Solid nanocomposite material comprising nanoparticles of a hexacyanometallate or octacyanometallate of an alkali metal and of a transition metal, of formula [Alk.sup.+.sub.x]M.sup.n+[M′(CN).sub.m].sup.z− in which Alk is an alkali metal, x is 1 or 2, M is a transition metal, n is 2 or 3, M′ is a transition metal, m is 6 or 8, z is 3 or 4, attached to at least one surface of a porous inorganic solid support, in which the nanoparticles are attached by adsorption to the at least one surface of the solid support, and in which the surface is a basic surface. Method for preparing this material. Method for extracting at least one metal cation from a liquid medium containing it, wherein the liquid medium is brought into contact with the material.

A method is provided for synthesizing metal cyanometallate (MCM). The method provides a solution of A.sub.XM1.sub.Y(CN).sub.Z; where “A” is selected from a first group of metals and M1 is selected from a second group of metals. The method adds a material including M2 to the solution to form a liquid phase material that may be either a suspension or a solution. M2 is selected from the second group of metals. The method adds acid to the liquid phase material. The addition of acid to the liquid phase material decomposes the M2 material into M2-ions. Simultaneous with the addition of the acid, a precipitate of A.sub.NM1.sub.PM2.sub.Q(CN).sub.R.FH.sub.2O is formed, where N is in a range of 1 to 2. A variation of the above-described synthesis method is also provided.

A method is provided for synthesizing metal cyanometallate (MCM). The method provides a solution of A.sub.XM1.sub.Y(CN).sub.Z; where “A” is selected from a first group of metals and M1 is selected from a second group of metals. The method adds a material including M2 to the solution to form a liquid phase material that may be either a suspension or a solution. M2 is selected from the second group of metals. The method adds acid to the liquid phase material. The addition of acid to the liquid phase material decomposes the M2 material into M2-ions. Simultaneous with the addition of the acid, a precipitate of A.sub.NM1.sub.PM2.sub.Q(CN).sub.R.FH.sub.2O is formed, where N is in a range of 1 to 2. A variation of the above-described synthesis method is also provided.

An ammonia chemical species desorption process desorbs ammonia chemical species adsorbed onto a Prussian blue derivative more simply at lower cost under milder conditions as compared with using an aqueous solution of a salt or strong acid, and only water. This ammonia chemical species desorption process includes an ammonia chemical desorption step of bringing carbon dioxide and water into contact with a Prussian blue derivative represented by the following general formula (1), thereby desorbing an ammonia chemical species.

A.sub.xM[M′(CN).sub.6].sub.y.zH.sub.2O  (1)

where x is 0 to 3, y is 0.1 to 1.5, z is 0 to 6, A is at least one cation of hydrogen, ammonium, an alkaline metal, and an alkaline earth metal, and M and M′ are each independently at least one cation of at least one of atoms having atomic numbers 3 to 83 except for ammonium, an alkali metal, and an alkaline earth metal.

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition according to Formula III—An electrochemical cell including a system having an anode, a cathode, and an electrolyte wherein the anode includes a material, including the material including at least one composition represented by Formula III: A.sub.xMn.sub.y[Mn(CN).sub.(6)].sub.z(Vac).sub.(1-z).n(H.sub.2O)m(Che) wherein, in Formula III, A includes one or more alkali metals including Na; and wherein 0<j≤4, 0≤k≤0.1, 1.2<x≤4, 0<y≤1, 0.8<z≤1, 0<n≤4; 0≤m≤0.2 and wherein x+2y−4z=0.

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition according to Formula III—An electrochemical cell including a system having an anode, a cathode, and an electrolyte wherein the anode includes a material, including the material including at least one composition represented by Formula III: A.sub.xMn.sub.y[Mn(CN).sub.(6)].sub.z(Vac).sub.(1-z).n(H.sub.2O)m(Che) wherein, in Formula III, A includes one or more alkali metals including Na; and wherein 0<j≤4, 0≤k≤0.1, 1.2<x≤4, 0<y≤1, 0.8<z≤1, 0<n≤4; 0≤m≤0.2 and wherein x+2y−4z=0.

Embodiments of the present invention provide for syntheses and uses of tri-substituted mono-hydrogen ferrocyanides for efficient hydroxyl radical generators. For example, the present invention provides for the syntheses of mono-hydrogen ferrocyanides of the general formula M.sub.3HFe(CN).sub.6 in which iron has an oxidation number of +2 (ferro) and the positive counter-ion, M, belongs mainly to the group of the alkali metals such as Na+, K+ and Li+, or to organic alkyl cations such as imidazole derivatives.

Embodiments of the present invention provide for syntheses and uses of tri-substituted mono-hydrogen ferrocyanides for efficient hydroxyl radical generators. For example, the present invention provides for the syntheses of mono-hydrogen ferrocyanides of the general formula M.sub.3HFe(CN).sub.6 in which iron has an oxidation number of +2 (ferro) and the positive counter-ion, M, belongs mainly to the group of the alkali metals such as Na+, K+ and Li+, or to organic alkyl cations such as imidazole derivatives.

Stable solutions comprising high concentrations of charged coordination complexes, including iron hexacyanides are described, as are methods of preparing and using same in chemical energy storage systems, including flow battery systems. The use of these compositions allows energy storage densities at levels unavailable by other iron hexacyanide systems.

A method to extend a shelf life of a sodium nitroprusside solution includes: dissolving about two parts by weight of a 2-hydroxybenzyl alcohol and about one part by weight of a sodium nitroprusside in about seventy-five parts by weight of a polyethylene glycol. Compositions for preserving a sodium nitroprusside solution are also described.