Proposed are a photocatalyst, including titanium dioxide particles including titanium dioxide (TiO.sub.2), a carbon material located on all or part of the surface of the titanium dioxide particles and including at least one selected from the group consisting of graphene, reduced graphene oxide (rGO), and carbon nanotubes (CNTs), and bimetallic nanoparticles supported on the carbon material and including first metal nanoparticles and second metal nanoparticles, and a water treatment method using the same. In the photocatalyst and the water treatment method using the same, the photocatalyst including bimetallic nanoparticles and graphene oxide is prepared, thereby exhibiting high reduction efficiency and high selectivity to nitrogen gas even without the use of an external electron donor.

The present disclosure provides for methods and systems that include a support of optically transparent quartz fibers having a meso-porous layer of TiO.sub.2-based catalytic layer on the fibers. The methods, systems, and compositions of the present disclosure provide chemical-free advanced oxidation to improve the affordability of UV AOPs for water treatment.

Apparatus for facilitating a chemical reaction through the application of light, including a light source providing illumination at a selected wavelength, a lens material adapted to be in physical contact with the light source, when in use, and a receptacle for holding a reaction vial in which the chemical reaction takes place, the receptacle adapted to position a portion of the reaction vial in physical contact with the lens material when in use, wherein the lens material has a refractive index that facilitates the transmission of the illumination from the light source to the reaction vial. Alternatively, the receptacle and vial may be replaced by a reaction plate in which reaction wells are formed.

A method and a system for producing a change in a medium disposed in an artificial container. The method places in a vicinity of the medium at least one of a plasmonics agent and an energy modulation agent. The method applies an initiation energy through the artificial container to the medium. The initiation energy interacts with the plasmonics agent or the energy modulation agent to directly or indirectly produce the change in the medium. The system includes an initiation energy source configured to apply an initiation energy to the medium to activate the plasmonics agent or the energy modulation agent.

A method and a system for producing a change in a medium. The method places in a vicinity of the medium an energy modulation agent. The method applies an initiation energy to the medium. The initiation energy interacts with the energy modulation agent to directly or indirectly produce the change in the medium. The energy modulation agent has a normal predominant emission of radiation in a first wavelength range outside of a second wavelength range (WR2) known to produce the change, but under exposure to the applied initiation energy produces the change. The system includes an initiation energy source configured to apply an initiation energy to the medium to activate the energy modulation agent.

A wash water processing method and a wash water processing apparatus in a simple structure capable of effectively decomposing organic matters and killing bacteria contained in wash water, extending the life of a filter of a filtration apparatus and an ion-exchange resin and, furthermore, extending a bacteria-killing/washing interval of a washing processing part. In the wash water processing apparatus (11) and the washing method, a wash water accommodation part (12) into which processed water processed in a washing processing part (10) flows and a filtration mechanism part (14) are connected and the wash water accommodation part has connected in a circulatable manner thereto an inflow flow path and an outflow flow path of a sterilization and purification unit which organically couples respective functions of an ozone supply part which supplies ozone, an ultraviolet irradiation part which irradiates with ultraviolet rays, and a photocatalysis part which causes a photocatalyst to act.

A system for generating a plasma discharge in liquid utilizes first and second electrodes spaced apart in an interior space of a vessel holding the liquid. A channel can be defined in certain embodiments at least partially by at least one of the first and second electrodes, and an inlet in fluid communication with the interior space is configured to generate a vortical fluid flow in the vessel. A method for generating a plasma discharge in liquid is also provided.

Disclosed are various combinations of three different metal-oxide photocatalysts with three different bandgaps that can be used to harvest multiple wavelengths of incident solar radiation and to thus efficiently degrade recalcitrant contaminants. The photocatalysts are from the class of transition metal oxides and are non-toxic compounds based on earth-abundant materials. In some embodiments, particles of the photocatalysts are formed to be greater in diameter than about 0.1 μm in order to make them easier to filter out after treating the contaminant. In some embodiments, the metal-oxide photocatalysts are zinc oxide which is ultraviolet active, hematite which is active in the visible spectrum, and copper oxide which is active in the near infrared spectrum. Various combinations in various embodiments achieve measured contaminant degradation rates greater than the sum of the degradation rates of the individual photocatalysts that make up the combination.

A method is provided for processing wastewater having organics even together with high-concentration ammonia-nitrogen, using an apparatus, comprising a catalyzation tank and a subsequent neutralization tank. Organic ammonia-nitrogen wastewater is introduced into tank for reaction without being pre-adjusted by acidic agent or mixing with other additives. A persulfate oxidant is used to process high-efficiency oxidative degradation for ammonia-nitrogen and toxic organics in wastewater through catalyzing oxidation of ultraviolet activation, tiny-amount-transition-metal catalyzation, or both of them, for simultaneous reductions or complete removals of ammonia-nitrogen and organic carbon contents. After neutralization according to actual needs, the final output is complied with biological treatment conditions, discharged-water quality standards, or recycled-water standards. With the high-efficiency catalyzing oxidation, various toxic organics, aromatics, and heterocyclic compounds are degraded; furthermore, ammonia-nitrogen are converted into non-toxic nitrogen gas and nitrate-nitrogen. Finally, ammonia-nitrogen and nitrate-nitrogen in wastewater can be reduced with efficiency, or even completely removed.

A method for producing crystalline α-Fe2O3 nanoparticles involving ultrasonic treatment of a solution of an iron (III)-containing precursor and an extract from the seeds of a plant in the family Linaceae. The method involves preparing an aqueous extract from the seeds of a plant in the family Linacae and dropwise addition of the extract to the solution of an iron (III)-containing precursor. The method yields crystalline nanoparticles of α-Fe.sub.2O.sub.3 having a spherical morphology with a diameter of 100 nm to 300 nm, a mean surface area of 240 to 250 m.sup.2/g, and a type-II nitrogen adsorption-desorption BET isotherm with a H3 hysteresis loop. A method for the photocatalytic decomposition of organic pollutants using the nanoparticles is disclosed. An antibacterial composition containing the crystalline α-Fe.sub.2O.sub.3 nanoparticles is also disclosed.