Treatment for reducing the environmental availability of environmental contaminants

Abstract

The present invention provides a treatment for reducing the environmental availability of one or more environmental contaminants in solids, liquids, and combinations of solids and liquids.SOLUTION: Adding and / or applying a halogen-containing sorbent to the environmental pollutant, wherein the halogen-containing sorbent comprises one or more halogens selected from fluorine, chlorine, bromine and / or iodine, and / or one or more substrate materials, thereby reducing the environmental availability of at least a portion of the one or more environmental pollutants in the material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the remediation of environmental contaminants to reduce their environmental availability. [Background technology]

[0002] Many contaminants are known to be toxic to humans and the environment. One of these known environmental contaminants, mercury, is classified as a priority hazardous substance by the U.S. Department of Health and Human Services' Agency for Toxic Substances and Disease Registry (ATSDR). The U.S. National Cleanup Priorities List (NPL), maintained by the U.S. Environmental Protection Agency (EPA), lists numerous sites contaminated with mercury. These sites contain a variety of contaminants, including solids (e.g., soil, litter, waste), liquids (e.g., groundwater, lakes, ponds), and combinations of solids and liquids (e.g., sediments, slurries, sediments). The majority of these sites have not been recontaminated to remove mercury. Unacceptable levels of mercury or mercury compounds may be present in sites not listed on the U.S. NPL. Environmental contaminants other than mercury pose similar concerns.

[0003] Mercury contamination can arise from a variety of different sources (e.g., mining and ore processing, chlor-alkali plants, and battery manufacturing processes). Many landfills are contaminated with mercury-containing waste. Furthermore, mercury contaminants often exist in the same location in multiple forms, including metallic mercury, organic mercury compounds, and inorganic mercury compounds. Different mercury forms and / or different substances often require different treatment methods.

[0004] Materials contaminated with mercury tend to also contain multiple other environmental contaminants. For example, some materials are also contaminated with organic matter and / or other heavy metals, and these other environmental contaminants present similar challenges. Therefore, depending on the contaminated material, the state of the material, the type of waste, the form of mercury, and other contaminants or environmental pollutants present, reducing the environmental availability of environmental contaminants at a particular location can be technically challenging and costly. Reducing the environmental availability of environmental contaminants is particularly interesting because it also reduces the contaminant's bioavailability, thereby reducing its bioaccumulation, particularly in materials such as soil, groundwater, sediments, and slurries.

[0005] Current commercial remediation treatments applied to soils and other solids include stabilization / solidification, washing, thermal desorption, and vitrification. Treatments applied to water and other liquids include precipitation / coprecipitation, adsorption, filtration, and bioremediation. Treatments applied to sediments and other solid-liquid combinations include in situ capping, dredging / excavation, combinations of these methods, as well as monitored natural remediation (MNR) and enhanced monitored natural remediation (EMNR). Monitored natural remediation relies on natural processes to protect the environment and receptors from unacceptable exposure to contaminants, while enhanced MNR applies materials or amendments to enhance natural remediation processes (e.g., adding a thin cap or reactive amendments such as carbon). All of these remediation techniques offer benefits in controlling the environmental impacts of environmental contaminants, including human health and ecological risks. However, they also have limitations.

[0006] Another factor to consider in some remediation techniques is the propensity of environmental contaminants to migrate (or leach from) the site after being sequestered or stabilized. The U.S. EPA also regulates this and has a test, the Toxicity Characteristic Leaching Procedure (TCLP), designed to determine the mobility of both organic and inorganic analytes present in liquid, solid, and multiphase wastes.

[0007] Before selecting a remediation method for an actual contaminated site, complex bench- and pilot-scale investigations and screening tests must be conducted to evaluate the technology and determine its suitability. Furthermore, due to variations at each site treated, remediation of mercury and other environmental contaminants is costly and time-consuming. Therefore, new, more commercially attractive processes are needed to reduce the environmental and biological availability of environmental contaminants in solids, liquids, and combinations thereof. Summary of the Invention

[0008] The present invention provides a process for reducing the environmental availability of at least a portion of one or more environmental contaminants in a material containing the one or more environmental contaminants. An advantage provided by the process of the present invention is a reduction in the environmental availability of toxic environmental contaminants in the material. Such toxic contaminants include mercury and methylmercury, as well as heavy metals and ecologically toxic organics.

[0009] An advantage provided by the process of the present invention is that by reducing the environmental availability of environmental contaminants in a material, the bioavailability and bioaccumulation of such contaminants is also reduced. When the environmental contaminant is mercury, another advantage is that the process of the present invention does not require the presence of sulfide, so the reduction in environmental availability, and therefore bioavailability, is not adversely affected by acidic conditions that allow sulfide to form sulfate or sulfate compounds. This absence of sulfate also minimizes mercury methylation.

[0010] The treatment of the present invention can be used as the sole treatment to reduce the environmental availability and / or presence of environmental contaminants (e.g., mercury) in a material, or can be used to complement and / or facilitate reducing the environmental availability and / or amount of such environmental contaminants in a material beyond that achieved by existing technology.

[0011] One embodiment of the present invention is a process for reducing the environmental availability of at least a portion of one or more environmental contaminants in a material containing the contaminants. The process includes adding and / or applying a halogen-containing sorbent to the material. In the halogen-containing sorbent, the halogen comprises one or more halogens selected from fluorine, chlorine, bromine, and / or iodine, and one or more substrate materials. Adding and / or applying the halogen-containing sorbent to the contaminant-containing material reduces the environmental availability of at least a portion of the one or more environmental contaminants in the material.

[0012] These and other embodiments and features of the present invention will become further apparent from the following detailed description and appended claims. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a graph showing equilibrium mercury sorption isotherm data from Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] The figures depict embodiments of certain aspects of the invention and are not intended to impose limitations on the scope of the invention.

[0015] The present invention provides a treatment for reducing the environmental availability of environmental contaminants. As used herein, the term "reducing environmental availability" refers to stabilizing, immobilizing, fixing, encapsulating, separating, containing, destroying, rendering harmless, decomposing, and decaying, reducing the amount, reducing the mobility, and / or reducing the ability to migrate of at least one environmental contaminant. Stabilization and / or immobilization can be performed in a medium. Reducing the environmental availability of an environmental contaminant can reduce the contamination. The bioavailability of the contaminant is reduced, and therefore its bioaccumulation is reduced.

[0016] As used herein, the term "environmental pollutant(s)" refers to chemical elements or compounds, or mixtures thereof, known to be harmful to humans and / or to adversely affect the environment (ecosystem). Environmental pollutants are typically regulated by one or more government agencies. Examples of environmental pollutants include all forms of mercury (e.g., elemental mercury, organic mercury compounds, and inorganic mercury compounds), other organic substances (e.g., including but not limited to, hydrophobic organic compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, furans, and / or chlorinated pesticides), toxic elements, organic and inorganic heavy metal compounds (e.g., including but not limited to, compounds containing As, Pb, Zn, Cu, Cr, and / or Cd), and other environmental contaminants known to those skilled in the art.

[0017] As used herein, terms such as "treated," "contacted," and "purified" indicate that a halogen-containing adsorbent interacts with a material containing one or more environmental contaminants in a manner that results in a reduction in the environmental availability of the one or more environmental contaminants.

[0018] The remediation agent in the practice of the present invention is a halogen-containing sorbent, sometimes referred to herein as a "halogenated sorbent." Halogen-containing sorbents are typically formed from one or more halogen-containing compounds and one or more substrate materials. Many substrate materials, particularly activated carbon, are available or are available in a wide range of particle sizes, from nanometers to centimeters.

[0019] Substrate materials include carbonaceous materials and inorganic materials. Suitable carbonaceous materials include, but are not limited to, activated carbon, carbon black, charcoal, and charcoal. A preferred carbonaceous material is activated carbon, which can be used in many forms, including, but not limited to, powder, granular, or extruded, and has a high specific surface area. Powdered activated carbon is a particularly preferred form of activated carbon.

[0020] Suitable inorganic materials include inorganic oxides (e.g., alumina (amorphous and crystalline), silica, magnesia, and titania), natural zeolites (e.g., chabazite, clinoptilolite, faujasite), synthetic zeolites (e.g., zeolites with high Si:Al ratios such as synthetic chabazite (ZSM-5, beta zeolite, sodalite), zeolites with moderate Si:Al ratios (Y zeolite, A zeolite), silica alumina phosphate (SAPO) zeolites, ion-exchanged zeolites, uncalcined zeolites), clay minerals (e.g., kaolin, kaolinite, bentonite, montmorillonite), inorganic hydroxides (e.g., iron hydroxide), mixed metal oxides (e.g., hydrotalcite, metallated bilayer clay), diatomaceous earth, cement dust, hydrotreating catalysts (e.g., alumina, silica, or titania), including catalysts on substrates, CaCO3, and combinations of any two or more of the foregoing. Preferred inorganic materials include inorganic oxides (especially silica), natural zeolites (especially chabazite), and clay minerals (especially kaolinite and bentonite). CaCO3 is also a preferred substrate material.

[0021] The halogen element in the halogen-containing adsorbent can be fluorine, chlorine, bromine, iodine, or a mixture of any two or more halogens. Bromine is the preferred halogen. Suitable halogen-containing compounds include, but are not limited to, elemental iodine and / or iodine compounds, elemental bromine and / or bromine compounds, elemental chlorine and / or chlorine compounds, elemental fluorine and / or fluorine compounds, and other suitable halogen compounds, as known to those skilled in the art. Types of halogen-containing compounds that can be used include hydrohalic acids, alkali metal halides, alkaline earth halides, and ammonium halides.

[0022] Hydrohalic acids include hydrogen chloride, hydrogen bromide, and hydrogen iodide. Alkali metal halides include sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, and potassium iodide. Alkaline earth halides include magnesium chloride, magnesium bromide, calcium chloride, and calcium bromide. Ammonium halides include ammonium chloride, ammonium bromide, and ammonium iodide.

[0023] Preferred halogen-containing compounds include elemental bromine, hydrogen bromide, sodium chloride, sodium bromide, potassium iodide, and calcium bromide. Bromine-containing compounds are preferred halogen-containing compounds, more preferred are hydrogen bromide and elemental bromine, and especially preferred is elemental bromine.

[0024] Halogen-containing adsorbents can be made from materials and halogen-containing compounds as described in U.S. Patent Nos. 6,953,494 and 9,101,907, and International Patent Publication No. WO 2012 / 071206. In some embodiments, the preferred halogen-containing adsorbent is a bromine-containing adsorbent. In some embodiments, the preferred halogen-containing adsorbent is halogen-containing activated carbon. In other embodiments, the preferred halogen-containing activated carbon is halogen-containing activated carbon, bromine-containing activated carbon, and iodine-containing activated carbon. In preferred embodiments, the halogen-containing adsorbent is halogen-containing activated carbon and bromine-containing activated carbon. In a more preferred embodiment, the halogen-containing adsorbent is halogen-containing activated carbon. Bromine-containing activated carbon is commercially available from Albemarle Corporation.

[0025] In other embodiments, preferred halogen-containing adsorbents are chlorine-containing activated carbon and iodine-containing activated carbon. In yet other embodiments, preferred halogen-containing adsorbents are halogen-containing chabazite, halogen-containing bentonite, halogen-containing kaolinite, and halogen-containing silica.

[0026] In another embodiment, preferred halogen-containing adsorbents include bromine-containing silica, bromine-containing kaolinite, and bromine-containing bentonite.

[0027] The amount of halogen (or halogen content) on the material typically corresponds to a total bromine content (or calculated as bromine) in the range of about 0.1 wt. % to about 20 wt. %, preferably about 0.5 wt. % to about 15 wt. %, more preferably about 2 wt. % to about 12 wt. %, and even more preferably about 3 wt. % to about 8 wt. %, based on the total weight of the halogen-containing adsorbent.

[0028] As used herein, the phrases "as bromine," "reported as bromine," "calculated as bromine," and similar phrases with respect to halogen refer to the amount of halogen where the value is calculated in terms of bromine, unless otherwise specified. For example, the amount of halogen in a halogen-containing adsorbent is reported as a bromine value, although elemental fluorine may be used.

[0029] Bromine-containing activated carbon suitable for use in the process of the present invention can have a wide range of particle sizes and distributions, from nanometers to centimeters, and can be formed from activated carbon forms, including, for example, but not limited to, powdered, granular, or extruded, and can have high specific surface areas, various unique pore structures, and other characteristics well known to those skilled in the art.

[0030] Halogen-containing adsorbents, particularly bromine-containing adsorbents, and more particularly bromine-containing adsorbents, can reduce the environmental availability of contaminants in a material through means including, but not limited to, oxidation and / or adsorption. Adsorption can reduce the environmental availability of environmental contaminants by reducing the mobility of such contaminants. Other ways in which halogen-containing sorbents can reduce the environmental availability of contaminants are by promoting the decomposition of such contaminants through surface reactions, and / or by inhibiting the formation of contaminants such as methylmercury, and / or by other mechanisms. In the process of the present invention, whether applied to solids, liquids, or combinations thereof, environmental contaminants adsorbed by halogen-containing sorbents are stabilized so that desorption into the environment is substantially minimized.

[0031] Mercury and other environmental pollutants are adsorbed onto or removed by halogen-containing adsorbents, particularly bromine-containing activated carbon. Different halogen (especially bromine) species can be formed on halogen-containing adsorbents, particularly bromine-containing adsorbents, especially bromine-containing activated carbon. For example, one bromine species, bromine, can oxidize elemental mercury to form mercury bromide, which can be adsorbed into the pores of the activated carbon. Another species, bromide ions, can chemically bond with ionic mercury for adsorption onto the surface of the activated carbon. Other components may catalyze the oxidation of mercury and facilitate stabilization or adsorption of the oxidized mercury product.

[0032] Some halogen-containing adsorbents, particularly bromine-containing activated carbon, can physically and chemically adsorb mercury in various oxidation states, including elemental mercury, oxidized mercury, and organic mercury. Mercury adsorbed on bromine-containing activated carbon is stable over a wide range of pH values. "Stable" here means that mercury does not separate from the adsorbent in significant amounts after adsorption.

[0033] The sorbents used in the processes of the present invention can be combined with other optional components, such as pH buffers (e.g., including, but not limited to, carbonates and phosphates), carriers (e.g., including, but not limited to, sand and mud), binders (e.g., including, but not limited to, mud, clay, and polymers), and / or other additives (e.g., including, but not limited to, iron compounds and sulfur compounds).

[0034] In the practice of the present invention, the halogen-containing sorbent can be used in various forms, including as a dry sorbent or in combination with a suitable fluid (e.g., in a slurry). As used herein, the term "suitable fluid" refers to fluids such as water, as well as other fluids. Given the teachings of the present disclosure, one of ordinary skill in the art would have the knowledge to select an appropriate fluid, as the selection will depend on variables (e.g., the composition of the material, the composition of environmental contaminants present in the material, etc.).

[0035] Some treatments of materials can be carried out both in-situ and ex-situ.

[0036] Thermal desorption and retort treatment are two common ex situ thermal processes for mercury remediation. These techniques involve heating the contaminated medium to volatilize the mercury, followed by condensation of the vapor to liquid elemental mercury. Bromine-containing activated carbon may be used to adsorb mercury in place of a liquid mercury condenser, or to remove mercury in the exhaust gases exiting the condenser.

[0037] In some applications, the halogen-containing adsorbent remains in or with the material. In other applications, the adsorbent may be recovered after use. When the halogen-containing adsorbent is recovered after use, it can be discarded or regenerated and reused.

[0038] A substance containing one or more environmental contaminants may be a solid, a liquid, a combination of a solid and a liquid, or a combination of one or more solids and one or more liquids. If the substance is a solid, it may contain multiple solids. If the substance is a liquid, it may contain multiple liquids.

[0039] In some processes of the present invention, one or more solids, one or more liquids, or at least one Whether applied to a material comprising a combination of one solid and at least one liquid, the use of a halogen-containing sorbent can be a stand-alone remediation method or can complement the use of other remediation methods. In other processes according to the present invention, a halogen-containing sorbent can be used in addition to one or more other remediation agents in the same remediation process.

[0040] Adding a halogen-containing sorbent to the contaminated waste adsorbs one or more contaminants. In some embodiments, the halogen-containing sorbent remains in the material to stabilize and / or solidify the material. In other embodiments, the combined halogen-containing sorbent and material, often along with binders and other compounds, are placed in a landfill.

[0041] As used herein, the term "solid(s)" includes, but is not limited to, soil, trash, waste, and other such materials known to those skilled in the art. Soil is a preferred solid to treat in the practice of the present invention. The treatment of the present invention is provided to reduce the environmental availability of at least a portion of one or more environmental contaminants in a solid that contains one or more environmental contaminants. Materials that are solids may be referred to herein as solid objects.

[0042] Addition and / or application of a halogen-containing adsorbent to the solid, (a) injecting the halogen-containing adsorbent into the solid through holes and / or depressions and / or channels optionally present in the substrate, whether already present or manually created (e.g., by drilling holes in the substrate); and / or (b) applying a halogen-containing adsorbent to the surface of the solid; and / or (c) incorporating a halogen-containing adsorbent onto at least a portion of the surface of the solid; and / or (d) placing a halogen-containing adsorbent in the vacuum well in which the solids are treated; and / or (e) adding a halogen-containing adsorbent to the contained solids; and / or (f) incorporating a halogen-containing adsorbent into the solid; and / or (g) adding a halogen-containing adsorbent to the reactive barrier; and / or (h) forming a reactive barrier containing a halogen-containing adsorbent.

[0043] The incorporation of the halogen-containing adsorbent into the surface of the solid as in (c) above can be achieved by incorporating the halogen-containing adsorbent into a portion of the solid and then applying the adsorbent-solid combination to the surface of the solid, or by incorporating the halogen-containing adsorbent into the surface of the solid.

[0044] Some preferred methods of adding and / or applying the halogen-containing adsorbent to a solid include: (a) injecting a halogen-containing adsorbent into a solid; (b) applying a halogen-containing adsorbent to the surface of the solid; and / or (c) incorporating a halogen-containing adsorbent onto at least a portion of the surface of the solid.

[0045] An embodiment of treating a solid to reduce the environmental availability of one or more environmental contaminants includes (i) drilling holes, depressions, and / or channels in the solid, (ii) covering the surface of the solid with a layer of a halogen-containing sorbent, and (iii) heating portions of the solid to cause the one or more environmental contaminants (e.g., mercury) to migrate toward the surface having the halogen-containing sorbent thereon.

[0046] Another embodiment of treating a solid to reduce the environmental availability of one or more environmental contaminants includes (i) drilling holes, depressions, and / or channels in the solid, (ii) filling some of the holes or channels with a halogen-containing sorbent, and (iii) purging heated air into the holes or channels to migrate one or more environmental contaminants (e.g., mercury) toward the holes filled with the halogen-containing sorbent.

[0047] In some embodiments of the present invention, a solid is heated to vaporize environmental contaminants (e.g., mercury) in a vacuum well. As in (d) above, if a halogen-containing sorbent is present in the vacuum, the halogenated sorbent can absorb the vaporized environmental contaminant(s). In these processes, the halogen-containing sorbent is placed in the vacuum well and contacted with vapors generated at one or more locations in the vacuum well before the vapors are released into the atmosphere. One application of this process is in soil vapor extraction (SVE) for mercury remediation, where a halogen-containing sorbent (particularly bromine-containing activated carbon) can be placed in the vacuum well to adsorb mercury.

[0048] In situ, using halogen-containing adsorbents in certain types of solid materials, soils and / or before or immediately after soil stabilization and solidification (S / S) in ex situ treatments. One ex situ treatment is the immobilization of mercury in halogen-containing adsorbents. The agent, one or more binders, and other ingredients are added to the contaminated material and mixed in a reactor. The mixture is then stabilized and cemented or placed in a landfill. In some embodiments, bromine-containing powdered activated carbon can be used in the S / S treatment process. Mercury adsorbed on the bromine-containing powdered activated carbon is stabilized during concrete production and curing. See, e.g., U.S. Patent Nos. 8,404,038 and 8,420,033. This is advantageous because fly ash and cement are typical binders used in S / S technology.

[0049] In another embodiment of the present invention, where a halogen-containing sorbent (especially bromine-containing powdered activated carbon) is the remediation agent for mercury-contaminated soil, the halogen-containing sorbent is spread over the contaminated soil. In this manner, the soil is undisturbed and the halogen-containing sorbent (especially bromine-containing activated carbon) is present in the top layer of the soil, blocking mercury migration from the soil.

[0050] Halogenated adsorbents (especially bromine-containing activated carbon) can be mixed with another agent to create a mixture that improves the penetration of the halogen-containing adsorbent into solids (especially soil). The amount of halogen-containing adsorbent added can be less than 10% of the top layer of soil, and the top layer of soil can be up to 10 cm thick. In some embodiments, a pH adjuster is also applied, either separately or mixed with the halogen-containing adsorbent, optionally together with an agent that improves the penetration of the halogen-containing adsorbent into solids.

[0051] The treatments of the present invention are provided for reducing the environmental availability of at least a portion of one or more environmental contaminants in a liquid containing the one or more environmental contaminants. As used herein, the term "liquid(s)" includes, but is not limited to, groundwater, wastewater, surface water, saltwater, freshwater (e.g., lakes, ponds), and other such materials known to those skilled in the art. Materials that are liquids may be referred to herein as liquids.

[0052] The addition and / or application of the halogen-containing adsorbent to the liquid includes: (a) injecting a halogen-containing adsorbent into the liquid, optionally with filtration of the adsorbent used; and / or (b) applying a halogen-containing adsorbent to the surface of the liquid; and / or (c) incorporating a halogen-containing sorbent into the liquid; and / or (d) passing the liquid over a fixed bed containing a halogen-containing adsorbent; and / or (e) passing the liquid through a filter containing a halogen-containing adsorbent; and / or (f) pumping the liquid through a fixed bed or column containing a halogen-containing adsorbent; and / or (g) adding a halogen-containing adsorbent to the contained amount of the liquid.

[0053] The halogen-containing adsorbent can be incorporated into a liquid as described above in (c) by incorporating the halogen-containing adsorbent into the bulk liquid or by incorporating the halogen-containing adsorbent into a portion of the liquid to form a slurry, and then combining the slurry with the remaining liquid.

[0054] Some materials are combinations of at least one solid and at least one liquid, including sediments, slurries, sediments, pore water (e.g., soil pore water or sediment pore water), and other solid-liquid combinations. Sediments, soil pore water, and sediment pore water are preferred formulations to treat in the practice of the present invention. These combinations are sometimes referred to as multiphase materials. The treatments of the present invention are provided to reduce the environmental availability of at least a portion of one or more environmental contaminants in combinations that include one or more environmental contaminants. Materials that are combinations are sometimes referred to as formulations herein.

[0055] Adding and / or applying a halogen-containing sorbent to the formulation can include adding and / or applying a halogen-containing sorbent to the formulation. In such processes, adding and / or applying a halogen-containing sorbent to the formulation can include: (a) injecting the halogen-containing sorbent into the formulation through holes and / or depressions and / or channels optionally present in the substrate, whether already present or manually created (e.g., by drilling holes into the formulation); and / or (b) applying a halogen-containing adsorbent to the surface of the formulation; and / or (c) combining a halogen-containing adsorbent with at least a portion of the surface of the formulation, as described above for solid and / or liquid materials; and / or (d) combining a halogen-containing sorbent with the formulation; and / or (e) placing a halogen-containing adsorbent in the vacuum well in which the formulation is treated in a manner similar to that described for solid materials; and / or (f) adding a halogen-containing adsorbent to the formulation; and / or (g) coating the surface of the material with a layer comprising a halogen-containing adsorbent; and / or (h) placing a halogen-containing adsorbent in the cap; and / or (i) adding a halogen-containing adsorbent to the reactive barrier; and / or (j) forming a reactive barrier containing a halogen-containing adsorbent; and / or (k) disposing a halogen-containing adsorbent in the geotextile mat.

[0056] Combining a halogen-containing adsorbent with the formulation as in (d) above can be accomplished by combining the halogen-containing adsorbent with the formulation or with a portion of the formulation to form a mixture, and then combining the mixture with the surface of the formulation. In these embodiments, the halogen-containing adsorbent can include, for example, but is not limited to, a halogen-containing activated carbon adsorbent, preferably a bromine-containing carbon adsorbent, and more preferably a bromine-containing activated carbon adsorbent.

[0057] Some preferred methods for adding and / or applying the halogen-containing sorbent to the formulation include: (a) injecting a halogen-containing sorbent into the formulation; (b) applying a halogen-containing adsorbent to the surface of the formulation; (c) combining a halogen-containing adsorbent with at least a portion of the surface of the formulation; and / or (d) combining the formulation with a halogen-containing adsorbent.

[0058] As will be apparent to those skilled in the art, many variables regarding the use of the present invention must be considered depending on the material being treated. For all processes of the present invention, whether applied to solids, liquids, or combinations thereof, given the teachings herein, one skilled in the art will have the knowledge at hand to determine the amount of halogen-containing sorbent to use, including whether any components are used in combination with the sorbent, and if so, the specific optional components and amounts that will be beneficial, the number of applications of the present process and the duration of such applications that will be beneficial, whether the present process is used in combination with known remediation methods, and if so, how to use them to achieve beneficial results.

[0059] The following examples are presented for illustrative purposes and are not intended to impose limitations on the scope of the present invention.

[0060] In the examples, unless otherwise stated, the amount of mercury present in the samples was measured via cold vapor atomic absorption spectrometry on an atomic absorption spectrometer equipped with a mercury vapor analyzer (CVAA, Atomic Absorption Mercury Spectrometer with Zeeman Background Correction, Ohio Lumex Co., Model No. RA915+).

[0061] In all examples, experiments using plain (untreated) activated carbon are included for comparison. [Example]

[0062] Example 1 Powdered activated carbon (average particle size 15 μm) was treated with vapor-phase Br2 at elevated temperatures to form a bromine-containing powdered activated carbon with a bromine content of 8% by weight, as described in U.S. Patent No. 6,953,494. The bromine-containing activated carbon adsorbent was used to remove mercury from a synthetic mercury-containing solution. Bromine-containing powdered activated carbon (0.4 g / L) was placed in several reaction bottles. A solution was prepared with Hg(NO3)2 at pH 2 and added to the reactor bottle containing the adsorbent. Each reaction bottle contained a different Hg 2+The samples were rotated at 32 ± 2 revolutions per minute for 24 hours, and each resulting mixture was passed through a syringe filter (0.45 μm pore membrane) to separate the adsorbent from the liquid. Another series of experiments was conducted in parallel using untreated (plain) activated carbon for comparison. The mercury concentration of the liquid filtered from each solution was then measured.

[0063] In these experiments, the maximum mercury adsorption by the bromine-containing activated carbon was 8 wt.%, while the maximum mercury adsorption by the untreated activated carbon was 3 wt. The results are summarized in Table 1.

[0064] The adsorption isotherms for both Br-PAC and untreated powdered activated carbon (PAC) fit the Langmuir equation. The calculated Langmuir equilibrium adsorption capacities are consistent with the experimental data. Figure 1 shows the equilibrium mercury adsorption isotherms for both sets of experiments. Data are shown as squares, and calculated Langmuir isotherms are shown for both Br-PAC (filled squares and solid line) and the comparative experiment using untreated activated carbon (open squares and dashed line). Here, the x-axis is the equilibrium aqueous Hg concentration (mg / L) and the y-axis is the Hg adsorbed on the adsorbent (mg / g). [Table 1]

[0065] Example 2 Granular activated carbon with particle sizes ranging from 0.6 mm to 2.4 mm was treated with vapor-phase Br2 at elevated temperatures to form bromine-containing granular activated carbon with a bromine content of 3% by weight, as described in U.S. Patent No. 6,953,494. The bromine-containing granular activated carbon was packed into several quartz columns, 15 cm high and 1.5 cm in diameter. The synthetic wastewater solution was treated with HgCl2 or Hg(NO3)2. 2+ The Hg concentration was measured by adding 100 mg of HCl to deionized water at a pH of 6.8 ± 0.2. 2+The concentration was adjusted to approximately 4000 ng / L. The synthetic wastewater solution was passed from top to bottom through each column at different flow rates of 0.1, 0.3, 0.5, and 1.0 BV / min (BV is bed volume). Influent and effluent samples were taken from each column every 3 hours, and the samples were analyzed for mercury content by atomic absorption spectrometry using U.S. EPA Method 1631.

[0066] The bromine-containing granular activated carbon used in this example is much more efficient than commercially available activated carbon (Filtrasorb® 300, Calgon Corp.), which has a particle size of 0.8-1.0 mm, and was tested in mercury-contaminated water near the Y-12 plant in Oak Ridge, Tennessee. Data generated for the Filtrasorb® 300 sorbent are included in T&N Associates, Mercury Treatability Study Final Report: Oak Ridge Y-12, prepared for the USDA Department of Energy, Office of Environmental Management under subcontract 395064-14-AMU, Oak Ridge, Tennessee, June 1998. Plant, Report BJC / OR-46. The results are summarized in Table 2 below. [Table 2]

[0067] Example 3 This example demonstrates that mercury from an unsaturated solution, when captured by bromine-containing activated carbon, does not leach from the bromine-containing activated carbon.

[0068] Fly ash containing bromine-containing powdered activated carbon (Br-PAC, 5% Br by weight) containing mercury captured from flue gas was tested for mercury leaching in solutions of different pH values ​​with several different amounts of mercury in the fly ash / Br-PAC. In these tests, 5 g of each fly ash / Br-PAC sample was rotated in each solution (100 mL) at 32 ± 2 revolutions per minute for 24 hours, filtered, and the filtered liquid was then analyzed for mercury. The results are summarized in Table 3 below.

[0069] These TCLP tests show that mercury leachability is much lower than the U.S. EPA leachate limits at pH values ​​of 3, 8, and 11. Even though the amount of mercury in the fly ash / Br-PAC sample is higher than in the (comparison) fly ash-only baseline sample, less mercury leaches from the fly ash / Br-PAC sample than from the fly ash-only sample. Similar results have been reported for mercury in basic leachate (pH 11.12, aqueous Na2CO3) and near-neutral leachate (pH 8.03, water) (Nelson, Jr., S., et al., 2004). al., “Evaluation of Fly Ash Containing B-PAC™ Brominated Mercury Sorbent,” presented at the 2005 World of Coal Ash Conference, 2005, unpublished conference presentation). [Table 3]

[0070] The data in Table 3 show that at various pH values, samples containing fly ash and bromine-containing powdered activated carbon had the least amount of mercury in the leachate. The negative values ​​in the "Difference" column in Table 3 indicate that not only was the mercury adsorbed on the bromine-containing powdered activated carbon not released, but that the bromine-containing powdered activated carbon also removed the mercury present in the acetic acid extraction solvent.

[0071] Example 4 The stability of adsorbed mercury in bromine-containing powdered activated carbon (Br-PAC) mixed with soil was tested. Br-PAC (8% Br by weight), prepared as in U.S. Patent No. 6,953,494, was placed in contact with the soil mixture at various ratios. Each sample was treated with 50 ppm Hg (as HgCl2 solution) and then rotated at 32 ± 2 revolutions per minute for 24 hours. The samples were then tested for mercury adsorption capacity. Upon completion of the adsorption test, the solids of each sample (including the adsorbent and soil) were separated from the liquid, and the solid samples were dried and tested under the U.S. EPA's Toxicity Characterization Leaching Procedure (TCLP) to determine the amount of mercury desorbed from each sample. The conditions used were 0.1 M acetic acid, pH = 2.88 ± 0.5, and a solid-to-liquid ratio (S / L) of 1:20. The results are summarized in Table 4. [Table 4]

[0072] Example 5 Kinetic data for mercury adsorption onto and in Br-PAC (formulated as in U.S. Patent No. 6,953,494) and plain PAC were generated. Experiments were performed using solutions containing 50 ppm mercury. Different amounts of adsorbent were added to each mercury solution. The adsorbent-containing solutions were sampled at several time intervals. The results are summarized in Tables 5A-5D. The kinetic data show that Br-PAC reached a steady state of adsorption in approximately 30 minutes (0.5 g / L) to approximately 5 minutes (1.5 g / L), while plain PAC did not reach a steady state at 24 hours. [Table 5A] [Table 5B] [Table 5C] [Table 5D]

[0073] Example 6 The stability of adsorbed mercury in brominated powdered activated carbon (Br-PAC) mixed with soil under acidic conditions was tested. Br-PAC (8 wt. % Br), prepared as in U.S. Patent No. 6,953,494, was placed in contact with the soil mixture at 1 wt. %. Each sample was treated with 50 ppm Hg (as HgCl2 or Hg(NO3)2 solution) and then rotated at 32 ± 2 rpm for 24 hours. The samples were then tested for mercury adsorption capacity. The results are summarized in Table 6. [Table 6]

[0074] Example 7 Br-PAC was prepared as described in U.S. Patent No. 6,953,494. Several halogen-containing adsorbents were prepared by either (1) adding an aqueous solution of a halide salt to activated carbon or inorganic material, mixing thoroughly, and then drying the mixture, or (2) blending powdered halide salt with carbon or inorganic material until a relatively homogeneous mixture was obtained. These bromine-containing adsorbents were tested for their ability to absorb mercury from a synthetic mercury-containing solution.

[0075] The halogenated adsorbent was placed in a reaction bottle. A solution was prepared with HgCl2 or Hg(NO3)2 and added to the reaction bottle containing the adsorbent. Each reaction bottle contained the same concentration of Hg 2+ The samples were rotated at 32 ± 2 revolutions per minute for 24 hours, and each resulting mixture was passed through a syringe filter (0.45 μm pore membrane) to separate the adsorbent from the liquid. A parallel comparative experiment was performed using untreated (plain) activated carbon. The mercury concentration of the liquid filtered from each solution was then measured. Parameters were not optimized, particularly for the halogenated adsorbents made from inorganic halide salts. The results are summarized in Table 7. [Table 7]

[0076] Further embodiments of the present invention include, but are not limited to, the following.

[0077] A) A process for reducing the environmental availability of at least a portion of one or more environmental contaminants in a material that contains one or more environmental contaminants, said process comprising: adding and / or applying a halogen-containing adsorbent to the material, wherein the halogen-containing adsorbent is a bromine-containing activated carbon adsorbent, a chlorine-containing activated carbon adsorbent, an iodine-containing activated carbon adsorbent, a bromine-containing chabazite, a bromine-containing bentonite, a bromine-containing kaolinite, or a bromine-containing silica; thereby reducing the environmental availability of at least a portion of one or more environmental contaminants in the material.

[0078] B) The same process as in A), wherein the halogen-containing adsorbent has a halogen content, calculated as bromine, of about 0.1 to about 20 weight percent based on the total weight of the halogen-containing adsorbent.

[0079] C) The same process as in A), wherein the halogen-containing adsorbent has a halogen content, calculated as bromine, of about 0.5 wt. % to about 15 wt. % based on the total weight of the halogen-containing adsorbent.

[0080] D) The same process as in A), wherein the halogen-containing adsorbent has a halogen content, calculated as bromine, of about 2% to about 12% by weight based on the total weight of the halogen-containing adsorbent.

[0081] E) The same process as in A), wherein the halogen-containing adsorbent has a halogen content, calculated as bromine, of about 3% to about 8% by weight based on the total weight of the halogen-containing adsorbent.

[0082] F) The same treatment as any of A) to E), except that the material is soil.

[0083] G) A process similar to any of A) through E), except that the material is sediment.

[0084] H) A treatment similar to any of A) to E), where the material is soil pore water or sediment pore water.

[0085] I) A process similar to A), wherein the adsorbent is bromine-containing activated carbon, the halogen content, calculated as bromine, is about 0.1 wt. % to about 20 wt. % based on the total weight of the halogen-containing adsorbent, and the material is soil, sediment, soil pore water, or sediment pore water.

[0086] J) The same treatment as in I), wherein the halogen content, calculated as bromine, is from about 0.5% to about 15% by weight, preferably from about 2% to about 12% by weight, and more preferably from about 3% to about 8% by weight, based on the total weight of the halogen-containing adsorbent.

[0087] K) The same treatment as in A), wherein the adsorbent is bromine-containing chabazite, bromine-containing bentonite, bromine-containing kaolinite, or bromine-containing silica, the halogen content, calculated as bromine, is from about 0.1 wt. % to about 20 wt. % based on the total weight of the halogen-containing adsorbent, and the material is soil, sediment, soil pore water, or sediment pore water.

[0088] L) The same treatment as in K), wherein the halogen content, calculated as bromine, is from about 0.5% to about 15% by weight, preferably from about 2% to about 12% by weight, and more preferably from about 3% to about 8% by weight, based on the total weight of the halogen-containing adsorbent.

[0089] M) A process similar to A), wherein the adsorbent is chlorine-containing activated carbon, the halogen content, calculated as bromine, is about 0.1 wt. % to about 20 wt. % based on the total weight of the halogen-containing adsorbent, and the material is soil, sediment, soil pore water, or sediment pore water.

[0090] N) A process similar to A), wherein the adsorbent is iodine-containing activated carbon, the halogen content, calculated as bromine, is about 0.1 wt. % to about 20 wt. % based on the total weight of the halogen-containing adsorbent, and the material is soil, sediment, soil pore water, or sediment pore water.

[0091] O) The same treatment as in K), wherein the halogen content, calculated as bromine, is from about 0.5% to about 15% by weight, preferably from about 2% to about 12% by weight, based on the total weight of the halogen-containing adsorbent.

[0092] A component referenced by chemical name or formula anywhere in this specification or claims is identified, regardless of whether it is described in singular or plural, if the component exists prior to contact with another substance (e.g., another component, solution, or otherwise) referenced by chemical name or chemical type. It does not matter if a chemical change, transformation, and / or reaction occurs in the resulting mixture or solution, since such change, transformation, and / or reaction is a natural result of bringing the particular components together under the conditions necessary in accordance with this disclosure. Thus, the component is the component with which it is brought together in connection with performing a desired operation or forming a desired composition. Also, even when the following claims refer to substances, ingredients, and / or materials in the present tense (e.g., "comprising," "is," etc.), the reference is to the substance, ingredient, or material as it was then present immediately before it was first contacted, blended, or mixed with one or more other substances, ingredients, and / or materials according to this disclosure. Thus, there is no practical concern in the fact that a substance, ingredient, or material may lose its original identity due to chemical reaction or transformation during the course of a contacting, blending, or mixing operation, when performed in accordance with this disclosure and the ordinary skill of a chemist.

[0093] The present invention may comprise, consist of, or consist essentially of the materials and / or procedures recited herein.

[0094] As used herein, the term "about" modifying the amount of a component in a composition or used in a method of the present invention refers to variations in numerical quantity that may occur, for example, due to typical measuring and liquid handling procedures used in making concentrates or using solutions in the real world, due to inadvertent errors in these procedures, due to differences in the manufacture, source, or purity of components used to make the composition or carry out the method, etc. The term about also encompasses amounts that vary due to different equilibrium conditions of a composition resulting from a particular initial mixture. Whether modified by the term "about," the claims encompass the equivalent of the quantity.

[0095] As used herein, the article "a" or "an," when used herein, is not intended to, and should not be construed as, limiting the scope of the detailed description or claims to the single element to which the article refers, unless otherwise expressly indicated. Rather, the article "a" or "an," when used herein, is intended to cover one or more such elements, unless the context clearly indicates otherwise.

[0096] While the invention has been described with respect to one or more preferred embodiments, it should be understood that other modifications may be made without departing from the scope of the invention as set forth in the following claims.

Claims

1. 1. A process for reducing the environmental availability of at least a portion of one or more environmental contaminants in a material that contains one or more environmental contaminants, said process comprising: adding and / or applying a halogen-containing sorbent to the material, the halogen-containing sorbent comprising one or more halogens selected from fluorine, chlorine, bromine, and / or iodine, and / or one or more substrate materials; thereby reducing the environmental availability of at least a portion of one or more environmental contaminants in said material.

2. The process of claim 1 , wherein the halogen-containing adsorbent comprises a substrate material selected from one or more carbonaceous materials.

3. The process of claim 2 wherein the carbonaceous material is activated carbon.

4. 10. The process of claim 1, wherein the halogen-containing adsorbent comprises a substrate material selected from one or more inorganic materials.

5. The inorganic material is an inorganic oxide, natural zeolite, CaCO ３ 5. The process of claim 4, wherein the inorganic particles are selected from the group consisting of ammonium nitrate, ...

6. 6. The process of claim 5, wherein the inorganic material is selected from chabazite, silica, kaolinite, and bentonite.

7. The process of any one of claims 1 to 6, wherein the halogen-containing adsorbent is a bromine-containing adsorbent.

8. 10. The process of claim 1, wherein the halogen-containing adsorbent is a halogen-containing activated carbon adsorbent.

9. 10. The process of claim 1, wherein the halogen-containing adsorbent is a bromine-containing activated carbon adsorbent.

10. 10. The process of any one of claims 1 to 9, wherein the halogen-containing adsorbent has a halogen content, calculated as bromine, of about 0.1 to about 20 wt. % based on the total weight of the halogen-containing adsorbent.

11. The process of any one of claims 1 to 10, wherein the material containing the environmental pollutant is a solid.

12. adding and / or applying the halogen-containing adsorbent to the solid, (a) injecting the halogen-containing adsorbent into the solid; (b) applying the halogen-containing adsorbent to the surface of the solid; (c) incorporating the halogen-containing adsorbent onto at least a portion of the surface of the solid; (d) placing the halogen-containing adsorbent in a vacuum well where the solids are to be treated; (e) adding the halogen-containing adsorbent to the contained solids; (f) combining the halogen-containing adsorbent with the solid; (g) adding said halogen-containing adsorbent to a reactive barrier; and / or 12. The process of claim 11, comprising: (h) forming a reactive barrier comprising the halogen-containing adsorbent.

13. The process of any one of claims 1 to 10, wherein the substance containing the environmental pollutant is a liquid.

14. adding and / or applying the halogen-containing adsorbent to the liquid; (a) injecting the halogen-containing adsorbent into the liquid; (b) applying the halogen-containing adsorbent to the surface of the liquid; (c) combining the halogen-containing adsorbent with the liquid; (d) passing the liquid over a fixed bed comprising the halogen-containing adsorbent; (e) passing the liquid through a filter containing the halogen-containing adsorbent; (f) pumping the liquid through a fixed bed or column containing the halogen-containing adsorbent; and / or 14. The process of claim 13, comprising: (g) adding said halogen-containing adsorbent to a contained amount of liquid.

15. The process of any one of claims 1 to 10, wherein the material containing the environmental pollutant is a combination of at least one solid and at least one liquid.

16. adding and / or applying the halogen-containing adsorbent to the formulation; (a) injecting the halogen-containing sorbent into the formulation; (b) applying the halogen-containing adsorbent to the surface of the formulation; (c) combining the halogen-containing adsorbent with at least a portion of the surface of the formulation; (d) combining said halogen-containing adsorbent with said formulation; (e) placing the halogen-containing adsorbent in a vacuum well in which the formulation is to be treated; (f) adding said halogen-containing adsorbent to the formulation in which it is contained; (g) coating the surface of the material with a layer comprising the halogen-containing adsorbent; (h) placing the halogen-containing adsorbent in a cap; (i) adding said halogen-containing adsorbent to a reactive barrier; (j) forming a reactive barrier comprising said halogen-containing adsorbent; and / or 16. The process of claim 15, comprising: (k) disposing the halogen-containing adsorbent in a geotextile mat.

17. 13. The process of claim 11 or 12, wherein the solid is soil.

18. The adding and / or applying (a) injecting the halogen-containing sorbent into the soil; (b) applying the halogen-containing adsorbent to the surface of the soil; and / or 17. The process of claim 16, comprising: (c) combining the halogen-containing sorbent with at least a portion of the surface of the soil.

19. 17. The process of claim 15 or 16, wherein the formulation is a deposit.

20. said adding and / or applying (a) injecting the halogen-containing sorbent into the formulation; (b) applying the halogen-containing adsorbent to the surface of the formulation; (c) combining the halogen-containing adsorbent with at least a portion of the surface of the formulation; and / or 20. The process of claim 19, comprising: (d) combining the halogen-containing adsorbent with the formulation.

21. 10. The process of claim 1, wherein the material is soil or sediment and the halogen-containing adsorbent is a bromine-containing activated carbon adsorbent.

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