Magnetic beads comprise a plurality of magnetic nanoparticles, dispersed in a non-magnetic matrix. The magnetic beads have an average particle size of 0.1 μm to 100 μm. The matrix may comprise an inorganic metal oxide or a polymer. The magnetic beads have a specific surface area of at least 40 m.sup.2/g.

Process for producing a haematite pigment having an a* value greater than 20, especially greater than 25, CIELAB units measured as a full shade in alkyd resin to DIN EN ISO 787-25:2007, by reacting iron sulfate with oxygen in the presence of a pigment seed, characterized in that a) water comprising i) at least one pigment seed selected from the group consisting of FeOOH and Fe.sub.2O.sub.3 and ii) iron sulfate forms an initial charge and b) at least one alkaline earth metal carbonate, especially CaCO.sub.3, MgCO.sub.3, CaMg(CO.sub.3).sub.2 or mixtures thereof and c) oxygen-containing gas
are added to the initial charge, where at least 95% by weight of the total amount of iron sulfate used in the process is present in the initial charge a) prior to addition of components b) and c).

Process for producing a haematite pigment having an a* value greater than 20, especially greater than 25, CIELAB units measured as a full shade in alkyd resin to DIN EN ISO 787-25:2007, by reacting iron sulfate with oxygen in the presence of a pigment seed, characterized in that a) water comprising i) at least one pigment seed selected from the group consisting of FeOOH and Fe.sub.2O.sub.3 and ii) iron sulfate forms an initial charge and b) at least one alkaline earth metal carbonate, especially CaCO.sub.3, MgCO.sub.3, CaMg(CO.sub.3).sub.2 or mixtures thereof and c) oxygen-containing gas
are added to the initial charge, where at least 95% by weight of the total amount of iron sulfate used in the process is present in the initial charge a) prior to addition of components b) and c).

A method for producing crystalline α-Fe2O3 nanoparticles involving ultrasonic treatment of a solution of an iron (III)-containing precursor and an extract from the seeds of a plant in the family Linaceae. The method involves preparing an aqueous extract from the seeds of a plant in the family Linaceae and dropwise addition of the extract to the solution of an iron (III)-containing precursor. The method yields crystalline nanoparticles of α-Fe.sub.2O.sub.3 having a spherical morphology with a diameter of 100 nm to 300 nm, a mean surface area of 240 to 250 m.sup.2/g, and a type-II nitrogen adsorption-desorption BET isotherm with a H3 hysteresis loop. A method for the photocatalytic decomposition of organic pollutants using the nanoparticles is disclosed. An antibacterial composition containing the crystalline α-Fe.sub.2O.sub.3 nanoparticles is also disclosed.

The present invention provides a method for preparing iron oxide magnetic particles and iron oxide magnetic particles prepared thereby, wherein the method includes (a) synthesizing a complex by reacting iron and one or more compounds selected from the group consisting of an aliphatic hydrocarbonate having 4 to 25 carbon atoms and an amine compound, (b) synthesizing an iron oxide crystal nucleus by mixing the complex with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, and (c) forming a shell by mixing the iron oxide crystal nucleus and an MXn compound with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, wherein M is a heavy atom element, X is a halogen element, and n is an integer of 1 to 6.

The present invention provides a method for preparing iron oxide magnetic particles and iron oxide magnetic particles prepared thereby, wherein the method includes (a) synthesizing a complex by reacting iron and one or more compounds selected from the group consisting of an aliphatic hydrocarbonate having 4 to 25 carbon atoms and an amine compound, (b) synthesizing an iron oxide crystal nucleus by mixing the complex with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, and (c) forming a shell by mixing the iron oxide crystal nucleus and an MXn compound with a mixture of an unsaturated aliphatic hydrocarbon-based compound having 4 to 25 carbon atoms and an ether-based compound, wherein M is a heavy atom element, X is a halogen element, and n is an integer of 1 to 6.

Embodiments of the present disclosure are directed to hydrogen-selective oxygen carrier materials and methods of using hydrogen-selective oxygen carrier materials. The hydrogen-selective oxygen carrier material may comprise a core material, which includes a redox-active transition metal oxide; a shell material, which includes one or more alkali transition metal oxides; and a support material. The shell material may be in direct contact with at least a majority of an outer surface of the core material. At least a portion of the core material may be in direct contact with the support material. The hydrogen-selective oxygen carrier material may be selective to combust hydrogen in an environment that includes hydrogen and hydrocarbons.

Embodiments of the present disclosure are directed to hydrogen-selective oxygen carrier materials and methods of using hydrogen-selective oxygen carrier materials. The hydrogen-selective oxygen carrier material may comprise a core material, which includes a redox-active transition metal oxide; a shell material, which includes one or more alkali transition metal oxides; and a support material. The shell material may be in direct contact with at least a majority of an outer surface of the core material. At least a portion of the core material may be in direct contact with the support material. The hydrogen-selective oxygen carrier material may be selective to combust hydrogen in an environment that includes hydrogen and hydrocarbons.

The present invention provides iron oxide magnetic particles including an iron oxide and MX.sub.n, wherein M includes one or more selected from the group consisting of Cu, Sn, Pb, Mn, Ir, Pt, Rh, Re, Ag, Au, Pd, and Os, X includes one or more selected from the group consisting of F, Cl, Br, and I, and n is an integer of 1 to 6.

The present invention relates to an improved process for producing iron oxide red pigments by the Penniman process using nitrate (also referred to as nitrate process or direct red process) and apparatuses for carrying out the process.