Tetraoctylammonium N-lauroyl sarcosinate and trioctylmethylammonium salicylate are water-immiscible solvents which contain a large amount of dissolved water and may be called “hydrophobic–hydrophilic” ionic liquids (HHILs). We found that several representative water-soluble reagents – Arsenazo I, Arsenazo III, Alizarin Red S, Nitroso-R salt, and Xylenol Orange – are strongly partitioned into the HHIL phase from aqueous solutions over a wide pH range. Metal ions that form complexes with these reagents are extracted efficiently from aqueous solutions. We studied the details of extraction in two representative systems, Sc(III) with Arsenazo III and Co(II) with Nitroso-R salt. A sensitive, selective, and rapid procedure for the extraction-photometric determination of cobalt with HHILs and Nitroso-R salt has been developed.

Procedures for the determination of aluminum in water for injections (Aqua ad iniectabilia) and high-purity water (Aqua valde purificata) at a level of several µg L⁻¹ using atomic-emission spectrometry with a novel microwave plasma (MP–AES) and inductively coupled plasma (ICP–AES) are proposed. Regardless of the atomic-emission technique used, the procedure for aluminum needs no sample preparation (acidification only), no preconcentration, shows high sensitivity (limits of detection of 0.4 and 0.7 µg L⁻¹ for ICP–AES and MP–AES with a polymeric inert concentric nebulizer, respectively, and 0.03 µg L⁻¹ for ICP–AES with an ultrasonic nebulizer), high precision (repeatability, relative standard deviation, <5%), and high throughput (25 samples per hour), and is considerably simpler and more expedient from the viewpoint of the analysis cost and time compared with the standard spectrofluorimetric procedure of the US and the European Pharmacopoeia.

In this study, a technical scheme of an ammonium recovery process from diluted municipal or industrial wastewaters was developed, and the main operational parameters of adsorption/desorption and air-stripping/acid-scrubbing or membrane units were examined. The proposed approach combines the removal of ammonium nitrogen by an ion-exchange mechanism on metakaolin-based geopolymers (MKGPs) followed by adsorbent regeneration. A regeneration agent was purified by the air-stripping technique or membrane technology. A ready-to-use market-grade fertilizer or industrial-grade ammonia water could be obtained as the final product. The properties and regeneration ability of MKGP, prepared from activated kaolinite clay, were compared with new geopolymer adsorbents based on papermill sludge (FS MKGP). Adsorption fixed-bed column experiments with continuously circulated regeneration solution purified by air-stripping or the membrane approach were conducted to determine the limits of the regeneration solution’s application. Sodium and potassium salts were tested as regeneration agents, and the influence of regeneration solution composition on ammonium removal and recovery rates was investigated. Based on a breakthrough curve analysis, the removal rate of ammonium N by FS MKGP was found to be 3.2 times higher than that by MKGP for actual wastewater samples. Moreover, there were substantial differences in the regeneration regime between the two adsorbents. For the air-stripping technique, a liquid-phase temperature of 45°C was minimal and enough for efficient ammonia transfer to the gaseous phase. For the membrane technique, a feed-phase temperature of 40°C was enough for removing ammonia from the regeneration solution, while no heating of a receiving phase was required.

Optimal conditions for the complexation of transition metal ions [Cu(II), Ni(II), Co(II, III), and Fe(II, III)] with 1-nitroso-2-naphthol-2,6-disulfonic acid have been determined by spectrophotometry...

Optimal conditions of complexation copper(II) with 1-nitroso-2-naphtol-3,6-disulfonic acid were found by the spectrophotometric method. The optimum pH interval for the formation of a complex is...

The distribution of 4-(2-pyridylazo)resorcinol, PAR (5 × 10–4–1 × 10–2M) in the systems tetraoctylammonium N-lauroylsarcosinate (TOALS)–water and trioctylmethylammonium salicylate (TOMAS)–water is...