864results about "Radioactive contaminants" patented technology

A self-contained, portable water purification system, including (a) an ozone supply, (b) an ozone contact chamber for mixing a contaminated or potentially contaminated water stream with ozone generated by such ozone supply, (c) an ozone destruction unit for destructing ozone contained in the water stream and converting said water stream into an oxygen-rich and ozone-depleted water stream, and (d) a downstream biologically active carbon filter, for receiving such oxygen-rich and ozone-depleted water stream and biologically destructing at least a portion of contaminants contained therein.

The present invention provides a method for oxidizing a substance (e.g., in a waste stream, drinking water, a paper pulp slurry, or on a surface), which uses free radicals and reactive species generated from multiple oxidants. The method comprises combining peroxynitrite or peroxynitrous acid and at least one additional oxidizing agent for a period of time sufficient to oxidize the substance of interest. The peroxynitrite or peroxynitrous acid preferably is formed by irradiation of nitrate ion and/or nitric acid (e.g., with UV or gamma rays). The yield of free radicals and reactive species, which are the intermediate species that perform the oxidation may be increased by addition of a catalysts, electromagnetic radiation, sonic waves, and/or electrolysis.

A water purification method comprising adding a purification agent to water having a contaminant concentration of 1 μg/L to 10 g/L, the purification agent containing an adsorbent having an average particle size of 100 nm to 500 μm, an iron-based flocculant, and an alkaline substance; causing the adsorbent to adsorb at least a part of the contaminants in water; settling the adsorbent with the adsorbed contaminants by the iron-based flocculant; and removing the sediment from water, wherein the purification agent is added in an amount of 0.01 g to 20 g per liter of water, can purify contaminated water conveniently and efficiently.

A method and apparatus for treating radioactive waste water containing contaminating ions, colloids and suspended solids having like (usually negative) charges preventing their precipitation. An electric current is passed through the waste water in an EC assembly to cause electro-coagulation of the contaminants and anodes of this assembly are made of a metal that dissolves to provide cations for neutralizing the negative charges and forming precipitates containing neutralized contaminants. Precipitates are then separated from waste water by an electro-magnetic or other filtering unit. The water pH and conductivity may be adjusted before the EC assembly and additives may be introduced into its effluent for enlargement of precipitate particles, improvement of filtration, improvement of dewaterability, and/or enhancement of magnetism.

Methods for the removal of alkaline and sulfate scales from aqueous saline streams such as seawater, oil-gas fields produced waters, formation waters, and the like. Such processing methods can also be extended for the simultaneous removal of hydrogen sulfide, and/or sulfur dioxide, and/or oxides of nitrogen, and/or carbon dioxide from gaseous streams. The same processing concept with modified methods can further be employed for the removal of gases such as radon, hydrogen sulfide, sulfur dioxide, oxides of nitrogen, and carbon dioxide from gaseous streams.

Described are chemical formulations that remove heavy metals from waste solutions containing a chelating agent. Also disclosed are methods for removing heavy metals from waste solutions utilizing such chemical formulations.

Embodiments provided herein include methods and apparatuses for purification and recycling of hydrofracture water used in natural gas drilling and production. Embodiments include removal of dissolved solids by precipitation with sodium sulfate and by evaporation using, for example, a multiple effect evaporator.

Oxyanions of various contaminant elements, such as chromium, antimony, molybdenum, tungsten, vanadium and uranium, are removed from water and other aqueous feeds by treating the feed with (1) a sorbent comprising one or more rare earth compounds, usually mixed or supported on particulate solids having a cation exchange capacity less than 20 milliequivalents per 100 grams or (2) an aqueous solution of one or more soluble rare earth compounds.

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.

A control assembly for an electrocoagulation cell (1) comprising a plurality of electrodes, a releasable connection means (6) between at least a selection of the electrodes and electrical connection means (9, 10, 9A, 10A) attached to the releasable connection means (6) which in use is connectable to a power supply (12). An electrocoagulation system comprising a plurality of electrodes (2), an electrolytic cell (1) having an internal chamber which contains the plurality of electrodes (2), and a power supply (12) connectable to a power source and also connectable to the electrodes said power supply having control means (14, 24) for providing a selected constant output current or selected constant output voltage whereby the electrolytic cell may process samples of varying characteristics.

A method for removing dissolved contaminants from solution using a surface-activated crystalline titanium oxide product having a high adsorptive capacity and a high rate of adsorption with respect to dissolved contaminants, in particular, arsenate and arsenite. Preferably, the titanium oxide product includes crystalline anatase having primary crystallite diameters in the range of 1-30 nm. The surface-activated titanium oxide is combined with other filter media to further improve the removal of dissolved contaminants.

In one aspect the invention provides a system for treating a wastestream, particularly a radwaste, for safe disposal and, in final processing converting it into one or both forms including an aqueous form for safe discharge to the environment and a solidified form for safe disposal. In another aspect the invention provides the capacity to employ a step where a specific target element strategy can be set up synchronizing sorbent substance choices and multiple recycle options to remove target substances from wastestream as a part of its Sorption or Powder Sorbent Isotopic Reduction step (II). Other steps cooperate with Sorption step (II) including Oxidation (I), Solid-Liquid separation (III), and Selective Ion Exchange (IV) to deliver the wastestream to final processing.

A method for treating low barium frac water includes contacting a frac water stream with a radium selective complexing resin to produce a low radium stream, passing the low radium stream through a thermal brine concentrator to produce a concentrated brine; and passing the concentrated brine through a thermal crystallizer to yield road salt.

This invention relates to a method of installation of an electrocoagulation (EC) system to remove contaminants from wastewater which includes the steps of: (i) measuring conductivity of the wastewater; (ii) from the result obtained in step (i) determining the number of electrically connected electrodes or unipolar electrodes required in the EC system for efficient removal of the contaminants, and (iii) from step (ii) assessing a range of current and/or voltage to be applied to an EC cell included in the EC system.

A process and system for treating waste water containing contaminants to prevent excessive accumulation on demineralizer media of a driver contaminate capable of such accumulation before another contaminant can reach a predetermined level of accumulation. The waste water is treated upstream of the demineralizer media with removal means for specifically removing the driver contaminant while leaving the other contaminant for subsequent removal by the demineralizer media. The amount of accumulation on the demineralizer media of the other contaminant is monitored, and the supplying of treated waste water to the demineralizer media is terminated when its accumulation reaches the predetermined level.

The invention relates to bio-electrochemical systems for treating wastewater, and sour gas produced by anaerobic digestion of organic material. The invention further relates to novel anode/cathode pairing schemes, and electric and hydraulic architectures for use in bio-electrochemical systems.

The invention discloses a micron-grade magnetic core coated ferrocyanide adsorbent for removing Cs ions in radioactive wastewater and a preparation method thereof. The adsorbent takes magnetic Fe₃O₄ as a core, the surface is coated with a dense SiO₂ single layer serving as a protective layer, and an active component is metal ion stabilized potassium ferrocyanide coated on the outer layer, wherein stabilized metal ions comprise Ti, Zn, Cu, Ni, Co, and Zr. The particle size of the adsorbent is 0.2-5 μm, the adsorbent in the outermost layer is conductive to improving the adsorption efficiency for Cs⁺ ions, and an external magnetic field is adopted for realizing solid-liquid phase separation. The preparation method comprises the following steps: coating a hydrated metal oxide of Ti, Zr or Co, Ni, Cu or Zn on the surface of Fe₃O₄SiO₂ to form a composite magnetic material, wherein the hydrated oxide performs hydroxyl polymerization reaction with the surface of SiO₂ to produce M—O—Si bonds to improve the bonding strength between M and the surface of SiO₂; and finally reacting the composite magnetic material with a potassium ferrocyanide solution to form the required composite adsorbent, wherein the metal ions M achieve the effects of stabilizing the ferrocyanide and also achieve a bridge effect for bonding the ferrocyanide and the composite magnetic material together.

The invention provides a method and a device for processing radioactive wastewater. According to the method and the device, the radioactive wastewater is processed by a disk tubular reverse osmosis (DTRO) membrane component, so that effects of efficient decontamination factors and high cycles of concentration can be obtained at the same time. The method comprises the steps of enabling the radioactive wastewater to flow through a first-level membrane component and a second-level membrane component in sequence to obtain second-level water; and enabling first-level concentrated water out of the first-level membrane component to enter a third-level membrane component and obtain a concentrated solution.

The invention discloses a preparation method of porous geological polymer microspheres. The porous geological polymer microspheres are prepared by a dispersion suspension solidification method. Compared with the prior art, low-temperature curing and one-shot molding granulation are realized without requirements of high-temperature calcination and curing and addition of other auxiliaries; and at the same time, large-scale use of solid wastes is realized, and raw materials are widely available, cost is low, process is simple, and the whole process is non-toxic and pollution-free; in addition, the preparation efficiency is high with a ball-forming degree exceeding 90%; the size of the particles can be adjusted, and the pore size distribution is uniform; the pore volume is large, and can be regulated, and a specific surface area of the microspheres reaches 110m2/g, thus, the porous geological polymer microspheres can be directly used for packed columns for column separation. Experiments show that the porous geological polymer microspheres have a good adsorption effect on heavy metals, and can be used as adsorbents for heavy metals, and have a broad application prospect in the aspect ofremoving heavy metals and radioactive elements in water.

Various aspects of the present invention pertain to methods of sorption of various materials from an environment, including radioactive elements, chlorates, perchlorates, organohalogens, and combinations thereof. Such methods generally include associating graphene oxides with the environment. This in turn leads to the sorption of the materials to the graphene oxides. In some embodiments, the methods of the present invention also include a step of separating the graphene oxides from the environment after the sorption of the materials to the graphene oxides. More specific aspects of the present invention pertain to methods of sorption of radionuclides (such as actinides) from a solution by associating graphene oxides with the solution and optionally separating the graphene oxides from the solution after the sorption.

The invention provides a method for the preparation of a sorbent capable of efficiently and selectively sorbing cesium ions from an aqueous solution. The method comprises impregnating the pores of a high-porosity carrier material such as silica gel and porous adsorbent resin with water-soluble potassium or sodium hexacyanoferrate (II) and contacting the carrier material with a solution of a copper salt in a solvent in which the water-soluble hexacyanoferrate (II) is hardly soluble such as ethyl alcohol to convert the water-soluble hexacyanoferrate (II) into water-insoluble copper hexacyanoferrate (II). The cesium ions sorbed on the sorbent can be readily desorbed and the sorbent can readily be regenerated. Alternatively, the carrier material is impregnated with a water-soluble hexacyanoferrate (III) which is converted into copper hexacyanoferrate (III) followed by a reducing reaction of the same into copper hexacyanoferrate (II).

A composition of matter wherein the composition comprises a siliceous substrate having silanols on the surface and a polymer selected from the group consisting essentially of a water soluble polymer, a water soluble copolymer, an alcohol soluble polymer, an alcohol soluble copolymer, and combinations of such polymers, wherein the polymer is chemically bonded to the siliceous substrate by a silane linking material having the general formula

O_3/2SiQY

that is derived from an alkoxy-functional silane having the general formula

(RO)₃SiQX

and processes for preparing the crosslinked polymer that is chemically bonded to the surface of the siliceous substrate.