Mercury in air

Red mercury(ll) oxide is obtained by heating mercury in air or oxygen (preferably under pressure) at 450°C ... 

APPARATUS USED BY LAVOISIER IN HIS EXPERIMENTS ON BURNING MERCURY IN AIR... 

The substance he used was the red oxide of mercury obtained by heating mercury in air. He found that the air so obtained was not imbibed by water. 

OSPAR. 1997. JAMP guidelines for the sampling and analysis of mercury in air and precipitation. London. 

An example of a monoatomic un-ionized substrate solution is that of mercury in air-free water, which contains zero-valent mercury atoms [140],... 

Mercuric oxide, HgO, is formed as a yellow precipitate by adding a base to a solution of mercuric nitrate or as a red powder by heating dry mercuric nitrate or, slowly, by heating mercury in air. The yellow and red forms seem to differ only in grain size it is a common phenomenon that red crystals (such as potassium dichromate or potassium ferricyanide) form a yellow powder when they are ground up. Mercuric oxide liberates oxygen when it is strongly heated. 

With the exception of mercury ore deposits, the amount of mercury that naturally exists in any one place is usually very low. In contrast, the amount of mercury that may be found in soil at a particular hazardous waste site because of human activity can be high (over 200,000 times natural levels). The mercury in air, water, and soil at hazardous waste sites may come from both natural sources and human activity. 

Friese KH, Roschig M, Wuenscher G, et al. 1990. A new calibration method for the determination of trace amounts of mercury in air and biological materials. Fresenius J Anal Chem 337(8) 860-866. 

Roels H, Abdeladim S, Ceulemans E, et al. 1987. Relationships between the concentrations of mercury in air and in blood or urine in workers exposed to mercury vapour. Ind Occup Hyg 31(2) 135-145. 

Temmerman E, Vandecasteele C, Vermeir G, et al. 1990. Sensitive determination of gaseous mercury in air by cold-vapour atomic-fluorescence spectrometry after amalgamation. Anal Chim Acta 236(2) 371-376. 

Scheide E P and Taylor J K 1974 Piezoelectric sensor for mercury in air Environ. 

Fig. 15.17 Assembly for determination of vapour mercury in air. (a) Sampling apparatus (b) measuring instruments.

There are, however, some new instruments that do not require pre-concentration for elemental mercury in air, such as AAS with Zeeman background correction (Pogarev etal. 2002) and mobile laser systems for remote measurements (Edner etal. 1992). In general, total gaseous Hg in air can be determined with high precision and accuracy. 

The use of gold coated piezoelectric crystals as sensors for mercury in air was investigated by Scheide et al.(47). The crystal was incorporated into a variable oscillator circuit, and changes in the frequency due to the increase in mass resulting from the ability of gold to amalgamate mercury facilitated the measurement of mercury in air at sub-part-per billion level. Calibration curves were obtained from part-per-million to subpart-per-billion concentration of mercury. Reversibility was achieved by heating the crystal in an oven to 150°C. 

In a similar study, 14 MHz gold crystal were used for the measurement of mercury in air (48). Linear relationship were established between the frequency change and the action period of mercury vapor. The calculated detection limit based on 3a criterion is 3 X 10 g/m with a measurement period of 10 min. 

The slight mass increase caused by the absorption of mercury on a gold-plated piezoelectric crystal can be measured as a change in the resonant frequency of the crystal. A piezoelectric detector for mercury in air was described by Scheide and Taylor (1974). Another detector was constructed by Ho and Guilbault (1981), who used it for determination of mercury in water after CV generation. A detection limit of about 1 ng per sample can be deduced, which might also be applied on biological samples. 

Huiliang, H., Jagner, D., and Renman, L. (1987a) Determination of mercury in air by means of computerized flow constant-current stripping analysis with a gold fibre electrode. Anal. Chim. Acta, 201, 269-273. 

Respiratory absorption of elemental mercury in air (1.0-30.0 xg Hg/m ) by humans ranged from 74 to 100% when inhaled through the nose and exhaled through the mouth for dogs, this value was 25%. However, respiratory absorption in humans was only about 20% when inspiration and expiration was through mouth only. Two human males exposed to radiolabeled methylmercury as CH ° HgCl via inhalation had variable half-life retention times (Tbl/2) of mercury. One subject had a Tbl/2 value of 103 days for the early period of observation (days 1-44 post-administration) and 39 days thereafter the second had a... 

This chapter will review information relevant to the biogeochemical cycle of mercury, specifically (i) the speciation chemistry of mercury, (ii) the fate of mercury in air, water and sediment, and (iii) the effects of landscape changes on mercury fate. The chapter will end with a summary of a recent multidisciplinary mercury mass balance conducted in Kejimkujik Park (Nova Scotia, Canada). 

Figure 1. Schematic diagram of pathways for the transformation and transport of mercury in air, water and sediment.

Although the determination of mercury in air by absorption spectroscopy was practiced before the advent of AAS, significant utilization of the cold-vapor technique arose during the 1960s (following the work of Hatch and Ott) and has continued, essentially unaltered in procedure, to the present. 

The concentration of total mercury in air can be determined with high precision and accuracy. There are still, however, analytical problems in separating and analyzing all the specific mercury compounds that can be present in air. Since concentrations of organomercurials are so low, a preconcentration step has to be employed. In general, two approaches are possible for measurements of mercury compounds in air (1) Selective adsorption methods (usually coupled with nonselective detectors), in which the separation is operationally defined and a true species identification is not obtained (therefore it is not clear whether the species determined are the actual mercury compounds present in the atmosphere). (2) Gas chromatographic methods, which allow identification of various organic species by their unique retention times and specific mercury detection system. The... 

Mercury, in Air Quality Guidelines, 2nd ed.. World Health Organization R onal Office for Europe, Copenhagen (MOO), chapter 6.9, p. 1. 

Dalton s third hypothesis is another way of stating the law of conservation of mass — that is, matter can be neither created nor destroyed. For chemical reactions this principle had been demonstrated experimentally by Antoine Lavoisier who heated mercury in air to form mercury(II) oxide and showed that the increase in mass of the oxide over the pure mercury was exactly equal to the decrease in the mass of the gas. Because matter is made of atoms that are unchanged in a chemical reaction, it follows that mass must be conserved as well. Dalton s brilliant insight into the nature of matter was the main stimulus for the rapid progress of chemistry during the nineteenth century. 

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