Hiroshi Okushita

Pervaporation of cyclohexane/cyclohexanone/cyclohexanol mixture through polyoxyethylene grafting nylon 6 membrane

Abstract The polyoxyethylene grafting nylon 6 membrane was effective for a selective separation of cyclohexanone and cyclohexanol from a cyclohexane/cyclohexanone/cyclohexanol mixture by pervaporation. In particular, the present membrane showed high permselectivity toward cyclohexanol over the cyclohexane feed fraction of 0.9. From the FTIR analyses, it was concluded that there was a hydrogen-bonding interaction between hydroxyl group in cyclohexanol and that in polyoxyethylene grafting chain.

Selective separation of Ga3+ through membrane impregnated with N-octadecanoyl-N-phenylhydroxylamine

Selective separation of Ga3+ was studied through a microporous polypropylene membrane impregnated with N-octadecanoyl-N-phenylhydroxylamine (ODPHA). The present membrane selectively concentrated Ga3+ from a Ga3+Al3+ mixture against the concentration gradient, with a counter flow of H+ as a driving force. The selective separation of Ga3+ was found to be attributed to the specific interaction between ODPHA and Ga3+. A microporous membrane impregnated with ODPHA concentrated Ga3+ selectively from a Ga3+Al3+ solution by acounter-current transport mechanism. For practical use, the selective separation of Ga3+ in the presence of a large amount of Al3+ was investigated. The separation of Ga3+ from the solution containing 50–300 fold more Al3+ was achieved, and the separation factor was evaluated to be above 300.

Membrane separation of Ga3+ by selective interaction of Ga3+ with N-octadecanoyl-N-phenylhydroxylamine

Abstract The specific interaction of N-octadecanoyl-N-phenylhydroxylamine (ODPHA) and Ga3+ was evaluated by the Langmuir-Blodgett method. The surface pressure-area isotherm for ODPHA on a Ga 3+ Al 3+ solution containing a 388 excess of Al3+ at pH 2.4 was similar to the isotherm for ODPHA on a pure Ga3+ solution at the same pH. A microporous polymeric membrane impregnated with ODPHA showed selective permeation of Ga3+ from a solution containing a 388 excess of Al3+ one Ga3+ at pH 2.4. The separation factor towards Ga3+ reached over 300.

Synthesis of polyoxyethylene grafting nylon 6 and the selective separation of cyclohexane/cyclohexanone/cyclohexanol mixture through its membranes

A polymer membrane having polyoxyethylene grafting nylon 6 was prepared by reacting of nylon 6 and ethylene oxide. The chemical compositions of the polyoxyethylene grafting nylon 6 were determined by 1H NMR. Degree of substitution for amide group, x, and degree of polymerization for polyoxyethylene, n, in bulk polymerization at 80°C for 4–9.5 h were evaluated: x = 0.32 ± 0.01–0.56 ± 0.02 and n = 2.8 ± 0.1–6.0 ± 0.3. The polyoxyethylene grafting nylon 6 membrane showed a selective separation of cyclohexanol from a cyclohexane/cyclohexanone/cyclohexanol mixture by a pervaporation technique. The FTIR and flux analyses verified that the selectivity for cyclohexanol was attributed to the hydrogen-bonding interaction between hydroxyl group in cyclohexanol and the hydroxyl group in polyoxyethylene grafting chain. The pervaporation and an adsorption experiment of cyclohexanol through the present membrane showed that hydroxyl group in graft chain acted as a carrier for cyclohexanol.

Separation of Ga3+ from a Ga3+-Al3+ solution using a long-chain alkylated cupferron membrane

A porous membrane impregnated with a long-chain alkylated cupferron [N-(alkylphenyl)-N-nitrosohydroxylamine ammonium salt] kerosene solution almost completely concentrated Ga3+ from a Ga3+–Al3+ binary solution against the concentration gradient, the counter flow of H+ providing the driving force.