11 documents found, page 1 of 2
A green and sensitive method to determine phenols in water and wastewater sampl...
Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de; Silva, Luis Henrique Mendes da; Silva, Maria do Carmo Hespanhol da; Minim, Luis AntonioA greener and more sensitive spectrophotometric procedure has been developed for the determination of phenol and o-cresol that exploits an aqueous two-phase system (ATPS) using a liquid–liquid extraction technique. An ATPS is formed mostly by water and does not require organic solvent. Other ATPS components used in this study were the polymer, polyethylene oxide, and some salts (i.e., Li2SO4, Na2SO4 or K2HPO4 +...
Copper recovery from ore by liquid–liquid extraction using aqueous two-phase sy...
Lemos, Leandro Rodrigues de; Santos, Igor José Boggione; Rodrigues, Guilherme Dias; Silva, Luis Henrique Mendes da; Silva, Maria C. Hespanhol daWe investigated the extraction behavior of Cu(II) in the aqueous two-phase system (ATPS) formed by (L35 + MgSO4 + H2O) or (L35 + (NH4)2SO4 + H2O) in the presence of the extracting agent 1-(2-pyridylazo)-2-naphthol (PAN). At pH = 3 and a PAN concentration of 0.285 mmol kg−1, both ATPS lead to the effective separation of Cu(II) from other metallic ions (Zn(II), Co(II), Ni(II) and Fe(III)). High separation factors...
Aqueous two-phase systems of copolymer L64 + organic salt + water: Enthalpic L6...
Andrade, Vivianne Molica de; Rodrigues, Guilherme Dias; Carvalho, Raquel Moreira Maduro de; Silva, Luis Henrique Mendes da; Silva, Maria C. Hespanhol daPhase diagrams of two-phase systems (ATPS) composed by the triblock copolymer L64 + organic salt (sodium tartrate, sodium succinate, sodium citrate, or ammonium citrate) + water, at different temperatures (278, 288, and 298 K) are presented in this work. Contrary to behavior of ATPS formed by inorganic salts, the study of the temperature influence in the liquid–liquid equilibrium behavior of L64–organic salts A...
Liquid–liquid equilibrium of aqueous two-phase systems composed of poly(ethylen...
Lemos, Leandro Rodrigues de; Patrício, Pamela da Rocha; Rodrigues, Guilherme Dias; Carvalho, Raquel Moreira Maduro de; Silva, Maria C. Hespanhol daPhase diagrams of aqueous two-phase systems composed of PEO1500 + salt (di-potassium phosphate + potassium hydroxide or ammonium sulfate or zinc sulfate) + water were determined at (283.15, 298.15, and 313.15) K. All systems produce a large two-phase region; however the influence of temperature on the binodal position seems to be very small. By analyzing the effects of ammonium sulfate or zinc sulfate, it was o...
Aqueous two-phase systems: a new approach for the determination of p-aminophenol
Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de; Patrício, Pamela da Rocha; Silva, Luis Henrique Mendes da; Silva, Maria do Carmo Hespanhol daA new method has been developed for the spectrophotometric determination of p-aminophenol (PAP) in water, paracetamol formulations and human urine samples with a recovery rate between 94.9 and 101%. This method exploits an aqueous two-phase system (ATPS) liquid–liquid extraction technique with the reaction of PAP, sodium nitroprusside and hydroxylamine hydrochloride in pH 12.0, which produces the [Fe2(CN)10]^10...
Application of hydrophobic extractant in aqueous two-phase systems for selectiv...
Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de; Silva, Luis Henrique Mendes da; Silva, Maria C. Hespanhol daThis work developed a new and efficient method of extracting and separating Co(II), Ni(II) and Cd(II) in aqueous two-phase systems (ATPS) composed of triblock copolymer (L64) + Na2C4H4O6 + water and L64 + Li2SO4 + water using the hydrophobic extractant 1-nitroso-2-naphtol, which complexes the metal ions and partitions in the triblock copolymer micelles in the ATPS top phase. Metal extraction from the salt-rich ...
Use of aqueous two-phase PEG-salt systems for the removal of anionic surfactant...
Murari, Gabriella Frade; Penido, Jussara Alves; Silva, Heriveltom Morais da; Baeta, Bruno Eduardo Lobo; Aquino, Sergio Francisco deLinear 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 prese...
Green selective recovery of lanthanum from Ni-MH battery leachate using aqueous...
Oliveira, Wbiratan Cesar Macedo de; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa; Lemos, Leandro Rodrigues deIn 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 sel...
A method for dye extraction using an aqueous two-phase system : effect of co-oc...
Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; Lemos, Leandro Rodrigues de; Mageste, Aparecida BarbosaThis 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 t...
Partition study of textile dye remazol yellow gold RNL in aqueous two-phase sys...
Alvarenga, Juliana Maria de; Fideles, Renata Aparecida; Silva, Maira Vieira da; Murari, Gabriella Frade; Taylor, Jason Guy; Lemos, Leandro Rodrigues deThe 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...