Uncommon biphasic behaviour induced by very high metal ion concentrations in HCl/H2O/[P44414]Cl and HCl/H2O/PEG-600 systems.

In this work, the important role played by metal ions such as Fe(ii/iii), Cr(iii) and Ni(ii) in the formation and binodal behaviour of aqueous biphasic systems (ABS) composed of HCl and the ionic liquid, [P44414]Cl, or the polymer, PEG-600, is investigated. The concentration of metal ions used in this work exceeds several g L-1 for an industrial foreseen application. Experiments have also been carried out by varying the concentration of metal ions at different temperatures. Fe exhibits a totally different behaviour compared to Ni and Cr. In particular, the binodal curves in the presence of the ionic liquid are far from the classical curves found in the literature, displaying an onion-shape form, while for Ni and Cr, the curves follow the classical trend. When any of the three metal ions is mixed with the polymer and HCl medium, only Fe(iii) induces a biphasic system. Insights into the chemical driving forces at work are discussed.

Flame Retardant-Functionalized Cotton Cellulose Using Phosphonate-Based Ionic Liquids.

Cellulose from cotton fibers was functionalized through a dissolution-regeneration process with phosphonate-based ionic liquids (ILs): 1,3-dimethylimidazolium methylphosphonate [DIMIM][(MeO)(H)PO2] and 1-ethyl-3-methylimidazolium methylphoshonate [EMIM][(MeO)(H)PO2]. The chemical modification of cellulose occurred through a transesterification reaction between the methyl phosphonate function of ILs and the primary alcohol functions of cellulose. The resulting cellulose structure and the amount of grafted phosphorus were then investigated by X-ray diffraction, ICP-AES, and ¹³C and ³¹P NMR spectroscopy. Depending on the IL type and initial cotton / IL ratio in the solution, regenerated cellulose contained up to 4.5% of phosphorus. The rheological behavior of cotton cellulose/ILs solutions and the microscale fire performances of modified cellulose were studied in order to ultimately prepare flame retardant cellulosic materials. Significant improvement in the flame retardancy of regenerated cellulose was obtained with a reduction of THR values down to about 5-6 kJ/g and an increase of char up to about 35 wt%.

Rh(III) Aqueous Speciation with Chloride as a Driver for Its Extraction by Phosphonium Based Ionic Liquids.

In this work, the aqueous speciation of Rh(III) in chloride medium was investigated by UV-vis spectroscopy for ligand to metal ratios R = (Cl-)/(Rh) ranging from 300 to 5000, at fixed Rh concentration (2.4 × 10-3 M). Under the chemical conditions of this work, no time evolution was observed, which allows for the fitting of the UV-vis data by Principal Component Analysis (PCA) and Multi-Curve Resolution (MCR). From this, and by comparison with literature data, the three independent species [RhCl4]-, [RhCl5]2- and [RhCl6]3- were identified, their individual absorption spectra derived and their respective contribution to the collected experimental UV-vis spectra calculated. Then, extraction of Rh(III) towards the ionic liquid trihexyltetradecylphosphonium chloride was performed. Comparison with the speciation data gives insight into the extraction mechanism and the extracted species.

Understanding the fundamentals of acid-induced ionic liquid-based aqueous biphasic system.

Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated exceptional performance in bioseparation processes. However, IL-based ABS are of limited interest for metal extraction as most metals are not stable in their neutral or alkaline pH conditions. In the quest for better extraction systems for metals, the development of IL-based ABS with highly acidic solutions (AcABS), induced by the mixture of a hydrophilic IL ([P44414]Cl), a mineral acid (HCl, HNO3 or H2SO4) and water, opens new possibilities. A comprehensive investigation of fundamental aspects of IL-based AcABS was performed, including the temperature dependence of the phase diagrams, tie-lines and ion exchange behavior, evidencing the unique characteristics of these new systems. In particular, the favorable biphasic formation with an increase in temperature showcases the lower critical solution temperature (LCST) behavior of the phosphonium-based IL and opens many possibilities for AcABS application by creating stimuli responsive systems. The anion exchange identified highlights the IL-based AcABS complexity that renders the analytical characterization of the phases mandatory, instead of the traditional method coupling an empirical fit of the binodal with the lever-arm rule. Through judicious selection of the inorganic acid, different extraction systems can be obtained by tuning the degree of anion-exchange, underlining the versatility of the proposed AcABS system.

Lithium-Ion Battery Cathode Recycling through a Closed-Loop Process Using a Choline Chloride-Ethylene Glycol-Based Deep-Eutectic Solvent in the Presence of Acid.

This study evaluates the ability of a choline chloride:ethylene glycol-based deep eutectic solvent (DES) to dissolve lithium cobalt oxide (LCO) which is used as a cathode active material in Li-ion batteries. Both a commercial powder and spent cathodes have been used. It was demonstrated that if HCl is added in a small proportion, a rapid and efficient LCO dissolution can be achieved. Indeed, if more than three protons are added per one cobalt atom present in the LCO structure, a complete dissolution of the material is accomplished within 2 h at 80 °C. This result might be considered as a viable alternative compared to the literature where much longer reaction times and higher temperatures are applied to achieve similar results with the same DES system used either pure or in presence of additional reducing agents. It was further demonstrated that Co and Li can be fully precipitated after Li2 CO3 addition. This precipitation does neither pollute the DES nor leads to its degradation provided the pH does not exceed 10. Finally, it was shown that two additional reuse cycles can be carried out without any decrease of recovery efficiency, while no degradation products have been detected within the DES phase.

Evaluation of eHealth assistance in-hospital care for improved quality of life in patients.

Health conditions contribute significantly to patients' quality of life. Healthcare infrastructure and healthcare services, including their accessibility, belong to objective factors influencing their perception of their health. The growing disparity between supply and demand for specialized inpatient facilities due to the aging population calls for new solutions, including eHealth technologies. Automatized activities could be taken over by eHealth technologies that do not require a constant presence of staff. We tested whether eHealth technical solutions reduce patients' health risks on a sample of 61 patients on the covid-19 unit in Tomas Bata hospital in Zlin. We have applied the randomized control trial to select patients for the treatment and the control groups. Moreover, we tested eHealth technologies and their help to staff in the hospital. Due to the severity of the covid-19 disease and its rapid course and the size of the sample in our research, we did not demonstrate a statistically significant impact of eHealth technologies on patient health. The evaluation results confirm that even the limited number of technologies deployed proves to be an effective help for staff in critical situations like the pandemic. The main issue is psychological support to staff in hospitals and relieving stressful work.

A HNO3 -Responsive Aqueous Biphasic System for Metal Separation: Application towards CeIV Recovery.

An acidic aqueous biphasic system (AcABS) presenting a desired and reversible phase transition with HNO3 concentration and temperature was developed herein as an integrated platform for metal separation. The simple, economical, and fully incinerable (C,H,O,N) AcABS composed of tetrabutylammonium nitrate ([N4444 ][NO3 ])+HNO3 +H2 O was characterized and presented an excellent selectivity towards CeIV against other rare earth elements and transition metals from both synthetic solutions and nickel metal hydride (NiMH) battery leachates. The acid-driven self-assembly of AcABS bridges the gap between traditional ABS and liquid-liquid extraction whilst retaining their advantageous qualities, including compatibility with highly acidic solutions, water as the primary system component, the avoidance of organic diluents, rapid mass transfer, and the potential integration of the leaching and separation steps.

Legal situation and current practice of waste incineration bottom ash utilisation in Europe.

Almost 500 municipal solid waste incineration plants in the EU, Norway and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals. Metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. As a result from a cooperation network between European experts an up-to-date overview of documents regulating IBA utilisation is presented. Furthermore, this work highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the emission by leaching are defined. An analysis of the defined parameter reveals that leaching parameters are significantly more to be considered compared to total content parameters. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test (monolithic materials) are in place. A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. The overall utilisation rate of IBA in construction works is approximately 54 wt%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances.

Quantitative extraction of Rh(iii) using ionic liquids and its simple separation from Pd(ii).

The extraction of Pd(ii) and Rh(iii) from acidic solutions containing between 1 and 8 M HCl towards three ionic liquids, namely [P66614][Cl], [P66614][Br] and [P66614][DCA], based on the trihexyltetradecylphosphonium cation ([P66614]) and chloride, bromide or dicyanamide (DCA) anions, respectively, is reported. Extraction of Pd(ii) is quantitative up to 6 M HCl (D > 3000). A value of 258 for the distribution coefficient of Rh(iii) extracted from 1 M HCl towards [P66614][Br] is also reported. [P66614][Cl] and [P66614][Br] were found to be very efficient at separating these two metals from aqueous solutions containing at least 6 mol L-1 HCl.

Possibilities and limitations in separating Pt(IV) from Pd(II) combining imidazolium and phosphonium ionic liquids.

An investigation on a process designed for separating Pt(IV) and Pd(II) dissolved in acidic aqueous solution containing HCl using two ionic liquids, 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIM][NTf2]) and trihexyltetradecylphosphonium bromide (Cyphos 102), is presented. To this end, the single extraction of platinum in [OMIM][NTf2] has been investigated as a function of the initial concentration of Pt(IV) ions dissolved in 1 M HCl. The distribution coefficient for Pt(IV), present in water as a PtCl6(2-) anion, decreases with the concentration of Pt(IV). The extraction of Pd(II) towards [OMIM][NTf2] or Cyphos 102 as a function of the concentration of HCl in the aqueous phase is also reported. Pd(II), present as PdCl4(2-) in water, is not extracted using [OMIM][NTf2]. On the other hand, the distribution coefficients of Pd(II) using Cyphos 102 are above 2000. In this ionic liquid, Pd(II) is extracted as a PdBr4(2-) anion. Separation of Pt(IV) from Pd(II) was then carried out starting from aqueous phases containing 1 M HCl and various initial concentrations of Pt(IV). The influence of the number of extraction steps using [OMIM][NTf2] on the extraction of Pt(IV) was also studied. Unlike the results obtained from single extraction experiments of Pt(IV), consecutive extraction of Pt(IV) in water using [OMIM][NTf2] does not improve significantly the extraction of this metal ion. The second step of the extraction process carried out using Cyphos 102 leads to the quantitative extraction of Pd(II) and Pt(IV) remaining in the aqueous phase.

Sorption of selenium oxyanions on TiO2 (rutile) studied by batch or column experiments and spectroscopic methods.

Selenium is a known toxic element released in the environment by anthropogenic activities. The present study is devoted to the aqueous sorption behaviour of selenium oxyanions (selenate and selenite) on a reference oxide surface, namely rutile TiO(2). Batch sorption kinetics and isotherms have been studied using different physico-chemical conditions of the solution (changes of pH and ionic strength). The sorption was favoured for both anions in acidic conditions, in agreement with a surface complexation mechanism and CD-MUSIC predictions. Spectroscopic investigations of the sorbed rutile powder were also consistent with such a mechanism. EXAFS spectra confirmed that for selenite anions, an inner-sphere mechanism was the most probable process observed. Dynamic sorption experiments using a column filled with rutile powder also substantiated that a part of the surface complexes follows the inner-sphere mechanism, but also evidenced that an outer-sphere mechanism cannot be excluded, especially for selenate anions.

Comparison between batch and column experiments to determine the surface charge properties of rutile TiO2 powder.

This paper reports a comparative study of three methods for determining the surface charge and acid-base behavior of a TiO(2) rutile material. Electrophoretic mobility measurements were performed using two different batch protocols: (i) a "static" mode that consisted of immersing the rutile powder in aqueous solutions of given pH's and ionic strengths for 10 h, and (ii) a "dynamic" mode that consisted of using an automatic titrator to continuously adjust the solution pH with a contact time of 15 min. The same apparatus (a Nanosizer from Malvern) was used to measure the zeta potential of the particles in both methods. These batch experiments were next compared to the determination of the surface charge of rutile using nonlinear chromatography in column experiments. In that case, the rutile powder was compacted to enable the formation of a proper column bed. Therefore, Raman scattering and X-ray photoelectron spectra were used, as well as other physical information such as specific surface area and morphology of the particles, to verify that the rutile powder and compacted form were identical. The three approaches were then compared and discussed in relation to the acid-base behavior of the rutile material.