Methods for suppressing mercury vapor emissions

Abstract

The present invention provides a process for inhibiting the emission of mercury vapor from materials containing volatile mercury.

Description

[Technical field]

[0001] The present invention relates to the suppression of mercury vapor emissions using sorbents. [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 hazard by the U.S. Department of Health and Human Services' Agency for Toxic Substances and Disease Registry (ATSDR).

[0003] Mercury species, especially elemental mercury, volatilize from a variety of contaminated materials, including mining wastes, metal processing wastes, soils, building materials, internally contaminated surfaces, and biomass waste. When the contaminated material or surface is disturbed, mercury evaporates from the contaminated material or surface, increasing mercury levels in the air, often exceeding standards for a safe working environment set by the U.S. Occupational Safety and Health Administration (OSHA). At ambient conditions, the rate of evaporation of elemental mercury from a material is limited by temperature and air-mass equalization parameters, so that the amount of mercury evaporated at ambient conditions is typically only a small fraction of the available evaporable mercury.

[0004] Decontamination, demolition, and decommissioning activities where mercury contamination is present in buildings and / or site soils shall not result in indoor mercury vapor concentrations below the OSHA threshold of 0.1 milligrams per cubic meter of air (mg / m 3 mercury exposure during such activities may exceed the permissible exposure limit (PEL) for mercury in airborne contaminated soil (PEL), which is currently enforced as an 8-hour time-weighted average. Furthermore, such activities in populated areas are often restricted by air permits that require meeting airborne mercury concentration limits measured outside the fence line of the activity site. These issues can make permitting and conducting such activities costly without measures to limit mercury evaporation during the activity.

[0005] During the redevelopment of some industrial sites, when concentrations of elemental mercury in the soil fall below regulatory action levels, hazardous levels of mercury vapor may ingress into new structures constructed on the sites. Thus, the presence of volatile mercury in the soil may require expensive systems to prevent mercury vapor from ingressing into buildings on such sites.

[0006] In some cases, the entire material may be classified as hazardous because it fails the TCLP or SPLP leaching tests for mercury. The U.S. EPA also regulates this, using the Toxicity Characteristic Leaching Procedure (TCLP), a test designed to measure the mobility of analytes such as mercury, and the Synthetic Precipitation Leaching Procedure (SPLP), to measure the amount of mercury that migrates. The soil around and under the building may also be classified as hazardous due to Hg contamination. Disposal of waste and soil classified as hazardous is costly and may prevent desirable activities at the site.

[0007] Controlling the release of mercury vapour from materials in some locations can be technically challenging depending on the material containing the evaporative mercury, the state of the material and the form of mercury present.

[0008] Another factor determined by TCLP or SPLP leaching testing of some mercury treatments is the tendency of mercury to migrate (or leach) out of the treatment medium.

[0009] Before selecting a technology to reduce mercury vapor emissions from actual materials containing evaporable mercury, extensive bench- and pilot-scale studies should be performed to determine whether the technology is suitable. Research and screening tests need to be conducted. Furthermore, mitigation of mercury vapor can be costly and time-consuming due to variability in the materials being treated. Thus, new and more commercially attractive processes for mitigating mercury vapor from materials containing evaporable mercury are needed. Summary of the Invention

[0010] The present invention provides a process for inhibiting the emission of mercury vapor.An advantage provided by the process of the present invention is that it inhibits the emission of mercury vapor from materials containing evaporable mercury.

[0011] Another advantage of the process of the present invention is that acidic conditions do not adversely affect mercury vapor emission control. Yet another advantage of the process of the present invention is that mercury cannot be leached from the sorbent.

[0012] Halogen-containing sorbents, particularly halogen-containing activated carbon, and more particularly bromine-containing activated carbon, adsorb volatile and / or pre-volatilized mercury when applied, sprinkled, or sprayed onto or on a material containing volatile mercury to form a protective barrier. The halogen-containing sorbents used in the present invention not only provide a protective barrier that inhibits the release of mercury vapor to meet OSHA requirements, but can also reduce the leachability of mercury from treated materials, thereby allowing the materials to be disposed of by less expensive means.

[0013] The mercury captured by the halogen-containing sorbents used in the practice of the present invention is generally non-leachable as measured by either the TCLP or SPLP methods.

[0014] The process of the present invention may be used as the sole method for controlling mercury vapor emissions, or the process of the present invention may be used to complement and / or enhance mercury vapor emission controls achieved by existing technologies.

[0015] One embodiment of the present invention is a process for inhibiting the release of mercury vapor from a material containing volatile mercury. The process includes applying a halogen-containing sorbent to the material containing volatile mercury and perturbing the material to volatilize the mercury. Application of the halogen-containing sorbent to the material inhibits at least a portion of the release of mercury vapor from the material.

[0016] These and other embodiments and features of the present invention will become further apparent from the following description and appended claims. [Brief description of the drawings]

[0017] [Figure 1] 1 is a graph showing the amount of mercury passing through a mixture of ordinary powdered activated carbon and sand over time in Comparative Example 1. [Diagram 2] 1 is a graph showing the amount of mercury passing through a mixture of brominated powdered activated carbon and sand over time in Example 2. [Diagram 3] 1 is a graph showing the amount of non-leachable mercury measured in Example 4.

[0018] The drawings depict embodiments of certain aspects of the invention and are not intended to impose limitations on the scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Mitigating mercury vapor emissions refers to reducing the amount of mercury vapor by capturing mercury before, during, or after its evaporation from a material.

[0020] Throughout this specification, the term "capture" refers to the stabilization, immobilization, fixation, encapsulation, or Refers to the isolation, containment, destruction, detoxification, decomposition, and decay, reduction in the amount of mercury, reduction in the mobility of mercury, and / or reduction in the ability of mercury to migrate.

[0021] As used throughout this specification, terms such as "treated," "contacted," and "improved" indicate that the halogen-containing sorbent interacts with a material containing volatile mercury in a manner that inhibits the release of mercury vapor.

[0022] The mercury vapor emission inhibitors in the practice of the present invention are halogen-containing sorbents, sometimes referred to herein as "halogenated sorbents." Halogen-containing sorbents are typically formed from one or more halogen-containing compounds and one or more substrate materials. Many substrate materials, particularly activated carbons, are available or accessible in a wide range of particle sizes, from nanometers to centimeters.

[0023] Substrate materials include carbonaceous materials and inorganic materials. Suitable carbonaceous materials include, but are not limited to, activated carbon, carbon black, char, and coke. A preferred carbonaceous material is activated carbon, which can be used in many forms, including, but not limited to, powder, granule, or extrusion, and has a high specific surface area. Powdered activated carbon is a particularly preferred form of activated carbon.

[0024] Suitable inorganic materials include inorganic oxides such as alumina (amorphous and crystalline), silica, magnesia and titania, natural zeolites such as chabazite, clinoptilolite and faujasite, synthetic zeolites such as synthetic chabazite, A zeolite, sodalite, zeolites with high Si:Al ratios (ZSM-5, beta zeolite), zeolites with medium Si:Al ratios (Y zeolite), silica alumina phosphate (SAPO) zeolites, ion-exchanged zeolites, uncalcined zeolites, clay minerals such as kaolin, kaolinite, bentonite and montmorillonite, inorganic hydroxides such as iron hydroxide, mixed metal oxides such as hydrotalcite and metallated bilayer clays, diatomaceous earth, cement dust, hydrotreating catalysts including catalysts on substrates such as alumina, silica or titania, 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), with CaCO3 also being a preferred substrate material.

[0025] The halogen element in the halogen-containing adsorbent can be chlorine, bromine, iodine, or a mixture of any two or more of these halogens. Bromine and iodine are preferred halogens, and bromine is more 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, for example. Iodine-containing compounds and bromine-containing compounds are preferred halogen-containing compounds, and bromine-containing compounds are more preferred.

[0026] The types of halogen-containing compounds that can be used include hydrohalic acids, alkali metal halides, alkaline earth halides, and ammonium halides. Hydrohalic acids include hydrogen chloride, hydrogen bromide, and hydrogen iodide. Alkali metal halides include sodium chloride, sodium bromide, sodium iodide, 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. Preferred halogen-containing compounds include elemental bromine, hydrogen bromide, sodium chloride, sodium bromide, potassium iodide, and calcium bromide. Hydrogen bromide and elemental bromine, especially elemental bromine, are more preferred.

[0027] Halogen-containing adsorbents, particularly bromine-containing adsorbents, can be made from substrate materials and halogen-containing compounds as described in U.S. Pat. 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 a halogen-containing activated carbon. In other embodiments, the preferred halogen-containing activated carbon is a chlorine-containing activated carbon, a bromine-containing activated carbon, and an iodine-containing activated carbon. In a preferred embodiment, the halogen-containing adsorbent is an iodine-containing activated carbon and a bromine-containing activated carbon. In a more preferred embodiment, the halogen-containing adsorbent is a bromine-containing activated carbon. Bromine-containing activated carbon is commercially available from Albemarle Corporation.

[0028] In other embodiments, preferred halogen-containing adsorbents are halogen-containing chabazite, halogen-containing bentonite, halogen-containing kaolinite, and halogen-containing silica, and more preferred halogen-containing adsorbents are iodine-containing chabazite, bromine-containing chabazite, iodine-containing bentonite, bromine-containing bentonite, iodine-containing kaolinite, bromine-containing kaolinite, iodine-containing silica, and bromine-containing silica, and even more preferred are bromine-containing silica, bromine-containing kaolinite, and bromine-containing bentonite.

[0029] The amount of halogen (or halogen content) on the substrate material is typically equal to a total bromine content (or calculated as bromine) in the range of about 0.1% to about 30% by weight, based on the total weight of the halogen-containing adsorbent, preferably about 0.1% to about 25% by weight, more preferably about 0.1% to about 20% by weight, even more preferably about 0.5% to about 15% by weight, still more preferably about 2% to about 12% by weight, and even more preferably about 3% to about 8% by weight.

[0030] As used throughout this specification, the phrases "as bromine," "reported as bromine," "calculated as bromine," and similar phrases relating to halogen refer to the amount of halogen, and unless otherwise noted, the numerical value is calculated for bromine. For example, elemental fluorine can be used, but the amount of halogen in a halogen-containing sorbent is reported as a bromine value.

[0031] Halogen-containing activated carbons 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, but not limited to, powders, granules, or extruded forms, and have high specific surface areas, a variety of unique pore structures, and other characteristics well known to those skilled in the art.

[0032] Halogen-containing sorbents, particularly halogen-containing carbonaceous sorbents, particularly iodine-containing and bromine-containing sorbents, and more particularly bromine-containing carbonaceous sorbents, can inhibit the release of mercury vapor from materials through means including, but not limited to, oxidation and / or adsorption. Adsorption can reduce the release of mercury vapor by reducing the mobility of mercury. In the process of the present invention, mercury adsorbed by the halogen-containing sorbents is stabilized such that desorption (and re-emission) is substantially minimized.

[0033] Mercury is adsorbed on halogen-containing adsorbents, particularly halogen-containing activated carbon, more particularly iodine-containing and bromine-containing adsorbents, and even more particularly bromine-containing carbonaceous adsorbents. On halogen-containing adsorbents, particularly halogen-containing activated carbon, various bromine species can be formed. For example, a bromine species, bromine, can oxidize elemental mercury to form mercuric bromide, which can be adsorbed in the pores of the activated carbon, another species, bromide ion, can chemically combine with ionic mercury and adsorb on the surface of the activated carbon, and another component can catalyze the oxidation of mercury and promote the stabilization or adsorption of the oxidized mercury product in the adsorbent.

[0034] Some halogen-containing sorbents, particularly halogen-containing activated carbon, especially iodine- and bromine-containing sorbents, and more particularly bromine-containing carbonaceous sorbents, are capable of physically and chemically adsorbing mercury in a variety of oxidation states, including elemental mercury, oxidized mercury, and organic mercury. Mercury adsorbed on halogen-containing activated carbon, especially bromine-containing activated carbon, is stable over a wide range of pH values, where "stable" means that the mercury does not separate in significant amounts from the sorbent after adsorption.

[0035] The sorbents used in the processes of the present invention may 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).

[0036] In the practice of the present invention, the halogen-containing sorbent can be used in various forms, such as alone as a dry sorbent, or mixed with another dry solid such as sand, or in combination with a suitable fluid, such as a suspension or slurry. As used herein, the term "suitable fluid" refers to a fluid, such as water and other fluids, and preferably the fluid is water. In some embodiments, a slurry of the halogen-containing sorbent in water that can be sprayed onto the material containing volatile mercury is preferred. When used in a slurry or suspension, the halogen-containing sorbent is about 0.1% to about 45% by weight of the slurry or suspension, preferably about 5% to about 40% by weight, and above 45% by weight of the halogen-containing sorbent forms a paste. When used as a dry solid, the halogen-containing sorbent can be used alone or mixed with at least one additional dry component.

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

[0038] The halogen-containing sorbents can be used as the sole treatment or can complement other treatment methods. Other processes according to the invention can use the halogen-containing sorbents in addition to one or more other mercury treatment agents in the same treatment sequence.

[0039] When a halogen-containing sorbent is added to a material containing volatile mercury, the halogen-containing sorbent may adsorb the mercury before, during, and / or after evaporation. In some embodiments, the halogen-containing sorbent remains with or within the material. In other embodiments, the combined halogen-containing sorbent and material are placed in a landfill, often along with binders and other compounds.

[0040] The process of the present invention is provided for inhibiting at least a portion of the emission of mercury vapor in a material containing evaporable mercury.

[0041] The materials treated in the practice of the invention are typically solids. In some embodiments, instead of or in addition to the bulk material, the surface of the material is treated with the halogen-containing sorbent. In other embodiments, the material is treated by introducing the halogen-containing sorbent below the surface of the material. As used herein, the terms "material" and / or "materials" include, but are not limited to, walls, floors, ceilings, equipment, building materials, soil, rubble, waste, mining by-products, fly ash, cement, and other such materials. Waste materials include mining waste, metal processing waste, and biomass waste. Preferred materials for treatment in the practice of the invention include soil, waste, and other materials. These include waste materials, particularly mining wastes, mining by-products, fly ash, and building materials.

[0042] Applying a halogen-containing adsorbent to a material (a) applying a halogen-containing adsorbent to the surface of the material; and / or (b) binding a halogen-containing adsorbent to at least a portion of the surface of the material; and / or (c) adding a halogen-containing sorbent to the reactive barrier; and / or (d) forming a reactive barrier containing a halogen-containing sorbent; and / or (e) introducing a halogen-containing adsorbent into the subsurface of the material.

[0043] As in (b) above, binding the halogen-containing adsorbent to the surface of the material can be accomplished by binding the halogen-containing adsorbent to a portion of the material and then applying the combination of the adsorbent and the portion of the material to the surface of the material, or by binding the halogen-containing adsorbent to the surface of the material.

[0044] Some preferred methods for applying the halogen-containing adsorbent to a solid include: (a) applying a halogen-containing adsorbent to the surface of the material; and / or (b) associating a halogen-containing adsorbent with at least a portion of the surface of the material.

[0045] To inhibit the release of mercury vapor, the halogen-containing sorbent can be applied, sprinkled, or sprayed as an aqueous suspension or slurry onto the mercury-containing material and its surfaces.

[0046] A preferred method for applying the halogen-containing adsorbent is to spray a suspension or slurry of the halogen-containing adsorbent, in particular to coat or partially coat the surface of the material, or to spread a dry solid containing the halogen-containing adsorbent over the surface of the material.

[0047] In another embodiment of the present invention, a halogen-containing sorbent, particularly halogen-containing activated carbon, is a treatment for mercury-contaminated soil, and the halogen-containing sorbent is preferably spread on top of the soil. In this method, the halogen-containing sorbent, particularly halogen-containing activated carbon, is present in the top layer of the soil and inhibits the release of mercury vapor by blocking the migration of mercury from the soil. Subsurface treatment is another preferred method for treating soil.

[0048] The halogen-containing adsorbent, particularly the iodine-containing or bromine-containing adsorbent, more particularly the bromine-containing activated carbon, can be mixed with another agent to create a mixture that improves the penetration of the halogen-containing adsorbent into the material, particularly the soil. The amount of the halogen-containing adsorbent added can be less than 10% of the top layer of the soil, and the thickness of the top layer of the soil can be up to 10 cm. In some embodiments, a pH adjuster is also applied separately from the halogen-containing adsorbent or mixed with the halogen-containing adsorbent, and optionally together with an agent that improves the penetration of the halogen-containing adsorbent into the material.

[0049] The perturbation may be artificial or naturally occurring and includes any suitable perturbation of the material that causes at least a portion of the volatile mercury to evaporate from the material. Typical perturbations include heating (especially to cause desorption from the soil), vibration, light waves, sound waves, movement of at least a portion of the material, and encapsulation of at least a portion of the material. Encapsulation of a material or a portion of a material is considered a perturbation. For example, encapsulation may increase the concentration of mercury vapor in an enclosed space above the material because mercury vapor released from the material cannot dissipate and / or the surface of the enclosed material heats up, thereby increasing the concentration of mercury vapor in the enclosed space above the material. Heating is a preferred perturbation. Another preferred perturbation is encapsulation of at least a portion of the material. When the material is perturbed, the brominated sorbent is capable of absorbing mercury. Materials treated in the present invention typically would not naturally release mercury if the material were not perturbed. Not putting it out.

[0050] When the material is perturbed, mercury volatilizes from the material. In some cases, for example, due to naturally occurring perturbations, no perturbation needs to be applied. In some embodiments, the naturally occurring perturbation releases mercury over time, and the halogen-containing sorbent captures the mercury as it evaporates from the material. In some embodiments, an artificial perturbation is applied to the material.

[0051] Heating the material to which the halogen-containing sorbent has been added and / or applied typically induces desorption of mercury. Naturally occurring forms of heating include solar heating, which is the preferred perturbation. Artificial methods of thermal desorption include thermal desorption, which typically involves covering the area to be heated and removing vapor under the covered area at least during heating. Halogen-containing sorbents can inhibit the release of mercury vapor by capturing mercury as it leaves the material being heated.

[0052] In the heating perturbation in the practice of this invention, temperatures are typically from about ambient (about 25°C) to about 45°C, which is generally sufficient to volatilize mercury from the material. Gas flows are not typically applied in solar heating. Mercury emission control in flue gases is typically performed at much higher temperatures (150°C-300°C), usually using high gas flow rates.

[0053] Mercury adsorbed by halogen-containing powdered activated carbon is stable during the manufacture and hardening of concrete, see, e.g., U.S. Patents 8,404,038 and 8,420,033, which is advantageous when treating fly ash and cement, as well as materials containing fly ash and / or cement.

[0054] In some embodiments, halogen-containing sorbents are used in decontamination, demolition, and decommissioning activities, for example, by applying them to the interior and / or exterior of buildings prior to and / or during demolition to suppress mercury vapor and allow all waste to be classified as non-hazardous, thereby reducing the cost of decontamination, demolition, and decommissioning activities, increasing worker safety, and in some cases enabling decontamination, demolition, and decommissioning activities at contaminated sites where decontamination, demolition, and decommissioning activities were not previously possible.

[0055] In other embodiments, the halogen-containing sorbents are used in decontamination processes, often in the work environment, by applying (preferably spraying) the halogen-containing sorbents to walls, ceilings, and equipment. One example of a site to be decontaminated is the carbon adsorption bed building of a non-ferrous metal processing plant.

[0056] In yet another embodiment, the halogen-containing sorbent is sprayed as a suspension or slurry onto soil being worked on under an enclosure (e.g., a tent) to inhibit the release of mercury vapor from the soil so that mercury concentrations within the enclosure remain below safe working concentrations (as defined by OSHA). Although the soil may not contain enough mercury to warrant a specific remediation, when an enclosure is placed over the work area, mercury may concentrate within the enclosure.

[0057] In other embodiments, a halogen-containing sorbent can be added or applied to the fly ash or other material containing loosely bound mercury, and the loosely bound mercury in the fly ash or other material can be vaporized and absorbed by the halogen-containing sorbent, preferably the halogen-containing sorbent is mixed with or sprayed onto the fly ash or other material.

[0058] The following examples are presented for illustrative purposes and are not intended to impose limitations on the scope of the invention. EXAMPLES

[0059] Experimental Apparatus and Procedures Two 12-inch (30.5 cm) tall, 2-inch (5.1 cm) diameter glass columns were used as beds for the adsorption tests. Approximately 1 inch (2.5 cm) of glass wool was inserted into the bottom of each column. The moisture content of the sand was measured, and when the moisture content exceeded 3%, the sand was dried in an oven at a relatively low temperature (50°C). For each column, a fixed amount of sand (26 mL, approximately 2 inches (5 cm) high when packed into the column) was weighed out. For the mixtures, the desired amount of powdered activated carbon (PAC) or brominated powdered activated carbon (Br-PAC) was weighed relative to the amount of dry sand and mixed with the dry sand to homogenize the mixture. Sufficient water was then added to the mixtures and to the sand-only samples to increase the moisture content to approximately 8% by weight. Each column was filled with sand or sand mixture on top of the glass wool to form a bed, and the columns were then sealed. The sealed columns were mounted on stands in an oven, and tubing was connected to the columns.

[0060] A mercury generator supplying elemental mercury vapor was connected to a diffusion tube in the oil bath. A bypass line for mercury vapor was installed around the column to allow for troubleshooting and as an additional controlled flow.

[0061] The settings of the valve (perfluoroalkoxy (PFA), Swagelok Company) were adjusted to bypass the mercury generator and column. The compressed air flow was turned on and the flow rate of the air stream was adjusted to approximately 5 L / min using the regulator and the rotameter needle valve as needed. The oil containing the mercury generator was added to the air stream passing through the diffusion tube to give the desired concentration of mercury vapor (approximately 50 μg / m 3 The oven containing the column was heated to 35° C. and maintained at this temperature for the duration of the column test.

[0062] Valve settings were then adjusted to direct the airflow through the mercury generator but bypass the columns. The sample valve was opened to a mercury vapor analyzer (atomic fluorescence spectroscopy, Jerome® J505) and analysis of the airflow began. The mercury generator temperature and / or airflow rate were adjusted as necessary to achieve the desired mercury vapor concentration. Once a stable mercury concentration was achieved in the airflow, the valves were set to direct the flow of the mercury-containing airflow from the bottom of the columns up through the material in each column. The airflow exiting the top of each column was analyzed for the presence of mercury vapor.

[0063] After the test was completed, the valves were adjusted to bypass the columns and the mercury vapor in the air stream was measured to ensure it matched the baseline concentration measured earlier. Each column was then flushed with a separate stream of mercury-free air (bypassing the mercury generator). The air exiting the columns was analyzed to ensure that no mercury was being released from the columns. The columns were removed from the oven and the material in each column was poured into separate glass sample vials, pushing the glass wool out of the columns to ensure that all material was collected from each column in the sample vials. The material in each sample vial was analyzed for total mercury and leachable mercury.

[0064] Example 1 - Comparative In the first test, wet sand (8 wt% water) was added to the column and mercury vapor was passed through the column to ensure that the sand did not adsorb significant amounts of mercury vapor. To perform a timed test, clean, dry sand was mixed with powdered activated carbon (PAC, 1 wt%) and deionized (DI) water (8 wt%), amounts relative to the dry weight of the sand. The PAC / wet sand mixture was added to the column.

[0065] The mercury generator was started, the gas bypassing the PAC / wet sand column was sampled once, and the gas exiting the PAC / wet sand column was sampled at various time intervals. The amount of mercury in the samples was measured to determine the amount of mercury that passed through the column. The results are summarized in Table 1 and shown graphically in Figure 1. Figure 1 shows the amount of mercury passing through the powdered activated carbon / wet sand mixture over time. Sample 1 is from gas that bypassed the column and contains the entire amount of mercury vapor generated in the mercury generator (baseline), while samples 2-23 are from columns containing a mixture of wet sand and 1 wt% powdered activated carbon. All experiments are comparative. [Table 1]

[0066] The data above indicate that the PAC / sand mixture captures a portion of the mercury passing through the column, but a significant amount of mercury vapor passes through the PAC / sand mixture and is not captured. The data suggest that a significant amount of the PAC became saturated with mercury vapor approximately 50 minutes into the test, since the amount of mercury passing through the PAC / sand mixture increased after 50 minutes.

[0067] Example 2 In the first test, wet sand (8 wt.% water) was added to the column and mercury vapor was passed through the column to ensure that the sand did not adsorb significant amounts of mercury vapor. To perform a timed test, clean, dry sand was mixed with brominated powdered activated carbon (Br-PAC, 1 wt.%) and deionized (DI) water (8 wt.%), amounts relative to the dry weight of the sand. The Br-PAC / wet sand mixture was added to the column.

[0068] The amount of mercury that passed through each column was determined by starting the mercury generator, sampling the gas bypassing the Br-PAC / wet sand column once, and sampling the gas leaving the Br-PAC / wet sand column at various time intervals and measuring the amount of mercury in the gas samples. The results are summarized in Table 2 and shown graphically in Figure 2. Figure 2 shows the amount of mercury passing through the Br-PAC / wet sand mixture over time. Sample 1 is from gas that bypassed the column, contains the entire amount of mercury vapor generated in the mercury generator (baseline), and is for comparison. Samples 2-20 are from columns containing a mixture of wet sand and 1 wt% Br-PAC. The bromine content of the Br-PAC was 8 wt%. [Table 2]

[0069] As the data above show, the Br-PAC / sand mixture quickly captured most of the mercury vapor and prevented it from passing through the column. Moreover, this suppression of mercury vapor persisted throughout the entire 5-hour test.

[0070] Example 3 The PAC / sand and Br-PAC / sand mixtures used in the above examples were analyzed to measure the total mercury adsorbed by the mixtures and to confirm mercury adsorption. These results are summarized in Table 3. Total mercury in the Br-PAC / sand mixture was significantly higher after 5 hours compared to the PAC / sand mixture. [Table 3]

[0071] Example 4 Leaching tests were performed on the PAC / sand and Br-PAC / sand mixtures from the above examples using a synthetic precipitation leaching procedure (SPLP). The total mercury remaining in each sample after the leaching tests were performed is considered to be non-leachable mercury. The results are summarized in Table 4 and shown graphically in Figure 3. The data at 1 hour shows a 163% increase in non-leachable mercury for the Br-PAC / sand mixture compared to the PAC / sand mixture, and the data at 5 hours shows a 229% increase in non-leachable mercury for the Br-PAC / sand mixture compared to the PAC / sand mixture. [Table 4]

[0072] Further embodiments of the present invention include, but are not limited to, the following.

[0073] A) A process for inhibiting the release of mercury vapor from a material containing evaporable mercury, comprising: applying a halogen-containing adsorbent to the material, the halogen comprising one or more halogens selected from chlorine, bromine, and iodine; perturbing the material to volatilize mercury; and inhibiting at least a portion of the release of mercury vapor from the material.

[0074] B) The process of A), wherein the halogen-containing adsorbent comprises a substrate material selected from one or more carbonaceous materials.

[0075] C) The process of B), wherein the carbonaceous material is activated carbon.

[0076] D) The process of A) wherein the halogen-containing adsorbent comprises a substrate material selected from one or more inorganic materials.

[0077] E) The process according to D), wherein the inorganic material is selected from inorganic oxides, natural zeolites, CaCO3, and clay minerals.

[0078] F) The process according to E), wherein the inorganic material is selected from chabazite, silica, kaolinite, and bentonite.

[0079] G) The process of A), wherein the halogen-containing adsorbent is a halogen-containing activated carbon adsorbent, a halogen-containing chabazite, a halogen-containing bentonite, a halogen-containing kaolinite, or a halogen-containing silica.

[0080] H) The process described in A), wherein the halogen-containing adsorbent is a halogen-containing activated carbon adsorbent.

[0081] I) The process according to any one of A) to H), wherein the halogen is bromine and / or iodine.

[0082] J) The process described in any one of A) to H), wherein the halogen is bromine.

[0083] K) the halogen-containing adsorbent is a halogen content of about 0.1% by weight to about 30% by weight, calculated as bromine based on the total weight of the halogen-containing adsorbent; or a halogen content of about 0.1% by weight to about 25% by weight, calculated as bromine based on the total weight of the halogen-containing adsorbent; or a halogen content of about 0.1% by weight to about 20% by weight, calculated as bromine based on the total weight of the halogen-containing adsorbent; or The process of any one of A) to J), wherein the halogen-containing adsorbent has a halogen content of about 3% to about 8% by weight, calculated as bromine, based on the total weight of the halogen-containing adsorbent.

[0084] L) applying the halogen-containing adsorbent to the material, (a) applying a halogen-containing adsorbent to the surface of the material; and / or (b) binding a halogen-containing adsorbent to at least a portion of the surface of the material; and / or (c) adding a halogen-containing sorbent to the reactive barrier; and / or (d) forming a reactive barrier containing a halogen-containing sorbent; and / or (e) The process of any one of A)-K), comprising introducing a halogen-containing adsorbent below the surface of the material.

[0085] M) The process according to L), wherein the halogen-containing adsorbent is added and / or applied in the form of a slurry or suspension.

[0086] N) The process of M), wherein the halogen-containing adsorbent is about 5% to about 45% by weight of the slurry or suspension.

[0087] O) The process of L), wherein the halogen-containing adsorbent is applied to the material by spraying a suspension or slurry of the halogen-containing adsorbent, by spreading a dry solid containing the halogen-containing adsorbent on the surface of the material, or by introducing the halogen-containing adsorbent under the surface of the material.

[0088] P) introducing said halogen-containing adsorbent beneath the surface of said material to remove said halogen The process of claim 1, wherein a containing adsorbent is applied to the material.

[0089] Q) The process described in any one of A) to P), wherein the material containing volatile mercury is soil, waste, mining by-products, fly ash, or building materials.

[0090] R) The process according to any one of A) to P), wherein the material is soil, waste, or a mining by-product.

[0091] S) The process according to any one of A) to P), wherein the material is fly ash or a building material.

[0092] T) The process described in S), wherein the material containing volatile mercury is soil.

[0093] U) The process described in any one of A) to T), wherein the perturbation is heating or encapsulating at least a portion of the substance.

[0094] V) The process described in U), wherein the heating is solar heating.

[0095] W) The process of A), wherein the adsorbent is a halogen-containing activated carbon, the halogen content is from about 0.1% to about 30% by weight, calculated as bromine based on the total weight of the halogen-containing adsorbent, and the material is soil, waste, mining by-products, fly ash, or building material.

[0096] X) The process according to W), wherein the halogen content is from about 0.1% to about 25% by weight, preferably from about 0.1% to about 20% by weight, and more preferably from about 0.5% to about 15% by weight, calculated as bromine based on the total weight of the halogen-containing adsorbent.

[0097] Y) The process according to any one of A) to X), wherein the halogen is bromine and / or iodine.

[0098] Z) The process described in any one of A) to X), wherein the halogen is bromine.

[0099] An ingredient referred to anywhere in this specification or claims by chemical name or formula, whether referred to in the singular or plural, is identified as being present prior to contact with another substance (e.g., another component, solvent, etc.) referred to by the chemical name or chemical type. It does not matter what chemical changes, transformations, and / or reactions (if any) occur in the resulting mixture or solution, because such changes, transformations, and / or reactions are the natural result of bringing the specified ingredients together under the conditions required in accordance with this disclosure. Thus, ingredients are identified as ingredients that are brought together in connection with performing a desired operation or in forming a desired composition. Also, even if the claims herein may refer to substances, components, and / or ingredients in the present tense (such as "comprising," "is," etc.), the reference refers to the substance, component, or ingredient that was present immediately prior to being first contacted, blended, or mixed with one or more other substances, components, and / or ingredients in accordance with this disclosure. Thus, the fact that a substance, component, or ingredient may have lost its original identity by chemical reaction or change in the course of a contacting, blending, or mixing operation, when carried out in accordance with this disclosure and within the ordinary skill of a chemist, is of no practical importance.

[0100] The present invention may comprise, consist of, or consist essentially of the materials and / or procedures recited herein.

[0101] As used herein, the term "about" modifying the amount of a component in the composition or used in the method of the present invention refers to the variation in the numerical amount that may occur due to, for example, typical measuring procedures and liquid handling procedures used to make concentrates or use solutions in the real world, inadvertent errors in these procedures, differences in manufacture, source, or purity of the components used to make the composition or carry out the method. The term about also encompasses amounts that differ due to different equilibrium conditions of the composition obtained from a particular initial mixture. Whether or not modified by the term "about", the claims include the equivalent of the amount.

[0102] Unless expressly indicated otherwise, the article "a" or "an" as used herein is not intended, and should not be construed as, limiting the description or claims to the single element to which the article refers. Rather, as used herein, the article "a" or "an" is intended to cover one or more such elements, unless the context expressly indicates otherwise.

[0103] This invention is susceptible to considerable variation in its practice, and therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.

Claims

1. A process for suppressing the release of mercury vapor from a substance containing volatile mercury, which comprises applying a halogen-containing adsorbent to the substance, wherein the halogen comprises one or more halogens selected from chlorine, bromine, and iodine, said applying, perturbing the substance to volatilize mercury, and suppressing the release of at least a portion of the mercury vapor from the substance.

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

3. The process according to claim 2, wherein the carbonaceous material is activated carbon.

4. The process according to claim 1, wherein the halogen-containing adsorbent comprises a base material selected from one or more inorganic materials, and optionally, the inorganic material is selected from inorganic oxides, natural zeolites, CaCO 3 , and clay minerals.

5. The process according to claim 4, wherein the inorganic material is selected from chabazite, silica, kaolinite, and bentonite.

6. The process according to claim 1, wherein the halogen-containing adsorbent is a halogen-containing activated carbon adsorbent.

7. The process according to any one of claims 1 to 6, wherein the halogen is bromine and / or iodine.

8. The process according to any one of claims 1 to 6, wherein the halogen is bromine.

9. The process according to any one of claims 1 to 6, wherein the halogen-containing adsorbent has a halogen content of about 0.1 to about 30% by weight calculated as bromine based on the total weight of the halogen-containing adsorbent.

10. Applying the halogen-containing adsorbent to the substance comprises (a) applying the halogen-containing adsorbent to the surface of the substance, and / or (b) binding the halogen-containing adsorbent to at least a part of the surface of the substance, and / or (c) adding the halogen-containing adsorbent to a reactive barrier, and / or (d) forming a reactive barrier containing the halogen-containing adsorbent, and / or (e) introducing the halogen-containing adsorbent under the surface of the substance, the process according to any one of claims 1 to 6. **Claim 11** The process according to claim 10, wherein the halogen-containing adsorbent is added and / or applied in the form of a slurry or suspension. **Claim 12** The process according to claim 11, wherein the halogen-containing adsorbent is about 5 wt% to about 45 wt% of the slurry or suspension. **Claim 13** The halogen-containing adsorbent is applied to the substance by spraying a suspension or slurry of the halogen-containing adsorbent, spreading a dry solid containing the halogen-containing adsorbent on the surface of the substance, or introducing the halogen-containing adsorbent under the surface of the substance, the process according to claim 10. **Claim 14** The process according to any one of claims 1 to 6, wherein the substance containing volatile mercury is soil, waste, mining by-products, fly ash, or building materials. **Claim 15** The process according to claim 14, wherein the substance containing volatile mercury is soil. **Claim 16** The perturbation is heating or encapsulating at least a part of the substance, and optionally, the heating is solar heating, the process according to any one of claims 1 to 6.

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