A composition that absorbs oxygen and emits carbon dioxide in response to absorbing oxygen including ascorbic acid, an organic acid, a catalyst that promotes oxidation of the organic acid and emission of carbon dioxide and a soluble transition metal salt characterized by multiple oxidation states.

Purified air is provided, having a TVOC content of from less than 5 ppb to about 500 ppb, a Biologicals content of from less than 1 CFU/M.sup.3 to 150 CFU/M.sup.3 and a Particulate content of from about 1,000 0.3 μm particles per ft.sup.3 to about 50,000 0.3 μm particles per ft.sup.3, or from about 600 0.5 μm particles per ft.sup.3 to about 500,000 0.5 μm particles per ft.sup.3.

A magnetic magnesium-manganese layered double metal oxide composite and preparation and application. A soluble magnesium salt and a soluble manganese salt are dissolved in water to obtain a magnesium-manganese salt complex liquid; and a soluble carbonate and a soluble hydroxide are dissolved in water to obtain a carbonate-hydroxide complex liquid; a ferroferric oxide powder is added to the carbonate-hydroxide complex liquid, and then ethanol is added for ultrasonic dispersion to obtain a dispersion liquid; then the magnesium-manganese salt complex liquid is added for aging, centrifuging, washing, drying, grinding for sieving, and calcinating at 250-550° C. to obtain a magnetic magnesium-manganese layered double metal oxide composite. The composite of the present invention has relatively strong magnetism to Cd removal, and is featured by high adsorption efficiency, rapid adsorption rate and stability. Moreover, the composite can not only immobilize Cd efficiently, but also can be separated and recycled by magnet.

An atmospheric water harvesting material includes a deliquescent salt, a photothermal agent, and a polymeric hydrogel matrix containing the deliquescent salt and photothermal agent.

Disclosed are a transition metal-doped carbon microsphere, a preparation method therefor and an application thereof. The transition metal-doped carbon sphere has a uniform solid porous structure, and the transition metal is uniformly distributed inside the carbon sphere. The preparation method comprises that a carbon microsphere uniformly doped with manganese, vanadium, molybdenum and tungsten is prepared by means of a one-step hydrothermal method, is mixed with potassium oxalate, and is roasted in a protective atmosphere to obtain an activated metal-doped carbon sphere. The doped transition metal elements remain uniformly dispersed after being roasted, and do not agglomerate. The transition metal-doped carbon microsphere obtained has the following characteristics: it exhibits good adsorption properties for heavy metal ions Cr(VI), with the maximum adsorption amount being 660.7 mg/g; it can achieve advanced removal of Cr(VI) from the wastewater of which the initial Cr(VI) concentration is lower than 200 mg/L, with the residual Cr(VI) concentration after adsorption being lower than 0.05 mg/L; and it shows good application prospect in the treatment of wastewater containing heavy metal.

Disclosed in certain embodiments are systems for removing pollutants from an air flow, which may include a substrate and a catalyst-adsorbent material disposed on the substrate.

Purified air is provided, having a TVOC content of from less than 5 ppb to about 500 ppb, a Biologicals content of from less than 1 CFU/M.sup.3 to 150 CFU/M.sup.3 and a Particulate content of from about 1,000 0.3 μm particles per ft.sup.3 to about 50,000 0.3 μm particles per ft.sup.3, or from about 600 0.5 μm particles per ft.sup.3 to about 500,000 0.5 μm particles per ft.sup.3.

Purified air is provided, having a TVOC content of from less than 5 ppb to about 500 ppb, a Biologicals content of from less than 1 CFU/M.sup.3 to 150 CFU/M.sup.3 and a Particulate content of from about 1,000 0.3 μm particles per ft.sup.3 to about 50,000 0.3 μm particles per ft.sup.3, or from about 600 0.5 μm particles per ft.sup.3 to about 500,000 0.5 μm particles per ft.sup.3.

Processes, compositions, and sensors for sensing a variety of toxic chemicals based on colorimetric changes. Exemplary process for sensing a toxic chemical includes contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide or a porous mixed-metal oxide/hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent is determined to thereby detect exposure to, or the presence of, the toxic chemical or byproduct thereof.

Processes, compositions, and sensors for sensing a variety of toxic chemicals based on colorimetric changes. Exemplary process for sensing a toxic chemical includes contacting a toxic chemical, or byproduct thereof, with a sorbent that includes a porous metal hydroxide or a porous mixed-metal oxide/hydroxide and a transition metal reactant suitable to react with a toxic chemical or byproduct thereof. The sorbent is contacted with the toxic chemical or byproduct thereof for a sampling time. A difference between a post-exposure colorimetric state of the sorbent and a pre-exposure colorimetric state of the sorbent is determined to thereby detect exposure to, or the presence of, the toxic chemical or byproduct thereof.