the non-linear Freundlich model, with an R2 of 0.9868, RMSE of 0.37, and maximum sorption capacity of 85.38 mg g− 1 obtained by the Langmuir model. The bixin film was applied in spiked environmental samples (lake and mining effluent), and it achieved 86 % Hg2+ removal. The results show that the bixin film is a suitable alternative for efficiently removing mercury from various aqueous systems. This introduces a new class of biosorbent based on apocarotenoids, which are sustainable, low cost, nontoxic, and easily obtainable.
Equilibrium phase behavior of aqueous two-phase system formed by triblock copolymer þ sulfate salt þ water at different temperatures.
(2018) Gonçalves, Laryssa Fernanda da Silva; Felisberto, Nehander Carlos Mendes; Silva, Keycianne da Cruz; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de
Equilibrium data for the ternary liquid-liquid system formed of a triblock copolymer (L64 or F68), sulfate salts (Cu(II) or Fe(III)) and water were investigated in this work. The effects of temperature (278.15, 288.15 and 298.15 K), the nature of the cation and the copolymer molar mass on the phase diagram of the aqueous two-phase system were investigated. An increase in temperature decreased the biphasic region for the entire system. Cu(II) and F68 were better able to induce phase separation compared to Fe(III) and L64. The nature of the cation and the copolymer molar mass effect are discussed as a function of the formation of aqua acids through the reaction between the cation and water (Brønsted acids) and in relation to Flory-Huggins theory for macromolecule solutions, respectively. The consistencies of the tie line and binodal curve experimental compositions were evaluated by applying the Othmer-Tobias and Merchuk correlations, respectively.
Extraction of arsenic(III) in aqueous two-phase systems : a new methodology for determination and speciation analysis of inorganic arsenic.
(2019) Assis, Roberta Condé de; Faria, Betania Aparecida de Araujo; Caldeira, Cláudia Lima; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias
This work utilizes the liquid–liquid extraction technique of aqueous two-phase systems (ATPS) formed by a polymer and electrolyte to develop a novel methodology for the extraction, determination, and speciation analysis of inorganic arsenic. To optimize the methodology, the following parameters were studied: pH of the system, nature of the ATPS-forming electrolyte and the polymer, tie-line length (TLL) of the system, type and concentration of extractants, and the mass ratio of the top and bottom phases. The highest extraction (%E = 98%) was obtained for an ATPS composed of L64 + Na2SO4 + H2O, at pH = 6.00, TLL = 33.55% w/w using the ammonium pyrrolidine dithiocarbamate (APDC) extractant in a molar ratio (APDC/As(III)) of 960, and with a mass ratio of 1/4. In these same conditions, As(V) was not extracted satisfactorily (%E = 18%) to ATPS top phase, with a separation factor equal to 530 after three extractions, showing the great potential of the system for the speciation analysis of inorganic arsenic. Moreover, the method was validated employing HG-ICP OES with a coefficient of determination of 0.9957 and limits of detection and quantification equal to 0.20 μg kg−1 and 0.66 μg kg−1, respectively, proving that the method is capable of detecting the low concentrations required by legislation. The relative standard deviation (RSD) values varied between 4.88 and 9.45%, and the RSD in inter-day precision was 11.07%, which are in accordance with the limits of the validation guide used by the National Institute of Metrology, Quality and Technology, COD-CGCRE-008. Furthermore, relative error rates ranged from −7.44 to 9.90% and recovery percentages were between 92.6 and 110% for the accuracy studies. This method was also applied in a spiked tap water sample, presenting a recovery value equal to 87.10%.
Extraction of estrogen hormones from water samples using an aqueous two-phase system : a new approach for sample preparation in the analysis of emerging contaminants.
(2021) Domingues, Junielly Tomaz; Orlando, Ricardo Mathias; Almeida, Mariana Ramos; Lemos, Leandro Rodrigues de; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias
In this study, an environmentally friendly method of extracting steroid hormones, 17α-ethinylestradiol, levo norgestrel, gestodene, cyproterone acetate and estradiol valerate, using an aqueous two-phase system was developed. The aqueous two-phase system was applied as an organic solvent-free liquid–liquid extraction technique for the determination of these compounds by UV–Vis spectrophotometry in environmental samples. The experimental conditions were evaluated through the pH value of the medium (3.00–11.0), the nature of the electrolyte and polymer forming the system, the tie-line length (26.76–62.53% w/w), the temperature (278.15–313.15 K), and the mass ratio between the bottom and top phases of the system (1–5). The recovery efficiency was evaluated using the partition coefficient and the analytical signal of each hormone in the top phase. The study was carried out through univariate and multivariate optimization and, for the first time, in teractions of tie-line length, polymer forming the system and temperature were observed, and these directly influenced the partition of hormones in aqueous two-phase system. An overall experimental condition for the recovery of all hormones simultaneously (L35 + Na2SO4 + H2O, at pH = 3.00, tie-line length = 64.06% w/w, temperature = 298.15 K and mass ratio between the bottom and top phases of the system = 5) was determined. Partition coefficients (8.8 ± 0.8) to (4533 ± 48) were obtained for the hormones in samples of drinking water, samples from lake and river water, and filtered water from a water treatment plant. Thereby, the aqueous two phase system proved to be an innovative and good organic solvent free liquid–liquid extraction of hormones in environmental samples.
Extraction of yttrium from fluorescent lamps employing multivariate optimization in aqueous two-phase systems.
(2020) Leite, Daniela da Silveira; Carvalho, Pablo Luis Gutierrez; Almeida, Mariana Ramos; Lemos, Leandro Rodrigues de; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias
This paper presents for the first time the application of aqueous two-phase systems for yttrium recovery from fluorescent lamp residues, a rare earth element with high added value and widely used in the technology in dustry. A multivariate study was carried out, using experimental design, for yttrium extraction employing ATPS using alizarin red as extracting agent, in order to expand the possibilities of the ATPS application in industrial scales. The optimized variables, employing 26–1 fractional design, were pH (3.00–9.00), extracting agent con centration (2.3–23.0 mmol kg−1), tie-line length (TLL), ATPS-forming copolymers (L35 and L64) and electro lytes (Na2SO4 and C6H5Na3O7·2H2O), and mass ratio between top and bottom phases (mTP/mBP = 0.5–2.0). It was observed for the first time, that the metal ions partition in ATPS is mainly influenced by the salt-forming anion species distribution as a function of pH at high TLL values. The extraction of yttrium was optimized in a 23 factorial design with no lack of adjustment and it was able to predict the extraction response with accuracy close to 96%. The optimized conditions of yttrium extraction were applied using a leach liquor from real sample of fluorescent powder. After five extraction steps, 90% of yttrium was selectively recovered.
Green selective recovery of lanthanum from Ni-MH battery leachate using aqueous two-phase systems.
(2017) Oliveira, Wbiratan Cesar Macedo de; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues de
In view of the importance of resource recycling and the use of environmentally safe systems to extract the metals contained in wastes, the present study concerns the extraction/separation of lanthanum from spent Ni–MH batteries. Investigation was made of the extraction behavior of lanthanum using aqueous twophase systems (ATPSs), and a new environmentally safe hydrometallurgical method was developed for the selective extraction of La from Ni-MH battery leachate. The extraction behavior of La was evaluated considering the influence of the following parameters: concentration of different extractant; pH; ATPS-forming electrolyte (Li2SO4, Na2SO4, MgSO4, Na2C4H4O6, or Na3C6H5O7); ATPS-forming polymer (L64 or PEO1500). The recovery efficiency was evaluated by analyzing the extraction percentage (%E), and the best conditions for analyte extraction were achieved using the ATPS formed by PEO1500 + Li2SO4, at pH 6.00, with 1,10-phenanthroline as the extractant agent (%E = 74.1%). The method was applied to a real Ni-MH battery leachate. After three successive extraction steps, high separation factor (S) values were obtained for the separation of lanthanum from concomitant metals (SLa,Ce = 180; SLa,Pr = 184; SLa,Nd = 185).Astripping assay was carried out, and after a single step, 88.5% of the lanthanum was available for a possible electrowinning step.
Hydrometallurgical recovery of Zn(II) and Mn(II) from alkaline batteries waste employing aqueous two-phase system.
(2019) Leite, Daniela da Silveira; Carvalho, Pablo Luis Gutierrez; Lemos, Leandro Rodrigues de; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias
In this study, a greener method for the recovery of zinc and manganese from alkaline batteries waste was developed using Aqueous Two-Phase System (ATPS). ATPS is a liquid-liquid extraction technique. Zn(II) and Mn(II) were extracted using the diluted liquor from samples of spent alkaline batteries, and the experimental conditions were evaluated considering the effects of the following parameters: (i) nature and concentration of the extractants (1-(2-pyridyl-azo)-2-naphthol (PAN), (bis-4-trimethylpentyl) phosphinic acid (Cyanex 272), diphenylthiocarbazone (dithizone, C13H12N4S) and bis-(2-ethylhexyl) phosphoric acid (D2EHPA)); (ii) pH (3.00, 6.00 and 11.0), (iii) ATPS-forming electrolytes (Na2SO4, C6H5Na3O7 or C4H4Na2O6); (iv) ATPS-forming polymers (L35 and L64); and (v) tie-line length (TLL) and mass ratio between top and bottom phases (mTP/mBP). The recovery efficiency was evaluated using the extraction percentage (%E) and separation factor () between Zn(II) and Mn(II). The best conditions for selective extraction of the metal ions were achieved using an ATPS composed by L64 + Na2SO4 + H2O at pH = 3.00, TLL = 41.83% w/w and mTP/mBP = 1 using dithizone as the extracting agent and leach liquor with dilution factor equal to 10. This resulted in a value for separation factor of  = 1.2 × 106, in one extraction stage.
Hydrometallurgical separation of copper and cobalt from lithium-ion batteries using aqueous two-phase systems.
(2017) Leite, Daniela da Silveira; Carvalho, Pablo Luis Gutierrez; Lemos, Leandro Rodrigues de; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias
A new green hydrometallurgical method was developed for the selective extraction of copper and cobalt from spent lithium-ion batteries, using an aqueous two-phase system (ATPS) extraction technique. The method was optimized for the extraction of Cu(II) and Co(II), considering the influence of the following parameters: type and concentration of extractant (1-(2-pyridyl-azo)-2-naphthol (PAN), 1-nitroso-2-naphthol (1N2N), or bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272)); pH (1.00, 6.00, or 11.0); ATPS-forming electrolyte (Na2SO4 or Na3C6H5O7); tie-line length (TLL) of the system; and mass ratio of the top and bottom phases (mTP/mBP). The recovery efficiency was evaluated in terms of the extraction percentage (%E) and the separation factor (S) between copper and cobalt. The best conditions for selective extraction were achieved using an ATPS composed of L64+Na2SO4+H2O,with pH=6.00, TLL=50.3% (w/w),mTP/mBP=1, and PAN as the extracting agent, which resulted in βCu,Co=3.22×102. The method was subsequently applied to a real lithium-ion battery sample, previously leached with HCl and HNO3. Improved separation of copper and cobalt was achieved using successive extraction steps, resulting in βCu,Co=5.40×105. A stripping assaywas also performed, and after a single step, 70.5% of the copper was available for an electrowinning process
Liquid-liquid extraction of rare earth elements using systems that are more environmentally friendly : advances, challenges and perspectives.
(2022) Neves, Heyder Pereira; Ferreira, Gabriel Max Dias; Ferreira, Guilherme Max Dias; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Leão, Versiane Albis; Mageste, Aparecida Barbosa
The rare earth elements, a group of metals consisting of the lanthanide series, together with yttrium and scan- dium, are increasingly important in high technology industries worldwide. Given the need to expand production of these elements, there is a search for processes to obtain them that are less environmentally damaging, since the rare earths production chain is associated with several environmental problems and concerns. Solvent extraction, one of the important steps involved in the obtaining of rare earth elements, is receiving much attention in the scientific and industrial community, with a renewed search for approaches that avoid the use of organic solvents. Among the various options, cloud point extraction and the use of aqueous two-phase systems are alternatives to the use of traditional organic solvents. This review considers these two more environmentally friendly techniques and their use for the extraction and/or separation of rare earth elements. The issues addressed include their potential to replace traditional liquid–liquid extraction, in terms of the efficiency, toxicity, and biodegradability of the components forming the systems, as well as their potential applications and future perspectives.
Liquid−liquid equilibrium of aqueous two-phase systems composed of nonionic surfactant (Triton X‑100, Triton X‑165, or Triton X‑305) and choline chloride.
(2019) Silva, Sílvia Juliana Barros e; Ferreira, Gabriel Max Dias; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa
The study of aqueous two-phase systems (ATPSs) formed by ionic liquids based on the choline cation and nonionic surfactants has received attention in recent years because of the biodegradability and nontoxicity of their components. In this work, liquid–liquid equilibrium data were obtained for ATPSs composed of Triton X (Triton X-100, Triton X-165, and Triton X-305), choline chloride, and water, at 298.15, 313.15, and 328.15 K. In general, these systems presented a top phase rich in choline chloride and a bottom phase rich in surfactant, although the phenomenon of phase inversion was observed for a specific thermodynamic condition of the system formed by Triton X-165. It was observed that increase of the temperature led to an increase of the biphasic region, indicating an endothermic phase separation process. In addition, higher hydrophobicity of the surfactant increased its ability to promote phase segregation (the biphasic region increased in the following order: Triton X-100 > Triton X-165 > Triton X-305). The reliability of the equilibrium data was confirmed using the Othmer–Tobias and Bancroft correlations.
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 Dias
This 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.
Partition study of textile dye remazol yellow gold RNL in aqueous two-phase systems.
(2015) Alvarenga, Juliana Maria de; Fideles, Renata Aparecida; Silva, Maira Vieira da; Murari, Gabriella Frade; Taylor, Jason Guy; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa
The removal of organic dye pollutants from wastewater produced by the textile industry is a complex problem that presents potential health risks to the general public. Remazol Yellow Gold RNL (YR) dye is readily used to dye cellulose base materials and the methods developed for its removal from aqueous systems are either inefficient or too expensive to be adopted by smaller textile manufactures. Our approach is based on aqueous two-phase system (ATPS) using salts and either polymers or ionic liquids to extract Remazol Yellow Gold RNL from wastewater. Parameters such as the nature of the electrolyte, molecular mass of polymer and tie line length (TLL) on the dye partition coefficient (KYR) were all evaluated. A phase diagram for the polyethylene glycol (PEG 4000 g mol_1) and magnesiumsulfate system at 298.15 Kwas obtained and used to study the partitioning of YR. The KYR values demonstrate the potential of both systems for the removal of dyes from industrial effluents. The partition mechanismwas discussed based on the Haynes model and using the of Gibbs standard energy change (DtrG_). The driving force (enthalpy and/or entropy) that governs the partitioning of the dye depends on the nature of the ATPS. The optimized conditions that gave the best system was successfully applied to the removal of YR from wastewater obtained from a local textile manufacturer. The high KYR values in the presence of the effluent demonstrate the potential and robustness of the ATPS for the treatment of effluents from textile industries.
Partitioning of salicylic and acetylsalicylic acids by aqueous two-phase systems : mechanism aspects and optimization study.
(2019) Vieira, Alício Wagner; Molina, Gustavo; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de
Emerging contaminants such as drugs and pharmaceuticals have attracted attention in recent years due to their adverse effects in humans and the environment. They are difficult to monitor, since they are present at very low concentrations in environmental matrices. Acetylsalicylic acid (ASA) and salicylic acid (SA) are the most highly consumed drugs worldwide. In this investigation, an extensive study of acetylsalicylic acid and salicylic acid partitioning was carried out in aqueous two-phase systems (ATPSs) formed by a polymer, salt, and water. In the univariate analysis, the length of the tie line and the nature of the polymer and electrolyte that form the ATPS were found to have strong effects on the partition coefficients (K) of ASA and SA, while pH had a significant effect on the partition coefficient of ASA only. In all conditions, the analytes partitioned preferentially to the top phase (K >>1), indicating a preferential interaction of the analytes with the components of this phase. A multivariate study of the optimal SA partition conditions was carried out through a central composite design, showing that the optimal ATPS for SA partitioning is composed of [PEO1500] = 29.06 %wt and [Li2SO4] = 11.94 %wt at pH 6.1. Under these optimal conditions, the expected value for K is ±940. Eight replicates of this system reported a real value of K = 949 (±47). Thus, the ATPS was demonstrated to be an efficient system for the extraction of SA and ASA, with high K values.
Processo verde para aproveitamento de subproduto e resíduos do beneficiamento do arroz negro : uma alternativa para extração de antocianinas.
(2019) Fernandes, Tayrine Silva; Mageste, Aparecida Barbosa; Silva, Gilmare Antônia da; Mageste, Aparecida Barbosa; Silva, Gilmare Antônia da; Moreira, Renata Pereira Lopes; Rodrigues, Guilherme Dias
O presente estudo teve como objetivo desenvolver um método verde para extração de antocianinas, utilizando soluções aquosas do polímero poli(etileno glicol) (PEG), que são não tóxicas para a saúde e para o meio ambiente. Além disso, pretendeu-se valorizar um subproduto do beneficiamento do arroz negro, o arroz negro quebrado (ANQ), uma vez que este é usado apenas na produção de farinha e ração animal. Variações no tempo, concentração de polímero, temperatura, massa de ANQ e massa molar de PEG foram estudadas usando planejamentos experimentais multivariados (triagem e metodologia de superfície de resposta). As melhores condições de extração encontradas foram 25 ºC por 10 h, em uma concentração de PEG 1500 de 36,59% (m/m), com massa de ANQ de 1,4000 g, sendo a concentração de antocianinas monoméricas totais de 131 mg 100g-1. Uma análise comparativa na condição otimizada foi feita para a extração com metanol/ácido clorídrico (MeOH/HCl), e a concentração encontrada foi 148 mg 100g-1. A estabilidade térmica dos extratos de antocianinas em PEG e em solução tampão (extração em MeOH/HCl) foi estudada nas temperaturas 5, 25 e 40 ºC nos valores de pH 1,0 e 5,0, durante 60 dias. Os resultados indicaram que o aumento da temperatura favoreceu a degradação do corante, especialmente em 40 ºC. O extrato mantido em solução tampão foi mais estável à 40 ºC em relação ao extrato mantido em PEG, sendo que nas demais temperaturas ambos exibiram estabilidades equiparáveis. O extrato rico em antocianinas (em PEG) foi aplicado para coloração de um sabonete comercial incolor, e a cor do produto foi mantida por mais tempo comparado à estabilidade da cor apenas do extrato em PEG. De modo a expor o potencial de extração a partir de outros resíduos gerados na produção de arroz negro, foi realizada a extração de antocianinas a partir da casca (CAN) e do farelo de polimento (FAN), sendo as concentrações 148 mg 100g-1 e 883 mg 100g-1, respectivamente.
Selective separation of Cu, Ni and Ag from printed circuit board waste using an environmentally safe technique.
(2018) Souza, Wagner Barbosa de; Abreu, Christian Silva; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues de
Printed circuit boards (PCBs) make up a large part of e-waste and include high concentrations of high-value metals. Therefore, the recovery of these metals is interesting from both the environmental and economic points of view. Here, the extraction/separation of copper, nickel and silver from PCB leachate was studied using an aqueous two-phase system (ATPS) formed by triblock copolymers with an electrolyte and water, which is in compliance with the principles of green chemistry. The best conditions for the selective extraction consisted of 1-(2-pyridylazo)-2-naphthol (3.5 mmol kg−1) at pH = 6.0 in 6 sequential steps for the Cu(II), dimethylglyoxime (5.00 mmol kg−1) at pH = 9.0 for the Ni(II) and thiocyanate (5.20 mmol kg−1) at pH = 9.0 for the Ag(I). These conditions were applied sequentially for extraction of Cu, Ni and Ag from the PCB leachate, obtaining high separation factor (S) values between the analyte and the metallic concomitants (SCu,Ni = 1,460, SCu,Fe = 15,500, SCu,Ag = 15,900, SNi,Fe = 32,700, SNi,Ag = 34,700 and SAg,Fe = 4800). The maximum extraction percentages (%E) for Cu, Ni and Ag were 99.9%, 99.9% and 99.8%, respectively. After the extraction, a single step stripping process was performed, resulting in more than 82% of the ion available in a clean lower phase. For the first time, an ATPS has been used for sequential extraction of several metal analytes from a real sample.