| dc.description.abstract | Oil and gas production, industrial manufacturing, mining, and agriculture all produce significant amounts of wastewater, often containing harmful heavy metal ions such as cadmium, lead, and arsenic. Radioactive disasters such as Chernobyl, Three Mile Island, and the Fukashima Daiichi nuclear accidents have introduced radioactive nuclides such as cesium-137 into water streams. These heavy metals and radionuclides, when ingested, can cause irreversible damage to human health. In this research, functionalized hydrogels with the ability to adsorb these contaminants have been synthesized. It is the purpose of this project to test and quantify how well these hydrogels can remove dissolved cadmium, lead, arsenic, and cesium.
The hydrogels for this research are PAAm (polyallylamine) modified with DHBA (2,3-dihydroxybenzoic acid), TGA (thioglycolic acid), and ferrocyanide. Tests with varying initial concentrations and contact times were performed for adsorption isotherm models, adsorption speeds, and kinetic models. Selectivity tests were performed to see how well the hydrogels dealt with competing contaminant species. Varying pH tests were performed to quantify how hydrogels handled different pH environments. Reusability tests were performed to see if and how many times these hydrogels can be reused. Finally, column studies were performed to see how well the hydrogels will perform in a steady state environment. All experimental samples were analyzed by an ICP-OES instrument.
Results from these experiments suggest that both the base PAAm and TGA modified heavy metal hydrogels have very high adsorption capacities, quick adsorption rates, and great reusability. The cesium capturing hydrogels also showed high adsorption capacities and quick adsorption rates, but was not able to be recovered using our methods. All three hydrogels showed adsorption capacities and rates which rival current research top performers and are promising for industry applications. | en |
