metal-organic frameworks with photocatalytic bactericidal activity for integrated air cleaning - top quality air purifiers

Air filtration has become a necessary condition for passive pollution control.
However, most commercial air purifiers rely on dense fiber filters with good particulate matter (PM)
But the biological killing effect is poor.
Here we introduce a series of metals-
Organic Framework (MOFs)
And their potential in air pollution control and personal protection.
Specifically, zinc
Ministry of Finance, Imidazolate (ZIF-8)
It shows that E. coli is almost completely inactivated (E. coli)(>99.
Failure efficiency 9999%)
Salt water is added within 2 h after simulated solar irradiation.
The mechanism study shows that in ZIF-
Charge transfer from Ligand to metal (LMCT)
Responsible for oxygen-
Reduction of related active oxygen species (ROS)
It is the leading disinfection mechanism.
Air filter made by ZIF
8 shows significant performance of Integrated pollution control,> 99.
In 30 min and 99% PM removal, the photo-catalytic killing efficiency of bacteria in the air was 97%.
This work may help to design novel porous solids with catalytic antibiotic capabilities for public health protection.
Air is the most important source of supply for the vast majority of life on Earth, and its quality has a direct impact on human health.
Due to the lack of air exchange, people's time in closed spaces such as families, schools, offices, vehicles and hospitals has increased, and air pollutants are particularly worrying, in particular, given their threats to vulnerable groups such as children, elderly people and patients.
Air purifiers and fresh air vents are widely used air refreshing equipment to regulate indoor air quality and protect people from health hazards such as particulate matter (PM)
Biological Aerosol and volatile organic compounds (VOCs), and so on.
Most of these air purification devices are equipped with fiber filters, which have dense mesh networks and the necessary thickness.
Due to the physical barrier and adhesion effects, these filters have a good capture efficiency for PM and meet the high efficiency particulate air standard.
However, there are significant shortcomings in these commonly used fiber filters, including high air resistance and limited ability to inhibit harmful microorganisms.
In particular, they can only keep parts of pathogens such as bacteria, fungi and viruses on the surface of the filter, rather than completely clear them.
In the end, with the accumulation of organic pollutants as nutrients, the filter becomes an easy breeding ground for pathogenic microorganisms, which leads to a second air pollution.
At the same time, the accumulation of organisms may help to reduce the loss of ventilation and filter life.
Therefore, it is ideal to develop integrated filtration materials that can effectively remove PM and interrupt the spread of bacteria in the air by completely killing bacteria.
Pathogens coexist with other pollutants (
PM and VOCs. )
Biological purification becomes complex and challenging in a natural air environment.
Including chemical spray disinfection and ultraviolet rays (UV)
Some outstanding problems have limited its further development and practical application.
For example, the widespread use of traditional chemical disinfectants (
Carbon dioxide, epoxy ethylene, etc. )
It is very energy-consuming, and it is also easy to form harmful by-products in the presence of other air pollutants.
Ultraviolet sterilization is a very useful method, but it lacks continuous effect, inevitably leads to ozone pollution, and the antibacterial efficiency is very low with sunlight as the light source.
Alternatively, heterogeneous catalysis is an efficient and cost-effective method.
Effective ways to eliminate biological pollution.
Active oxygen species produced (ROS)
Such as oh base (OH), superoxide (O)
Single-line oxygen (O)
And hydrogen peroxide (HO)
It can be used as a powerful antioxidant to destroy harmful microorganisms.
Semiconductors, such as zinc and TiO, are potential photo catalysts with biokilling activity, showing good performance in air disinfection.
However, their disinfection efficiency is far from satisfactory, especially at high airflow speeds combined with other contaminants such as PM and VOCs. Metal-
Organic Framework (MOFs)
As an emerging porous crystal material, great research has been made in the field of gas storage, separation and catalysis.
Recently, we and others have begun to study the possibility of MOFs as an air pollution control adsorbent and catalyst.
Progress has been made to efficiently remove PM by developing MOF-based filters (MOFilter)
In our previous work
Large surface area, high hole rate, well
The dispersed active center and adjustable function make MOFs not only a good candidate for air filtration, but also a non-homogeneous photo catalyst for oxidation of air pollutants.
In particular, MOFs provides us with an opportunity to optimize the catalytic performance at the molecular level by reasonably tuning the metal cluster or organic Chain Home, which is considered to be MOFs relative to conventional semiconductors
Due to the extraordinary design capabilities of MOFs, in the decomposition of water, CO reduction, ROS-
Toxic chemicals are mainly oxidation.
We decided to explore the possibility of high efficiency glow in MOFs
Catalytic air sterilization.
Combined with strong PM filtration capability and interesting antimicrobial activity, we strive to develop an efficient integrated air filter based on MOFs (Fig. ).
Here, after careful comparison, ZIF-8 (zinc-Imidazolate MOF)
Selected from 5 typical water stability MOFs.
Better than ZIF-11 (zinc-
MOF of benzimazole)
Three representative MOF photo catalysts100(Fe), NH-MIL-125(Ti), and NH-UIO-66(Zr), ZIF-8 exhibits >99.
9999% pairs ()
In the salt water that is simulated by the sun.
It is worth noting that ZIF-
8 is also superior to the widely used bio-killing photo-catalyst nano-oxide and ruiti TiO in terms of inactivation rate and efficiency.
Electron shunmagnetic resonance (EPR)
Measurements, ROS quenching experiments combined with zinc leaching, and sterilization tests confirm that the light-induced zinc intermediate catalytic center in porous MOF can easily activate O, producing O, by electron transfer, the formation of ROS such as O and HO is the reason for ZIF-excellent sterilization activity8.
Thanks to its good features, ZIF-
8 Further treatment as the MOFilter is outstanding in integrated air pollution control and personal protection.
As a filter medium, MOFilter achieves the capture efficiency of 97% PM at a flow rate of 0.
7 u2009 m u2009 s and light-induced connections --
Kill the surface of bacteria in the air with> 99.
Achieve 99% sterilization efficiency in 30 minutes.
This study emphasizes the importance of MOFs in environmental photo-catalysis and provides new ideas for the design of porous luminous biological materials.