Abstract: Tritium is isolated and recovered from tritium-containing water by a membrane electrode including a manganese oxide having a spinel crystal structure and containing hydrogen ions or lithium ions and having one surface coated with a membrane of an ion conductive material.

Abstract: To provide an absorbing material to separate tritium from heavy water. By using a deuterium ion- or hydrogen ion-containing manganese oxide having a spinel-type crystal structure as a tritium absorbing material collecting tritium from heavy water containing tritium, tritium can be separated and recovered inexpensively from the heavy water.

Abstract: Tritium is isolated and recovered from tritium-containing water by a membrane electrode including a manganese oxide having a spinel crystal structure and containing hydrogen ions or lithium ions and having one surface coated with a membrane of an ion conductive material.

Abstract: A method of using hydrogen- or lithium-containing manganese oxide having a spinel crystal structure as a tritium adsorbent to trap tritium from tritium-containing water makes it possible to inexpensively separate tritium from water.

Abstract: By means of a series of wet multistage oxidation process comprising: Step 1 for adding an alkaline reagent to an aqueous solution of a manganese compound containing a divalent manganese thereby precipitating a manganese hydroxide; Step 2 for adding an aqueous hydrogen peroxide while keeping the temperature of the water of the aqueous solution comprising the manganese hydroxide at room temperature thereby converting into a manganese oxide; and also Step 3 for adding a dilute acid to the manganese oxide in a state where the water is coexisting, a nanometer-sized manganese dioxide having a ramsdellite-type crystal structure is obtained.

Abstract: Provided is a tritium adsorbent. Use of hydrogen- or lithium-containing manganese oxide having a spinel crystal structure as a tritium adsorbent to trap tritium from tritium-containing water makes it possible to inexpensively separate tritium from water.

Abstract: A method for synthesizing a catalyst which reforms a methane gas into a hydrogen gas efficiently at a relatively low temperature comprising a palladium deposition step in which a manganese dioxide having a ramsdellite-type crystal structure is immersed in a palladium-containing aqueous solution to allow the palladium to be deposited on the surface of said manganese dioxide, and a heat treatment step in which said manganese dioxide having the palladium deposited thereon is heated under a reducing atmosphere to change said manganese dioxide to a manganese oxide Mn3O4 having the palladium carried thereon.

Abstract: A method for synthesizing a catalyst which reforms a methane gas into a hydrogen gas efficiently at a relatively low temperature comprising a palladium deposition step in which a manganese dioxide having a ramsdellite-type crystal structure is immersed in a palladium-containing aqueous solution to allow the palladium to be deposited on the surface of said manganese dioxide, and a heat treatment step in which said manganese dioxide having the palladium deposited thereon is heated under a reducing atmosphere to change said manganese dioxide to a manganese oxide Mn3O4 having the palladium carried thereon.

Abstract: Provided is a catalyst material comprising aggregates of nanoneedles of mainly R-type manganese dioxide and having a mesoporous structure. With this, water can be oxidatively decomposed under visible light at room temperature to produce oxygen gas, proton and electron. Also provided is a catalyst material comprising aggregates of nanoparticles of mainly hydrogenated manganese dioxide. With this, acetic acid or an inorganic substance can be synthesized from carbon dioxide gas.

Abstract: By means of a series of wet multistage oxidation process comprising: Step 1 for adding an alkaline reagent to an aqueous solution of a manganese compound containing a divalent manganese thereby precipitating a manganese hydroxide; Step 2 for adding an aqueous hydrogen peroxide while keeping the temperature of the water of the aqueous solution comprising the manganese hydroxide at room temperature thereby converting into a manganese oxide; and also Step 3 for adding a dilute acid to the manganese oxide in a state where the water is coexisting, a nanometer-sized manganese dioxide having a ramsdellite-type crystal structure is obtained.

Abstract: Provided is a catalyst material comprising aggregates of nanoneedles of mainly R-type manganese dioxide and having a mesoporous structure. With this, water can be oxidatively decomposed under visible light at room temperature to produce oxygen gas, proton and electron. Also provided is a catalyst material comprising aggregates of nanoparticles of mainly hydrogenated manganese dioxide. With this, acetic acid or an inorganic substance can be synthesized from carbon dioxide gas.

Abstract: By controlling the heating speed and the pressure in carbonizing a wood powder, a macroporous carbon material is formed. Herein provided are the macroporous carbon material starting from a wood material, and a method for producing it.

Abstract: A novel technique that is able to efficiently remove, in addition to pentavalent arsenic, trivalent arsenic that has been considered to be difficult to remove. By using a manganese oxygen compound which is characterized by being a product of burning or heating which comprises an oxygen compound of bismuth and an oxygen compound of manganese and by containing manganese as a major component, an aqueous arsenic solution is treated to adsorptively remove the arsenic.

Abstract: A novel technique by which not only pentavalent arsenic but trivalent arsenic, which has been difficult to remove, can be efficiently removed. The manganese/oxygen compound which adsorbs arsenic is characterized by being a product of burning or heating which comprises an oxygen compound of bismuth and an oxygen compound of manganese and by containing manganese as a major component. It is used to treat an aqueous arsenic solution to thereby adsorptively remove the arsenic.