General and Quantitative Chemistry

Determining the Beer Sequestering Agent Chemistry 112-505 Abstract Charcoal is currently used to remove or sequester polycyclic aromac hydrocarbons (PAHs) from water. Magnec clay was made and its sequestering abilies were compared with charcoal. Experimentaon resulted in charcoal having a lower concentraon of a model PAH proving it to be the beer sequestering agent. Introducon Polycyclic aromac hydrocarbons are currently a problem in Texas, as they are contaminants in water that are suspected to be human carcinogens and are toxic to aquac wildlife. Research has shown a correlaon between airborne PAHs and a child’s intellect (Perera). The current sequestering agent is charcoal, but research is being done to replace charcoal with a more eﬃcient agent. Research is underway developing a type of modiﬁed magnec clay that is layered with octahedral atoms between layers of tetrahedral atoms. Having these layers gives the clay a high surface area meaning it could potenally adsorb PAHs from the water supply and possibly be an eﬀecve sequestering agent. Depending on the eﬃciency and the eﬀecveness the magnec clay is in adsorbing PAHs it could replace the charcoal in being the primary agent used in removing PAHs in water. Materials and Methods The magnec clay capable of adsorbing PAHs was made. A soluon containing .794 grams of FeCl 3 , .398 grams of FeSO 4 · 7H 2 O and 40 mL of dislled water was mixed in a 250 mL Erlenmeyer ﬂask. The soluon was heated to 70⁰C. Once all of the FeCl 3 and FeSO 4 · 7H 2 O had dissolved, .297 grams of Bentonite was added to the soluon. The ﬂask was swirled, and 20 mL of 2.5 NaOH were added drop- wise. The soluon cooled, and then was centrifuged for 10 minutes. Aﬅer centrifuging, the supernatant was discarded. Dislled water was added to the precipitate and the soluon was centrifuged again for 10 minutes. Once it was ﬁnished, the supernatant was removed and the clay was placed in the designated beaker. In the second half of the experiment, the sequestering abilies of the clay and charcoal were compared. Two 10mL soluons of 50% red dye were created; a .1056 gram sample of clay was added to one soluon, while .1050 gram sample of charcoal in the other. Both soluons were centrifuged for 5 minutes. Each soluon was ﬁltered to remove parcles from the soluon. Each soluon was placed in the spectrophotometer and the transmiances were recorded. The transmiances of diluted soluons of red dye with concentraons 100%, 50%, 25% and 12.5% were recorded. The absorbance values for all soluons were calculated. Results and Discussion The λ max value for the Procion Red MX-5B dye was approximated to be 538nm. The spectrophotometry data is shown below in Table 1. Table 1. The transmiances of the tested wavelengths are shown in the table below. Wavelength (nm) Transmiance (%) 500 9.8 510 7.8 520 7 530 6.6 532 6.8 534 6.4 536 6.4 538 6.2 540 6.4 542 6.4 550 7.2 The transmiances of the clay and charcoal recorded at 538nm were 30.8% and 62.0% respecvely. This makes the absorbance values of the clay and charcoal .511 and .208 respecvely. These results are shown in Table 2 below. The calibraon curve created from the absorbance and concentraon values of the four diluted red dye soluons is shown below in Figure 1. Table 2. The transmiance and absorbance values of the four diluted red dye, clay and charcoal at 538nm. Soluon Transmiance (%) Absorbance 100% Red Dye 3.6 1.444 50% Red Dye 18.6 0.73 25% Red Dye 42 0.377 12.5% Red Dye 67.4 0.171 Clay 30.8 0.511 Charcoal 62 0.208

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