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Red mud (RM) is composed of a waste alkaline solution (pH = 13.3) obtained from the production of alumina. It contains high concentrations of hematite (Fe2O3), goethite (FeOOH), gibbsite [Al(OH)3], a boehmite (AlOOH), anatase (Tetragonal–TiO2), rutile (Ditetragonal dipyramidal–TiO2), hydrogarnets [Ca3Al2(SiO4)3−x(OH)4x], quartz (SiO2), and perovskite (CaTiO3). It was shown to be an excellent catalytic mixture for biodiesel production. To demonstrate the value of RM, an environmentally friendly process of transesterification in aqueous medium using waste cooking oil (WCO), MeOH, and waste alkaline solution (WAS) obtained from aluminum production was proposed. Triglycerides of WCO reacted with MeOH at 60 °C to yield mixtures of fatty acid methyl esters (FAMEs) in the presence of 0.019% (w/w) WAS/WCO using the WAS (0.204 mol L−1, predetermined by potentiometric titration) from aluminum production by the Bayer process. The use of the new catalyst (WAS) resulted in a high yield of the products (greater than 99% yield).

Methyl Salicylate (MS), the principal constituent of Wintergreen oil (WO) was obtained from acetyl salicylic acid (ASA) by sequential transesterification-esterification reaction promoted by NbCl5for the first time. The reagents were added simultaneously, and the reaction process involved the transesterification and esterification reactions, which were accompanied by thin layer chromatography and gas chromatography. The conversion rate via GC was 100%, and the MS yield was 94%. A cytotoxicity of 50% and 64% for cultured S. aureus and metastatic melanoma cells, respectively, was observed for a concentration of 0.6 mg/mL, whereas no cytotoxicity for non-tumor cells was observed for this concentration, and it is considered to be the optimum concentration.

Red mud (RM) is composed of a waste alkaline solution (pH = 13.3) obtained from the production of alumina. It contains high concentrations of soluble hematite (Fe2O3), goetite (FeOOH), gibisite [Al(OH)3], a boemite (AlOOH), anatase (Tetragonal - TiO2), rutile (Ditetragonal dipyramidal - TiO2), hydrogarnets [Ca3Al2(SiO4)3−x(OH)4x], and perovskite (CaTiO3). It was shown to be an excellent catalytic mixture for biodiesel production. To demonstrate the value of RM, an environmentally friendly process of transesterification in aqueous medium using waste cooking oil (WCO), MeOH and waste alkaline solution (WAS) obtained from aluminum production was proposed. Triglycerides of WCO reacted with MeOH at 60 oC to yield mixtures of fatty acid methyl esters (FAMEs) in the presence of 0.019% (w/w) WAS/WCO using the WAS (0.204 mol L-1, predetermined by potentiometric titration) from aluminum production by the Bayer process. The use of the new catalyst (WAS) resulted in a high yield of the products (greater than 99% yield).

Red mud (RM) is a residue obtained from the production of alumina. It contains a high concentration of metal oxides and waste concentrated sodium hydroxide solution (pH = 13). To increase the value of RM, an environmentally friendly process of transesterification using waste cooking oil (WCO), MeOH and concentrated sodium hydroxide solution (CSHS) from aluminum production was proposed. Triglycerides of WCO reacted with MeOH at 60 oC to yield mixtures of fatty acid methyl esters (FAMEs) in the presence of 2.03% (w/w) CSHS/WCO using the CSHS (0.204 mol L-1, predetermined by potentiometric titration) from aluminum production by the Bayer process or with the addition of 0.68% (w/w) fabric softener (3% w/w cetyltrimethylammonium chloride in solution) as a phase transfer (PTA) agent. The addition of PTA to the catalyst resulted in a better yield of the products (greater than 98% yield). A simplified mechanism is presented to account for the experimental results.

The presence of copper in distilled sugar cane spirits, especially cachaça produced in alembics, has impeded the marketing of this product. Red mud (RM) is a residue obtained from alumina production. It contains a high concentration of metal oxides and is very alkaline. The RM was dried at 100 oC and sifted through a 150-micron sieve. The sample was characterized by B.E.T. nitrogen adsorption, scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) and Atomic Absorption Spectrometry (A.A.S.). The textural parameters indicate that the total surface area (S.T.) was 21.9 m2g-1, and the total volume pore (V.T.) was 0.09 cm3g-1. The RM (1 g) was stirred for two hours with a 1.0 L cachaça sample containing 9.39 mg of copper L-1 and filtered under atmospheric pressure. The concentration of copper ions detected in the filtrate was 0.00 mg L-1. No copper ions were retained when the cachaça was filtered through the RM under high pressure without stirring prior to filtration.

Uric acid (UA) is an important component in biological matrices, and the development of new methods for extracting/separating UA from several complex matrices is necessary. A viable alternative is ...

This work presents, for the first time, a fast and highly sensitive electrochemical method for determination of three organophosphorus compounds (OPs), diazinon (DZN), malathion (MLT), and chlorpyrifos (CLPF), using a modified pyrolytic graphite electrode (PGE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA-MPA). The PGE was modified by a nanocomposite based on functionalized carbon nanotubes (CNTf) and silver nanoparticles (AgNPs). The OPs samples were directly analyzed on the modified working electrode surface by BIA-MPA system in Britton-Robinson (BR) buffer 0.15 mol L

Rituximab (RTX) is a specific monoclonal antibody for CD20 protein, which are mostly found in lymphocytes B. RTX is notably indicated for lymphomas, autoimmune disorders, leukemia and transplant rejections. A higher efficiency is achieved by adjusted doses, which is tailored by individual body weight and RTX pharmacokinetic parameters. Therefore, the individualized dosing is a usual practice to achieve the therapeutic success of this expensive drug. Therapeutic monitoring of RTX is commonly performed by chromatographic methods or immunoassays. These methods, however, suffer from lack of standardization in workflows, long turnaround times and high instrumentation costs with complex sample preparation. In this regard, immunosensors emerge as a feasible alternative to overcome these limitations. Herein, we developed an impedimetric immunosensor, which can detect RTX from both invasive and non-invasive samples, in this way our immunosensor is applicable in blood plasma and urine samples allowing a new analysis approach. A linear correlation between the charge transfer resistance and RTX from 2 to 14 μg ml−1 (r2 of 0.99) along with limit-of-detection and limit-of-quantification of 130 and 400 ng ml−1, respectively, was obtained. The immunosensor implemented proved to have sufficient precision and accuracy for on-site RTX detection in both blood serum and urine samples. Such affordable, label-free and highly sensitive electrochemical immunosensors could pave the way for on-site therapeutic drug monitoring, quality control and extended stability monitoring of different drugs, in a simple manner along with short turnaround times and low costs.

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Neste trabalho foram desenvolvidas duas metodologias para a recuperação de metais estratégicos a partir de fontes secundárias, baterias alcalinas e lâmpadas fluorescentes, empregando sistemas aquosos bifásicos como técnica de extração. Foi estudada a extração/separação de Zn(II) e Mn(II) usando licor de lixiviado de baterias alcalinas diluídos, em termos de %E e do fator de separação (SZn/Mn) em SAB. As variáveis avaliadas foram: pH (3,00, 6,00 e 11,0), natureza e concentração do agente extratante (PAN, ditizona, Cyanex 272 e D2EPHA), comprimento da linha de amarração, copolímeros (L35 e L64) e sais (Na2SO4, C6H5Na3O7 e C4H4Na2O6) formadores do sistema e razão entre massas de fase superior e inferior (mFS/mFI = 0,5 – 2,0). As melhores condições foram obtidas em SAB formado por L64 + Na2SO4 + H2O, em pH = 3,00, CLA = 41,83% m/m e mFS/mFI = 1, usando ditizona como agente extratante. Ao final, foi obtido um fator de separação SZn/Mn = 1,2 x 106 em apenas uma etapa de extração. Foi realizado um estudo multivariado, empregando planejamento experimental, para a extração de ítrio em SAB utilizando vermelho de alizarina como agente extratante. As variáveis otimizadas, empregando planejamento fracionário 26-1, foram: pH (3,00 a 9,00), concentração de agente extratante (2,3 a 23,0 mmol kg-1), comprimento da linha de amarração, copolímeros (L35 e L64) e sais (Na2SO4 e C6H5Na3O7.2H2O) formadores do sistema e razão entre massas de fase superior e inferior (mFS/mFI = 0,5 – 2,0). Pela primeira vez, foi observado que, em CLA elevados, a distribuição de espécies do ânion do eletrólito formado em função do pH, influencia diretamente na partição de íons metálicos em SAB. O modelo foi otimizado através de um planejamento 23, não apresentou falta de ajuste e foi capaz de prever a resposta de extração de ítrio com exatidão próxima de 96%. As condições ótimas de extração de ítrio foram aplicadas em amostras reais de lixiviado de pó fluorescente. Ao final de cinco etapas de extração, foi possível recuperar 90% do ítrio de forma seletiva. In this work two methodologies were developed for the recovery of strategic metals from secondary sources, as alkaline batteries and fluorescent lamps, using aqueous two-phase system as extraction technique. The extraction/separation of Zn(II) and Mn(II), from alkaline batteries waste, were studied in terms of extraction percentage (%E) and separation factor (SZn/Mn) in ATPS. The effects of the following parameters: nature and concentration of the extracting agents (PAN, Cyanex 272, Dithizone and D2EHPA); pH (3.00, 6.00 and 11.0), ATPSforming electrolytes (Na2SO4, C6H5Na3O7 or C4H4Na2O6) and copolymers (L35 and L64); tie-line length (TLL) and mass ratio between top and bottom phases (mTP/mBP). 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 Zn/Mn= 1.2 x 106, in one extraction stage. A multivariate study was carried out, using experimental design, for the yttrium extraction in ATPS using alizarin red as the extracting agent. The optimized variables, using fractional desing 26-1, were: pH (3.00 to 9.00), extracting agent concentration (2.3 to 23.0 mmol kg-1), tie line length, ATPS-forming copolymers (L35 and L64) and electrolytes (Na2SO4 and C6H5Na3O7.2H2O) and mass ratio between top and bottom phases (mTP/mTP = 0.5-2.0). It was observed, for the first time, that the metal ions partition in ATPS is directly influenced by the salt-forming anion species distribution as a function of the pH, in high TLL values. The model was optimized in a 23 factorial design with no adjustment lack and was able to predict the yttrium extraction response with accuracy close to 96%. The yttrium extraction in optimized conditions were applied in real samples of phosphorous fluorescent powder leach liquor. After five extraction steps, 90% of yttrium was selectively recovered.