CBE - Water adsorption in flexible porous materials; a path to refrigeration

As the global temperatures rise due to climate change, demand for air conditioning and other cooling is expected to increase. Conventional air-conditioning systems often rely on cooling the air below its dew point causing water to condense and controlling the humidity of the air. Going through the vapor to liquid phase change makes the dehumidification step energy intensive. This project consists of studying materials called Metal Organic Frameworks (MOFs) as more energy efficient adsorbents to remove water.  MOFs are made up of metal nodes and organic linkers which make up its chemical and mechanical properties, by changing these building blocks one can tune the material’s behavior and tailor it to a specific application. Some MOFs have responsive behavior, allowing them to change structure when they undergo external physical stimuli such as temperature, mechanical pressure, light, or gas or liquid exposure. MIL-53 is a well-known flexible MOF that can undergo structural transformation during the adsorption process. We will use molecular simulation methods, including Monte Carlo techniques and molecular dynamics, to investigate its behavior across a range of water loadings and thermodynamic conditions. Through these simulations we want to quantify the rotation, stretching and deformations that MIL-53 undergoes as it adsorbs water. Understanding the coupling between water adsorption and framework deformation can guide the design of new porous materials and adsorption-based dehumidification technologies that reduce the energy required for humidity control and refrigeration.