Chromium Essays

Chromium (Cr) is one of the known environmental toxic pollutants in the world which is from group VIII element of the first transition series and has a hard brittle gray transition metal with atomic number 24 and relative atomic mass 51.99 g/mol. Chromium is a naturally occurring element found in rocks, animals, plants, and soil. It can exit in several different forms and the most common forms are chromium, chromium (III) and chromium (IV). The major industrial application of chromium include the

sludge application [10]. One of these metals is chromium. It exists in different oxidation states in the environment, with trivalent and hexavalent chromium being the most stable and abundant forms in soils [10]. Because of its widespread use combined with a high human toxicity, Cr(VI) is considered as a major pollutant. In some cases, the contamination with Cr(VI) can be of natural origin. Starting from the mineral chromite (FeCr2O4 and MgCr2O4), chromium occurs naturally in the environment and can

Chromium is a transitional element, with three stable forms. It is a neutrally charged stable form, but naturally occurs in the environment. Trivalent chromium is a +3 charge stable form of chromium that can be naturally oxidized from its neutrally charged version, occurring in the environment (Mertz et al., 1974; Barrett et al., 1985; Alexander et al., 1990). Hexavalent chromium is a +6 charge stable form of chromium which is the product of industry, and it is very toxic to living things. Hexavalent

Chromium pollution has a major impact on the environment and restoring contaminated soil is difficult. In August 2011, ” a factory called Luliang Chemicals in Yunnan had dumped 5,000 tonnes of toxic chromium tailings on a hillside in the township of Yuezhou. The resulting water pollution killed fish and livestock, endangered the drinking water of tens of millions of people”[1]. According to Dong , the concentration of hexavalent chromium was 2,000 times over the limit[1]. Water containing hexavalent

bedrock and soil. Chromium weathered from the rocks is deposited on the soil and groundwater. Chromium is also generated anthropogenically from various industrial processes which includes electroplating, leather tanning, wood preservations, manufacturing of dye, paint, paper, petroleum refining processes, metal finishing, alloysteel manufacturing, and lasers(Owlad et al., 2010). According to BIS (Bureau of Indian Standards) and USEPA the maximum acceptable limit for Cr(VI) in drinking water is 0

going on. Donna tells Erin about the chromium which is what the power plant uses. Erin begins digging into the case more and finds evidence that the groundwater in Hinkley county is seriously contaminated with carcinogenic hexavalent chromium, but PG&E Pacific Gas and Electric) has been telling Hinkley county residents that they use a safer form of chromium. Ed ends up firing her from not being at the office, until he finds out what she has been doing. The chromium in the water

and various factors played their significance role in it. The experiment stated the Chromium removal and for that we had drawn a calibration curve (graph 6.1) between Absorbance on y axis and concentration on x axis through the table 6.1 as given below. To make calibration curve, we needed the absorbance of the Chromium solution which we got from atomic absorption spectrophotometer (AAS). For calculating % of Chromium removal we have, (C0 – C1) ÷ C0 × 100 Initial concentration (before adsorption) =C0

Erin abided the investigation, she expatiated the residence of Hinkley and found out that they were all suffering from illness that caused by Hexavalent Chromium. The Jensen’s manifestly filed a major lawsuit to PG&E, but the evidence Erin gathered were only bond to the PG&E Hinkley plants not with the main PG&E at Chicago. Ed realizing that this case was a tough one and they needed evidence to relate the

percentage of chromium content. On the surface of stainless steel a thin dense chromium oxide film will form to provide corrosion resistance and further prevents oxidation. Stainless steel is an inoxydable which means it can’t be readily oxidized (incapable of rusting). Stainless steel is notable because of its good corrosion resistance. Increase in Chromium content increases the corrosion resistance in stainless steels. Stainless steels are differing from carbon steels because of chromium content present

least10.5% chromium and a maximum of 1.2 % carbon. In order to define the stainless steel it can be said that the base alloy for this material is iron which contains a minimum of %11 Chromium (Cr) [1]. The European Standard EN10088 (EN2005) defines stainless steels as iron based alloys containing at least10.5% chromium and a maximum of 1.2% carbon. The main factor for the corrosion resistance of stainless steel is its chromium content. Under the influence of oxygen from air or water, the chromium rapidly

Stainless steels history: “Stainless steels have been discovered by England and Germany in 1910, but the practical application and production began in the United States in 1920. Until 1990, stainless steels were applied extensively and became more are more popular.” Nowadays, “it is not a doubt that stainless steels are an important class of alloys, and they are used in many different fields. In normal like cooking tools, even in complicated machine like space vehicles” Stainless steels property:

(NH4)2Cr2O7(s)=Cr2O3(s)+N2(g)+4H2O(g). After the lightning of Ammonium dichromate, Chromium (III) oxide was formed while the Nitrogen and Water escaped into the atmosphere in a gaseous phase. Ammonium dichromate((NH4)2Cr2O7) gave rise to Chromium (III) oxide (Cr2O3), Nitrogen Gas(N2) and water (H2O) In terms of microscopic level, the ratio between reactants and products is as follows. One mole of Ammonium dichromate will give rise to one mole of 1 mole of Chromium (III) oxide and 1 mole of Nitrogen gas and 4 moles of Water

depends on usage of heavy metals. Incorporated with this, heavy metals have major disadvantages of being toxic and having a long half-life. ( Godt, Scheidig, and Grosse-Siestrup et al, 2006; Gunduz and Akman, 2012; WHO, 1995; WHO, 2004) Cadmium, chromium and lead, among other heavy metals are known to be dangerous pollutants in our environment. Inhalation, ingestion and exposure of these heavy metals can lead to various health problems to humans, particularly in children (Clark, Brabander, Erdil

and even chopsticks are made from stainless steel. Normally, if steel was placed in my mouth, the oxygen could react with the iron in my mouth giving me a poor aftertaste. This doesn’t occur though because of stainless steels properties and how chromium oxide doesn’t have much of a taste. Steel has had many other significant impacts on society besides the ones Miodownik stated in the chapter indomitable. Steel is important in modern day society in the construction of buildings, particularly skyscrapers

using physical observations, logic, and mathematical calculations. In order to do this efficiently, several answer choices were given for the unknown metals. These choices were Bismuth, Manganese, Copper, Lead, Zinc, Tin, Cobalt, Nickel, Cadmium, and Chromium. For the unknown metal in this case (sample #21), the density was approximately 6.848g/cm3. This alone however, is not enough information to identify the metal. Based on observations, the unknown metal was very dark and black in color, as well as

how far away the electrons are from the nucleus which determines how easily it can be transferred or taken away. Potassium has a low IE because its final shell has 1 valence electron, meaning it requires very little energy to remove that electron. Chromium, Germanium and Bromine all have increases of ionization energy respectively making it harder and requiring more energy to remove an electron from the outer shell. Therefore also making the atom stability

affecting economic activity in the region. One of the things that affect it is tectonic activity. The Canadian Shield is a 2.5 billion year craton made of igneous rock. Today there are many metallic minerals in the area including nickel, gold, and chromium. These are all important contributors to the economy in the Canadian Shield. The Canadian Shield is the largest producer in Canada of nickel, copper, gold platinum group metals, copper, salt and structural materials. Mining benefits all areas of

CHAPTER 2 LITERATURE REVIEW 2.1 Panel Beating Industry Having a car is probably one of the most important essentials in a person’s life especially when that person is constantly on the move in regards to going all the way to his workplace or school every single day and wouldn’t want to take a cab or the bus and endure the long commute. However, there are a times when meeting an accidents on the road is simply inevitable. No matter how much of a defensive driver that person may be, there

properly. High Carbon Steel is best for shorter blades, that aren’t required to bend. Stainless steel- Stainless steel is highly resistant to rust because of the amount of chromium within the metal. Starting at 10.5% chromium their is little rust protection, gradually increasing to the maximum protection at 16% chromium. This metal is ideal for yard ornaments and other outside equipment. Iron- Iron is not as strong as steel, but is easily malleable. The more ancient replicas will be made out

Raspberry Ketone Raspberry ketone is a chemical entity that is found mainly in raspberries and some other fruits like peaches, grapes, vegetables and maple. The Raspberry Ketone has been in practiced for a weight loss. The fame began to rise when Dr Oz demonstrated its effects in a national TV show. They even named it as a “Miracle fat burner in a bottle” for the year 2012. The effects of Raspberry Ketone has been demonstrated in mice where it resulted in a potential weight loss. However any data