Mitsubishi Gas Chemical Company, Inc.

Dia Aqua Solutions Co., Inc.

Shoichiro Kajiwara

Takamitsu Tsuruga

Hirokazu Serizawa

Ken-ichi Kimizuka

Kazunori Nagai

Ryozo Kawai

Akira Naito

Hiroshi Takamiya

Hiroshi Kurata

Naoki Kogure

Kenichi Kimizuka

Koji Hirukawa

Sunao Ikuta

Hitoshi Yamaguchi

Yukari Shimizu

Kimihisa Iwashiro

Toru Hayakawa

Masakatsu Nakanishi

There is provided a method for highly treating distillation waste generated in the process of separating a distilled alcoholic material after alcoholic fermentation of starchy materials. The method includes the steps of adding sodium polyacrylate to the distillation waste from the starchy materials, then adding chitosan to treat the distillation waste, and further adding sodium polyacrylate to the waste. Furthermore, solid-liquid separation is then carried out. A liquid material thus separated is brought into contact with a reverse osmosis membrane.

Method for treatment of distillation waste from starchy materials

An electrolytic production of sodium persulfate in a decreased number of steps with low unit power cost is described. Sodium persulfate is caused to crystallize by the reaction between an anode product and sodium hydroxide. The resulting sodium persulfate slurry is separated into a mother liquor and sodium persulfate crystals which are recovered and dried to obtain product sodium persulfate. In the process of the invention, ammonia liberated in the reaction-type crystallization of sodium persulfate is recovered into a cathode product, which is then neutralized by sodium hydroxide and/or ammonia. The neutralized solution is combined with sodium sulfate recovered from the mother liquor after recovering the sodium persulfate crystals and reused as a part of the starting material for an anolyte feed solution.

Process for producing sodium persulfate

There are disclosed (1) a process for producing ammonium persulfate which comprises electrolyzing, as the starting raw material for an anode, an aqueous solution containing ammonium sulfate wherein ammonium ions are present in an amount of at least one equivalent based on sulfate ions; (2) a process for producing sodium persulfate which comprises the step (A) of electrolyzing an aqueous solution containing ammonium sulfate at an anode, the step (B) of producing sodium persulfate, the step (C) of crystallizing and separating the sodium persulfate and the step (D) of recycling the liquid produced at a cathode together with ammonia for use as the starting raw material for an anode in the step (A); and (3) a process for producing potassium persulfate which comprises the step (A&prime;) of electrolyzing an aqueous solution containing ammonium sulfate at an anode; and the step (B&prime;) of producing potassium persulfate. The above processes are capable of effectively producing respective persulfates in an industrially advantageous manner.

Process for producing persulfate

There is disclosed a process for producing sodium persulfate which comprises the step (1) of electrolyzing, at an anode, a solution containing ammonium sulfate, and the step (2) of producing sodium persulfate from the resultant liquid produced at the anode and sodium hydroxide and, as desired, the step of removing sodium sulfate, and further as desired, the step (3) of performing crystallization on the reaction liquid as produced in the step (2). According to the above process, it is made possible to efficiently produce sodium persulfate having a markedly high purity substantially free from nitrogen components at a high yield at a high current efficiency in electrolysis.

There is herein disclosed a method for preparing high-purity aqueous hydrogen peroxide by bringing aqueous hydrogen peroxide into contact with a strongly basic anion exchange resin, said method comprising the step of using the strongly basic anion exchange resin which is converted into a form of an exchange group at the time of the purification of aqueous hydrogen peroxide by bringing the strongly basic anion exchange resin into contact with a liquid agent passed through a filter having an average pore diameter of 1.0 .mu.m or less. According to the present invention, aqueous hydrogen peroxide containing inorganic impurities such as metals and metallic compounds can be purified to prepare extremely high-purity aqueous hydrogen peroxide.

Method for preparing high-purity aqueous hydrogen peroxide

A process for purifying an aqueous solution of hydrogen peroxide comprising bringing the aqueous solution of hydrogen peroxide into contact with a cation exchange resin or an anion exchange resin, aging the obtained intermediately purified aqueous solution of hydrogen peroxide by standing alone for 1 hour or more, and bringing the aged aqueous solution of hydrogen peroxide into contact with an ion exchange resin of the same type. The process provides a high purity aqueous solution of hydrogen peroxide and can advantageously be used in the field of production of semiconductors.

Process for purifying an aqueous solution of hydrogen peroxide

A water-soluble polymer prepared by melting and reacting a mixture of an oxycarboxylic acid having a melting point of 170.degree. C. or less and maleamic acid, or a mixture of a plurality of oxycarboxylic acids including at least one oxycarboxylic acid having a melting point of 170.degree. C. or less and maleamic acid, at a temperature of 170.degree. C. or less at the start of the reaction to obtain a polymer; and then hydrolyzing the polymer.

Biodegradable water-soluble polymer

An efficient method is proposed for the preparation of a highly purified aqueous hydrogen peroxide solution, which can be used even in a semiconductor process, from a crude aqueous solution containing metallic and inorganic impurities. The method comprises the steps of: (a) acidifying the crude solution by the addition of a specific amount of an acid such as sulfuric and nitric acids; and (b) passing the acidified crude solution through a column filled with a strongly acidic cation-exchange resin in the hydrogen-form or a mixture of the same with a strongly basic anion-exchange resin in the hydroxy-, carbonate- or hydrogencarbonate-form in a specified volume proportion so that the impurities are removed by ion-exchange. The efficiency of this purification treatment can be further enhanced by keeping the acidified crude solution for a certain length of time of, for example, at least 6 hours prior to the ion-exchange treatment in step (b).

Method for the preparation of purified aqueous hydrogen peroxide solution

A process for preventing growth of marine animals, i.e. shellfish, Polyzoa, and Hydrozoa on a surface, characterized by supplying hydrogen peroxide and/or a hydrogen peroxide-generating agent into sea water in contact with the surface is disclosed. Surfaces of apparatus and/or pipe constituting flow paths for sea water and plant utilizing sea water are kept clean by the process.

Growing community of inventors

Katsushika-ku, Japan

Shoichiro Kajiwara