WorldCat Identities

Passos, Helena

Overview
Works: 3 works in 3 publications in 1 language and 3 library holdings
Publication Timeline
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Most widely held works by Helena Passos
An integrated process for enzymatic catalysis allowing product recovery and enzyme reuse by applying thermoreversible aqueous biphasic systems1( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Abstract : An integrated biocatalysis-separation process: the reaction step occurs in a homogeneous medium, followed by enzyme and product separation in a liquid-liquid system promoted by temperature changes. Abstract : Herein, thermoreversible aqueous biphasic systems (ABS) composed of ammonium-based zwitterions (ZIs) and polymers are disclosed to act as integrated bioreaction-separation processes. The biocatalytic reaction involving laccase occurs in homogeneous media, after which small changes in temperature induce the formation of two phases and the complete separation of the enzyme from the products in a single-step. These systems also allow the recovery and reuse of the enzyme, along with the ZI-rich phase, contributing towards the development of sustainable biocatalytic processes
Mechanism of ionic-liquid-based acidic aqueous biphasic system formation1( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Abstract : This work represents a major contribution to the understanding of ionic liquid-based acidic aqueous biphasic system formation and application. Abstract : Ionic-liquid-based acidic aqueous biphasic systems (IL-based AcABS) represent a promising alternative to the solvent extraction process for the recovery of critical metals, in which the substitution of the inorganic salt by an acid allows for a 'one-pot' approach to the leaching and separation of metals. However, a more fundamental understanding of AcABS formation remains wanting. In this work, the formation mechanisms of AcABS are elucidated through a comparison with traditional aqueous biphasic systems (ABS). A large screening of AcABS formation with a wide range of IL identifies the charge shielding of the cation as the primary structural driver for the applicability of an IL in AcABS. Through a systematic study of tributyltetradecylphosphonium chloride ([P44414]Cl) with various chloride salts and acids, we observed the first significant deviation to the cationic Hofmeister series reported for IL-based ABS. Furthermore, the weaker than expected salting-out ability of H3 O + compared to Na + is attributed to the greater interaction of H3 O + with the [P44414] + micelle surface. Finally, the remarkable thermomorphic properties of [P44414]Cl based systems are investigated with a significant increase in the biphasic region induced by the increase in the temperature from 298 K to 323 K. These finding allows for the extension of ABS to new acidic systems and highlights their versatility and tunability
Mechanisms ruling the partition of solutes in ionic-liquid-based aqueous biphasic systems - the multiple effects of ionic liquids1( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

 
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