Revising Concepts on Liquid–Liquid Extraction: Data Treatment and Data Reliability

Abstract

This Spotlight article presents the state-of-the-art of electrospray deposition technique applied to the fabrication of proton exchange membrane fuel cell (PEMFC) components, mainly focusing on catalyst layers in gas diffusion electrodes. The atomization of a suspension of particles over a substrate under the influence of a strong electric field results in the growth of a film with macroporous morphology and many interesting properties. This so-called electrospray deposition has reported many noteworthy beneficial effects for the fabrication of the catalyst layers of gas diffusion electrodes of PEMFCs. The electrosprayed catalyst layers prepared from suspensions of catalyst particles and ionomers present a dendritic macroporous morphology with superhydrophobic character that improves the water management inside the cell and increases the performance by ∼20% with respect to standard electrodes prepared by airbrushing. Other interesting effects observed with electrosprayed catalyst layers are increased catalyst utilization and water absorption capabilities of the ionomer, improved performance under nonhumidified conditions, and a reduction in catalyst degradation. In addition, the electrospray deposition decreases platinum losses during fabrication thanks to the attractive electrostatic forces between the ion mist and the substrate compared with regular ink-based spray methods.

Liquid–Liquid Equilibrium Data for Novel Aqueous Two-Phase Systems Composed of Betaine-Xylitol Deep Eutectic Solvent + Alcohol (1-Propanol/2-Propanol/tert-Butanol) + Water

“…Considering the phase behavior of ATPS formed by DES and alcohol through experiments, the nonrandom two-liquid (NRTL) activity coefficient model was adopted to evaluate the liquid–liquid equilibrium data . This model was classified as a local composition model and was widely applied in partially miscible and totally miscible ATPS. − For instance, the phase equilibrium data of ATPS containing DES and tert -butanol were successfully correlated by the NRTL model, which was depicted using eqs – where x i represents the molar fraction of component i ; τ ij , τ ji , τ kj , G ij , G ki , and G kj are the i – j interaction parameters; subscripts i , j , and k refer to all components in the system; and α ij is a nonrandomized factor and fixed at 0.3 by the NRTL model.…”

A green hydrophobic deep eutectic solvent for extraction of phenol from aqueous phase

“…The method has advantages of easily operation, high accuracy and cost effective. An extensive discussion about the conventional methods in LLE analysis has been recently reported by Arce et al 31 . This approach has been used extensively in recent publications 32 , 33 .…”

Liquid–Liquid Equilibria Determination and Modeling of ATPS Based on PEG4000 and PVP29000 at 298.15 K and 0.1 MPa

“…52−54 Analogous results were obtained for the phase diagrams of {PVP29000 (1) + Na 2 Tartrate or K 2 Tartrate (2) + Water (3)}, as Figure 4 shows, with the literature-based data for {PVP3500 (1) + Na 2 Tartrate (2) + Water (3)}, 55 33 given by eq 9, and Bancroft−Hubard, 35 expressed by eq 10, ease the graphical representation and interpolation of tie-line compositions, reducing the need to conduct additional experimental procedures. In this work, the original purpose of these empirical models is kept, 46 i.e., it is believed that they do not provide any information on the so-called "reliability", "consistency", or "quality" of the tie-lines, but only on the suitability of these mathematical expressions for tie-line interpolation. As Table 6 shows, these correlations yielded very satisfactory fittings of the experimental data, with the one of Bancroft−Hubard 35 generally providing larger determination coefficients (R 2 ).…”