A method of exhaust gas scrubbing includes providing recycled concrete fines as a waste material rich in carbonatable Ca and/or Mg phases and with d.sub.90≤1000 μm and a Rosin-Rammler slope n from 0.6 to 1.4 , injecting the waste material into an exhaust gas stream containing CO.sub.2 and/or SO.sub.x for reaction with CO.sub.2 and/or SO.sub.x at a relative humidity of 50 to 100 Vol.-% and a temperature from 40 to 130° C. in an amount of dry waste material ranging from 5 to 30 kg/m.sup.3, withdrawing a partly carbonated and/or sulphurized waste material and purified exhaust gas, and recycling a part of the partly carbonated and sulphurized waste material while the remainder is discharged, as well as use of a waste material slurry for exhaust gas cleaning of CO.sub.2 and/or SO.sub.x.

An exemplary sequestering system, apparatus, and method are provided for carbon dioxide sequestration using at least one in-situ chemical species in fluid to produce at least one reaction product that sequesters carbon dioxide. In one embodiment, the system includes a reaction vessel and one or more diffusers. In one implementation, the reaction vessel is configured to receive a fluid supply, wherein the fluid includes at least one in-situ chemical species, and wherein the reaction vessel is further configured to receive a gas supply. The one or more diffusers are configured to receive at least a portion of the gas supply to diffuse carbon dioxide gas into at least a portion of the fluid, and wherein the reaction vessel is further configured to contain a mixture to allow the at least one in-situ chemical species to react with the carbon dioxide gas and forming at least one reaction product.

Provided is an adsorbent for capturing carbon dioxide and a method for manufacturing same, and more particularly, to an adsorbent for capturing carbon dioxide, including a magnesium oxide/titanium dioxide composite having wide surface area, large pore volume and good CO.sub.2 adsorption performance, and a method for manufacturing same. According to the present invention, a novel MgO based composite metal oxide which may stably adsorb CO.sub.2 at a low temperature such as room temperature is provided. The adsorbent for capturing carbon dioxide, including a magnesium oxide/titanium dioxide composite has good thermal stability, and controls basic sites easily, and is used in various fields for capturing carbon dioxide. In addition, by controlling the molar ratio of the metal ions of the magnesium oxide/titanium dioxide composite and controlling morphology, an adsorbent for capturing carbon dioxide having large surface area and pore volume and strong basic sites may be provided.

Methods and systems for bioremediation of heavy metal contaminants in waste materials (e.g., sludge and combustion wastes from a coal-fixed power plant). The systems described in the present application include at least one waste treatment unit (e.g., a flue gas cleaner or a waste lagoon) that includes one or more selected bacterial strains disposed therein consume and/or reclaim at least a portion of the heavy metal in the combustion wastes. Methods include inoculating a waste treatment unit with one or more selected bacteria that consume and/or reclaim at least a portion of the heavy metal in the combustion wastes. Methods may include periodic reinoculation of the waste treatment unit with fresh bacteria and period recovery of the bacteria from the waste treatment unit.

Methods and systems for capturing and storing carbon dioxide are disclosed. In some embodiments, the methods include the following: mixing materials including magnesium or calcium with one or more acids and chelating agents to form a magnesium or calcium-rich solvent; using the organic acids derived from biogenic wastes as acids or chelating agents; generating carbonate ions by reacting a gas including carbon dioxide with a carbonic anhydrase biocatalyst; reacting the solvent with the carbonate ions to form magnesium or calcium carbonates; recycling a solution containing the biocatalyst after forming magnesium or calcium carbonates for re-use in the generating step; using the magnesium and calcium carbonates as carbon neutral filler materials and using the silica product as green filler materials or inexpensive absorbents.

Dry processes, apparatus, compositions and systems are provided for reducing emissions of sulfur oxides, and sulfur dioxide in particular, and/or HCl and/or Hg in a process employing a combination of a lime-based sorbent, in particular hydrated lime and/or dolomitic hydrated lime, and a sorbent doping agent administered to achieve coverage of a three-dimensional cross section of a passage carrying SO.sub.x and/or HCl and/or Hg-containing gases with a short but effective residence time at a temperature effective to provide significant sulfur dioxide and/or HCl and/or Hg reductions with high rates of reaction and sorbent utilization. The once-through, dry process can advantageously introduce the sorbent and sorbent doping agent dry or preferably as a slurry to enable uniform treatment. Preferred sorbent doping agents include water-soluble or water-dispersible copper and/or iron compositions which can be heated to an active form in situ by the flue gases being treated.

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.

The present invention relates to the use of solid metal materials for catalyzing the hydration of carbon dioxide. It also relates to methods of and apparatus for hydrating carbon dioxide and capturing carbon. The solid metal materials may be nickel nanoparticles. The invention finds particular application in the sequestration of carbon dioxide either at the point of release or from the atmosphere.

Solar thermal units and methods of operating solar thermal units for the conversion of solar insolation to thermal energy are provided. In some examples, solar thermal units have an inlet, and a split flow of heat absorbing fluid to either side of the solar thermal unit, along a first fluid flow path and a second fluid flow path. Optionally, one or more photovoltaic panels can be provided as part of the solar thermal unit, which may convert solar insolation to electric power that may be used by a system connected to the solar thermal unit.

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.