Method and system are disclosed for the production and use of a chemical compound, where a given amount of CO.sub.2 is emitted in the production and the use, including producing a second chemical compound that is required for the production or the use of the first compound, where the production of the second compound consumes CO.sub.2 and sequesters it from the atmosphere so that the total net CO.sub.2 emitted in the production and use of the first compound is now reduced. In one embodiment, the second chemical compound is a negative-CO.sub.2-emissions hydrogen, oxygen or chlorine gas produced in an electrolytic cell.

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

A method for removing a halogen fluoride in a mixed gas by reacting the mixed gas containing a halogen fluoride including bromine or iodine with a removing agent, wherein the removing agent is a chloride, bromide or iodide of potassium, sodium, magnesium, calcium and barium. Also disclosed is a quantitative analysis method as well as a quantitative analyzer for a gas component contained in a hydrogen fluoride mixed gas, the method characterized by reacting a mixed gas containing a halogen fluoride and another gas component with a removing agent, thereby removing the halogen fluoride in the mixed gas, further removing produced by-products, and quantitatively analyzing a residual gas by a gas chromatograph.

Materials and methods for mitigating the effects of halide species contained in process streams are provided. A halide-containing process stream can be contacted with mitigation materials comprising active metal oxides and a non-acidic high surface area carrier combined with a solid, porous substrate. The halide species in the process stream can be reacted with the mitigation material to produce neutralized halide salts and a process stream that is essentially halide-free. The neutralized salts can be attracted and retained on the solid, porous substrate.

Embodiments of the present disclosure are directed to systems and methods of removing carbon dioxide from a gaseous stream using magnesium hydroxide and then regenerating the magnesium hydroxide. In some embodiments, the systems and methods can further comprise using the waste heat from one or more gas streams to provide some or all of the heat needed to drive the reactions. In some embodiments, magnesium chloride is primarily in the form of magnesium chloride dihydrate and is fed to a decomposition reactor to generate magnesium hydroxychloride, which is in turn fed to a second decomposition reactor to generate magnesium hydroxide.

Provided herein are methods of removing carbon dioxide from an aqueous stream or gaseous stream by: contacting the gaseous stream comprising carbon dioxide, when present, with an aqueous solution comprising ions capable of forming an insoluble carbonate salt; contacting the aqueous solution comprising carbon dioxide with an electroactive mesh that induces its alkalinization thereby forcing the precipitation of a carbonate solid from the solution and thereby the removal of dissolved inorganic carbon by electrolysis; and removing the precipitated carbonate solids from the solution, or the surface of the mesh where they may deposit. Also provided herein are flow-through electrolytic reactors comprising an intake device in fluid connection with a rotating cylinder comprising an electroactive mesh, and a scraping device and/or liquid-spray based device for separating a solid from the mesh surface.

A water generation system for generating liquid water from a process gas containing water vapor is disclosed. In various embodiments, the water generation systems comprise a solar thermal unit, a condenser and a controller configured to operate the water generation system between a loading operational mode and a release operational mode for the production of liquid water. A method of generating water from a process gas is disclosed herein. In various embodiments, the method comprises flowing a process gas into a solar thermal unit, transitioning from the loading operational mode to a release operational mode; flowing a regeneration fluid into the solar thermal unit and the condenser during the release operational mode; and, condensing water vapor from the regeneration fluid to produce liquid water.

The invention includes systems, methods, compositions, and processes for designing, manufacturing, and utilizing carbon dioxide-sequestering substrates that can fully or partially replace natural sand in coastal engineering applications. These engineered substrates can offset demand for scarce native sand resources, while also effecting the conversion of gaseous carbon dioxide to dissolved or solid-phase products thereby offsetting impacts of anthropogenic climate change.

A coupling system of CO.sub.2 capture in flue gas and CO.sub.2 mineralization based on industrial solid waste includes: 1) an adsorption reaction device configured to treat flue gas with the embedded adsorbents, 2) a thermal decomposition device designed to decompose the first carbonate products to oxides and carbon dioxide, wherein the produced oxides are circulated to the adsorption reaction device, and 3) an industrial solid waste mineralization system configured to treat the deactivated oxides and the as-produced carbon dioxide. The coupling system can not only realize carbon capture and utilization, but also can enable the reuse of waste and the production of high-quality carbonates. Meanwhile, the carbon capture line is also convenient to be organically integrated with the production line of carbon mineralization system based on industrial solid waste, reducing the cost of the whole process.

Aspects of the invention include methods of removing carbon dioxide (CO.sub.2) from a CO.sub.2 containing gas. In some instances, the methods include contacting CO.sub.2 containing gas with a bicarbonate buffered aqueous medium under conditions sufficient to produce a bicarbonate rich product. Where desired, the resultant bicarbonate rich product or a component thereof may then be stored or further processed, e.g., combined with a divalent alkaline earth metal cation, under conditions sufficient to produce a solid carbonate composition. Aspects of the invention further include systems for practicing the methods, as well as products produced by the methods.