Rebirth of a technological power - Chapter 282 Is seawater desalination technology already available?

The Zhuhai Air Show is just a microcosm of China’s development.

It has witnessed the transformation of China’s industry from weak to large, and from large to strong.

Behind its growing influence is a reflection of China’s growing influence.

Cai Jin returned to his hometown as soon as the Zhuhai Air Show ended.

Gold silver nest nest as their own kennel.

It is still my own home, where I am the safest and most comfortable place to stay.

When Cai Jin returned to the company, he ordered the research institute to develop seawater desalination technology.

In addition to the headquarters research institute, there are seven regional research institutes in North China, Northeast China, East China, Central China, South China, Southwest China, and Northwest China.

Each research institute has 2,000 scientific researchers, and the eight research institutes have a total of 16,000 scientific researchers. Together with logistics, administrative and other related staff, the number reaches 22,000!

The research institute is also the one with the highest average salary in Future Technology Group!

Last year, wages, bonuses, etc. that were considered salary expenses reached a full 8.8 billion, with an average annual salary of 400,000!

Among them, there are many cheap laborers such as postdoctoral fellows and fresh graduate students, as well as logistics, administrative and other related staff.

In research institutes, the annual salary of technical experts is very scary, and some have annual salaries of more than 10 million.

And it is foreseeable that as professional titles and technical levels improve, salary expenditures will show a rapid upward trend.

The research topics of the institute are diverse and there is nothing that is impossible except what is unexpected.

For every scientific researcher, undergraduates from prestigious universities have the minimum academic qualifications, there are many master’s degree candidates, and there are a lot of PhDs!

In Future Technology Group, the one with the highest academic qualifications is the research institute.

The research institute is not only responsible for the group’s scientific research projects, but also cooperates with external companies to carry out scientific research projects or carry out technology licensing.

As a result, not long after, the person in charge of the institute and a few people approached Cai Jin.

In the conference room, Cai Jin looked at several people curiously.

“Dean Li, why did you come to me just after the research project was sent to you? Is seawater desalination technology difficult?” Cai Jin was a little confused.

Li Qingguo, the director of the headquarters research institute and the largest leader of each research institute, is only fifty years old this year, but he is a leader in the field of materials. He was admitted to Harbin Institute of Technology as the top scorer in science in Jiangsu Province, and later went to Stanford University to study for a doctorate. He also worked as a postdoctoral fellow in the United States. After working in the United States for five years, he resolutely quit his good job, returned to China with his wife and children, and was specially appointed as a professor by Harbin Institute of Technology.

Three years ago, he was recruited to the research institute by Cai Jin and was responsible for the establishment of the research institute.

With the strong financial support of Future Technology Group, in just over a year, Li Qingguo established eight complete research institutes, established a complete organizational structure model, and made great efforts to recruit many technical talents.

In the past, biochemical and environmental materials were one of the four major university majors. This does not only refer to undergraduates, but also to those with doctoral degrees.

Finding a job is hard, and finding a good job is even harder!

Doing the hardest work and earning a meager salary.

Many people actually have no choice!

Under such circumstances, the recruitment of eight research institutes is to use a hoe to dig out the foundation.

“Director Cai, in fact, this research topic is not necessary.” Li Qingguo is a typical technician who speaks straightforwardly and will not make lies.

“Why?” Cai Jin was curious.

Li Qingguo said matter-of-factly: “Because seawater desalination technology is no longer a problem, both we and overseas have solved the problem.”

“What? Then why didn’t I see the application of technology?” Cai Jin was a little confused.

Li Qingguo explained patiently.

Only then did Cai Jin understand that seawater desalination technology has been a hot research topic for decades. Hundreds of scientific research institutions in various countries are studying seawater desalination technology.

In the past two decades, graphene has been widely used in seawater desalination.

Previously, theoretical calculations have proven that graphene can be used in seawater desalination, and the single-layer nanopore two-dimensional membrane produced has ultra-high selective separation efficiency compared with traditional seawater desalination membranes.

This technology is naturally very good, but the reason why it has not been applied to industry and stayed in the laboratory is because it has some problems that need to be solved.

The first problem is that the output of graphene was previously low and the price was high. If it is used in seawater desalination, the cost will be relatively high.

The second problem is that the grain boundaries existing inside large-area graphene will reduce the mechanical properties of graphene. The process of introducing nanopores will further reduce the mechanical properties, causing the separation film to easily undergo local rupture, greatly reducing the separation efficiency and separation Selectivity.

The current graphene desalination membranes are divided into two categories.

One type is the single-atom-thick nanoporous film studied by the team of MIT professor Rohit Karnik.

However, the mechanical strength of single-atom-thick graphene is weak, so the graphene used in experimental studies is supported by polymer films.

And sub-nanometer pores are directly introduced into graphene through high-energy electron beam bombardment or oxygen plasma etching. The pore size distribution range is wide, which greatly reduces the separation efficiency, so it cannot be applied in practice.

The other category is the graphene oxide film studied by the team of Andre Geim, the winner of the Explosives Physics Prize and professor at the University of Manchester.

Graphene oxide is easy to mass-produce, but after the graphene oxide film is immersed in the solution, the graphene oxide sheets will absorb water and expand the interlayer spacing, reducing the seawater desalination efficiency. Therefore, existing research work mainly focuses on how to control graphene oxide. The interlayer spacing between ene sheets.

In addition, there are also relevant research results in China.

That is a binary structure graphene film that combines graphene nanosieves and carbon nanotubes. This film combines the selective separation efficiency of the former with the strength advantages of the latter.

Single-atom-thick nanoporous two-dimensional materials have minimal water transmission resistance and maximum water penetration flux, making them ideal materials for constructing ultra-thin and efficient seawater desalination membranes.

However, applying ultrathin 2D materials to actual seawater desalination faces two major difficulties.

The first is how to prepare large-area, crack-free nanoporous two-dimensional films with excellent mechanical strength and flexibility.

The second is how to introduce sub-nanometer pores with high density and uniform pore size distribution inside the film to achieve efficient and selective passage of water molecules and effective interception of salt ions/organic molecules.

Regarding the first problem, carbon nanotubes have excellent mechanical properties and are similar in structure to graphene, and the two can interact through π-π bonds and van der Waals forces.

The carbon nanotube film formed by overlapping carbon nanotubes is a porous network structure film that not only perfectly matches the structure of graphene, but also does not affect water permeability.

Therefore, domestic research institutions thought of combining nanopore graphene with carbon nanotubes to make up for the shortcomings of the former.

They first grew a single layer of graphene on copper foil, and then covered some areas on it with a network of interconnected carbon nanotubes. After the copper foil was etched away, a graphene film supported by carbon nanotubes was obtained.

In order to obtain high-density sub-nanometer pores with uniform pore size distribution, they grew a layer of mesoporous silicon oxide with uniform pore size distribution on the surface of graphene as a mask, and used oxygen plasma etching to remove the graphene within the pores of mesoporous silicon oxide.

The longer the oxygen plasma etching time is, the more graphene is etched away and the larger the pore size of the graphene is.

In this way, the pore size of the graphene nanosieve can be controlled by adjusting the oxygen plasma etching time. When the etching time is controlled at 10 seconds, the pore diameter is 0.63 nanometers, which can effectively allow water molecules with a diameter of 0.32 nanometers to pass through and block salt ions with a diameter of 0.7 nanometers.

This kind of film can be suspended, bent, and stretched without polymer support without obvious cracks.

Test and calculation results show that the new film can withstand 380.6MPa stress and has a Young’s modulus of 9.7GPa, which is three times that of a carbon nanotube film and equivalent to 2.4 times the tensile stiffness and 10,000 times the bending strength of a nanohole graphene film. Stiffness.

So, they made a large and strong graphene mesoporous film.

So what about its filtering performance?

Within 10 seconds, the permeability of the etched graphene nanosieve/carbon nanotube film can reach 20.6 liters per square meter per hour per atmosphere.

After 24 hours of penetration, the salt ion rejection rate is greater than 97%.

Compared with the commercial cellulose triacetate desalination membrane, the water permeability of the new graphene nanosieve/carbon nanotube membrane is increased by 100 times, and the anti-pollution ability is stronger.

And because it is not restricted by the internal concentration polarization effect, the membrane can still maintain a high water permeability in a high-concentration salt environment.

The new graphene nanosieve/carbon nanotube film made by domestic research institutions does not require polymer support, is strong and durable, and has multiple advantages of permeability efficiency.

Of course, this seawater desalination technology is not without its problems, that is, it is difficult to mass produce. If the mass production problem is solved, it can be applied on a large scale.

“Dean Li, what’s the problem with the seawater desalination film here at the institute?” Cai Jin rubbed his temples, a little confused.

Li Qingguo said: “There is no big problem. Mass production of composite films of graphene and carbon nanotubes is not a problem. The quality of our films is very strong.”

“However, the current production of graphene and carbon nanotubes is not enough.”

“I remember that the output of graphene and carbon nanotubes is already very high. Why is it not enough?” Cai Jin was puzzled.

Many technologies and production processes for graphene and carbon nanotubes were invented by Cai Jin.

He even supported companies to produce graphene and carbon nanotubes.

After all, he doesn’t have the energy to produce materials in this area.

“Director Cai, the current output is very high, but this high output is relative. The output is very high, and there are many people who need it. Many high-end products need it.” Li Qingguo said.

Cai Jin was a little dumbfounded.

It turns out that the production capacity cannot keep up with the demand, and it is the kind of supply that exceeds demand.

Graphene, since its discovery, has been hailed as the thinnest and toughest material in the world, as well as the ‘black gold’ and ‘king of new materials’. Graphene can be 1/200,000th as thick as a human hair and 200 times stronger than steel. Previously, graphene has been regarded by scientists as the most important new material in the 21st century.

Graphene not only plays a huge role in the fields of electronic products, new energy batteries, and aerospace, but is also regarded as the key to triggering the next medical revolution in the medical field.

The application prospects of graphene are immeasurable, which has naturally attracted various countries to invest heavily in research and production.

In the past, China has ranked first in graphene production for many years, and its annual graphene production accounts for more than 50% of the world’s production.

In recent years, graphene production has increased significantly due to the butterfly effect caused by Cai Jin.

Just last year, graphene production exceeded 8 million tons, ten times more than before.

But such a large output is not enough!

“Output is not enough, just invest in increasing production,” Cai Jin said.

“Director Cai, the expansion of production by these enterprises cannot be achieved overnight. It requires a large amount of funds, talents, and equipment!” Li Qingguo was helpless.

With these new materials, who wouldn’t want to instantly achieve skyrocketing production capacity?

The problem is, these all take time.

Cai Jin was a little helpless. Obviously technology was not a problem, but he still had to wait. This was simply a cheat.

Cai Jin chatted with Li Qingguo and others, and gradually figured it out.

After all, graphene, nanotubes, etc. are actually being distributed, and they can still get some shares as long as they want it.

Since this is the case, Cai Jin will naturally not be polite.

Cai Jin asked Li Qingguo and others to come up with a complete plan to build a 2 million tons/day seawater desalination plant.

No matter what, a desalination plant must be built near them.

In recent years, in order to ensure their water supply needs, the government has continuously diverted water from the Jiulong River, and water plants have been built one after another.

But it’s still not enough. Other places always need to cut off water and electricity to supply them here.

If a 2 million tons/day seawater desalination plant is built, it will be enough to meet the water supply needs not only for them here, but even for the entire Narcissus City. Including the existing water plants, it is estimated that the water supply demand will be 20% in the next ten years. There is no need to worry about insufficient water supply capacity of the water plant all year round.

A desalination plant with a capacity of 2 million tons per day theoretically only requires 11,000 square meters of membrane, and the membrane has a service life of half a year, which means that it only needs 22,000 square meters of membrane per year.

No matter what, his face is still somewhat valuable.

Of course, a seawater desalination plant cannot be built at will. This matter must be communicated with the government and a good location chosen.

Not all places are suitable for building desalination plants.

Not long after, the general floor plan came out. Although it was not very detailed, the red lines, main buildings, etc. could still be seen.

Cai Jin took the drawings and took Li Qingguo directly to the city.

This matter needs to be communicated with the main leaders first. If the main leaders reach an agreement, then it will be easier to hold the meeting.

Even if it requires approval from the province or even the ministry, Cai Jin can help.

Cai Jin is still very concerned about the development of his hometown.

And this can also bring some additional income channels to Future Technology Group. Although Cai Jin doesn’t like the money he can earn, but no matter what, this kind of business is not a year or two, but twenty or thirty. years or even longer.