Environmental concerns acid rain

The additional burden of human air pollution, however, has made acid rain an important environmental concern. Acid rain may acidify lakes and streams, making the water unsuitable for some fish and other wildlife. Eur-ther damage has been reported in soil and tree vegetation, which are sensitive to the acid level of rainwater. 

In the 20 years since the Brunddand report, great developments have taken place in industries toward sustainable practices. As a case in point, the problem of acid rain, an issue of concern in 1987, has improved to a large extent, thanks to catalytic pollution abatement both in stationary and automotive emissions. Catalysis for Green Chemistry and Engineering will continue to have a cracial role in improving the environmental performance of industry [25-27]. Nowadays, catalytic procedures are often implemented according to the green chemistry... 

Using data on the mass efficiency and energy requirements of the processes, an estimate of the potenhal impact on the environment was undertaken. Key areas of public concern are greenhouse gas emissions, generation of acid rain, and any impact/effect on ozone depletion. In all of the areas evaluated, in particular the key areas of public interest, route 4 has significant environmental benefits, with reductions in emissions of between 60 and 80%. 

Concerns about the environmental effects of emissions resulting from the combustion of fossil fuels, particularly coal, continue to increase as the utilization of these fuels grows. The large amounts of sulfur dioxide and nitrogen oxides emitted into the atmosphere and the attempts to tie these fossil-fuel-derived pollutants directly to the undeniably difficult problem of acid rain have caused heated debates, numerous research studies, government actions, and serious efforts to reduce pollution. The issues are extremely complex, and our understanding of the origin, properties, behavior, and effects of these pollutants is incomplete. Often, theories are contradictory. 

Growing concern over environmental effects of acid rain has resulted in increased Interest in development of pre-combustion removal of sulfur from coal. Physical coal cleaning processes are effective for pyritic sulfur removal but do little to reduce the organic sulfur content of coal This paper reports the removal of organic sulfur from coal, employing ethyl or methyl alcohols as the solvent/ reactant. The process is based on the observation that, under supercritical conditions, reactions occur that selectively remove organic sulfur from the coal matrix. 

The usefulness of soaps is limited by their tendency to precipitate out of solution in hard water. Hard water is water that is acidic or that contains ions of calcium, magnesium, or iron. In acidic water (such as the acid rain of environmental concern), soap molecules are protonated to the free fatty acids. Without the ionized carboxylate group, the fatty acid floats to the top as a greasy acid scum precipitate. 

Humanity s major sources of energy are derived from fossil fuels, principally oil, gas, coal, and wood. The major combustion by-products of fossil fuel burning include sulfur dioxide (SO2), carbon dioxide (CO2), and nitric oxide (NO2), and partially oxidized hydrocarbons. The process of burning fossil fuels in thermal power plants, factories, homes, and motor vehicles emits enormous amounts of the aforementioned pollutants. The most important environmental concerns resulting from fossil fuel use are global climate change, acid rain, surface ozone, and partic-ulate-Zaerosol-bound toxins. 

Thirty-four minor and trace elements are of potential environmental concern (n ). Sulfur is the element of major concern due to its abundance in flue gases from some coal-burning plants and its subsequent contribution to "acid rain." Sulfur as acidic ions of sulfate can also contribute to pollution of surface water and groundwater. Other elements of greatest concern are As, B, Cd, Pb, Hg, Mo, and Se. With the exception of B and Se, these elements are strongly associated with mineral matter in the coal and are concentrated in waste piles from coal preparation plants. If the waste disposal site is not constructed as a closed system, pollution of nearby groundwater is possible. Boron and Se may contribute to the pollution risk as they are associated with both mineral and organic components. On the other hand, certain coal-mine wastes have potential for recovery of valuable metals such as zinc and cadmium (18). 

Finally, EPA must be granted under whatever resolution is ultimately chosen a high degree of flexibility to cope with the wide variations in the extent of knowledge concerning environmental effects and the characteristics of the control problem. All or nothing approaches will lead to acid rain-type impasses. The benefits of tailoring responses to the data at hand... 

Carbon dioxide is a minor component in Earth s atmosphere and an important component in the carbon cycle. Because CO2 is always in the atmosphere, when it rains, CO2 dissolves in rainwater, forming carbonic acid, H2CO3. The result is that rain is always slightly acidic. If rain is always acidic, why is increased acidity in rain such an environmental concern ... 

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