(6ej) Modeling the UV/H2O2 Oxidation of Trace Organic Compounds in a Continuous-Flow Reactor with Reflective Walls

During the last 10 years I have been involved in research related to wastewater treatment. The combination of my previous experiences have made me passionate about this field. My concern about water pollution is genuine; moreover, this branch of research is a global priority in order to ensure a sustainable future. Being born in an overpopulated city with many environmental concerns where potable water is not always available created in me the desire to contribute to the solution of environmental problems and water scarcity. Currently, my research is mainly focused on understanding the mechanisms of degradation of contaminants of emerging concern in wastewater, in order to develop mathematical models that predict the behavior of these contaminants in different natural and engineered systems. Understanding these mechanisms will allow the design of more efficient means of treatment. As a researcher I would like to continue my research in the combination of treatment technologies for the degradation of emerging contaminants, developing methods for the design of treatment trains for wastewater potable reuse.

Teaching Interests:

As an instructor, I am committed to inclusive excellence and active learning in my classes. I understand that, besides being up to date in the advances in my field of research, I need to keep finding strategies to facilitate the learning process of diverse students. I am willing to adapt my teaching style to include a variety of ways of participation, so that students with different learning styles, different capabilities and personal and academic backgrounds can engage in my classes and learn while I learn from them too.

I have previously taught Chemical Engineering laboratories at the undergraduate level, specifically Environmental analysis, Kinetics and reactors, Transport phenomena, Unit operations and Thermodynamics. I have also taught General Chemistry laboratory and assisted the lecture in an active learning environment. I would like to continue teaching classes related to Chemical and Environmental Engineering as a lecture or in laboratory settings.

Abstract:

The occurrence and fate of trace organic compounds (TOrCs) in the aquatic environment are important issues in environmental chemistry. Advanced oxidation processes (AOPs) can be used to remove a wide range of TOrCs by means of reactive species among which hydroxyl radical is prevalent. The UV photolysis of hydrogen peroxide (UV/H₂O₂) produces hydroxyl radicals and is a well-established AOP technology used in full-scale treatment of wastewater effluents.

Understanding of the UV/H₂O₂ AOP process is based on simulation of physicochemical aspects of the process. Recent UV/H₂O₂ process models include consideration of hydroxyl radical scavenging by compounds in complex water matrices and by organic intermediates produced from the oxidation of the parent targets.

Continuous-flow AOPs are commonly used for the destruction of TOrCs that survive conventional wastewater treatment processes. The UV/H₂O₂ process is applied to large-scale operations using tubular reactors that contain one or more UV lamps. A common configuration consists of a single concentric lamp located at the center of a pipe.

Poor absorbance by hydrogen peroxide in the UV range contributes to energy demand in UV/H₂O₂ processes. In poor light-absorbing matrices, a significant portion of the energy is wasted. This inefficiency can be remedied by reflecting unabsorbed light into the reactive mixture. In this work, two novel flow-through UV reactors with a concentric lamp and a reflective surface are used to investigate the destruction of trace organics in wastewater. A kinetic model for the oxidation of p-cresol by hydrogen peroxide photolysis developed previously was modified to account for annular flow hydrodynamics, surface light reflection and the full mechanism of p-cresol oxidation by hydroxyl radicals. In addition, a mechanism for the degradation of caffeine, bisphenol A and carbamazepine is proposed and calibrated.

The model includes elementary reactions of the UV/H₂O₂ system; direct UV photolysis of the target; and reactions of hydroxyl radical with the target, H₂O₂ and reaction intermediates. The model incorporates UV light reflection from the reactor walls, as well as the hydrodynamics of the annular flow. The model accurately predicts the destruction of the target compounds in a wide range of experimental conditions. Experimental and theoretical results demonstrate that wall provides a significant enhancement of the rate of conversion of the target for high transmittance solutions.