The present invention relates to Mn-activated luminescent materials, to a process for preparation thereof and to the use thereof as luminophores or conversion luminophores in light sources. The present invention further relates to a radiation-converting mixture comprising the luminescent material of the invention and a light source comprising the luminescent material of the invention or the radiation-converting mixture. The present invention further provides light sources, especially LEDs, and lighting units comprising a primary light source and the luminescent material of the invention or the radiation-converting mixture. The Mn-activated luminescent materials of the invention are especially suitable for creation of warm white light in LEDs.

Separation of rhenium disulfide nanomaterials and related fluid density gradient media.

Separation of rhenium disulfide nanomaterials and related fluid density gradient media.

The present invention relates to a process for the production of ammonium perrhenate (APR), which includes the use of Ca(OH)2 and to ammonium perrhenate which can be obtained by the method according to the invention.

The present invention relates to a process for the production of ammonium perrhenate (APR), which includes the use of Ca(OH)2 and to ammonium perrhenate which can be obtained by the method according to the invention.

A method is provided which can separate rhenium from a solution containing rhenium by a simple procedure in a shorter time. A method of selectively recovering rhenium from a solution containing rhenium and one or more different metals is also provided. A method of recovering rhenium is used. The method involves (A) adding an electron donor (aliphatic secondary alcohol or aliphatic secondary thioalcohol) and a ketone compound to a solution containing perrhenate ions, (B) irradiating the solution after the addition step with ultraviolet light to precipitate a reduced species of the perrhenate ions contained in the solution, and (C) separating the reduced species of perrhenate ions from the solution, the reduced species being precipitated during the ultraviolet light irradiation.

A method is provided which can separate rhenium from a solution containing rhenium by a simple procedure in a shorter time. A method of selectively recovering rhenium from a solution containing rhenium and one or more different metals is also provided. A method of recovering rhenium is used. The method involves (A) adding an electron donor (aliphatic secondary alcohol or aliphatic secondary thioalcohol) and a ketone compound to a solution containing perrhenate ions, (B) irradiating the solution after the addition step with ultraviolet light to precipitate a reduced species of the perrhenate ions contained in the solution, and (C) separating the reduced species of perrhenate ions from the solution, the reduced species being precipitated during the ultraviolet light irradiation.

A technique for exfoliating a transition metal dichalcogenide material to produce separated nano-scale platelets includes combining the transition metal dichalcogenide material with a liquid to form a slurry, wherein the transition metal dichalcogenide material includes layers of nano-scale platelets and has a general chemical formula MX.sub.2, and wherein M is a transition metal and X is sulfur, selenium, or tellurium. The slurry of the transition metal dichalcogenide material is treated with an oxidant to form peroxo-metalate intermediates on an edge region of the layers of nano-scale platelets of the transition metal dichalcogenide material. The peroxo-metalate intermediates is treated with a reducing agent to form negatively charged poly-oxo-metalates to induce separation of the transition metal dichalcogenide material into the separated nano-scale platelets of the transition metal dichalcogenide material.

A technique for exfoliating a transition metal dichalcogenide material to produce separated nano-scale platelets includes combining the transition metal dichalcogenide material with a liquid to form a slurry, wherein the transition metal dichalcogenide material includes layers of nano-scale platelets and has a general chemical formula MX.sub.2, and wherein M is a transition metal and X is sulfur, selenium, or tellurium. The slurry of the transition metal dichalcogenide material is treated with an oxidant to form peroxo-metalate intermediates on an edge region of the layers of nano-scale platelets of the transition metal dichalcogenide material. The peroxo-metalate intermediates is treated with a reducing agent to form negatively charged poly-oxo-metalates to induce separation of the transition metal dichalcogenide material into the separated nano-scale platelets of the transition metal dichalcogenide material.

The present invention provides techniques that selectively recover Re from reductive amination catalysts. In particular, the present invention allows Re to be recovered selectively relative to Ni, Co, and/or Cu, and particularly Ni, that are often present on reductive amination catalysts. The present invention uses a combination of oxidation and extraction techniques to selectively recover Re relative to Ni, Co, and/or Cu. Advantageously, the recovery is selective even when using aqueous solutions for extraction.