Is Chemical Separation Without Causing Harm to the Environment Possible? Nanotechnology May Help

Using nanotechnology, Penn engineers are developing new membranes for energy-efficient organic separations by rethinking their physical construction.

As a Phys.org report said, chemical separation processes are vital in the production of numerous products from gasoline to whiskey.

Such processes are vigorously expensive, accounting for roughly 10 to 15 percent of global energy consumption,

Specifically, employment of the so-called "thermal separation processes," like distillation for separating petroleum-based hydrocarbons, is profoundly invested in the chemical industry and has a very big associated energy footprint.

Membrane-Based Separation

Membrane-based separation processes comprise the possibility to substantially decrease such energy consumption, a Penn Today report said.

Membrane filtration processes that's separating contaminants from the air breathed and the water drunk have turned commonplace.

Nevertheless, membrane technologies for the separation of hydrocarbon, as well as other organic materials are far less developed.

Nanofiltration that utilizes self-assembling membranes has seen a major area of study for Chinedum Osuji, for Eduardo Glandt, a Presidential Professor in the Department of Chemical and Biomolecular Engineering, and his lab.

Such membranes' performance was underscored in a previous study that describes how the construction of the membrane itself contributed to the minimization of the limitation of the trade off between selectivity and permeability encountered in traditional nanofiltration membranes.

Tunability Opens Doors for Membrane Technology

The new research, published in Science Advances, details the manner the uniform pores of this membrane can be fine-tuned by altering the size or concentration of the self-assembling molecules that eventually form the material.

Such a tunability now opens doors for the function of this membrane technology in addressing more diverse real-world organic filtration problems.

Researchers in the Osuji lab, including Yizhou Zhang, the first author of the study and former postdoctoral researcher; Dahin Kim, a postdoctoral researcher; Ruiqui Dong, a graduate student, and Donghua University's Xunda Feng were contributors to this project.

One problem the team encountered was the difficulty of keeping membrane stability in organic solvents with different polarities.

The group selected molecule species, surfactants, that showed low solubility in organic fluids, and which could be effectively associated together chemically to offer the stability needed.

Nanoporous Polymer

Such membranes developed in the study were created first, by forming lyotropic mesophases of the surfactant in water, spreading the soft gel as a thin film, and then employing a chemical reaction to associate the surfactants together to construct a nanoporous polymer.

The pores' size in the polymer is set by the self-constructed structure of the lyotropic mesophase. At a certain concentration, explained Osuji, in an aqueous solution, the surfactant molecules are aggregating and forming cylindrical rods, and then, such rods will self-assemble into a hexagon-shaped structure, producing a gel-like material.

One of the many ways permeability or size of the pores in the membranes can be manipulated is by changing the size and concentration of the surfactant molecules used for the creation of the membrane itself.

In this research, said Osuji, both of those variables can be manipulated to tune the pore sizes from 1.2 down to 0.6 nanometers.

Related information about the use of nanotechnology is shown on Aperture's YouTube video below:

Check out more news and information on Nanotechnology in Science Times.