A method for transporting nitride (N.sup.3) ions in an electrochemical cell includes providing nitrogen to a first side of a solid electrolyte membrane to form nitride ions and transporting the nitride ions across the solid electrolyte membrane. The solid electrolyte membrane includes a metal nitride. The method may be used for ionically-mediated separation and/or compression of nitrogen or to form ammonia.

A method for transporting nitride (N.sup.3) ions in an electrochemical cell includes providing nitrogen to a first side of a solid electrolyte membrane to form nitride ions and transporting the nitride ions across the solid electrolyte membrane. The solid electrolyte membrane includes a metal nitride. The method may be used for ionically-mediated separation and/or compression of nitrogen or to form ammonia.

A method for removing a contaminant from a fluid is provided. A positively charged layered double hydroxide is combined with a negatively charged clay material to form adsorption material. The adsorption material is contacted with an aqueous solution containing the contaminant to adsorb the contaminant onto the adsorption material.

Chlorous acid is generated from a chlorite salt precursor, a chlorate salt precursor, or a combination of both by ion exchange. The ion exchange material facilitates the generation of chlorous acid by simultaneously removing unwanted cations from solution and adding hydrogen ion to solution. Chlorine dioxide is generated in a controlled manner from chlorous acid by catalysis. Chlorine dioxide can be generated either subsequent to the generation of chlorous acid or simultaneously with the generation of chlorous acid. For catalysis of chlorous acid to chlorine dioxide, the chlorous acid may be generated by ion exchange or in a conventional manner. Ion exchange materials are also used to purify the chlorous acid and chlorine dioxide solutions, without causing degradation of said solutions, to exchange undesirable ions in the chlorous acid and chlorine dioxide solutions with desirable ions, such as stabilizing ions, and to adjust the pH of chlorous acid and chlorine dioxide solutions.

Chlorous acid is generated from a chlorite salt precursor, a chlorate salt precursor, or a combination of both by ion exchange. The ion exchange material facilitates the generation of chlorous acid by simultaneously removing unwanted cations from solution and adding hydrogen ion to solution. Chlorine dioxide is generated in a controlled manner from chlorous acid by catalysis. Chlorine dioxide can be generated either subsequent to the generation of chlorous acid or simultaneously with the generation of chlorous acid. For catalysis of chlorous acid to chlorine dioxide, the chlorous acid may be generated by ion exchange or in a conventional manner. Ion exchange materials are also used to purify the chlorous acid and chlorine dioxide solutions, without causing degradation of said solutions, to exchange undesirable ions in the chlorous acid and chlorine dioxide solutions with desirable ions, such as stabilizing ions, and to adjust the pH of chlorous acid and chlorine dioxide solutions.

The invention relates to a method for exchanging interlayer anions of a layered double hydroxide (LDH) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions, which comprises the successive steps of: (1) exchanging the starting interlayer anions of a layered double hydroxide with polyoxometalate anions in order to obtain a layered double hydroxide with polyoxometalate anions as interlayer anions, and (2) exchanging the polyoxometalate anions of the layered double hydroxide obtained in step (1) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions in order to obtain a layered double hydroxide with other anions as interlayer anions.

The invention relates to a method for exchanging interlayer anions of a layered double hydroxide (LDH) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions, which comprises the successive steps of: (1) exchanging the starting interlayer anions of a layered double hydroxide with polyoxometalate anions in order to obtain a layered double hydroxide with polyoxometalate anions as interlayer anions, and (2) exchanging the polyoxometalate anions of the layered double hydroxide obtained in step (1) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions in order to obtain a layered double hydroxide with other anions as interlayer anions.

Provided is a porous molding which is capable of removing ions in water to be treated, in particular, phosphorus ions at a very high liquid-permeation rate of at least SV 120 hr.sup.1, and which has a large adsorption capacity. The porous molding according to the present invention comprises an organic polymer resin and an inorganic ion adsorbent, and is characterized in that a total volume of pores having a pore diameter of 1-80 nm as measured by a nitrogen adsorption method is 0.05-0.7 cm.sup.3/g per unit mass of the inorganic ion adsorbent.

Provided is a porous molding which is capable of removing ions in water to be treated, in particular, phosphorus ions at a very high liquid-permeation rate of at least SV 120 hr.sup.1, and which has a large adsorption capacity. The porous molding according to the present invention comprises an organic polymer resin and an inorganic ion adsorbent, and is characterized in that a total volume of pores having a pore diameter of 1-80 nm as measured by a nitrogen adsorption method is 0.05-0.7 cm.sup.3/g per unit mass of the inorganic ion adsorbent.

Provided is a porous molding which is capable of removing ions in water to be treated, in particular, phosphorus ions at a very high liquid-permeation rate of at least SV 120 hr.sup.1, and which has a large adsorption capacity. The porous molding according to the present invention comprises an organic polymer resin and an inorganic ion adsorbent, and is characterized in that a total volume of pores having a pore diameter of 1-80 nm as measured by a nitrogen adsorption method is 0.05-0.7 cm.sup.3/g per unit mass of the inorganic ion adsorbent.