Related Experiment Video
Updated: Feb 1, 2026
09:45
Epitaxial Growth of Perovskite Strontium Titanate on Germanium via Atomic Layer Deposition
Published on: July 26, 2016
12.8K
Controlled TiO2 Growth on Reverse Osmosis and Nanofiltration Membranes by Atomic Layer Deposition: Mechanisms and
Xuechen Zhou1,2, Yang-Ying Zhao1,3, Sang-Ryoung Kim1
1Department of Chemical and Environmental Engineering , Yale University , New Haven , Connecticut 06511 , United States.
Environmental Science & Technology
|December 6, 2018
Summary
Atomic layer deposition (ALD) of titanium dioxide (TiO2) on thin-film composite (TFC) membranes offers precise surface modification. Fewer than 10 ALD cycles enhance RO membrane surface charge and NF membrane solute rejection without performance loss.
Area of Science:
- Materials Science
- Chemical Engineering
- Membrane Technology
Background:
- Thin-film composite (TFC) membranes require enhanced properties for advanced separation processes.
- Atomic layer deposition (ALD) offers precise control over surface coatings for membrane modification.
- Titanium dioxide (TiO2) is a robust metal oxide suitable for creating chemically stable membrane coatings.
Purpose of the Study:
- To investigate the application of ALD for TiO2 coating on reverse osmosis (RO) and nanofiltration (NF) membranes.
- To understand the influence of ALD process parameters on coating characteristics for different membrane types.
- To evaluate the impact of TiO2 ALD coatings on membrane performance, including water permeability and solute rejection.
Main Methods:
- Surface modification of TFC RO and NF membranes using ALD of TiO2.
- Characterization of TiO2 coating location and depth using techniques sensitive to pore structure and surface deposition.
- Assessment of membrane performance changes, including water flux, salt rejection, and solute rejection, after ALD treatment.
Main Results:
- ALD conditions, film growth, and deposition depth varied between RO and NF membranes due to precursor diffusion differences.
- TiO2 coatings were primarily surface-localized on RO membranes but penetrated the depth of NF membranes.
- Exceeding 10 ALD cycles negatively impacted water permeability and salt rejection for both membrane types.
- Fewer than 10 ALD cycles of TiO2 on RO membranes increased surface charge without compromising performance.
- TiO2 coating within NF membrane pores tuned pore sizes and enhanced rejection of specific solutes.
Conclusions:
- ALD of TiO2 is a viable method for tailoring TFC membrane properties, with outcomes dependent on membrane type (RO vs. NF).
- Optimizing ALD cycle count is crucial; fewer than 10 cycles can improve membrane functionality without degradation.
- ALD-modified NF membranes show potential for enhanced selective separation through pore size tuning.
Related Concept Videos
00:47Osmosis
193.4K
Approximately 60% to 95% of the weight of living organisms is attributed to water. Therefore, maintaining appropriate water balance within cells is of paramount importance. Osmosis is the movement of water across a semipermeable membrane, such as a cell’s plasma membrane. In living organisms, water plays a crucial role as a solvent—a molecule that dissolves other molecules.
193.4K
01:30Osmosis
10.8K
Osmosis is the movement of free water molecules through a semipermeable membrane. The water's concentration gradient across the membrane is inversely proportional to the solutes' concentration. Whereas diffusion transports material across membranes and within cells, osmosis transports only water across a membrane, and the membrane limits the diffusion of solutes in the water. Osmosis is a special case of diffusion.
Water, like other substances, moves from a high concentration of...
Water, like other substances, moves from a high concentration of...
10.8K
02:40Osmosis and Osmotic Pressure of Solutions
46.6K
A number of natural and synthetic materials exhibit selective permeation, meaning that only molecules or ions of a certain size, shape, polarity, charge, and so forth, are capable of passing through (permeating) the material. Biological cell membranes provide elegant examples of selective permeation in nature, while dialysis tubing used to remove metabolic wastes from blood is a more simplistic technological example. Regardless of how they may be fabricated, these materials are generally...
46.6K
02:45The Quantum-Mechanical Model of an Atom
57.3K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
57.3K
01:21The Resting Membrane Potential
142.5K
Overview
142.5K
01:24Resting Membrane Potential
21.8K
The relative difference in electrical charge, or voltage, between the inside and the outside of a cell membrane, is called the membrane potential. It is generated by differences in permeability of the membrane to various ions and the concentrations of these ions across the membrane.
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
21.8K