| Due to its persistence in nature and its ability to bio-accumulate, toxaphene, a once prevalently used pesticide, has been a major concern for health and environmental officials. The study of toxaphene and methods to remediate it effectively and efficiently will continue to be a major focus for environmental engineers and scientists alike. This research explored different remediation approaches relevant to toxaphene contaminants and was divided into two parts: mass removal technology of toxaphene from a contaminated site using cosolvent flushing, and dechlorination technologies of toxaphene applying zero-valent iron treatment and the effects of cosolvent solutions on it. Biodegradation technology and its combination with cosolvent flushing were also discussed for the purpose of identifying opportunities and needs.; The research revealed that the addition of cosolvent solution increased the solubility of toxaphene and decreased the sorption rate of toxaphene to the soil, thus reducing the retardation factor during cosolvent flushing. The alcohols with higher molecular weight exhibited a higher value of cosolvency power for toxaphene. Addition of Partial Miscible Organic Solvents (PMOSs) into Complete Miscible Organic Solvents (CMOSs) to form a ternary system could enhance the solubility and the cosolvent flushing effects. Straight-chain carbon alcohols exhibited a higher potential to enhance the solubility of toxaphene than branched chain carbon alcohols. The first-order bi-continuum transport model provided good simulation of the non-equilibrium sorption process for a miscible displacement column test with toxaphene. The application of cosolvent flushing can reduce the time required to conduct sorption experiments for highly hydrophobic organic compounds such as toxaphene. The experimental data validated the log-linear relationship between the sorption constant K p and cosolvent fractions fc, and between the reverse first-order rate k2 and fc. A log-log linear relationship was found between the k2 value and the Kp value, and the ratio of the k2 value as a function of the fraction of cosolvent could be estimated successfully using literature data and equations.; The application of zero-valent iron and bimetallic substrates can be potentially used as a passive technique in the degradation and removal of toxaphene from the environment. A power law relationship had been shown to depict the decrease of toxaphene concentration related to iron treatment as a function of time. The application of bimetallic substrates has been used to improve the dechlorination rate. (Abstract shortened by UMI.)... |
