No abstract

No abstract

We demonstrated a complete decomposition method for ionic liquids (ILs; organic cation part: butylmethyl or ethyl-methyl imidazolium, and inorganic anion part: PF 6 -, BF 4 -or Br -) in aqueous media by combining a hydrothermal mineralization method with a photocatalytic decomposition (PD) method. As a result, the hydrothermal treatment with Ca(OH) 2 mineralizer could effectively remove the inorganic anion part, such as PF 6 -or BF 4 -and the PD could decompose the organic cation part effectively. Therefore, the detoxification of ILs in aqueous media was accomplished by the present method.

A new treatment method for wastewater containing concentrated fluoride and fluoroborate ions by hydrothermal treatment were developed. The treatment is an earth-mimetic method to produce natural minerals by hydrothermal treatment with Ca(OH)2 as a mineralizer. Results of various analyses of the precipitate indicated that the recovered minerals were Ca2B2O5·H2O (parasibirskite) and CaF2 (fluorite). By optimizing the conditions, it was possible to recover more than 98 percent of the boron and 99.9 percent of the fluorine from model wastewater samples containing fluoride (7000 mg L−1) and fluoroborate (8000 mg L−1) ions. Moreover, in the case of fluoroborate ions, the present treatment simultaneously caused the decomposition of the fluoroborate ion, the formation of each minerals, and the preventation of redissolution of parasibirskite. Therefore, the present hydrothermal mineralization treatment with the Ca(OH)2 mineralizer is an effective technique to recover boron and fluorine from wastewater.

No abstract

Separation and purification methods V 0200Resource Recovery from Nd-Fe-B Sintered Magnet by Hydrothermal Treatment. -More than 99% of the Nd content of a commercially available Ni-coated Nd2Fe14B sintered magnet is recovered in the form of Nd2(C2O4)3·xH2O by hydrothermal treatment of the magnet at 110°C for 6 h in an aqueous mixture of HCl and (COOH)2. The hydrothermal treatment is an effective technique to extract and recover Nd selectively from the sintered magnets. -(ITAKURA, T.; SASAI, R.; ITOH*, H.; J.

Detoxification of polluted water and resource recovery of boron and fluorine by using a sampling-type hydrothermal mineralization treatment apparatus was investigated. The hydrothermal mineralization treatment is a geomimetic treatment, which recovers natural minerals from aqueous media under hydrothermal conditions. As a result, hydrothermal mineralization treatment for aqueous solutions containing borate or fluoroborate ions, followed by separation of the reaction solution from precipitate, effectively reduced boron and fluorine concentration in solution, and parasibirskite (Ca2B2O5·H2O) and fluorite (CaF2) formed in high yields. Both the boron and fluorine concentration after the treatment for 2 h at 150 °C was 4 mg dm−3 regardless of its initial concentration (5–3000 mg dm−3) and the ionic species (B(OH)4− or BF4−). Therefore, the hydrothermal mineralization treatment by using a sampling-type apparatus should be an effective method to detoxify the wastewater and ground water containing these ions and recover these ions as reusable mineral.

, was less than 0.1 mg/dm 3 . On the other hand, the hydrothermal mineralization treatments with solid-liquid separation under hydrothermal conditions were required for the treatment of P III O3 3-and P I O2 3-, in order to accomplish the national effluent standard of Japan (16 mg/dm 3 ). In this case, the phosphorus concentration in the solution treated under the optimal conditions was 0.20 mg/dm 3 . Thus, the hydrothermal mineralization with Ca(OH)2 is recommended as one of the detoxification and recovery techniques of phosphorus in aqueous solution.