An alumina-based adsorbent and method of making exhibiting high affinity and capacity towards cations and oxyanions in a broad pH range and presence of large excess of competitive ions. Alumina based adsorbent is a mixed oxide of alumina existing in tetra-, penta-, and octahedral coordination at specific ratio, and oxides of polyvalent metals of elements titanium, zirconium, tin, cerium, lanthanum, iron, or combinations thereof. The alumina-based adsorbent may be used for selective removal of oxyanions of fluoride, phosphorus, arsenic, chromium, and/or selenium, and/or cations of lead, mercury, cadmium, copper, and/or zinc, from drinking water, industrial streams and wastes, in medicine and food industry.

What is provided is a layered double hydroxide crystal for achieving higher ion-exchange capacity than that of the related art.

The layered double hydroxide crystal 1 according to the present embodiment is represented by Formula (1) and composed of a plurality of crystal grains 10 each of which has a lamination structure in which a plurality of plate-shaped crystals (11), (11), . . . are laminated, in which particle sizes of the plurality of crystal grains (10), (10), . . . are uniform on a microscale.

[Ni.sup.2+.sub.1-xFe.sup.3+.sub.x(OH).sub.2].[(Cl.sup.−).sub.X/2]  (1) (Where, 0.25<x≤0.9)

What is provided is a layered double hydroxide crystal for achieving higher ion-exchange capacity than that of the related art.

The layered double hydroxide crystal 1 according to the present embodiment is represented by Formula (1) and composed of a plurality of crystal grains 10 each of which has a lamination structure in which a plurality of plate-shaped crystals (11), (11), . . . are laminated, in which particle sizes of the plurality of crystal grains (10), (10), . . . are uniform on a microscale.

[Ni.sup.2+.sub.1-xFe.sup.3+.sub.x(OH).sub.2].[(Cl.sup.−).sub.X/2]  (1) (Where, 0.25<x≤0.9)

The amorphous inorganic anion exchanger of the present invention is represented by Formula (1) and has an average primary particle size observed with an electron microscope of at least 1 nm but no greater than 500 nm and an NO.sub.3 content of no greater than 1 wt % of the whole:
BiO(OH)  Formula (1).

The amorphous inorganic anion exchanger of the present invention is represented by Formula (1) and has an average primary particle size observed with an electron microscope of at least 1 nm but no greater than 500 nm and an NO.sub.3 content of no greater than 1 wt % of the whole:
BiO(OH)  Formula (1).

A composition, process and apparatuses for removal of one or more contaminant anions from water are provided. In an embodiment, the process includes treating the water with a composition comprising a layered metal hydroxy salt, wherein the layered metal hydroxy salt is a compound comprising (a) a metal (b) a framework hydroxide, and (c) a replaceable anion.

A composition, process and apparatuses for removal of one or more contaminant anions from water are provided. In an embodiment, the process includes treating the water with a composition comprising a layered metal hydroxy salt, wherein the layered metal hydroxy salt is a compound comprising (a) a metal (b) a framework hydroxide, and (c) a replaceable anion.

The present invention relates to a process for the preparation of Calcium Silicate Hydrate anion exchange membrane (cement paste) with an ionic conductivity of the order of 10.sup.−3 S/cm. The membrane can be formulated by mixing Ordinary Portland Cement (OPC) and water with the cement to water ratio of 1:0.45. After initial setting time, the membrane undergoes curing in 7% calcium chloride solution and the Cl.sup.− ions in the membrane is converted to OH.sup.− form by immersing into saturated Ca(OH).sub.2 solution with pH 14 and it has been washed to remove the excess alkali. This membrane has high mechanical strength (Ultimate Tensile Strength: 6.3 MPa) and does not deteriorate even at high temperature (up to 450° C.) and alkaline atmosphere (pH 11.5-14). Also disclosed is a method of producing in-situ formation of membrane electrode assembly. This invention encompasses a process for producing and using the membrane in water electrolysis and fuel cell.

The present invention relates to a process for the preparation of Calcium Silicate Hydrate anion exchange membrane (cement paste) with an ionic conductivity of the order of 10.sup.−3 S/cm. The membrane can be formulated by mixing Ordinary Portland Cement (OPC) and water with the cement to water ratio of 1:0.45. After initial setting time, the membrane undergoes curing in 7% calcium chloride solution and the Cl.sup.− ions in the membrane is converted to OH.sup.− form by immersing into saturated Ca(OH).sub.2 solution with pH 14 and it has been washed to remove the excess alkali. This membrane has high mechanical strength (Ultimate Tensile Strength: 6.3 MPa) and does not deteriorate even at high temperature (up to 450° C.) and alkaline atmosphere (pH 11.5-14). Also disclosed is a method of producing in-situ formation of membrane electrode assembly. This invention encompasses a process for producing and using the membrane in water electrolysis and fuel cell.

A hydrotalcite-like granular material having a grain size of 0.24 mm or larger is produced by drying a material that contains at least a hydrotalcite-like substance and that has a water content of 70% or lower at equal to or lower than a temperature at which the hydrotalcite-like substance is dehydrated of crystal water contained therein, preferably at 90° C. or higher and 110° C. or lower, such that the resulting hydrotalcite-like granular material has a water content of 10% or higher. In this manner, a hydrotalcite-like granular material that has a stable morphology and a high anion exchange performance and that can be produced at a low cost can be produced.