Activated Charcoal Case Study

5535 Words 23 Pages
Register to read the introduction… METHODS To design an activated charcoal system for removing pesticide contamination, a solution that could be used in conjunction with existing POU systems in our study region (and globally) was necessary. In addition, a sufficient source of carbon and an activation technique that would be appropriate for the local conditions and resources was needed. The production and design alternatives were tested qualitatively in the field and quantitatively in a laboratory at Santa Clara University to assess performance and feasibility. Carbon Source For the carbon source, it was economically important to use a readily available agricultural waste byproduct. In Bluefields and the surrounding rural towns, there were several alternatives to choose from including sugar cane husks, corncobs, and coconut shells and husks. Since coconut is commonly used throughout the world as an activated carbon source material,15 testing was initiated using both coconut shells and coconut husks. Although coconut husks can be carbonized much more efficiently than coconut shells due to their flammability, utilizing the husks as a filter medium proved unsuccessful due to fine charcoal residues leaching into the water during filtration. The husk-generated carbon was not very durable and physically broke down in the …show more content…
Because of its extensive global use, atrazine was used as the proof-of-concept test material for pesticide/herbicide removal by the chemically activated carbon. The U.S. Environmental Protection Agency has set the maximum contaminant level (MCL) for Atrazine at 3 ppb.23 This test is performed by adding samples, standards, and reagents to cuvettes coated with antibodies specific for atrazine. Once the color intensity of the atrazine/reagent product has been developed, the resulting color intensity and atrazine concentration are found using the colorimeter. This particular colorimeter can only test for 3 specific ranges of atrazine: (1) > 3.0 ppb, (2) < 0.5 ppb, and (3) between 0.5 to 3.0 ppb. Tests were conducted in accordance with the Pocket Colorimeter II instruction manual provided by the HachTM Company, Loveland CO.24 Three different chemically activated carbons were tested: one activated using a 25% calcium chloride solution, one activated using 50% sodium chloride solution, and a third activated using 25% sodium chloride solution. The chemically activated carbon samples were placed into separate beakers each containing either 5 ppb or 10 ppb stock atrazine solutions. Two minutes were allowed for the adsorption reactions to occur. This two minute time period was based upon the expected

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