Tokuyama Soda Kabushiki Kaisha

Katokichi Co., Ltd.

Koichi Doi

Yasuhiro Kagiyama

Toru Nonaka

Fumito Kishimoto

Takashi Tsugita

Shigeo Komatsubara

Shinya Takeuchi

Yuji Ishiyama

Disclosed is a membrane for the separation of a water-alcohol mixed liquid by the pervaporation method, which is composed of a chitosan having a molecular weight of 80,000 to 150,000 and a deacetylation degree adjusted to 80 to 95%. This separating membrane has an excellent selective permeability to water in the separation of a water-alcohol mixed liquid, and the mechanical strength of this separating membrane is very high. This separating membrane can be prepared by a process comprising dissolving a chitosan having a molecular weight of 80,000 to 150,000 and a deacetylation degree adjusted to 80 to 95% in an acidic aqueous solution to form a dope having a chitosan concentration of 9 to 12% by weight, shaping the dope into a membrane and immersing the membrane in an alkaline solution.

Membrane for separation of water-alcohol mixed liquid and process for

Disclosed is a process for washing a semiconductor substrate with an organic solvent, which comprises the first stage of supplying an organic solvent to be used for the organic solvent washing of a semiconductor substrate to a washing device and washing the semiconductor substrate, the second stage of supplying the organic solvent containing water, electrolytes and particulate or clustery suspended substances, which has been withdrawn from the first stage, to a pervaporation device and separating and removing mainly water, and the third stage of supplying the organic solvent withdrawn from the second stage to a distillation device to obtain the organic solvent as a distillate and recycling the distillate as the organic solvent to the first stage, the three stages being combined to form a continuous circulation systems.

Process for washing semiconductor substrate with organic solvent

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Tokyo, Japan

Koichi Doi