Catalyst materials comprising iron and palladium are described. Also described are methods for preparing such materials. In addition, methods for remediating materials such as sediments and groundwater using the catalyst materials are described.

A cost-effective system and method dissolves gas, such as oxygen, into water in a manner that prevents gas bubble carry over by using a bubble capture system (BCS). The system and method further eliminates or minimizes turbulence at the suction and discharge of a pump using an energy dissipation header (EDH). The BCS can create a top-down flow that permits bubbles to rise faster than the velocity of the downward flow of water. The EDH can use a pipe design, such as a slotted pipe design, that permits a maximum system water flow. The technology can be applied to water bodies to mitigate eutrophication and may also be applicable in other fields, such as wastewater lift stations, fish farms, oil and gas industry, tidal applications with low flushing rates, and winter under ice oxygenation to prevent fish kills.

Systems for treating wastewater containing organic nitrogen compounds are disclosed. The systems include a wet air oxidation unit having an oxidation zone, a catalytic zone, and a metal-based catalyst. Methods of treating wastewater containing organic nitrogen compounds are also disclosed. The methods include contacting the wastewater with an oxidant to produce a mixed liquor, contacting the mixed liquor with a metal-based catalyst to catalyze ammonia and produce a gas containing nitrogen and a liquid effluent containing nitrogen. Methods of retrofitting a wet air oxidation unit including providing a metal-based catalyst are also disclosed. Methods of facilitating treatment of wastewater in a wet air oxidation unit including providing a metal-based catalyst are also disclosed.

A novel solar-powered desalination and water purification system is disclosed herein. The system includes a nanofiber-impregnated graphene aerogel, an untreated water source, a water collection surface, and a purified water storage container. A novel photocatalytic nanofiber-impregnated graphene aerogel for desalination and photodegradation of contaminants for use in the disclosed system is also disclosed herein. The nanofiber-impregnated graphene aerogel exhibits excellent hydrophilicity, thermal insulation, and photodegradation capability, and allows for efficient solar-powered evaporation of water. The introduction of photocatalytic nanofibers into the graphene aerogel allows effective interfacial evaporation and in situ photodegradation of contaminants. The rate of water evaporation is preferably greater than 1.3 gal/ft.sup.2 per day, and the contaminant removal is preferably greater than 90%. A method of desalinating and purifying water using the disclosed system is also disclosed herein.

An iron-carbon composite material and a preparation method thereof are disclosed. The iron-carbon composite material includes a three-layer core-shell structure, which successively includes a porous graphite carbon outer layer, an iron carbide intermediate layer and a nano zero-valent iron core from outside to inside. The present invention wraps nano zero-valent iron in porous graphite carbon and iron carbide, which can prevent the oxidation of nano zero-valent iron, while iron carbide effectively improves the ability to fix arsenic, realizing high efficiency and long-term use of nano zero-valent iron. Iron carbide may effectively adsorb and fix arsenic, and especially efficiently oxidize As(III) to relatively low-toxic As(V).

An iron-carbon composite material and a preparation method thereof are disclosed. The iron-carbon composite material includes a three-layer core-shell structure, which successively includes a porous graphite carbon outer layer, an iron carbide intermediate layer and a nano zero-valent iron core from outside to inside. The present invention wraps nano zero-valent iron in porous graphite carbon and iron carbide, which can prevent the oxidation of nano zero-valent iron, while iron carbide effectively improves the ability to fix arsenic, realizing high efficiency and long-term use of nano zero-valent iron. Iron carbide may effectively adsorb and fix arsenic, and especially efficiently oxidize As(III) to relatively low-toxic As(V).

A plasma water treatment apparatus includes a plasma generator that generates plasma in water, and a porous dielectric that adsorbs nitrogen oxide generated in the water, surrounds the plasma generator, and includes silicon dioxide powder and carbon powder, thereby removing color of wastewater.

A method for producing and using an alkaline aqueous ferric iron carbonate solution is disclosed. The method broadly comprises reacting at least one ferric iron salt reagent with at least one alkali metal carbonate salt reagent and forming an alkaline aqueous ferric iron carbonate solution comprising an aqueous-soluble, ferric iron carbonate complex. The reacting generally includes reacting a solid with an aqueous solution. The reacting may include reacting a solid comprising one or both of the ferric iron salt reagent and alkali metal carbonate salt reagent with an aqueous solution. A method for removing reduced sulfur compounds from a reduced sulfur-containing fluid is also disclosed.

A method for producing and using an alkaline aqueous ferric iron carbonate solution is disclosed. The method broadly comprises reacting at least one ferric iron salt reagent with at least one alkali metal carbonate salt reagent and forming an alkaline aqueous ferric iron carbonate solution comprising an aqueous-soluble, ferric iron carbonate complex. The reacting generally includes reacting a solid with an aqueous solution. The reacting may include reacting a solid comprising one or both of the ferric iron salt reagent and alkali metal carbonate salt reagent with an aqueous solution. A method for removing reduced sulfur compounds from a reduced sulfur-containing fluid is also disclosed.

Water purification particles have porous particles and photocatalyst particles formed of titanium-based compound particles that are supported on the porous particles, have absorption at a wavelength of 500 nm in a visible absorption spectrum, and have an absorption peak at 2,700 cm.sup.−1 to 3,000 cm.sup.−1 in an infrared absorption spectrum, and a metal compound having a metal atom and a hydrocarbon group is bonded to the surface of each of the titanium-based compound particles through an oxygen atom.