In this research, the kinetics of Co(II) extraction from sulfate medium by the system of “[C₈H₁₇NH₃][Cyanex 272]+diluent sulfonated kerosene” were investigated using the single drop falling technique. The time of drop formation and coalescence was determined for calculating the Co(II) transfer flux. The influences of aqueous pH, Co(II) concentration and [C₈H₁₇NH₃][Cyanex 272] concentration on the revised Co(II)-transfer flux (F') were investigated with aim of obtaining reaction orders for extraction rate equations. With the conditions of Co(II) concentration of 0.24 mol/L, [C₈H₁₇NH₃][Cyanex 272] concentration of 0.24 mol/L, extraction temperature of 298 ± 0.5 K and the normal atmospheric pressure, activation energies (E_a) of extraction reaction for the aqueous pH of 3.0, 4.0 and 5.0 are 3.45, 3.83 and 5.17 kJ/mol, respectively. The equations of extraction rate were calculated and listed in our research based on the different aqueous pH of 3.0, 4.0 and 5.0. The extraction reaction is a diffusion control process according to the values of E_a. The details studies on the kinetics of Co(II) extraction from simulated aqueous solution are significant to optimize its extraction processes.

A novel approach for recovering yttrium from high ferric and strong acidic sulphate leach solutions of deep-sea mud by stepwise extraction and stripping has been developed. The results show that the first step extraction by N235+TBP system can extract H₂SO₄ well and adjust the raffinates to a desirable pH, while only the iron was selectively co-extracted with negligible loss of yttrium ions. The organic solution can be easily regenerated by using a 50 g/L H₂SO₄ solution to strip extracted iron followed by using deionized water to strip H₂SO_4. The raffinate could be directly used for the second step of yttrium extraction by P204+TBP system, while iron was co-extracted. The co-extracted yttrium and iron could be separated well through a sequentially stepwise stripping process using a 50 g/L H₂SO₄ solution and a 0.6 mol/L H₂C₂O₄ solution. Over the whole process, yttrium was separated well from the sulphate leach solutions and enriched into the strip liquor of yttrium sulfate. The organic extractants could be returned for recycling.

In 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C₄mimTf₂N)–water biphasic extraction system, a tiny volume of third phase is formed under existing trioctylphosphine oxide (TOPO). To study possible use of the third phase as extraction concentration media, extraction behavior of several metal-thiocyanato complexes into the third phase was investigated. Fe(III) and Ga(III) complexes were quantitatively extracted into the third phase, and Co(II) and Cu(II) complexes were extracted to some extent. The extracted ternary complex species were indirectly estimated using 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C₈mimTf₂N)–water biphasic system forming no third phase, and it was suggested that un- or smaller-charged complexes with high hydrophobicity have superiority for extraction into the third phase.

Extraction of 1,3-propanediol (PDO) was reported using the protic ionic liquid (PIL)-based aqueous two-phase system (ATPS). In this study, combinations of PILs (pyrrolidinium formate [Pyrr][HCOO] and propionate [Pyrr][C₂H₅COO] and inorganic salts (K₃PO₄ and K₂HPO₄) as phase-forming components of ATPS, were examined. PDO was successfully extracted with all ATPSs and the best extractability was shown in an ATPS composed of [Pyrr][C₂H₅COO] and K₃PO₄. By examining the composition, the highest distribution ratio of 4.52, which is approximately comparable with those of aprotic ionic liquid-based ATPS, was obtained.

We report here the effect of sequential refreshment of a water-immiscible ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P14TFSI), enhancing the production amount of paclitaxel with in situ extraction from an aqueous medium in a plant cell culture. The production amount of paclitaxel with refreshment of 2.5 vol% P14TFSI twice every 2 days was 8 times greater than that without the refreshment and 210 times greater than that of control culture in the absence of P14TFSI. The enhanced production amount of paclitaxel in the culture with P14TFSI might be due to the deceased feedback inhibition of paclitaxel and stress response against elevation of intracellular production of reactive oxygen species (ROS) derived from P14TFSI's abiotic stress.

In this study, we investigated an efficient recovery method of yttrium from a sulfuric acid leaching solution of spent Ni-MH battery electrode materials. In this newly proposed method, yttrium, one of the heavy rare earths (HREEs), was coprecipitated with light rare earths (LREEs) in the preliminary crude separation, and the residual yttrium was precisely recovered by solvent extraction using di-(2-ehylhexyl) phosphoric acid (D2EHPA) as the extractant. Yttrium in the leaching solution of 0.7 g/L that remained at 0.2 g/L after the coprecipitation operation; however, it could be reduced to 0.001 – 0.002 g/L by the solvent extraction process in the following step. In this technical report, we focused on the solvent extraction operation. The extractant, D2EHPA, has a high affinity for yttrium, and we confirmed the possibility of improving the recovery yield of yttrium from 43% by coprecipitation alone to 98% by introducing solvent extraction.