Although solvent extraction has been used in the recovery of rare metals from urban mines, some challenges remain. For example, large amounts of organic solvent are required for Pd (II) separation owing to the slow extraction kinetics of dihexylsulfide (DHS). This lengthens the separation process and increases the evaporation loss of diluents. In our previous work, we found that Pd (II) quickly separates from a hydrochloric acid medium using triphenylphosphine as a phosphorus-based extractant. In this work, we investigate the extraction and backextraction behavior of Rh (III), Pd (II), and Pt (IV) in a hydrochloric acid medium using the combination of triphenylphosphine sulfide (TPPS) and ionic liquids (ILs). Results show that the extraction mechanism of Pd (II) is based on the cooperative extraction effect of TPPS and ILs. Additionally, it was confirmed that the third phase during Pd (II) extraction was inhibited using TPPS-ILs. Furthermore, this study investigated the separation behavior of Rh (III), Pd (II), and Pt (IV) from a hydrochloric acid medium using TPPS-ILs as an extractant and a multiple back-extractant.

Basella alba is an annual plant, which grows leaves that look like spinach. The leaves of Basella alba are edible, but effective methods of using fruits have not been reported yet. The fruits of Basella alba are vivid purple, and there is a possibility of being effective for products such as foods and cosmetics. To improve the appearance of products or to make use of the color sense derived from raw materials, pigments are also added and retained in the products. Various kinds of surfactants are added in food, cosmetics and daily toiletries for emulsifying oil and water. Many kinds of additives are also mixed in all products. All products are exposed to light in the sales process for the prolonged storage time at shops and homes. Furthermore, product users are also exposed to sunlight, and raw materials of the products would receive stimulus of the sunbeam. Such an environmental stimulus should be assessed in the product with pigment–surfactant mixed system. In this study, we investigated two types of discoloration in heating the natural pigment–surfactant mixed system by irradiation of artificial sunlight. In the experiments with artificial sunlight irradiation, under the condition that the surfactant concentration was higher than critical micelle concentration, the decolorization rate of Basella alba extract increased. Also, their decolorization rate was affected by dissolved oxygen.

In addition to hydrological characterization of water-sealed type underground rock caverns, their mechanical stability is constantly monitored by measuring several properties, such as earthquake-induced vibration, strain, and tilt. Among them, tilt measurement is the most accurate monitoring method for rock deformation because of the tiltmeter's high resolution of 10^-9 rad, which enables the detection of minute deformations caused by earth tide, rock responses to earthquake, change in atmospheric pressure, and artificial disturbance by operation. This study aimed to correctly extract these responses from long-term tilt data measured by a high precision tiltmeter at the Kushikino station and clarify the mechanism of tilt change as a result of deformation of rock mass. Tilt changes due to a small change in the gas phase pressure at the top of the rock cavern, approximately 10 kPa pressure fluctuation, were analyzed and discussed. The gradient response due to the gas pressure change was extracted from the measurement data by BAYTAP-G, and its magnitude was identified as 2 to 8 nrad, which was almost the same tilt response magnitude observed at an issuance of stored crude oil. This tilt response to the increase in tank gas pressure was numerically confirmed to originate from minute elastic deformation of rock masses, by using finite element method. Because fluctuation of the gas phase pressure can be continuously monitored, the effectiveness of tilt measurement was proved as a minute strain sensor for deformation of the water-sealed type underground rock cavern.