Acid rain acidity

Neutron-to-proton ratio, 29-30 Newton, 457,635 Newton, Isaac, 136 Nickel hydroxide, 78 Nicotinic acid, 364-365 NIMBY syndrome, 526 Nitric acid acid rain and, 400 acid strength of, 567 commercial use, 76 copper penny dissolving in, 570 production, 570-571... 

The environmental benefits are related to energy savings and will in most cases support the usage of ATES in any country. The obvious benefit is the reduction of CO2 by using a large portion of natural renewable heat and cold in the systems. Besides the reduction of CO2, there are also fewer emissions of NOx and acidity (acid rain) to the atmosphere. 

Figure 8.9 Sulfurous acid is found in acid rain. It is a weak acid and is oxidised to sulfuric acid (a strong acid). Acid rain damages the environment quite badly.

The atmosphere is a major source of soil acidity. Even in unpolluted environments rainwater is slightly acidic, having a pH of about 5.7 due to the dissolution of atmospheric CO2 to form the weak carbonic acid (see Worked example 5.4). The CO2 concentration in the partially enclosed soil pore system can be significantly higher (typically up to about 10 times) than in the free atmosphere due to respiration of soil microorganisms and plant roots. This results in a lower pH. In areas affected by industrial pollution, sulfur dioxide and nitrogen oxides dissolve in rainwater to produce sulfuric and nitric acids (acid rain), which are both strong acids and cause even more acidity. 

Aardvark Abacus Abrasives Abscess Absolute zero Abyssal plain Acceleration Accelerators Accretion disk Accuracy Acetic acid Acetone Acetylcholine Acetylsalicylic acid Acid rain Acids and bases Acne... 

Sulfur dioxide, carbon dioxide, nitric oxide, heat, acids, acid rain, ozone, soot, polycyclic aromatic hydrocarbons, and volatile organic compounds Pesticides, nitrates, phosphates, greenhouse gases, and mineral salts... 

Oxides of nitrogen and sulfur can combine with the moisture in the atmosphere to form rain that can be highly acidic — acid rain. This rain can affect the pH of lakes and streams and has been known to seriously affect aquatic life. In fact, it s made some lakes devoid of life altogether. 

However, in many parts of the world, rain has become considerably more acidic. Acid rain is a term given to precipitation such as rain, snow, had, or fog, in which the water has a pH that is less than 5.6. In the United States, pH values of rain have decreased to about 4-4.5. In some parts of the world, pH values have been reported as low as 2.6, which is about as acidic as lemon juice or vinegar. Because the calculation of pH involves powers of 10, a pH value of 2.6 would be 1000 times more acidic than natural rain. 

Under weathering conditions, we often see deterioration profiles with circular external shapes. Indicating the effect of drops of liquid. Here, hygroscopic liquids are often involved, such as alcohols or sulfuric acid (acid rain), which are better solvents than plastics, thus leading to the same moisture profiles and the same mechanical stresses caused by desiccation [36]. 

If acid (acid rain) acts simultaneously on weathered polycarbonate, crazes can form even in high-quality material. Figure 5.56. The influence of acid on materials with various types of pre-weathering creates etch pitting. Obvious cracks, however, form only under damp weathering. 

Gas-liquid-aerosol equilibria in the lower troposphere determine the composition of wet atmospheric precipitation. The most relevant process in the context of precipitation analysis is the solubilisation of airborne gaseous substances and particulates that are in this way deposited to soils and water bodies. For example primary emissions of SO2 and NO are converted to S04 and NOa" by atmospheric processes and then swept to the earth s surface by wet deposition as acids (acid rain) or salts (e.g. eutrophicating NH4HSO4 and NH4NO3). 

Figure 10.1 Products of combustion contribute in vanous ways to the greenhouse effect, acid rain, and smog. (From Smith and Petela, Chem. Eng., 523 32, 1992 reproduced by permission of the Institution of Chemical Engineers.)...

Ophardt, G. E. Acid Rain Analysis by Standard Addition Titration, /. Chem. Educ. 1985, 62, 257-258. 

Acid phosphatase Acid phosphatases Acid pickling Acid rain... 

Selection of pollution control methods is generally based on the need to control ambient air quaUty in order to achieve compliance with standards for critetia pollutants, or, in the case of nonregulated contaminants, to protect human health and vegetation. There are three elements to a pollution problem a source, a receptor affected by the pollutants, and the transport of pollutants from source to receptor. Modification or elimination of any one of these elements can change the nature of a pollution problem. For instance, tall stacks which disperse effluent modify the transport of pollutants and can thus reduce nearby SO2 deposition from sulfur-containing fossil fuel combustion. Although better dispersion aloft can solve a local problem, if done from numerous sources it can unfortunately cause a regional one, such as the acid rain now evident in the northeastern United States and Canada (see Atmospheric models). References 3—15 discuss atmospheric dilution as a control measure. The better approach, however, is to control emissions at the source. 

Hydroxypivalyl hydroxypivalate or 3-hydroxy-2,2-dimethylpropyl 3-hydroxy-2,2-dimethylpropionate (9) is a white crystalline solid at room temperature. It is used to manufacture polyester resias for use ia surface coatiags where good resistance to weatheting and acid rain are of particular importance (6). 

Other problems occur in the measurement of pH in unbuffered, low ionic strength media such as wet deposition (acid rain) and natural freshwaters (see Airpollution Groundwatermonitoring) (13). In these cases, studies have demonstrated that the principal sources of the measurement errors are associated with the performance of the reference electrode Hquid junction, changes in the sample pH during storage, and the nature of the standards used in caHbration. Considerable care must be exercised in all aspects of the measurement process to assure the quaHty of the pH values on these types of samples. 

California land-use regulations and growth control Latin American environmental initiatives environmental issues, acid rain, recycling, greenhouse effect... 

As worldwide attention has been focused on the dangers of acid rain, the demand to reduce sulfur dioxide [7446-09-5] emissions has risen. Several processes have been developed to remove and recover sulfur dioxide. Sulfur can be recovered from sulfur dioxide as Hquid sulfur dioxide, sulfuric acid, or elemental sulfur. As for the case of hydrogen sulfide, sulfur dioxide removal processes are categorized as adsorption, absorption, or conversion processes. 

Municipal incinerators are often targeted as a primary cause of acid rain. In fact, power plants burning fossil fuels, which produce sulfur dioxide and nitrogen oxide, are actually the leading cause of acid rain, along with automotive exhaust (176,177). In Europe and Japan, studies show that only about 0.02% of all acid rain can be traced to incineration of PVC (178). 

P. Lightowlers and J. N. Cape, "Does PVC Waste Incineration Contdbute to Acid Rain " Chem. Ind. (June 1987). 

Fig. 9. Genesis of acid tain (13). From the oxidation of C, S, and N during the combustion of fossil fuels, there is a buildup in the atmosphere (gas phase, aerosol particles, raindrops, snowflakes, and fog) of CO2 and the oxides of S and N, which leads to acid—base interaction. The importance of absorption of gases into the various phases of gas, aerosol, and atmospheric water depends on a number of factors. The genesis of acid rain is shown on the upper right as an acid—base titration. The data given are representative of the environment in the vicinity of Zurich, Switzedand.

Even rain is not pure water. Reports from the U.S. Geological Survey show that it contains 2.3—4.6 ppm of soflds, or a yearly precipitation of 2.5—5 t/km. Recently (ca 1997), work conducted ia the United States and Europe has underscored the rather dangerous results of iacreased use of fossil fuels, where the SO and NO emissions that end up ia the rain lower its pH from 5.6 (slightly acidic) for uncontaminated rain, to acid rains. Such acid rain has serious effects on surface waters (1). About 40 x 10 t of SO and 25 x 10 t of NO were emitted ia the United States ia 1980. There are, however, encouragiag trends the 1970 Clean Air Act has led to a gradual reduction ia these emissions, bringing the SO emissions down from the previous levels cited by 10% by 1990, and the NO emissions down by 6%, with a consequent slight decrease ia rain acidity. A part of the Clean Air Act is also iatended to cap SO emissions from major poiat sources at 13.5 x 10 t (2). Between 1994 and 1995, total SO emissions ia the U.S. decreased remarkably by 13% and total NO emissions by 8%. 

Flue Ga.s Desulfuriza.tion. Citric acid can be used to buffer systems that can scmb sulfur dioxide from flue gas produced by large coal and gas-fired boilers generating steam for electrical power (134—143). The optimum pH for sulfur dioxide absorption is pH 4.5, which is where citrate has buffer capacity. Sulfur dioxide is the primary contributor to acid rain, which can cause environmental damage. 

Biological processes are also being studied to investigate abiHty to remove sulfur species in order to remove potential contributors to acid rain (see Air pollution). These species include benzothiophene-type materials, which are the most difficult to remove chemically, as weU as pyritic material. The pyrite may be treated to enhance the abiHty of flotation processes to separate the mineral from the combustible parts of the coal. Genetic engineering (qv) techniques are being appHed to develop more effective species. 

The usage pattern in Europe and Japan is more dependent upon the automotive industry. However, with the recent concern about acid rain, the European and U.S. markets should show increased interest in fluorocarbon elastomers for pollution control appHcations. On the other hand, the Japanese market has a sizable outlet in electrical and general machinery manufacturing (eg, copiers). Petroleum appHcations are of Htfle interest outside the United States. 

G. J. Heij and J. W. Erisman, Acid Rain Research Do We Have Enough Answers , Elsevier, Amsterdam, 1995. 

Review Group on Acid Rain, Department of Environment, London, 1990. 

K. N. Pilegaai d, N. O. Jensen and P. Huinmelshoj, in Acid Rain Research Do We Have Enough... 

A whole science, called metallography, is devoted to this. The oldest method is to cut the alloy in half, polish the cut faces, etch them in acid to colour the phases differently, and look at them in the light microscope. But you don t even need a microscope to see some grains. Look at any galvanised steel fire-escape or cast brass door knob and you will see the grains, etched by acid rain or the salts from people s hands. 

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