Quantitative removal of pharmaceutical compounds from wastewater is a current problem facing utilities management today. Insufficient remediation of these compounds may lead to antibiotic resistant bacteria, feminization of fish, and increased health concerns in the public. Radical-based advanced oxidation and reduction processes (AO/RPs) have been shown to be a promising method to effectively mineralize these compounds. This study investigates the applicability of sulfate radical based oxidation of antibiotics towards their quantitative removal from water. Specifically, the influence of dissolved organic matter (DOM) as a scavenger of oxidative species was investigated as pharmaceuticals may interact with the DOM macromolecule and retard the remediation abilities of radical-based AOPs. Kinetic competition studies were performed between the sulfate radical, small organic pharmaceuticals and DOM. Kinetic traces were obtained to find the pseudo first order rate constant of sulfate radical and the equilibrium constant of association between various pharmaceutical compounds and DOM. The average equilibrium constant between a library of samples of organic matter and antibiotics was found to be 128.1 ± 13.8 using a Langmuir adsorption model. Using a sequential model, the association constants from estrogenic steroids was observed to be an order of magnitude larger than the antibiotics, and the association of carcinogenic nitrosamines to DOM was correlated to the hydrophobic nature of the functional groups. The adsorption of these small organic compounds must be taken into consideration when designing remediation processes.

Selective remediation of pharmaceuticals in wastewater using sulfate radicals: Evidence for adsorption to dissolved organic matter

251st National Meeting (2016)

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