robust fabrication of thin film polyamide-tio 2 nanocomposite membranes with enhanced thermal stability and anti-biofouling propensity - thin polyester film
Development of nanotechnology
Enabling composite materials to lead to high manufacturing-
With enhanced penetration, heat-
Mechanical and antibacterial properties.
The main challenges of successful incorporation of nanoparticles (NPs)
Polymer film is a serious aggregation of NPs and weak compatibility of NPs with polymer.
These two phenomena lead to non-
Selective gaps on the interface between polymer and NPs, adversely affecting the separation performance of the membrane.
To overcome these challenges, we have developed a new method to prepare a solid TFN reverse osmosis membrane.
This method relies on simultaneous synthesis and surface modification of ti02 NPs in organic solvents (heptane)
Heat reaction by two-phase solvent.
Subsequently, a stable suspension of ti02 NPs in zhenggeng was used in the interface (in-situ)
Polymerization reaction, NPs is trapped in the matrix of polyamide (PA)membrane.
The ti02 NPs at 10 nm is effectively incorporated into the thin PA layer, which improves the thermal stability and resistance
Biological pollution properties of TFN membrane obtained.
These properties make our synthetic membrane highly therapeutic-
The temperature flow containing biological materials is required.
In recent years, the world's population has grown rapidly, the industry has been rapid, climate change is widespread, and the world is facing the threat of water shortage.
More than 1 today.
About 8 billion people-
The fifth population of the world lives in areas with severe water shortage;
There, millions of people die each year due to lack of clean and safe drinking water.
Therefore, the use of energy to meet the world's key water needs
Efficient and economical
High-tech production and recycling
High quality water has become a top priority.
Membrane technology is widely used in many water treatment processes such as seawater and bitter salt water desalination and industrial and urban wastewater recovery.
At present, film composites are used in most commercial seawater desalination and water treatment plants (TFC)
And reverse osmosis (RO)membranes.
The TFC film is made of thin selective layers usually made of polyamide (PA)
On the porous layer (e. g.
Jufang ketone (PES)
Supported by polyester fabric mesh).
Preparation of PA layer by Interface polymerization (IP)
Reaction between multi-functional amineg. , m-
P-2 amine (MPD)
, And a multi-functional YL chloride molecule, such as trimesyol chloride (TMC).
The multi-layer structure of the TFC film allows unique opportunities to independently adjust and enhance the performance of the selective and supporting layers using novel materials and advanced synthesis methods.
With respect to this, considerable efforts have been made to combine advances in nanotechnology with classical synthesis procedures for polymer films with the aim of preparing new multi-functional nano-composite films.
The first example of this work is reported to be the addition of nano-fillers to silicone rubber in 1973 for gas separation.
Later, in 2005, the application was extended to water filtration with the addition of Zeolite-
Turn NPs into a thin one.
Thin film nano-composite materials (TFN)PA membrane.
Since then, various nanoparticles (NPs)
Including organic (carbon-
Based on nano-materials such as carbon nanotubes, graphene and graphene oxide)and inorganic (
Metal and metal oxide)
Nanoparticles are used to prepare TFN films for various applications in gas separation, infiltration evaporation and water purification processes.
Recently, titanium dioxide (TiO)
Due to the low production cost, high chemical and thermal stability of tfn pa film, the most important thing is its catalytic activity under ultraviolet irradiation, which improves the selectivity and anti-pollution of tfn pa film.
There are two main ways to add TiO NPs to tfn pa membrane :(i)
Through self attachment
Assembled to the surface of the PA and (ii)
Integrated into the PA matrix during the IP response.
The former includes immersing the prepared TFC film in the TiO NP suspension system.
In the second method, TiO NPs is directly dispersed in one of the reaction monomer (either MPD-aqueous or TMC-organic)
Solution before IP response. The self-
Assembly is very effective in modifying the surface properties of the film because NPs is deposited directly on the surface of the film and therefore is easy to implement.
However, the weak attachment between TiO NPs and the surface of the host PA membrane may lead to the loss of NPs in the filtration process, thus limiting its application for a long timeterm operation.
The significant advantage of the integral method is to solve this problem by trapping TiO NPs in the PA matrix during the IP reaction.
However, the key challenge of this approach is the manufacture of defects
The free PA film needs to synthesize nano TiO NPs first, and then the stable dispersion of TiO NPs in the monomer solution needs to be prepared.
In recent years, various approaches have been reported to effectively incorporate NPs into the thin PA layer through aggregation.
Due to the strong interaction of most nano-materials with polar solvents, most of the studies so far have been limited to NPs in MPD-
One possible weakness of this approach, however, is that NPs cannot be integrated into the top-level PA layer, so their properties do not exist in the membrane/water interface.
With this in mind, it is better to spread NPs in TMC
Organic Solvent (e. g. heptane).
In this case, however, the aggregation of TiO NPs becomes more challenging because the thermodynamics of the resulting multi-phase systems is inherently unstable.
In the current work, we report a highly robust and efficient approach to incorporate TiO NPs into the PA matrix.
The synthesis and surface modification of nanoparticles are carried out simultaneously using fatty acids (OA)
Heat by two-phase solvent (BST)reaction.
Then add the stable TiO suspended solids in the obtained N-gengane to TMC-
Tfn pa film was prepared by heptaane solution.
Stable dispersion of nano TiO particles with very low aggregation rate expected in TMC-
Heptaane solution can effectively prepare nano-composite PA films with enhanced thermal mechanical properties, antibacterial properties and penetration properties.