Low groundwater pH is frequently cited as inhibiting the performance of in-situ bioremediation of chlorinated solvents at contaminated sites. A common method of pH control is injection of solutions containing alkalinity, but alternatives for prolonged, passive pH control are needed. This work explores pH-responsive hydrogel coatings on MgO nanoparticles as vehicles for controlled release of alkalinity. Chitosan cross-linked with glutaraldehyde was evaluated as a representative hydrogel coating. The effects of coating thickness and cross-linking on the rate of alkalinity release were experimentally evaluated using batch dissolution experiments. Dissolution rates were found to be up to an order of magnitude slower for coated particles than for uncoated particles. A diffusion model was developed for the dissolution rate of coated particles, and the model was able to account for the dissolution rate as a function of coating thickness over a range of pH.
|Commitee:||Chapra, Steven, Xu, Qiaobing|
|School Location:||United States -- Massachusetts|
|Source:||MAI 56/01M(E), Masters Abstracts International|
|Subjects:||Environmental engineering, Materials science|
|Keywords:||Chitosan, Controlled release, Dissolution kinetics, Groundwater remediation, Hydrogels, Ph control|
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