Fundamental Study on Multistage Extraction Using TDdDGA for Separation of Lanthanides Present in Nd Magnets

The separation of Dy from Nd has been studied from the viewpoint of recycling Dy from Nd magnets. N,N,N′,N′-tetradodecyl-DGA (TDdDGA) has a relatively high separation factor between Dy and Nd (above 10) in HNO3 medium. After basic research on batchwise multistage extractions using eight extraction stages with 0.1 M TDdDGA in n-dodecane as organic phase, ten stages with an aqueous phase (0.7 M HNO3 with metals), and six stages with another aqueous phase (0.7 M HNO3 without metals), approximately 99% of Dy was recovered into the organic phase with 1% coextraction of Nd.

High-performance ammonia-selective MFI nanosheet membranes

MFI zeolite nanosheet membranes exhibit high separation factor and flux for the separation of ammonia over hydrogen and nitrogen and hold promise for industrial use. These membranes also exhibit high performance for hydrogen separation from hydrocarbons.

Simultaneous separation of Am and Cm from Nd and Sm by multi-step extraction using the TODGA-DTPA-BA-HNO3 system

The simultaneous separation of Am and Cm from lanthanides is important for atomic energy fields. However, the process is difficult owing to the chemical behavior of trivalent metal ions with similar ionic radii. All lanthanides, Am, and Cm can be extracted by diglycolamide (DGA). In addition, relatively high separation factors between An and Ln were obtained by the extraction system of TODGA, DTPA (diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid) and HNO3. In this work, DTPA-BA (diethylenetriamine-N,N′,N″-triacetic-N,N″-bisamide), which is an improved version of DTPA, was employed for the separation of Ln and An. After performing a basic study on DTPA-BA, a relatively high separation factor (approximately 8) for actinides/lanthanides was obtained. Then, the multi-step extraction was performed. Thus, the recoveries of 94.7 % for Nd and 4.7 % for Am and Cm in organic phase, and 5.3 % Nd and 95.3 % for Am and Cm in aqueous phase were obtained.

VTOS Cross-Linked PDMS Membranes for Recovery of Ethanol from Aqueous Solution by Pervaporation

PDMS membranes were prepared by cross-linking with vinyltriethoxysilane (VTOS) on polyacrylonitrile (PAN) substrate to increase hydrophobicity and improve pervaporation (PV) performance. It was shown that the membranes had high ethanol permselectivity and flux. The effects of cross-linking temperature, the content of cross-linking agent, and feed temperature on PV performance of VTOS cross-linked PDMS membranes were investigated. For 6 wt% ethanol aqueous solution, the PDMS membrane had the high separation factor of 15.5 and total flux 573.3 g·m−2·h−1, respectively, when the feed temperature was 40°C, H-PDMS : VTOS : DBTDL = 1 : 0.2 : 0.02 and cross-linking temperature was 80°C.

Adsorption Studies of Arsenic on Manganese Dioxide Using Radiometric Techniques

Manganese dioxide has been tested as an adsorbent for the removal of arsenic using radiometric techniques. Optimum conditions for maximum adsorption in terms of equilibrium time, nature and composition of electrolytes, shaking time, effect of foreign ions and other metal ions have been investigated. On the basis of these data, high separation factor values were obtained in the case of CoII, HfIV and TeIV. The adsorption data were also found to obey the Freundlich equation, the mean sorption energy of As on MnO2 being 15.5 kJ/mol.