Compositions and methods for adsorption of a species (e.g., ammonia, water, a halogen) comprising metal organic frameworks (MOFs) are generally provided. In some embodiments, a MOF comprises a plurality of metal ions, each coordinated with at least one ligand comprising at least two unsaturated N-heterocyclic aromatic groups arranged about an organic core.

A refrigerator having oxygen control and freshness keeping functions, comprising a refrigerator body. The refrigerator body has a compressor bin and a refrigerator compartment. The refrigerator further comprises an oxygen control device. The oxygen control device comprises a gas-regulating membrane assembly and a gas extraction assembly. The gas-regulating membrane assembly has at least one gas-regulating membrane. The gas extraction assembly is disposed outside the refrigerator compartment, and is provided with a gas extraction pump. The gas extraction pump has a gas inlet pipe communicated with the gas outlet side of the gas-regulating membrane and a gas outlet pipe for exhausting the gas from the gas outlet side of the gas-regulating membrane to the compressor bin so as to cool a compressor.

A compact desiccant air breather with unidirectional air flow comprises a housing with a plurality of air inlets adjacent an upper end for air intake. A desiccant bed of water absorbing material is within the intake flow path of air and an air chamber is within the intake flow path of air downstream of the desiccant bed. A one-way inflow check valve is adjacent the desiccant bed between the desiccant bed and the air chamber and is configured to allow airflow from the desiccant bed material to the air chamber and to prevent reverse airflow. A coupling member has an air flow conduit there-through which is in fluid communication with the air chamber and forms an air intake flow path exit. A one-way exhaust check valve in fluid communication with the air chamber is configured to allow airflow from the air chamber to the exterior and to prevent reverse flow.

An ambient humidity control article for controlling the ambient humidity within 65%-75%. The article includes a substrate which has a predetermined water absorbability, and a humidity control layer coated on the substrate. The humidity control layer is made up of a humidity control composition. The amount of the composition coated on per cubic centimeter of the substrate is 0.54-0.74 grams. The composition includes at least one chloride salt and water. The chloride salt includes at least one of NaCl, NH.sub.4Cl, KCl and MgCl.sub.2. The weight percentage of the chloride salt is 18%-44.6%. The water absorption amount of the substrate is not less than 0.5 grams per cubic centimeter. The article can control the ambient humidity without the need to pre-adjust the objective space. The article has a large capacity of moisture absorption and desorption and can quickly achieve the desired humidity in the objective environment.

An ambient humidity control article for controlling the ambient humidity within 45%-55%. The article includes a substrate having a predetermined water absorbability, and a humidity control layer coated on the substrate. The amount of the composition coated on per cubic centimeter of the substrate is 0.54-0.74 grams. The composition includes at least one organic acid salt, at least one polyol and water. The count of carbon in the polyols is not greater than 5. The weight percentage of the organic acid salt and the polyols in the composition is 30.6%-58.8% and 9.3%-26.7%, respectively. The water absorption amount of the substrate is not less than 0.5 grams per cubic centimeter. The article can control the ambient humidity without the need to pre-adjust the objective space. The article has a large capacity of moisture absorption and desorption, and can quickly achieve the desired humidity.

A composition for controlling an ambient humidity within 65%-75%. The composition includes at least one chloride salt and water. The chloride salt includes at least one of NaCl, NH.sub.4Cl, KCl and MgCl.sub.2. The weight percentage of the chloride salt in the humidity control composition is 12%-29.75%. The composition can control the ambient humidity within 65%-75% without the need to pre-adjust the objective space. The composition has a large capacity of moisture absorption and desorption, and can quickly achieve the desired humidity in the objective environment.

A system and method to supply nitrogen gas is provided. Ambient air is compressed and stored in a storage receiver and then nitrogen is separated from the compressed air in a nitrogen membrane separation unit. The separated nitrogen is stored in a nitrogen storage tank under pressure and released through a pressure control valve. The system is confined to a small footprint and is useful as a nitrogen source where conventional compressed nitrogen tanks are a safety or space issue. Systems to prepare nitrogen infused beverages are also provided.

An air composition adjusting device includes: an oxygen separator that separates oxygen from external air to be supplied to a target space; a gas supply path including a high concentration gas supply path for oxygen through which the oxygen separator communicates with the target space; and a controller that performs an oxygen concentration raising operation of supplying a high oxygen concentration gas, which has a higher oxygen concentration than external air before being treated by the oxygen separator, to the target space through the high concentration gas supply path for oxygen.

An amine-functionalized, crosslinked porous copolymer can be synthesized by linking 1,4-benzenediamine and pyrrole with p-formaldehyde in the presence of concentrated hydrochloric acid catalyst. The polymer is permanently microporous, with a BET surface area of 250 to 350 m.sup.2/g. Due to the high concentration of polar amines within its backbone, the polymer exhibits a CO.sub.2 uptake of 17.5 to 30 cm3/g at 298 K and 1 bar, but demonstrated a remarkably high selectivity for CO.sub.2 over N.sub.2 at 298 K. Dynamic breakthrough experiments indicate that this material is an effective adsorbent for selectively separating CO.sub.2 from a dry and wet gas mixture containing N.sub.2 for over 45 cycles without significant loss of performance. Furthermore, the polymer can be regenerated at room temperature after each cycle by a simple N.sub.2 flow.

The disclosed embodiments relate to the design of a preconcentrator system for preconcentrating air samples. This preconcentrator system includes a plurality of preconcentrators that preconcentrate the air samples prior to chemical analysis, and a delivery structure comprising a manifold that selectively routes a sample airflow to the plurality of concentrators so that the plurality of preconcentrators receive a sample airflow concurrently or individually.