Littérature scientifique sur le sujet « Mercurio gassoso »

In this work a new lab-scale method dedicated to the evaluation of both concentration and oxidation level of mercury in flue gases from pulverised fuel fired boiler was proposed. To detect the abovementioned parameters, 2 main steps need to be evaluated. Firstly, a calorimeter bomb is utilised - by a proper implementation of mass balance of mercury within substrates and products, the quantity of oxidised mercury in gaseous products can be evaluated. Then, to simulate solid fuel fired power unit and to calculate mercury concentrations in flue gases, one of the stoichiometric mathematical models of combustion process must be applied. Early validation of the method showed considerable differences between solid fuels in mercury oxidation efficiencies and concentrations in flue gasses. Four examined fuels (lignite, hard coal and 2 types of solid biomass) was investigated. Calculated mercury concentrations in raw flue gas (>700°C) varied between 4 and 75 µg/m3ref. The lowest quantity of oxidised forms ofHg in flue gases were identified in the case of investigated lignite (27% of total Hg), while significantly higher – for selected hard coal (72%) and one type of biomass (with high chlorine concentration; up to 98%).

Power production from coal combustion is one of two major anthropogenic sources of mercury emission to the atmosphere. The aim of this study is the analysis of the carbon footprint of mercury removal technologies through sorbents injection related to the removal of 1 kg of mercury from flue gases. Two sorbents, i.e., powdered activated carbon and the coke dust, were analysed. The assessment included both direct and indirect emissions related to various energy and material needs life cycle including coal mining and transport, sorbents production, transport of sorbents to the power plants, and injection into flue gases. The results show that at the average mercury concentration in processed flue gasses accounting to 28.0 µg Hg/Nm3, removal of 1 kg of mercury from flue gases required 14.925 Mg of powdered activated carbon and 33.594 Mg of coke dust, respectively. However, the whole life cycle carbon footprint for powdered activated carbon amounted to 89.548 Mg CO2-e·kg−1 Hg, whereas for coke dust this value was around three times lower and amounted to 24.452 Mg CO2-e·kg−1 Hg. Considering the relatively low price of coke dust and its lower impact on GHG emissions, it can be found as a promising alternative to commercial powdered activated carbon.

Heavy metals are major cause of environmental pollution and due to their toxicity, they persist long in atmosphere. Toxic metals or heavy metals have ability to accumulate in human body and cause various respiratory disorders. Heavy metals sometimes become highly toxic by reacting with different environmental elements. Tobacco smoking is one of the major concerns for the accumulation of toxic metals in smokers’ lungs and people residing with smokers (known as passive smokers) also being affected, especially children. ETS (environmental tobacco smoke) represents inhaling of tobacco and release heavy metals in ambient air involuntary. The development of children pulmonary function severely gets affected due to passive smoking. Every year millions of people die because of tobacco. Heavy metal content is present in the lung tissue of smoker and non-smokers, and which get mixed with the blood at time of gasses exchange in alveoli and circulate in the body. Therefore, tobacco smoking is considered one of the serious global health concern due to its carcinogenic effects on human body. This majorly happens because of the presence of toxic metals like Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr). The concentration of both Pb and Cd, are potent human carcinogen. This study presents important information regarding effect of heavy metals inhaled content in tobacco and its transference to cigarette smoke and their accumulation in smokers’ lung tissue.

Il lavoro svolto nell'ambito del dottorato è stato indirizzato allo studio e alla comprensione del comportamento geochimico e delle modalità di dispersione di inquinanti in aria, rivolgendosi alla valutazione della qualità dell’aria, con particolare riferimento alla mobilità del mercurio e di altri composti gassosi, quali le specie dello zolfo (e.g. H2S e SO2), ad elevato impatto ambientale.