An adsorption system is placed in an air passage used to supply air to a room. The adsorption system includes an adsorption section that adsorbs a target substance except water, and a reduction section that reduces accumulation of moisture in the adsorption section. An adsorbent used in the adsorption section contains a metal-organic framework. The reduction section includes a heating element that heats the adsorption section and evaporates moisture in air that has flowed into the adsorption section.

A method for regeneration of a carbon dioxide absorbent includes steps of a) bringing a used carbon dioxide absorbent in contact with a carbon-containing dielectric material to form a dielectric energy-susceptible combination, and b) subjecting the dielectric energy-susceptible combination to a dielectric heating to remove carbon dioxide from the used carbon dioxide absorbent for the regeneration.

Disclosed is a CO.sub.2 concentration reducing device for separating and removing CO.sub.2 from a gas containing CO.sub.2 with a CO.sub.2 adsorbent, the CO.sub.2 concentration reducing device including: an adsorbent container which contains the CO.sub.2 adsorbent; and a heating unit which heats the CO.sub.2 adsorbent by an induction heating or a dielectric heating. Thus, a ventilation quantity can be reduced when CO.sub.2 accumulated in a room is removed, and an electric power required for the ventilation and the electric power required for air conditioning can be reduced.

Nanoparticle-treated particle packs, such as sand beds, may effectively filter and purify liquids such as waste water. When tiny contaminant particles in waste water flow through the particle pack, the nanoparticles will capture and hold the tiny contaminant particles within the pack due to the nanoparticles' surface forces, including, but not necessarily limited to van der Waals and electrostatic forces. Coating agents may help apply the nanoparticles to the particle surfaces in the filter beds or packs.

Hydrogen sulfide and mercaptans may be removed from a fluid or gaseous stream by introducing a composite to the fluid or gaseous stream containing a hydrogen sulfide scavenger adsorbed onto a water-insoluble adsorbent.

A method is described to regenerate an oxygen trap, comprising at least the following steps: circulating a current in the trap material (2) to reduce this material; measuring the value I.sub.m of the current and estimating its derivative dI.sub.m/dt in relation to time; estimating the length () of material reduced by the current as a function of the value of the current and its derivative; stopping circulation of the current when the length of reduced material is at least equal to a threshold value (.sub.s).

A structured material assembly for removing CO.sub.2 from a gas, comprises a substrate, a sorbent for adsorbing CO.sub.2 from the gas, and a desorption material integrated into the structured material assembly, which is responsive to inputted energy to generate heat to desorb CO.sub.2 from the sorbent. The CO.sub.2-containing gas may comprise ambient air.

Provided is a system and method for extracting organic solutes from water with a filter media. The system and method allow for regenerating the filter media following treatment of a water supply containing one or more organic solutes to allow the media to be reused for subsequent water treatment operations. The system and method also allows for regeneration of the displacement fluid for reuse in the regeneration of the media with recovery of at least one or more organic solutes from the displacement fluid. Additionally, the system and method allows for substantially continuous treatment of a water supply and regeneration of a filter media.

In one embodiment, a system includes at least one reusable nutrient cartridge including an outer housing having an inlet and an outlet, and nutrient-adsorbing material contained within the housing, the material being configured to adsorb nutrients, wherein the cartridge is configured to be charged with nutrients by flowing a nutrient stream through the inlet, through the nutrient-adsorbing material, and through the outlet to enable the nutrient-adsorbing material to adsorb the nutrients, wherein the cartridge is also configured to be later discharged of the nutrients by flowing water through the inlet, through the nutrient-adsorbing material, and through the outlet so as to transfer the nutrients to the water to generate a dilute nutrient solution suitable for use as a fertilizer.

The present disclosure relates to methods of synthesizing slurries comprising ferrihydrite nanoparticles, and systems and methods employing the same. The method may include the steps of preparing an aqueous solution having ferric iron cations, halide anions, and a two-line iron promoter, and precipitating the ferrihydrite nanoparticles in the aqueous solution, thereby producing a ferrihydrite slurry. The ferrihydrite slurries may be useful in treating a polluted fluid having sulfur contaminants therein.