With the recent wide spread concerns of the environmental and public health effects of endocrine disrupting chemicals (EDCs), it is becoming important to develop new techniques to remove these substances from wastewater. EDCs find their way to the environment mainly via effluents from WWTPs. They are often cited as moderately hydrophobic, hence they have tendency to distribute to organic solvents and can then be removed using liquid-liquid extraction (LLE) techniques. However, despite being a mature chemical engineering unit operation, LLE has not been studied for the removal of EDCs in water. This study investigated the removal of three EDCs of concerns including estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) using decamethylcyclopentasiloxane (D5) as an extraction solvent in three water matrix types (Milli-Q, tap water, and a secondary treated wastewater). The study showed that all three EDCs were distributed to D5 but at varying distribution coefficients: K E1 = 2.66, K E2 = 0.61 and K EE2 = 1.67 ±5% at pH 6 and 20 o C. Due to the high pKa values of the three EDCs, pH had no significant effect on K EDCs up to about pH 9.5 but higher pHs reduced the distribution ratios up to almost zero at pH 12. Van't Hoff Equation described the effect of temperature on K EDCs and showed that the process was endothermic. The overall estrogenic potency of the three EDCs in mixtures was quantified with an E2 equivalent potency, which was found to distribute well into the solvent at a K E2EQ 2 = 1.43. The study suggests that LLE is an effective method to remove estrogenic potency of wastewater.

The removal and recovery of highly potent endocrine disrupting chemicals (EDCs) estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) and the oxidation product 2hydroxyestradiol (2OHE2) in water was achieved on Polyamide 6 (PA6) particles. Hydrogen bonding was the main mechanism driving the adsorption of these EDCs on PA6 at pHs lower than the EDCs pKas (~10.5) and their adsorption was not affected by the water matrix nor by solute-solute interaction. The adsorption isotherms were linear and the values of the linearity constants for E2 and EE2 were almost double those for E1 and 2OHE2. This was correlated to the number of intermolecular hydrogen bonds via-OH groups of the EDCs (H-bond donors) available for interaction with PA6's surface via the amide groups (H-bond acceptors). The effect of pH on the adsorption of the EDCs on PA6 was significant only at Highlights  PA6 was effective to selectively remove and recover estrogenic EDCs in wastewater  H-bonding is largely responsible for EDCs adsorption on PA6 at pH

Ozonation has been proven effective for the removal of endocrine disrupting chemicals (EDCs) in water. However, conventional ozonation processesare still limited by ozone low solubility and stability in water. These limitations may be overcome by mixing a prior ozoneloaded non-polar solvent with the aqueous solution. This two-phase ozonation process combines Liquid-liquid extraction and Ozonation (LLO). Decamethylcyclopentasiloxane (D5) was chosen as the solvent to be charged with ozone for its non-toxicity, reusability and high ozone solubility. A concurrent LLO column reactor was designed for the simultaneous degradation of three endocrine disrupting chemicals (EDCs) in water: Estrone (E1), 17βestradiol (E2) and 17α-estradiol (EE2). Results showed that 98% of EDCs were removed effectively from a solution initially concentrated at 1 mg L-1. The efficacy of the degradation depends essentially of the column feeding flow rate, the ozone dose and the operating pH. The generation of byproducts during EDCs degradation by LLO was also investigated in this study. For a complete removal of both EDCs and byproducts, the dose of ozone had to be doubled.