Using Ionic Liquids to Improve CO Capture.

Most of our energy consumption proceeds from the use of fossil fuels and the production of natural gas. However, the presence of impurities in this gas, like CO, makes treatment necessary to avoid further concerns, such as greenhouse gas emissions, the corrosion of industrial equipment, etc.; thus, the development of CO capture and storage procedures is of the utmost importance in order to decrease CO production and mitigate its contribution to global warming.

Removal of Hazardous Organic Dyes from Liquid Wastes Using Advanced Nanomaterials.

The presence of organic dyes in aqueous environments is extremely hazardous to life due to the toxicity of these compounds. Thus, its removal from these various aquatic media is of the utmost importance, and several technologies are constantly being tested to meet this goal. Among these technologies, various types of degradation and adsorption techniques are typically used, and of the various types of materials used within these technologies, nanomaterials are constantly being developed and investigated, likely due to the various properties that these nanomaterials have.

Non-Dispersive Extraction of Chromium(VI) by Cyphos IL102/Solvesso 100 Using the Pseudo-Emulsion-Based Strip Dispersion Membrane Operation.

The removal of chromium(VI) from an acidic (HCl) medium through non-dispersive extraction with strip dispersion (NDXSD) was investigated using a microporous PVDF membrane support in a permeation cell. The ionic liquid Cyphos IL102 (phosphonium salt) in Solvesso 100 was used as an organic phase. In NDXSD, the stripping phase (NaOH) is dispersed in the organic phase on the cell side with an impeller stirrer adequate to form a strip dispersion.

Utilizing Deep Eutectic Solvents in the Recycle, Recovery, Purification and Miscellaneous Uses of Rare Earth Elements.

The boosted interest in using rare earth elements (REEs) in modern technologies has also increased the necessity of their recovery from various sources, including raw materials and wastes. Though hydrometallurgy plays a key role in these recovery processes, some drawbacks (apparent or not) of these processes (including the use of aggressive mineral acids, harmful extractants, and diluents, etc.) have led to the development of an environmental friendship subclass named solvometallurgy, in which non-aqueous solvents substituted to the aqueous media of the hydrometallurgical processing.

Solvent Extraction with Cyanex 923 to Remove Arsenic(V) from Solutions.

The removal of harmful arsenic(V) from aqueous solutions using Cyanex 923 (solvation extractant) was investigated using various experimental variables: equilibration time, the acidity of the aqueous phase, temperature, extractant and arsenic concentrations, and O/A ratio. Cyanex 923 extracted As(V) (and sulfuric acid) from acidic solutions; however, it could not be used to remove the metal from slightly acid or neutral solutions. The extraction of arsenic is exothermic and responded to the formation of HAsO·nL species in the organic phase (L represents the extractant, and the stoichiometric factor, n = 1 or 2, depends on the acidity of the aqueous phase).

Treatment of Stainless Steel Rinse Waters Using Non-Dispersive Extraction and Strip Dispersion Membrane Technology.

The extraction of Fe(III), Cr(III), and Ni(II) from stainless steel rinse water using non-dispersive extraction and strip dispersion membrane technology was carried out in a microporous hydrophobic hollow-fibre module contactor. The fibres were of polypropylene, whereas the organic extractant DP8R (bis(2-ethylhexyl) phosphoric acid) diluted in ExxsolD100 was used as the carrier phase. The rinse water containing the three elements was passed through the tube side, and the pseudo-emulsion formed by the organic phase of DP8R in Exxol D100 and an acidic strip solution were passed through the shell side in a counter-current operation; thus, a unique hollow fibre module was used for extraction and stripping.

Iron Control in Liquid Effluents: Pseudo-Emulsion Based Hollow Fiber Membrane with Strip Dispersion Technology with Pseudo-Protic Ionic Liquid (RNHHSO) as Mobile Carrier.

The transport of iron(III) from aqueous solutions through pseudo-emulsion-based hollow fiber with strip dispersion (PEHFSD) was investigated using a microporous hydrophobic hollow fiber membrane module. The pseudo-protic ionic liquid RNHHSO dissolved in Solvesso 100 was used as the carrier phase. This pseudo-protic ionic liquid was generated by the reaction of the primary amine Primene JMT (RNH) with sulphuric acid.

On the Use of Pseudo-Protic Ionic Liquids to Extract Gold(III) from HCl Solutions.

Solvent extraction of gold(III) from HCl media using pseudo-protic ionic liquids (PPILs) dissolved in toluene as the extractant phase is investigated. Three PPILs are generated from the reaction of commercially available amines and 1 M HCl solution and named as pri-NHHCl (derived from the primary amine Primene 81R), sec-NHHCl (derived from the secondary amine Amberlite LA2) and ter-NHCl (derived from the tertiary amine Hostarex A327). In the above structures, -NHHCl, -NHHCl and -NHCl represented the active groups (anion exchangers) of the respective PPIL.

Transport of Chromium(VI) across a Supported Liquid Membrane Containing Cyanex 921 or Cyanex 923 Dissolved in Solvesso 100 as Carrier Phase: Estimation of Diffusional Parameters.

An investigation of chromium(VI) transport across a supported liquid membrane containing the phosphine oxides Cyanex 921 and Cyanex 923 dissolved in Solvesso 100 as carrier phases was carried out in batch operation mode. Chromium(VI) transport was investigated as a function of different variables: hydrodynamic conditions in the feed (1000-1600 min) and stripping (600-1500 min) phases, HCl (0.25-2 M) and indium (0.

The Pseudo-Protic Ionic Liquids TOAHCl and TODAHCl as Carriers for Facilitated Transport of In(III) from HCl Solutions.

A study of indium(III) transport across an immobilized liquid membrane using the pseudo-protic ionic liquids TOAHCl and TODAHCl as carriers has been carried out using batch experiments. Metal transport is investigated as a function of different variables: hydrodynamic conditions in the feed (375-1500 min) and receiving (500-750 min) phases, HCl (0.5-7 M) and indium (0.

Dynamic Adsorption of HS onto a Goethite-Based Material.

The use of adsorption technology to remove HS from synthetic gas (HS and N) using a goethite-based adsorbent was investigated. The influence of the HS feed concentration (150-600 mg), the adsorbent dosage (1-4 g), and the gas flow rate (210-540 cm/min) on the breakthrough curves and HS adsorption on the adsorbent at the breakthrough point was investigated. Dynamic column experiments were performed to provide data for the theoretical models and to verify the performance of the system in the adsorption process.

Separation Iron(III)-Manganese(II) via Supported Liquid Membrane Technology in the Treatment of Spent Alkaline Batteries.

In this paper, the transport of iron(III) from iron(III)-manganese(II)-hydrochloric acid mixed solutions, coming from the treatment of spent alkaline batteries through a flat-sheet supported liquid membrane, is investigated (the carrier phase being of Cyanex 923 (commercially available phosphine oxide extractant) dissolved in Solvesso 100 (commercially available diluent)). Iron(III) transport is studied as a function of hydrodynamic conditions, the concentration of manganese and HCl in the feed phase, and the carrier concentration in the membrane phase. A transport model is derived that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of the iron(III) species-Cyanex 923 complex across the membrane phase.

Organic Dyes versus Adsorption Processing.

Even in the first quarter of the XXI century, the presence of organic dyes in wastewaters was a normal occurrence in a series of countries. As these compounds are toxic, their removal from these waters is a necessity. Among the separation technologies, adsorption processing appeared as one of the most widely used to reach this goal.

Obtention and Characterization of Ferrous Chloride FeCl·4HO from Water Pickling Liquors.

As a hazardous waste, water pickling liquors must be properly treated. An alternative consists of promoting the formation of ferrous salts from this residue due to their higher ferrous content. Since FeCl·4HO is widely used in several applications, obtaining pure crystals of this material appears to be an interesting prospect.

Transport of Au(III) from HCl Medium across a Liquid Membrane Using RNHCl/Toluene Immobilized on a Microporous Hydrophobic Support: Optimization and Modelling.

By the use of the tertiary amine A327 and 1 M HCl solution as precursors, the ionic liquid A327HCl was generated and used to investigate its performance in the transport of Au(III) from hydrochloric acid medium. The influence of the stirring speed (600-1800 min), ionic liquid concentration (1.25-50% ) in the membrane phase, and gold concentration (0.

Liquid-Liquid Extraction of Indium(III) from the HCl Medium by Ionic Liquid A327HCl and Its Use in a Supported Liquid Membrane System.

Ionic liquid A327HCl was generated by reaction of tertiary amine A327 and HCl, and the liquid-liquid extraction of indium(III) from the HCl medium by this ionic liquid dissolved in Solvesso 100 was investigated. The extraction reaction is exothermic. The numerical analysis of indium distribution data suggests the formation of A327HInCl in the organic phase.

Dispersion-free extraction of In(III) from HCl solutions using a supported liquid membrane containing the HA324HCl ionic liquid as the carrier.

By reaction of HCl and the tertiary amine HA324, an ionic liquid denoted HA324HCl was generated and used in the transport of indium(III) from HCl solutions. Metal transport experiments were carried out with a supported liquid membrane, and several variables affecting the permeation of indium(III) across the membrane were tested: stirring speed, metal and acid concentrations in the feed solutions and the carrier concentration in the supported organic solution. The metal transport results were also compared with those obtained using different carriers in the solid support.

Recovery of niobium and tantalum by solvent extraction from Sn-Ta-Nb mining tailings.

The slag from the extraction processes of metals from their ores may contain valuable components that, if adequately recovered, can be reintroduced in the technological life cycle. This is the case for the material obtained in Penouta mines in the North of Spain. These mineral sites are a main source of tin obtained from cassiterite.

Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground.

This paper describes the physicochemical study of the adsorption of dysprosium (Dy) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. Potassium hydroxide (KOH)-activated carbon is a microporous material with a specific Brunauer-Emmett-Teller (BET) surface area of 2330 m·g and pores with a diameter of 3.2 nm.

Facilitated Chromium(VI) Transport across an Ionic Liquid Membrane Impregnated with Cyphos IL102.

Chromium(VI) is a well-known hazardous element, thus, its removal from aqueous sources is of a general concern. Among the technologies used for the removal of this type of toxic elements, liquid membranes are gaining in importance and the same has occurred with the use of ionic liquids, considered for many, due to their properties, as green solvents. Thus, the present work joined the three previous points, presenting an experimental study about the removal of chromium(VI) by the use of a liquid membrane operation which used the commercially available Cyphos IL102 ionic liquid as a carrier.

Synthesis of Calcium Aluminates from Non-Saline Aluminum Dross.

The present work examines the synthesis of tricalcium aluminate (for use as a synthetic slag) from the non-saline dross produced in the manufacture of metallic aluminum in holding furnaces. Three types of input drosses were used with AlO contents ranging from 58 to 82 wt %. Calcium aluminates were formed via the mechanical activation (reactive milling) of different mixtures of dross and calcium carbonate, sintering at 1300 °C.

Tin and silver recovery from wave soldering dross.

This work proposes a method for the recovery of tin and silver from wave soldering dross produced during the manufacture of printed circuit boards. Samples of wave soldering dross were first subjected to carbothermic reduction to obtain an ingot containing the above metals plus other elements. This ingot was then subjected to electrorefining at different densities of electrical current, electrolyte flow rate, and cathode-anode separation distance, to determine the optimum conditions for recovering pure tin.

Sorption of indium (III) onto carbon nanotubes.

Indium has numerous applications in different industrial sectors and is not an abundant element. Therefore appropriate technology to recover this element from various process wastes is needed. This research reports high adsorption capacity of multiwalled carbon nanotubes (MWCNT) for In(III).

Sustainable remediation of mercury contaminated soils by thermal desorption.

Mercury soil contamination is an important environmental problem that needs the development of sustainable and efficient decontamination strategies. This work is focused on the application of a remediation technique that maintains soil ecological and environmental services to the extent possible as well as search for alternative sustainable land uses. Controlled thermal desorption using a solar furnace at pilot scale was applied to different types of soils, stablishing the temperature necessary to assure the functionality of these soils and avoid the Hg exchange to the other environmental compartments.

Oxidation and waste-to-energy output of aluminium waste packaging during incineration: A laboratory study.

This work reports the oxidation behaviour and waste-to-energy output of different semi-rigid and flexible aluminium packagings when incinerated at 850°C in an air atmosphere enriched with 6% oxygen, in the laboratory setting. The physical properties of the different packagings were determined, including their metallic aluminium contents. The ash contents of their combustion products were determined according to standard BS ISO 1171:2010.