Absorptivity of Bentonite ClayWhitney Mantooth*Allie SlavinskyAbstractThe experiment is to test the ability of two unknowns to find out which one wouldbetter absorb pollutants. Polycyclic Aromatic Hydrocarbons (PAHs) are pollutants found to be associated with cancer that can be found in water, soil, and air.6 This experiment tested two unknowns, clay and charcoal with 5 mLs of red dye added to each. The best absorbance and the quality of each unknown were compared. It was found which unknown would remove PAH better.IntroductionThis experiment was to test the absorbance of Bentonite clay and charcoal. Bentonite clay and charcoal can be used to remove pollutants from water; which include PAHs that are associated with cancer according to the United States Environmental Agency.5 PAHs are released from motors, stovetops, cigarettes, and asphalt according to National Primary Drinking Water Regulations.3 Finding a substance that absorbs PAHs, such as clay or mud, would help scientists find out how much pollution is in a certain area. Materials and MethodsWeek one of the project: 0.78 grams of FeCl3 and 0.39 grams of FeSO4 were obtained and set aside. An Erlenmeyer flask was filled with 40 mL of deionized water, and submerged in a water bath. The water bath was heated to 70oC, and once the desired temperature was obtained the FeCl3 and FeSO4 were added into the flask until the iron compounds were dissolved. Next, 0.30 grams of Bentonite were added into the flask. Once the clay was dispersed then 20 mL of 2.5 M of NaOH were added into the flask with a dropper, and swirled after each addition. Once the 20 mL was completely added to the flask, and then the solutions was put into centrifuge tubes and were centrifuged for ten minutes at 4000 rmp. The supernatant was then removed and a spatula was used to remove the clay from the tubes. The clay was then collected and set to dry for seven days.Next three dilutions were created using the red dye: 50% of 0.025 mM, 25% of 0.0125 mM, and 12.5% of 0.00625 mM. The 50% dilution had 5 mL of solvent and 5 mLof the solute. The 25% dilution had 7.5 mL of solvent, and 2.5 mL of solute. The 12.5% dilution had 8.75 mL of solvent and 1.25 mL of solute. The three dilutions were then added into three different cuvettes, and a fourth cuvette had a 100% of the red dye in it. The spectrophotometry was then blanked, and each of the dilutions was recorded. Two unknowns were created with clay and charcoal. Unknown one was created by adding 0.5057 grams of mud, in 5 mL of red dye (Procion Red MX-5B). A magnet was then used to pull out impurities from the solution. After the impurities were pulled out with a magnet, it was then filtered again using filter paper. Finally the solution was added into a cuvette. Unknown two was created using 0.4985 grams of charcoal and 5 mL of the red dye. Unknown two was then filtered, and the solution was put into a cuvette. Both unknowns were put into the spectrophotometer and recorded and compared to find maximum absorbance. Results and DiscussionBenzopyrene is a polycyclic aromatic hydrocarbon found in coal tar.1 Benzopyrene has a five Carbon ring structure, and Procion has a three Carbon ring and is made up of a one Carbon-Nitrogen ring.2 However; Procion Red Dye and Benzopyrene are very different according to Jiskha.2 Procion red is dark maroon in color, and has a λ of535-541.8Using a spectrophotometer the absorbance and λ max can be computed can compare from magnetic clay and charcoal. Also comparing the charcoal and clay to find the viscosity of each of them. It would also be helpful to find out, which one is more magnetic, which one carries more impurities, has better absorbance, compare pHs, and holds electricity better. During the experiment the absorbance of the clay and charcoal were measured. Absorption is proportional function to surface area, therefore the higher the surface area the higher the rate of absorption.5 Charcoal has 500 square meters per gram, while benotonite clay has 750 square meters per gram.6 It was expected that clay absorbs better than charcoal, however it was found in the experiment that charcoal is the better absorbent than clay.According to the data collected the λ535 max of charcoal was found to be 0.386, and λ750 max was found to be 0.354; while clay λ535 max was found to be 0.400 and λ750max was found to be 0.071. It was very difficult to filter the clay, because the magnet wasvery hard to maneuver. Many particulates still remained in the solution. Therefor, the solution had to be filtered again using filter paper. While it was filtered, there were still few particles floating around in the solution. The charcoal was more successful at filtering, however very small particles still remained, which could have also caused wrongful data. However, there were many particles were still remaining in the solution so it could have given an inaccurate absorbance when calculated. However, compared to the clay the charcoal cuvette had more particles floating in it. Figure 1: Calibration curve, the absorbance point was found to be 0.00005 M.The molar absorption of the two unknowns were found, mud 9.89X10-5 and charcoal 1.00X10-4 (shown below). The calculations show that charcoal is the better absorbent due to the higher rate of molar absorption versus clay. Molar Absorption of Mud(moles of dye / grams of agent) = X0.00005 moles / 0.5057 grams = 9.89X10-5Molar Absorption of Charcoal(moles of dye / grams of agent) = X0.00005 / 0.4985 grams = 1.00X10-40 0 0 0 0 0 000.10.20.30.40.50.60.70.8f(x) = 13274.35xR² = 0.99Calibration CurveAbsorbanceLinear (Absorbance)Concentration (M)AbsorbanceConclusionThe absorbance of Bentonite clay and charcoal were calculated in the experiment.Clay was expected to have the best absorbance, however it was found that the charcoal was the better absorber.5 The experiment was successful over all, despite impurities in both the filtered solutions.Bibliography1. BEnzo(a)pryene. 2005. Web. http://en.wikipedia.org/wiki/Benzo(a)pyrene. Retrieved on November 1, 2013.2. Jiska. 2012. Web. http://www.jiskha.com/display.cgi?id=1259801471. Retrieved on November 4, 2013.3. PAHs. 2011. Web. http://www.epa.gov/ogwdw/pdfs/factsheets/soc/tech/pahs.pdf Retrieved on November 4, 2013.4. Absorptivity of Bentonite Clay. Anti Essays. Retrieved November 10, 2013, from the World Wide Web: http://www.antiessays.com/free-essays/301328.html5. United States Environmental Protection Agency, Office of