Dissolved silica is ubiquitous in impaired waters, a fouling agent in desalination membranes, resistant to existing antiscalants, and difficult to remove from power plant feed waters, thereby inhibiting long term reuse of industrial water. According to the present invention, an inorganic anion exchanger, hydrotalcite (HTC), can provide highly selective removal of silica from aqueous solutions. Calcined HTC effectively removes silicate anion from different waste waters and waters with high concentration of competing ions, such as SO.sub.4.sup.2 and Cl.sup.. For example, calcined Mg.sub.6Al.sub.2(OH).sub.16(CO.sub.3).4H.sub.2O has a silica adsorption capacity of 45 mg SiO.sub.2/g HTC. Further, HTC can be easily regenerated and recycled.

Dissolved silica is ubiquitous in impaired waters, a fouling agent in desalination membranes, resistant to existing antiscalants, and difficult to remove from power plant feed waters, thereby inhibiting long term reuse of industrial water. According to the present invention, an inorganic anion exchanger, hydrotalcite (HTC), can provide highly selective removal of silica from aqueous solutions. Calcined HTC effectively removes silicate anion from different waste waters and waters with high concentration of competing ions, such as SO.sub.4.sup.2 and Cl.sup.. For example, calcined Mg.sub.6Al.sub.2(OH).sub.16(CO.sub.3).4H.sub.2O has a silica adsorption capacity of 45 mg SiO.sub.2/g HTC. Further, HTC can be easily regenerated and recycled.

Semiconductor-oxide nanotubes-based composite particles are useful for dye-removal. A method involves an ion-exchange mechanism operating under a dark-condition in an aqueous solution, for the processing of products consisting of the nanotubes of semiconductor-oxides deposited on, anchored to or attached to the surface of fly ash particles and metal-oxide (magnetic and non-magnetic) nanoparticles. The resulting micro-nano and nano-nano integrated composite particles can be used in the removal of an organic synthetic-dye from an aqueous solution and industry effluent via a surface-adsorption process, involving ion-exchange and electrostatic-attraction mechanisms. The composite particles can be recycled for the next cycle of dye-adsorption by decomposing the previously adsorbed dye on their surfaces via the use of either noble-metal-deposited or magnetically separable magnetic photocatalysts and exposure to ultraviolet (UV) or solar-radiation.

Semiconductor-oxide nanotubes-based composite particles are useful for dye-removal. A method involves an ion-exchange mechanism operating under a dark-condition in an aqueous solution, for the processing of products consisting of the nanotubes of semiconductor-oxides deposited on, anchored to or attached to the surface of fly ash particles and metal-oxide (magnetic and non-magnetic) nanoparticles. The resulting micro-nano and nano-nano integrated composite particles can be used in the removal of an organic synthetic-dye from an aqueous solution and industry effluent via a surface-adsorption process, involving ion-exchange and electrostatic-attraction mechanisms. The composite particles can be recycled for the next cycle of dye-adsorption by decomposing the previously adsorbed dye on their surfaces via the use of either noble-metal-deposited or magnetically separable magnetic photocatalysts and exposure to ultraviolet (UV) or solar-radiation.

A high capacity hybrid ion exchange material with enhanced ability to selectively remove molecular (organics) and anionic (fluoride ion and oxyanions of phosphorus and arsenic) species from drinking water, industrial streams, and wastes, for applications predominantly in the medical and food industries, and a method for preparing the same.

A high capacity hybrid ion exchange material with enhanced ability to selectively remove molecular (organics) and anionic (fluoride ion and oxyanions of phosphorus and arsenic) species from drinking water, industrial streams, and wastes, for applications predominantly in the medical and food industries, and a method for preparing the same.

Sorbent cartridge systems useful in regenerating or purifying dialysis solutions are described as well as methods to regenerate or purify spent dialysis solutions. Dialysis systems using the sorbent cartridge system of the present invention are further described.

Sorbent cartridge systems useful in regenerating or purifying dialysis solutions are described as well as methods to regenerate or purify spent dialysis solutions. Dialysis systems using the sorbent cartridge system of the present invention are further described.

An alumina-based adsorbent and method of making exhibiting high affinity and capacity towards fluoride ions and oxyanions of phosphorus and arsenic 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 fluoride ion and oxyanions of phosphorus and arsenic from drinking water, industrial streams and wastes, in medicine and food industry.

An alumina-based adsorbent and method of making exhibiting high affinity and capacity towards fluoride ions and oxyanions of phosphorus and arsenic 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 fluoride ion and oxyanions of phosphorus and arsenic from drinking water, industrial streams and wastes, in medicine and food industry.