Solubility Of Mercury Research Articles

Leaching of mercury from soils at extremely contaminated historical roasting sites (Idrija area, Slovenia)

Mercury (Hg) solubility and reactivity in soils at two extremely contaminated ancient small scale cinnabar roasting sites in the surroundings of the Hg mining area of Idrija (Slovenia) were determined in order to assess the mobility of Hg in the aqueous phase and to evaluate the extent of leaching of Hg into Idrijca River and further downstream. Water leaching experiments were performed on soil and SOM (soil organic matter) samples from historical roasting sites Pšenk and Frbejžene trate. The determined concentrations of leachable Hg in soil samples from the studied areas range from 16 to exceptionally high concentration of 18,000μg/kg, representing 0.0002 to 1.1% of total Hg in these samples, while in SOM samples leachable Hg concentrations range between 13.3 and 6000μg/kg, which corresponds to 0.0017–0.074% of total Hg determined in SOM. The soluble Hg concentrations in investigated soil profiles range from 183 to 18,000μg/kg (0.038–1.7% of total Hg). On the average, more than 90% of soluble Hg occurs in a non-reactive complex bound form, suggesting the preferential binding of Hg to humic matter. Soluble Hg in studied soil profiles generally increases with depth. The obtained results show that Hg is effectively transported to deeper soil layers, mainly as soluble organic complexes. It is estimated that there is still about 10kg of soluble Hg stored in soils of the investigated roasting sites, which is continuously leached to surface waters and deeper into the soil.

Thermodynamic properties of Au–Hg binary solid solution

We have summarized experimental data on the limited solubility of mercury in gold and on the composition of intermetallic phases in the Au–Hg binary system. Standard thermodynamic functions of Au1−xHgx (0≤xHg≤0.2) solid solution have been calculated. The obtained data can be used in different software packages for developing physicochemical models in natural and technological processes with participation of gold and mercury.

Experimental study on Hg0 removal by diperiodatocuprate (III) coordination ion solution

A new method has been developed to remove elemental mercury from flue gas. According to the low solubility of elemental mercury in water, a diperiodatocuprate (III) solution was prepared, and the influencing factors, such as DPC concentration, reaction temperature, solution pH, SO2 concentration and NO concentration were investigated. In the presence of SO2 and NO, removal efficiency of 90.5% for elemental mercury was obtained under the optimal experimental conditions, in which DPC concentration was 6.0mmol/L, reaction temperature was 323K, and pH was 9.0. Moreover, based on the research results of the hydrolyzing products of IO4−, and the analysis of the removal products of Hg0, the reaction mechanism of Hg0 removal was proposed.

Hg0(liq)-Hg0(solution) equilibrium and solubility of elementary mercury in water

The solubility metallic mercury in water and its dominating forms were studied. The prevalence of the Hgaq0 form in the high-temperature range was confirmed and the reaction constant Hgliq0 ai Hgaq0 (logK = logm = −8.01) at 25°C with the predominance of oxidized forms of mercury for the 20–80°C area of low temperatures was found.

Experimental study of metallic mercury solubility in water

Experimental study of metallic mercury solubility in water

Mobile mercury species in soils of natural and natural-technogenic landscapes

Literature data on mercury contents in natural waters are reviewed. Soils from natural and natural-technogenic landscapes of southern West Siberia are studied, and the solubility of their mercury in water, ammonium acetate, and hydrochloric extracts is determined. The concentrations of mercury from natural soils in water and ammonium extracts (0.045–0.060 μg/l) are consistent with its calculated approximate average solubility in unpolluted waters reported in the literature. The average content of mercury in extracts from urbanized soils is higher: its solubility in water extracts is 5.6–6.9 times higher; in ammonium acetate extracts, 3.8–12.4 times; and in hydrochloric extracts, 1.3–1.6 times. The boundary values of mercury solubility in water and ammonium acetate extracts from the studied soils (0.07–0.10 μg/l) permit revealing technogenic pollution at its early stages.

Ammonium thiosulphate enhanced phytoextraction from mercury contaminated soil – Results from a greenhouse study

According to the ‘hard and soft’ acid-base principle, mercury is a ‘soft metal’ and will preferentially form soluble chemical complexes with sulphur-containing ligands. In this work mercury uptake by Chenopodium glaucum L. growing on mercury-contaminated soil was promoted using ammonium thiosulphate. The relative geochemical fractionation of mercury in the soil was subsequently investigated as a function of plant growth with and without thiosulphate amendment. The results indicate that the solubility of mercury is significantly increased through the application of thiosulphate to the soil. Substantially higher mercury levels were found in C. glaucum L. treated with 2gkg−1 thiosulphate of soil when compared to the non-treated plants. Compared with initial soil, soluble and exchangeable fractions were increased both in planted and planted treated plants. However, no significant difference was observed between the soils of the planted and planted treated plants. The oxide-bound mercury concentration was significantly decreased for the planted soil (treated and non-treated) at the end of the experiment. Moreover, this fraction was highly correlated with the plant tissue mercury concentration. Taken together, thiosulphate assisted phytoextraction could be used to reduce environmental risk apparent for mercury-contaminated soil through reducing the oxide bound fractions, while managing the bioavailable fractions (compared with no treated plant).

Natural and mining-related mercury in an orogenic greywacke terrane, South Island, New Zealand

Mercury (Hg) is naturally present in warm springs and mesothermal (orogenic) gold-bearing quartz vein systems in the South Island of New Zealand. Mercury amalgamation was used historically in ore processing at gold (Au) mines, resulting in composite natural and anthropogenic Hg signatures at these sites. This study compares natural Hg enrichment of the Au vein systems, residual anthropogenic Hg added for amalgamation, and enrichment of naturally present Hg during ore processing. Mercury concentration data are presented for solids and water at historic mine sites, the modern Macraes mine, fault-related warm springs, and zones of naturally occurring cinnabar and Hg-bearing Au. Arsenic (As) concentrations are also presented, as As is the most environmentally significant element in this tectonic setting. Tailings and processing residues at historic mine sites (Blackwater mine, West Coast; Golden Point and Golden Bar, Hyde-Macraes shear zone) contain up to 1000 mg/kg Hg, and in adjacent surface waters Hg is at or slightly above background from 0.6 to 0.8 ng/L. Relative to South Island Hg, As is more environmentally significant: solid wastes at some historic mine and mineral processing sites contain up to 30.5 wt% As due to enrichment of natural As in mineralised rocks. Shallow groundwater and processing waters at the modern Macraes mine are up to 0.01 mg/L Hg due to natural Hg in mineralised rocks, and no significant Hg elevation is evident in nearby surface waters, which are <1 ng/L Hg. Mercury concentration in historic mine residues is 103 to 104 times higher than primary ore, and Hg is disproportionally increased relative to As, indicating that much of the Hg was added during the amalgamation process. Natural cinnabar deposition from warm springs results in localised, strongly elevated Hg, equal to or less than the Hg contents in historic mine processing residues. Warm spring precipitates are up to 111 mg/kg Hg and waters are 0.3 µg/L Hg, comparable to data reported for active North Island geothermal (epithermal-style) systems. Natural Hg content in the Au-bearing vein systems results in minor elevation of dissolved Hg in some catchments. South Island Au occurs as an Au-Ag-Hg alloy, up to 8.4 wt% Hg. Cinnabar (HgS) occurs in mesothermal-style veins and as detrital grains in Quaternary gravels hosting Au-Ag-Hg alloy. The Nevis River catchment water, which locally flows through gravels containing cinnabar and Hg-bearing alluvial gold, contains up to 7 ng/L dissolved Hg. This is rapidly diluted to near 3 ng/L by low-Hg waters, and no effects of anthropogenic Hg addition near alluvial mining areas were detected; the dissolved Hg is likely derived from Hg-bearing gold. Mobilisation of Hg from study sites to downstream environments is at least partially controlled by solubility of cinnabar and elemental mercury.

Solubility of helium in mercury for bubbling technology of the spallation neutron mercury target

The pitting damage of mercury target container that originates in the pressure wave excited by the proton beam incidence becomes a large problem to reach the high-power neutron source in JSNS and SNS. The lifetime of mercury container is decreased remarkably by the pitting damage. As one of solutions, the pressure wave is mitigated by injecting the helium micro bubbles in mercury. In order to inject the helium micro bubbles into mercury, it is important to understand the characteristic of micro bubbles in mercury. The solubility of mercury–helium system is a key factor to decide bubbling conditions, because the disappearance behavior, i.e. the lifetime of micro bubbles, depends on the solubility. In addition, the bubble generation method is affected by it. Moreover, the experimental data related to the solubility of helium in mercury hardly exist. In this work, the solubility was obtained experimentally by measuring precisely the pressure drop of the gas that is facing to mercury surface. The pressure drop was attributed to the helium dissolution into mercury. Based on the measured solubility, the lifetime of micro bubbles and the method of the bubble generation is estimated using the solubility data.

Bench-Scale Evaluation of Chemically Bonded Phosphate Ceramic Technology to Stabilize Mercury Waste Mixtures

This bench-scale study was conducted to evaluate the stabilization of mercury (Hg) and mercuric chloride-containing surrogate test materials by the chemically bonded phosphate ceramics technology. This study was performed as part of a U.S. EPA program to evaluate treatment and disposal alternatives to the current land disposal restriction (LDR) treatment standards for mercury. The stabilized materials were subjected to a suite of leaching tests: one test characterized the solubility and release behavior of mercury as a function of pH between the pH values of 2 and 12; the second test used the toxicity characteristic leaching procedure (TCLP); and the third leaching test used the TCLP “cage” modification. TCLP results showed that leachability of Hg decreased by approximately two orders of magnitude and a maximum of five orders of magnitude. The three leachability test methods produced similar amounts of leached mercury, but the test that studied mercury solubility as a function of pH released slightly high...

Investigations on the nucleation kinetics of Tetrathiourea mercury(II) tetrathiocyanato zinc(II) single crystals

The solubility and metastable zone width of Tetrathiourea mercury(II) tetrathiocyanato Zinc(II): Hg(N 2H 4CS) 4Zn(SCN) 4 (TMTZ) were determined for the first time and thereby the possibility of growing bulk size single crystals of TMTZ in a mixture solvent of ethanol and water was estimated. The induction period was recorded for the different supersaturation ratios ( S = 1.1, 1.2, 1.3 and 1.4), which reveals that the induction period of TMTZ decreases with increase in supersaturation. The metastable zone width of TMTZ was found to be in the range 35–45 °C. The measured value of interfacial tension values found to vary from 0.9318 to 2.048 mJ/m 2.

Determination of Henry’s law constant for elemental mercury

The assessment of the global mercury cycle involves estimations of the evasion of mercury form oceanic waters. In such estimations Henry’s law constant is often used. In this study the Henry’s law constant for elemental mercury has been re-determined in MQ water and artificial sea water. Moreover, for the first time it has been determined for 1.5 M sodium chloride (NaCl) solution which is of relevance for modeling of atmospheric waters at coastal locations. For all solutions, experiments has been conducted at five different temperatures between 278 and 308 K, using a novel technique, for mercury, based on direct measurements of the portioning of mercury between the aqueous and gaseous phase. Elemental mercury was extracted from the water column and the logarithm of the mass of extracted mercury was plotted against time. A dimensionless Henry’s law constant, defined as: k H ′ = [ Hg ( g ) ] / [ Hg ( aq ) ] was obtained from the slope of the curve. Almost no difference was observed in the values comparing the Milli-Q water and artificial sea water, however for the 1.5 M NaCl solution a salting-out effect was seen, i.e. the solubility of mercury in the water phase decreased. The decreased solubility will generate an increase in the value of Henry’s law constant.

Extractability and Bioavailability of Mercury from a Mercury Sulfide Contaminated Soil in Oak Ridge, Tennessee, USA

Historically as part of its national security mission, the U.S. Department of Energy’s Y-12 National Security Facility in Oak Ridge, TN acquired a significant fraction of the world’s supply of elemental mercury. During the 1950s and 1960s, a large amount of elemental mercury escaped confinement and is still present in the watershed surrounding the Y-12 facility. A series of remediation efforts have been deployed in the watersheds around the Oak Ridge site. However, most recently, concentration of total mercury in fish and water of the lower East Fork Poplar Creek (EFPC) of Oak Ridge has increased although majority of the mercury contamination in the local soils is present in the form of mercury sulfide. We have studied the extractability, solubility, and bioavailability of mercury sulfide in Oak Ridge soils. Dynamics of the dissolution of mercury sulfide by various extractants, including acids and a chelating agent, have been investigated. After three seasons of planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than is pure mercury sulfide reagent as indicated by their dissolution kinetics. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. This chelating chemical increases the solubility of mercury in HgS-contaminated Oak Ridge soil. The results also show that mercury sulfide in contaminated Oak Ridge soils was still to some extent bioavailable to plants. The increase of bioavailability of soil mercury sulfide after three seasons of planting may contribute to the recent increase of mercury levels in water of the Lower East Fork Popular Creek (LEFPC) of Oak Ridge.

Análise do processo experimental na solubilidade do mercúrio total em processo redutivo

The dental wastewater can contribute to the total daily mercury load on the environment. Factorial design of experiments is useful to analyze factors that influence this solubility. The aim of the present study was to design experiments to examine the effects of operational variables, humic acid, temperature, pH and contact time that may affect the solubility of total mercury as dental amalgam residue in reduction process. Based on the factorial design of experiments, the humic acid concentration was the most significant factor in this process, followed by other factors. The parameters affecting the solubility of total mercury showed that when the [HA], T and CT increases and pH decreases there is an important increase of total mercury concentration in process. For the tested conditions, the high total mercury concentration was obtained using the humic acid concentration = 1.0 g L-1, temperature = 35oC, pH = 4.0 and contact time = 10 days.

EDTA and urease effects on Hg accumulation by Lepidium sativum

The phytoextraction process was conducted under laboratory conditions with the use of garden cress plants ( Lepidium sativum). The experiment was carried out in a model soil, which was characterized before conducting the process. Inorganic forms of mercury (HgCl 2, HgSO 4, Hg(NO 3) 2) were used for contamination of the soil. The phytoextraction process was conducted after EDTA application to the soil and after urease application. Also the influence of simultaneous addition of ethylenediaminetetraacetic acid (EDTA) and urease into the soil on phytoextraction process was measured. In all variants of phytoextraction process the total mercury concentrations in roots, stems and leaves of garden cress were determined. The result showed that garden cress accumulated mercury from soil. The overall maximum concentration of mercury in its compounds was found in roots of the plant. In all cases, before addition of urease and EDTA, the translocation process and distribution of mercury in the plant tissues were limited. The addition of urease caused an increase of enzyme activity in the soil and at the same time caused an increase of mercury concentration in plant tissues. Application of EDTA increased solubility of mercury and caused an increase of metal accumulation by plants. After simultaneous addition of EDTA and urease into the soil garden cress accumulated about 20% of total mercury concentration in the soil. Most of mercury compounds were accumulated in leaves and stems of the plants (46.0–56.9% of total mercury concentration in the plant tissues).

Solubility of metallic mercury in octane, dodecane and toluene at temperatures between 100°C and 200°C

The solubility of metallic mercury in dodecane, octane and toluene has been investigated experimentally at temperatures up to 200°C and pressures up to 6 bars (toluene). The equilibrium Hg concentrations are very similar in octane and dodecane, reaching values of 821 ppm and 647 ppm, respectively at 200°C, whereas they are significantly lower in toluene (e.g., 280 ppm at 200°C). The behavior of Hg in toluene is nevertheless similar to that in the alkanes. There is a strong prograde dependence of Hg concentration on temperature in both types of solvent, which can be described by the following experimentally determined relationships: Dodecane: Log ( X Hg ) = − 1943.1 / T [ K ] + 0.8884 Octane: Log ( X Hg ) = − 2346.3 / T [ K ] + 1.6017 Toluene: Log ( X Hg ) = − 2768.3 / T [ K ] + 1.9726 The solubility of metallic mercury can be modeled satisfactorily using a modification of the scaled particle theory designed to predict the behavior of nonpolar solutes in polar solvents. This modification involves an adjustment of the Lennard Jones Potential and the hard-sphere diameters of solute and solvent to account for the effects of temperature. The results of this study suggest that hydrocarbons could play a significant role in transporting Hg in natural systems, which may explain the high concentrations of metallic mercury in some crude oils, as well as the common occurrence of petroleum in epithermal mercury deposits.

A novel approach to the estimation of aqueous solubility of some noble metal vapor species generated by reaction with tetrahydroborate (III)

The solubilities of stable, volatile metal species of Pd, Rh, Cd, Au and elemental Hg in an aqueous medium were estimated. Aqueous solutions were used to trap the species generated by reduction of the aquo ion with tetrahydroborate III. By continuously monitoring the headspace above the trap solution using ICP-MS detection, a saturation condition is readily discerned. Quantitation of the soluble fraction rapidly liberated by sparging the aqueous phase also permits its quantitation. The applicability of this approach was experimentally verified using cold vapour mercury generation to yield a solubility of elemental mercury of 40 ng/ml at 21 °C in a tin chloride reductant medium, in good agreement with a literature value of 44 ng/ml (after correction for salting out). The methodology was then applied to estimation of the solubilities of the gaseous species of Rh, Pd, Cd and Au, yielding values of 0.11, 3, >800 and 1.7 ng/l, respectively.

Preliminary studies on mercury solubility in the presence of iron oxide phases using static headspace analysis

Discharge of elemental mercury caused by certain industrial activities has been a leading cause of mercury contamination of natural aquatic systems. Although elemental mercury has a relatively low solubility in water, even such low concentrations may lead to unacceptable levels of contamination, depending on, among other factors, the potential of elemental mercury to oxidize and form ionic species, which generally have much higher solubility. A laboratory study was conducted to investigate the solubility of mercury in the presence of amphoteric oxides of iron, an electron acceptor. Investigations were performed with and without chloride in solution, a rather ubiquitous component of mercury wastes. Mercury was analyzed using a relatively fast and inexpensive technique, the static headspace method, and the results were selectively compared with those obtained using a more laborious and expensive, but conventional, United States Environmental Protection Agency-approved atomic absorption method. Mercury solubility decreased in the presence of iron oxides, suggesting adsorption of mercury ions at the oxide-water interface. There was indirect evidence of oxidation of elemental mercury to ionic species in the presence of free iron in solution. Mercury solubility generally increased in the presence of chloride in solution because of the formation of weakly adsorbing mercury-chloro complexes. The precision and accuracy of the static headspace method of mercury analysis were acceptable for a field-screening tool.

Reduction of net mercury methylation by iron in Desulfobulbus propionicus (1pr3) cultures: implications for engineered wetlands.

Although one potential drawback of wetland construction and restoration is the formation of monomethylmercury, it may be possible to decrease net mercury methylation with the use of an appropriate sediment amendment. Using pure cultures of the sulfate-reducing bacterium Desulfobulbus propionicus (1pr3), we tested the hypothesis that adding ferrous iron to sulfidic wetland sediments decreases mercury solubility and bioavailability and, therefore, net methylation. In sediment-free cultures, net mercury methylation decreased with increasing [Fe(II)]. After 72 h of incubation, more than four times as much net methylmercury formed in the lowest ([Fe(II)] = 10(-6) M) treatment (180 +/- 33 pM) as compared with the highest ([Fe(II)] = 10(-2) M) treatment (42 +/- 14 pM). In cultures containing a model wetland sediment, more than three times as much methylmercury was observed in 10(-6) M Fe(II) treatments (1,010 +/- 95 pM) as compared with treatments amended with 10(-2) M Fe(II) (300 +/- 46 pM). Initial filterable mercury measurements and chemical equilibrium speciation predictions suggest that the lower net methylmercury production in the high-iron treatments was due to a decrease in sulfide activity and a concomitant decrease in the concentration of dissolved mercury. Although iron amendments could potentially minimize net mercury methylation in engineered wetland sediments, further research under field conditions is required to assess the efficacy of this approach.

Use of a New Leaching Test Framework for Evaluating Alternative Treatment Processes for Mercury-Contaminated Soils

A new framework for evaluating leaching of wastes was used for assessing the efficacy of potential treatment processes for mixed wastes (radioactive and hazardous) that contain mercury. This framework is based on measurement of intrinsic leaching properties of the material of concern and using the testing results in conjunction with assumed management scenarios and mass transfer models to estimate release of constituents of potential concern over a defined time period. Two mercury-contaminated soils (ca. 4500 mg/kg) were used for the demonstrations. Four candidate treatments were examined: vacuum thermal desorption, encapsulation and amalgamation with sulfur polymer cement, and two forms of solidification/stabilization. Fundamental leaching properties (i.e., acid neutralization capacity of the materials, mercury solubility as a function of pH and mercury release rates) were measured. Testing results provided valuable information on the response of the materials to the impact of stresses that may be encountered under different management scenarios. Mercury release estimates for percolation and mass transfer-controlled scenarios were compared to release estimates based on total content and Toxicity Characteristic Leaching Procedure (TCLP) results. Results showed that testing over a range of conditions and evaluation of test results for assumed management scenarios using simple mass transfer models, provides release estimates that are much more reflective of the waste and its plausible management than release estimates based on total content or single batch test results.