Research Areas
Research in my group spans a range of environmental issues including subsurface contaminant transport and remediation, environmentally friendly cleaning and extraction systems, water technologies for emerging regions, and educational innovations. Since 2001 several of these research areas has been conducted in collaboration with colleagues at the National Research Center for Environmental and Hazardous Waste Management (NRC-EHWM) at Chulalongkorn University in Bangkok, Thailand (www.nrc-ehwm.chula.ac.th/). Research activities in my laboratory will be discussed in four areas:
(1) surfactant-based environmental technologies, ranging from subsurface remediation to solvent replacement and biodiesel production,
(2) sorption and transport of organic compounds and nanomaterials,
(3) water treatment technologies for arsenic and fluoride removal in emerging regions and emerging issues, and
(4) educational innovations in engineering education. The full vitae can be viewed for representative publications in each area.
1. Surfactant-based environmental technologies
My surfactant-based research initially focused on developing an advanced technology for extracting trapped oil (residual NAPL) from the subsurface. This research focused on (a) developing advanced surfactant solubilization and microemulsion systems capable of more efficiently removing contaminants from the subsurface while minimizing surfactant losses in the subsurface and (b) developing / modifying separation processes for decontaminating the surfactant stream and thus allowing surfactant reuse. A major focus of this work was developing alcohol-free surfactant systems in an effort to improve the environmental friendliness of prior microemulsion work. Based on successful laboratory and field demonstrations of this technology, several colleagues and I co-founded Surbec Environmental (www.surbec.com) to implement the technology in the marketplace. My group has also evaluated surfactant-modified surfaces for in situ sorbing barriers and adsorptive water treatment systems, with a recent focus on using surfactant systems (e.g., mixed surfactants, polymerizable surfactants, etc.) to improve compound sorption and minimize surfactant desorption / losses.
In developing our subsurface remediation technology my group learned a number of things about microemulsions that we have subsequently applied in other fields. We learned that extended surfactants and surfactants combined with lipophilic and hydrophilic linkers are more effective at enhancing solubility and lowering interfacial tension than conventional surfactants. We learned that a surfactant gradient system can maximize extraction while minimizing vertical migration concerns. We extended these concepts into washing of drill cuttings, where we further demonstrated the potential of extended surfactants. We also evaluated these concepts in laundry detergency, where we likewise demonstrated the exciting potential of these concepts for improving detergent systems. This work is a natural outgrowth of our Institute for Applied Surfactant Research (www.cems.ou.edu/iasr/) and our company Surfactant Associates (www.surfactantassociates.com).
In our detergency research we first worked with triglyceride oils, and quickly realized the unique challenges posed by these oils. We are currently making great strides in understanding and advancing our ability to make microemulsions with triglyceride oils without alcohol addition or elevated temperatures. Initially this work focused on detergency, with an intermediate project on skin cleaners, and most recently this work has focused on developing an environmentally friendly alternative to hexane for vegetable oil extraction (green chemistry / green processing) for either cooking oil or biodiesel production.
It is rewarding to see how fundamental advances in one application (e.g., subsurface remediation) has fostered research and development of new technologies in a wide range of seemingly unrelated areas.
2. Sorption and transport of organic compounds and nanomaterials
My group has studied the equilibrium and kinetics of sorption and transport for a wide range of organic compounds, initially focusing on pesticides and fluorescent dyes and more recently focusing on pharmaceuticals and personal care products. Most recently I have collaborated on research evaluating the transport of nanomaterials in the environment. Overall, this work has evaluated the impact of compound chemistry (hydrophobicity, degree of ionization, impact of functional groups, co-transport of pharmaceuticals and surfactants), media chemistry (e.g., nature of and degree of activation for different sources of organic matter, impact of sorption limited intraparticle diffusion on transport, surface area, point of zero charge and zeta potential) and fluid properties (ionic strength, competing ions) on compound sorption and transport.
3. Water technologies for emerging regions and emerging issues
Statistics indicate that over 1.1 Billion people lack access to safe drinking water and 2.6 Billion suffer from inadequate sanitation in the world; these are staggering statistics given the technological advances and economic prosperity of our times. The UN has designated 2005-2015 as the International Decade of Action with a focus of addressing this critical situation. In the summer of 2005, I worked with two colleagues I to help establish the Water Technologies for Emerging Regions (WaTER) Center at OU (WaTER.ou.edu). The WaTER Center has a goal of bringing water and sanitation to remote villages. This center seeks to engage both undergraduate and graduate students in classroom activities, service projects and laboratory research that are responsive to these critical needs. Example activities include a new course focused on this topic (CE 5020 – Water Technologies for Emerging Regions), sponsorship of a student chapter of Engineers without Borders (with projects in Honduras and Guatemala so far), graduate research on simple technologies for removing naturally occurring arsenic and fluoride from ground water, and participation in / interaction with remote village water projects in China and South Africa. Collaboration with Chulalongkorn University in Bangkok, Thailand also provides a unique opportunity to build on this area. The arsenic research builds on past work to develop a polyelectrolyte-enhanced ultrafiltration (PEUF) system for helping larger communities meet to the newly lowered arsenic standard of 10 micrograms per liter.
4. Engineering Education Innovations
Dr, Sabatini has incorporated educational reforms into his teaching - in the classroom, in the research laboratory and through small discussion groups. This educational scholarship has resulted in numerous conference presentations and refereed journal articles. His classroom innovations have included team-teaching a revised senior design course, and more recently revamped the introduction to CEES course to be design-based, incorporating active and lifelong learning activities into all his classes, and engaging Ph.D. students in co-teaching his classes. In addition, he has actively incorporated undergraduates into his research program -- with increasing experience the students become more independent and actually prepare proposals, present their results, etc. This approach has proven successful, as evidenced by the act that two of his undergraduate research students have garnered NSF Graduate Fellowships and one Goldwater Scholarship. With colleagues in the department he participated in the highly successful Sooner City project, an NSF-funded Action Agenda project that integrated a common infrastructure design theme throughout the CEES curriculum; elements of this project have been implemented by a number of other universities. More recently, he and colleagues are building on the Sooner City project by integrating Sooner Village throughout the curriculum – Sooner Village will engage students in infrastructure issues as faced by remote villages in emerging regions, and will be a nice contrast and complement to the Sooner City activities.