Reverse osmosis– a technology first put to utilize in the 1960s– removes salt and pollutants from water by passing the water through a semipermeable membrane, which permits the water to go through while obstructing the impurities. To discuss precisely how it works, researchers have utilized the theory of solution-diffusion. This theory presumes that the water molecules diffuse and liquify through the membrane by method of their concentration gradient– that is, the molecules move from locations of high concentration to any place there are fewer molecules. Although this theory has actually been commonly accepted for more than 50 years and is even taught in textbooks, Elimelech stated he has actually long had concerns about it..
” Some of the presumptions do not make any sense,” stated Elimelech, the Sterling Professor of Chemical and Environmental Engineering. He said, the theory is based in part on the concept that pressure across the membrane is consistent. “Whenever you have water flow through any permeable material, there is constantly a pressure drop.”.
Particularly, they used simulations of the molecules motions, which revealed that water transport is driven by changes in pressure within the membranes. They even more show that water molecules travel as clusters through a network of pores in the membrane.
Supplementing the computer system simulations, the researchers performed experiments that permitted them to observe water passing through membranes. The results showed that the manner in which water permeates the membrane depends upon the membrane pore size, the size of the water particles, and viscosity of the water. This was likewise inconsistent with the solution-diffusion design..
In general, the experiments and simulations demonstrated that, rather than being driven by the concentration of particles, reverse osmosis is driven by pressure changes within the membrane..
Due to the fact that previous measurements related to reverse osmosis were based on a faulty understanding of it on a molecular level, Elimelech stated, numerous efforts to advance the field have satisfied a dead end. Having a more precise theory to discuss reverse osmosis, he said, could break the ice toward developing more reliable materials and techniques to improve the process.
Reference: “Water transport in reverse osmosis membranes is governed by pore circulation, not a solution-diffusion mechanism” by Li Wang, Jinlong He, Mohammad Heiranian, Hanqing Fan, Lianfa Song, Ying Li and Menachem Elimelech, 14 April 2023, Science Advances.DOI: 10.1126/ sciadv.adf8488.
Other authors of the research study include Li Wang, Mohammad Heiranian, Hanqing Fan (all from Yale); Jinlong He and Ying Li from University of Wisconsin-Madison; and Lianfa Song from Texas Tech University.
This work was supported by the National Alliance for Water Innovation (NAWI), moneyed by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Advanced Manufacturing Office, under Funding Opportunity Announcement Number DE-FOA-0001905 through a subcontract to Yale University and University of Wisconsin-Madison.
A brand-new study has actually discovered that the extensively accepted theory of how reverse osmosis works, called the solution-diffusion design, is essentially inaccurate. The research group carried out experiments and computer simulations which demonstrated that reverse osmosis is driven by pressure changes within the membrane, rather than concentration gradients. This finding challenges the conventional understanding that has been taught for over 50 years and could lead to more reliable usages of reverse osmosis in applications such as desalination, wastewater treatment, and energy production. Credit: Yale University
Researchers have actually found that the accepted theory of reverse osmosis, based upon concentration gradients, is inaccurate. Rather, pressure modifications within the membrane drive the process, possibly leading to more effective uses in desalination, wastewater treatment, and energy production.
The process of reverse osmosis has actually shown to be the cutting edge approach for removing salt from seawater and increasing access to clean water. Other applications include wastewater treatment and energy production.
Now a team of researchers expose in a brand-new research study that the basic description for how reverse osmosis works– one that has been accepted for more than 5 years– is fundamentally wrong. While doing so, the researchers provide an alternate theory. Remedying the record, these insights could lead to more efficient uses of reverse osmosis. The results of the study, led by the laboratory of Prof. Menachem Elimelech, are released in Science Advances.
A new study has actually found that the commonly accepted theory of how reverse osmosis works, called the solution-diffusion model, is fundamentally incorrect. The research group carried out experiments and computer system simulations which showed that reverse osmosis is driven by pressure modifications within the membrane, rather than concentration gradients. Now a team of researchers expose in a new research study that the basic description for how reverse osmosis works– one that has been accepted for more than five years– is basically wrong. Correcting the record, these insights could lead to more effective uses of reverse osmosis. Reverse osmosis– an innovation first put to use in the 1960s– eliminates salt and impurities from water by passing the water through a semipermeable membrane, which permits the water to go through while obstructing the pollutants.