A method for preparing an anion adsorbent may be provided, which comprises the steps of: mixing at least two metal salts with each other, thereby forming a stack structure in which cationic compound layers and anionic compound layers containing anions and water of crystallization are alternately stacked on one another; performing a first heat treatment on the stack structure to expand between the cationic compound layers, thereby preparing a preliminary anion adsorbent; and performing a second heat treatment on the preliminary anion adsorbent to remove the anions and the water of crystallization from the anionic compound layers while allowing at least one of the anions to remain, thereby preparing the anion adsorbent.

The present disclosure provides a universal preparation method for in-situ growth of a layered double hydroxide (LDH) layer on a substrate surface, and belongs to the technical field of material synthesis. In the present disclosure, an LDH protective layer is grown in situ on a surface of a substrate by means of electrodeposition combined with hydrothermal treatment. Specifically, a seed crystal layer of the LDH is formed on the substrate surface by the electrodeposition, and then obtained LDH seed crystals are crystallized and grown by Ostwald ripening through the hydrothermal treatment. In this way, the LDH protective layer is formed in which an interlayer anion is a nitrate. The protective layer protects the substrate against corrosion. Moreover, since the interlayer anion is the nitrate, the protective layer can be exchanged with other corrosion-inhibiting anions, and is modifiable.

The present disclosure provides a universal preparation method for in-situ growth of a layered double hydroxide (LDH) layer on a substrate surface, and belongs to the technical field of material synthesis. In the present disclosure, an LDH protective layer is grown in situ on a surface of a substrate by means of electrodeposition combined with hydrothermal treatment. Specifically, a seed crystal layer of the LDH is formed on the substrate surface by the electrodeposition, and then obtained LDH seed crystals are crystallized and grown by Ostwald ripening through the hydrothermal treatment. In this way, the LDH protective layer is formed in which an interlayer anion is a nitrate. The protective layer protects the substrate against corrosion. Moreover, since the interlayer anion is the nitrate, the protective layer can be exchanged with other corrosion-inhibiting anions, and is modifiable.

The present disclosure relates to a method for producing lanthanide doped layered double hydroxides (Ln-doped LDHs). The method includes the steps of preparing a carbonate free alkaline solution; preparing a solution of metal salts comprising a salt of a lanthanide; co-precipitating the alkaline solution and the solution of metal salts to form a mixture and Ln-doped LDH precipitate wherein the pH of the mixture is maintained at a constant value; aging the precipitate; and separating the precipitate from the solution. The alkaline solution is an aqueous ammonia solution. The present disclosure is also related to lanthanide-doped layered double hydroxides (La-doped LDHs) obtainable by such a method, as well as to the use of the lanthanide-doped layered double hydroxides obtainable by such a method.

The present disclosure relates to a method for producing lanthanide doped layered double hydroxides (Ln-doped LDHs). The method includes the steps of preparing a carbonate free alkaline solution; preparing a solution of metal salts comprising a salt of a lanthanide; co-precipitating the alkaline solution and the solution of metal salts to form a mixture and Ln-doped LDH precipitate wherein the pH of the mixture is maintained at a constant value; aging the precipitate; and separating the precipitate from the solution. The alkaline solution is an aqueous ammonia solution. The present disclosure is also related to lanthanide-doped layered double hydroxides (La-doped LDHs) obtainable by such a method, as well as to the use of the lanthanide-doped layered double hydroxides obtainable by such a method.

Surface-modified layered double hydroxides (LDHs) are disclosed, as well as processes by which they are made, and uses of the LDHs in composite materials. The surface-modified LDHs of the invention are more organophilic than their unmodified analogues, which allows the LDHs to be incorporated in a wide variety of materials, wherein the interesting functionality of LDHs may be exploited.

The hydrotalcite-like compound according to an embodiment of the present invention is represented by the following general formula (I), wherein the hydrotalcite-like compound has, in an X-ray diffraction (XRD) pattern thereof obtained with Cu-K? radiation, two peaks assigned to (003) diffraction at a diffraction angle 2? in a range of from 100 or more to 14? or less, and wherein a ratio R.sub.XRD (S.sub.P2/S.sub.P1) of an area intensity of a second peak P2 having a peak top at a diffraction angle 2? in a range of from more than 12? to 14? or less to an area intensity of a first peak P1 having a peak top at a diffraction angle 2? in a range of from 10? or more to 12? or less is 0.7 or more and 50 or less:

##STR00001##

The hydrotalcite-like compound according to an embodiment of the present invention is represented by the following general formula (I), wherein the hydrotalcite-like compound has, in an X-ray diffraction (XRD) pattern thereof obtained with Cu-K? radiation, two peaks assigned to (003) diffraction at a diffraction angle 2? in a range of from 100 or more to 14? or less, and wherein a ratio R.sub.XRD (S.sub.P2/S.sub.P1) of an area intensity of a second peak P2 having a peak top at a diffraction angle 2? in a range of from more than 12? to 14? or less to an area intensity of a first peak P1 having a peak top at a diffraction angle 2? in a range of from 10? or more to 12? or less is 0.7 or more and 50 or less:

##STR00001##

Layered double hydroxides (LDHs) are disclosed, as well as methods by which they may be manufactured. The LDHs are subjected to a solvent treatment step during manufacture, which confers high surface area and pore volume properties to the LDHs. The particular solvents used in the preparation of the LDHs renders allows for an overall more efficient and environmentally-friendly manufacturing process.

Catalyst supports prepared from Ni.sup.2+-containing layered double hydroxides are disclosed. together with processes by which they are made and catalyst compositions comprising them. When used in the polymerisation of an olefin. the catalyst supports give control over the molecular weight distribution of the resulting polyolefin.