The presence of wide spectrum antimicrobial agents triclosan (TCS) and triclocarban (TCC) in the environment has become a concern due to the adverse impact on the environment. Montmorillonite, a widely distributed clay mineral in the natural environment, has been used as an obstacle in landfills to avoid contamination of soil and water by contaminants in leachates due to its high surface area, cation exchange capacity, and abundance. The research reported here focuses on understanding the abiotic oxidative transformation of TCS and TCC by Fe(III)-modified montmorillonite. The overall objectives of this work were: 1) to investigate TCS and TCC oxidative transformation kinetics and transformation products in different environmental conditions, and 2) to elucidate their reaction pathways. TCS was reacted with Fe(III)-modified montmorillonite under the following experimental conditions: 1) at 40% relative humidity and room temperature for up to 100 d with and without UV light exposure; and 2) in aqueous environment with different initial TCS concentrations, light exposure, pH levels, and in the presence of natural organic matters. Reaction in the presence of Na- montmorillonite was conducted for comparison with results from TCS reaction in the presence of Fe(III)-modified montmorillonite. In addition, transformation of TCS in the presence of other types of minerals was also investigated. Transformation of TCC on Fe(III) and Na-montmorillonite in an aqueous environment with and without exposure to light was also studied at different initial TCC concentrations. TCS and TCC transformation products were a) characterized using LC/MS, GC/MS, and computational modeling, and b) quantified using HPLC/UV and GC/MS. The main TCS transformation products were 2,4-dichlorophenol, 2,4-dichlorophenol dimer, chlorophenoxy phenols and, TCS dimers and trimers. 2,8-dichlorodibenzo-p-dioxin was identified under UV light and the sun simulator experiments. Formation of 4-chloroaniline and 3,4-dichloroaniline were confirmed as transformation products of TCC. To the best of our knowledge, this is the first time that 4-chloroaniline and 3,4-dichloroaniline were confirmed as abiotic transformation of TCC. This research has generated a better understanding of the abiotic environmental fate of TCS and TCC and demonstrates the feasibility of utilizing Fe(III)-modified montmorillonite as remediation material for TCS, TCC and other related pharmaceutical and personal care products (PPCPs).

The presence of pharmaceuticals and personal care products (PPCPs) in the environment has become a matter of concern during the last decade. Increased production of PPCPs along with their increased use has led to release of these compounds in the environment via various routes. PPCPs includes large group of compounds including veterinary and human antibiotics, analgesics and anti-inflammatory drugs, psychiatric drugs, β-blockers, X-ray contrasts, and steroid hormones, etc. Many of the compounds used in PPCPs have been shown to possess adverse effects to living organisms and act as endocrine disrupting agents (ECDs). This dissertation includes the investigation of the occurrence of antibiotic compounds added to personal care product and the transformation of hormones used in pharmaceuticals such as contraceptives. The results obtained in this study can provide information on the fate and transformation of the studied compounds once released in the environment. An analytical method employing sonication extraction and HPLC-ESI-MS detection was developed. The developed method was used to detect antibiotic compounds triclosan (TCS) and triclocarban (TCC) in biosolids-applied soil and biosolids. Both TCS and TCC were detected at high concentrations in biosolids and at lower concentrations in biosolids-applied soil. TCS and TCC concentrations decreased in biosolids composts and in biosolids-applied soil collected at deeper depths. The developed method was able to provide efficient detection limits and reliable quantification of target compounds. A molecularly imprinted polymer (MIP) was synthesized to achieve efficient clean-up of TCS and TCC from biosolids-applied soil and biosolids samples using 4,4’- DBP-4-vp-EGDMA. The motivation behind this project was to be able to eliminate the use of expensive instruments such as LC-MS and employ easily available instruments such as LC-UV. The synthesized MIP was able to achieve efficient clean-up and allowed quantification and identification of TCS and TCC in a complex matrix. Transformation of hormones such as 17β-estradiol, estriol, ethynlestradiol, estrone and testosterone was studied by employing Fe (III)-saturated montmorillonite catalysts. The use of Fe (III) – saturated montmorillonite as a catalyst proved be to very efficient in transformation of the studied hormones. Complete removal of hormones was observed in aqueous environment. LC-UV was used for detection and quantification of hormones.