874results about "Radioactive contaminants" patented technology

A method for producing a surface-activated crystalline titanium oxide product having a high adsorptive capacity and a high rate of adsorption with respect to dissolved contaminants includes the steps of preparing a titanium oxide precipitate from a mixture comprising a hydrolysable titanium compound and heating the precipitate at a temperature of less than 300° C., without calcining the precipitate. Preferably, the titanium oxide product includes crystalline anatase having primary crystallite diameters in the range of 1-30 nm. The surface-activated crystalline titanium oxide product is used in methods to remove dissolved inorganic contaminants from dilute aqueous streams by suspending the product in an aqueous stream or by filtering an aqueous stream through a bed of the product. In another method, a hydrolysable titanium compound is added to an aqueous stream so that titanium oxides form as a co-precipitate with dissolved contaminants within a bed of particulate material.

The invention discloses a method for treating radioactive wastewater. The method for treating the radioactive wastewater comprises the steps of firstly carrying out reverse osmosis treatment on the radioactive wastewater, then enabling the radioactive wastewater to enter a continuous electrodeionization unit to be treated, and further removing radionuclide so as to enable treated wastewater to reach discharge requirements; and respectively filling different mixed ion exchange resin in a plain water chamber and a thick water chamber in a continuous electrodeionization membrane stack of the continuous electrodeionization unit, wherein mixed ion exchange resin filled in the plain water chamber comprises, by volume ratio, 30%-60% of strong-acid cation exchange resin, 40%-60% of strong-base anion exchange resin, and 0%-30% of weak-base anion exchange resin, mixed ion exchange resin filled in the thick water chamber comprises, by volume ratio, 20%-50% of strong-acid cation exchange resin, and the balance strong-base anion exchange resin. A weak dissociation polymer portion is used for improving selectivity of continuous electrodeionization membrane stack to trace amount radionuclide, radionuclide with extremely concentration can be effectively removed, and the method for treating the radioactive wastewater ensures that the final discharged water satisfies the discharge requirements.

The process of heavy metals removal from the waste water using silica dispersion without mixing silica dispersion with the waste water. This is achieved due to the membrane device where silica dispersion and waste water stream are separated by membrane with pore sizes smaller that size of the silica particles. The process is organized as counter-flow, which means that silica dispersion and waste water flow in the opposite directions. This provides the maximum utilization of the adsorption capacity corresponding to the adsorbent being in equilibrium with the high initial concentration of the contaminant in distinction from the low utilization when adsorbent works in equilibrium with the low output concentration. In the particular instance the membrane device comprises a lumen of a bundle of hollow fibers with silica dispersion flowing either inside or outside of the fibers and wastewater flowing on the opposite side of the fiber membrane. This process eliminates step of separating silica from the wastewater. It opens way to use colloidal silica as adsorbent with highly developed surface area. Continuous monitoring of the silica particles zeta potential yields information for preventing colloidal silica solidification within the device. Solidification of the colloidal silica afterwards solves problem of untreated residual discharge.

A system and method for removal of uranium and other contaminants from aqueous solution, utilizing live algae, are described. The system includes a bioreactor, in which a reaction mixture of live algae, preferably photosynthetic algae, and contaminated solution are introduced; a means for introducing carbon dioxide gas in the reaction mixture; a means for exposing the reaction mixture to light; means for mixing and impelling the reaction mixture; and means for separating out algae from remediated solution.