Unconventional Materials and Paradigms for Water Purification and Quality Control in the 21st Century
Friday, November 02, 2018 at 4:00pm to 5:00pm
Innovations across the entire spectrum of technology, policy, business, and society are needed to address the challenge of providing an adequate amount of clean water in the 21st century. In this talk, I will present our work on exploring unconventional materials and paradigms for water purification and quality control to address this challenge. At the smallest scale, we present the development of atomically thin membranes made from a single atom-thick layer of graphene, where water can rapidly flow through engineered angstrom-sized pores that reject contaminant molecules and salt ions. I will discuss advances in pore creation, fabrication, and scale-up that illustrate the feasibility of realizing this new class of membrane that could lead to more energy-efficient, compact, and versatile water purification systems. At a larger scale, we show that the sapwood of conifers can be used as natural, chemical-free, low-cost, and easily manufactured filters to remove microbes and turbidity from drinking water. These filters exploit the naturally-occurring membranes in the xylem tissue of plants to remove microbes and present opportunities to create unique pay-as-you-go business models for household water filters with replacement costs of only a few cents. We present human-centric filter device design and field studies that illustrate the potential of xylem filters to provide clean water to people without access to existing water purification technologies. At the systems scale, we present our findings through field studies in India and technology development to address the gap in monitoring trace contaminants in water by ‘dry sampling’ – a paradigm that repurposes materials developed to easily preserve and convey water samples from the water source to a central laboratory, thereby enabling the measurement of trace contaminants that is not possible with local infrastructure. These studies illustrate the opportunities and challenges involved in fundamental research and development and its translation to ground reality to provide clean water in the coming decades.
Rohit Karnik, Associate Professor & Associate Department Head for Education, Department of Mechanical Engineering, Massachusetts Institute of Technology