Lead accumulator

Problem Young people are exposed to regular and rechargeable batteries almost everyday - they use them in calculators, radios, toys, etc. They may know about the lead battery in their parent s car. In order to understand how they work, an 

Material Beaker, battery (4.5 V), voltmeter (multimeter), electric motor, cable and alligator clips two lead strips, sulfuric acid solution (20%). 

Procedure Fill a beaker two-thirds with sulfuric acid. Place lead strips at opposite ends and hold in place with alligator clips. Electrolyze the sulfuric acid with a battery of 4.5 V supply. Wait for about one minute, remove the battery. Measure the voltage using a voltmeter, then connect with an electric motor. 

Observation While the electrolysis is running, a gas develops on both sides of the lead plates, thereby turning one of the lead strips dark brown. After this, a voltage of approximately 2 V can be measured, the electric motor works for a short while and then stops. 

Tip Lead accumulators can be charged over and over again. If an original car battery is available, it can be dismantled and compared with the model experiment the original one will contain six cells, which supply a total of 6 x 2 V = 12 V. 

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The most widely-used storage battery is the lead accumulator. Each cell consists essentially of two lead plates immersed in an electrolyte... 

The absorption, distribution, and accumulation of lead in the human body may be represented by a three-part model (6). The first part consists of red blood cells, which move the lead to the other two parts, soft tissue and bone. The blood cells and soft tissue, represented by the liver and kidney, constitute the mobile part of the lead body burden, which can fluctuate depending on the length of exposure to the pollutant. Lead accumulation over a long period of time occurs in the bones, which store up to 95% of the total body burden. However, the lead in soft tissue represents a potentially greater toxicological hazard and is the more important component of the lead body burden. Lead measured in the urine has been found to be a good index of the amount of mobile lead in the body. The majority of lead is eliminated from the body in the urine and feces, with smaller amounts removed by sweat, hair, and nails. 

Blei-rhodanid, n, lead thiocyanate, -rohr, n., -rShre, /. lead tube or pipe, -rostprozess, m. lead roasting, -rot, n. red lead, minium, -safran, m. orange lead, -salbe, /. (Pharm.) lead ointment, cerate of lead subacetate, -salpeter, m. lead nitrate, -salz, n. lead salt, specif, lead acetate, -sammler, m. lead accumulator lead storage battery. 

Apart from the improvement and scaling up of known systems such as the lead accumulator or the nickel/cadmium cell, new types of cells have also been developed. Here, rechargeable lithium batteries and nickel-systems seem to be the most promising the reason for this will be apparent from the following sections [3]. 

The demand for electrically operated tools or devices that can be handled independently of stationary power sources led to a variety of different battery systems which are chosen depending on the field of application. In the case of rare usage, e.g., for household electric torches or for long-term applications with low current consumption, such as watches or heart pacemakers, primary cells (zinc-carbon, alkaline-manganese or lithium-iodide cells) are chosen. For many applications such as starter batteries in cars, only rechargeable battery systems, e.g., lead accumulators, are reasonable with regard to costs and the environment. 

The different applications led to an immense number of configurations and sizes, for example small round cells for hearing aids or large prismatic cells for the lead accumulators used in trucks. Here the great variety of demands has the consequence... 

Some attempts have been made to transform the conventional lead accumulator into a dissolution accumulator by replacing sulfuric acid with tetrafluoro-boric acid (HBF4) but the highly corrosive and toxic acid was not finally accepted [16]. 

The lead accumulator has been studied from the thermodynamic point of view by Dolezalek. The reaction is ... 

The agreement is remarkably good, which shows that the lead accumulator is almost theoretically reversible, and the example is all the more interesting in that it contains direct measurements of the maximum work (i.e., the diminution of free energy) of an isothermal process carried out in two entirely different ways. 

Reactions between concentrated solutions e.g., the electromotive force of the lead accumulator corresponds almost exactly with the heat of dilution of the acid when the latter is concentrated, whilst in dilute solutions the difference is very great (Nernst, Wiecl. Ann., 53, 57,1894). 

Johnson AH, Siccama TG, Friedland AJ. 1982. Spatial and temporal patterns of lead accumulation in the forest floor in the northeastern United States. J Environ Qual 11 577-580. 

Benaroya, R.O., Tzin, V., Tel-Or, E., and Zamski, E., Lead accumulation in the aquatic fern Azollafilicu-loides, Plant Physiology and Biochemistry, 42, 639-645, 2004. 

It is important to note that the gout patients with high mobilizable lead and renal impairment had blood lead levels and ZPP concentrations that were no different from the rest of the group, indicating that there was no indication of lead overexposure in these individuals until the EDTA lead mobilization test was administered. Based on these results, it may be concluded that more extracellular lead accumulates in the renal impairment associated with some forms of gout. 

The O Flaherty Model simulates the age-dependence of lead kinetics on such factors as absorption efficiency, excretion efficiency, uptake into bone and loss from bone, and partitioning between plasma and red blood cells. The model does not incorporate age, dose rate, or time dependence of lead accumulation in every organ (e g., kidney) because the complex patterns of lead accumulation in certain tissues are not known (O Flaherty 1991a) (see Section 2.4.1). However, the basic model structure allows for additional modules to be incorporated, depending on its intended use in risk assessment. For example, additional modules that are currently being developed are a pregnancy model and a model of net bone loss in older women and men. 

Areola 00, Williams-Johnson M, Jadhav AL. 1999. Relationship between lead accumulation in blood and soft tissues of rats subchronically exposed to low levels of lead. Toxic Substances Mechanisms 18 1-13. 

Steenhout A, Pourtois M. 1981. Lead accumulation in teeth as a function of age with different exposures. Br J Ind Med 38 297-303. 

Satake and coworkers131 studied lead accumulation and location in the shoots of the aquatic liverwort, Scapania undulata, in stream water (Pb content, 20 p-gl-1) at a mine in England. The lead concentration in the shoots ranged from 7 to 24 mgPbg-1 on a dry weight basis, giving an enrichment ratio of 3.5 x 105 — 1.2 x 106. Lead was localized in the cell wall131. 

The relationship between incidence of lead shot in waterfowl gizzards and biological effects varies widely and is probably a function of shot availability caused by differences in shooting intensity, size of pellets, availability of grit, firmness of soil and sediments, and depth of surface water (Street 1983). Also, lead accumulations and the frequency of avian lead toxicosis following... 

Behan, M.J., T.B. Kinraide, and W.I. Selser. 1979. Lead accumulation in aquatic plants from metallic sources including shot. Jour. Wildl. Manage. 43 240-244. 

Fimreite, N. 1984. Effects of lead shot ingestion in willow grouse. Bull. Environ. Contam. Toxicol. 33 121-126. Finley, M.T. and M.P. Dieter. 1978. Influence of laying on lead accumulation in bone of mallard ducks. Jour. Toxicol. Environ. Health 4 123-129. 

Gallardo, M.T., R.F. Benson, and D.F. Martin. 1999. Lead accumulation by three aquatic plants. Book of Abstracts, Part 1, ENVR 112, 218th American Chemical Society National Meeting, New Orleans, August 22-26, 1999. 

Henny, C.J., L.J. Blus, D.J. Hoffman, R.A. Grove, and J.S. Hatfield. 1991. Lead accumulation and osprey production near a mining site on the Coeur d Alene River, Idaho. Arch. Environ. Contam. Toxicol. 21 415-424. 

Stewart, J. and M. Schulz-Baldes. 1976. Long-term lead accumulation in abalone (Haliotis spp.) fed on lead-treated brown algae (Egregia laevigata). Mar. Biol. 36 19-24. 

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