Purify Water and Air on the Earth
Planetary Potentiality from Small Rice Husks

More than 100 million tons of rice husks are generated worldwide each year. By making use of these excess by-products as raw materials, Sony is driving the Triporous™ project, a project that addresses the global challenge of water and air purification. So, what kind of project is this? We spoke with Seiichiro Tabata, who invented Triporous, Shun Yamanoi, who has made success in the mass-production of the material and product development in the healthcare and apparel sectors, and Makoto Koike, who is the senior manager of Strategy Gp in Intellectual Property Incubation Department, which owns this project.


  • Makoto Koike

    IP Incubation & Investment Department,
    Intellectual Property Division,
    Sony Corporation

  • Seiichiro Tabata

    IP Incubation & Investment Department,
    Intellectual Property Division,
    Sony Corporation

  • Shun Yamanoi

    IP Incubation & Investment Department,
    Intellectual Property Division,
    Sony Corporation

Micropores, mesopores, and macropores

──First, what kind of material is Triporous and what kind of properties does it have?

Seiichiro Tabata:Triporous is a porous material made from rice husks. It can adsorb high-molecular-weight organic substances in water and air that cannot be adsorbed by conventional porous materials (such as activated carbon). It has been confirmed, in particular, that this material can adsorb not only organic molecules, but also viruses and bacteria in water. In addition, with large pores called mesopores and macropores, Triporous can adsorb substances at very high speed.

──Could you tell us more about mesopores and macropores?

Tabata:Going through a unique manufacturing method invented by Sony, Triporous has three different sizes of pores: micropores with a diameter less than 2 nm (which can also be found in conventional activated carbon), mesopores with a diameter of 2 to 50 nm, and macropores with a diameter larger than 50 nm. To explain the manufacturing method briefly, we first carbonize the rice husks to clear the silica accumulated between the cells of the husks. Then, we etched off the silica to form macropores. Finally, we perform an activation process (high-temperature process that uses water vapor) to develop mesopores and micropores. "Triporous" is named after a combination of "Tri-" meaning 3 and "porous" meaning having many small holes.

──We couldn't easily imagine Sony has something to do with rice husks. How and when did you pay attention to rice husks and bring it to the Triporous business?

Tabata:When I joined Sony in 2006, my research theme was the development of new electrode materials using excess biomass (excess natural resources) for power storage devices, such as lithium-ion batteries and electric double-layer capacitors. As a matter of fact, when I was a student in a university laboratory, I was researching the porous carbon electrodes made from artificial resin using silica microparticles as a mold. Having this experience, I thought a natural substance could also produce the same material if it contains silica. After I repeated research and analysis, I discovered that rice husks are composed of silica microparticles and lignocellulose (a carbon source), and when I made the material from the husks, a porous carbon material with a unique structure was produced.

At that time, we were aiming to apply these to battery electrodes, but later discovered a unique adsorption property derived from its unique pore structure, so we organized it as a basic patent. Since then, we have conducted various laboratory experiments with our members and obtained a lot of patents and know-how on the Triporous technology.

──How did you come up with the idea of using it for other than battery electrodes?

Tabata:In the latter half of 2007, there was a growing movement in the laboratory to emphasize research in the environmental and medical fields. Triporous was also expected to contribute to those fields in some way and we were inspired by the adsorption characteristics of Triporous, thinking it could be applied in environmental and medical domains. We did a lot of laboratory experiments, and when we discovered a dye molecule that can be adsorbed only by Triporous, we were so excited. After this finding, its uniqueness was recognized by many experts through academic conferences and papers, which gave us even more confidence.

What we needed was co-creative innovation

──The Triporous project is driven and promoted by Intellectual Property Division of Sony. What kind of activities does this division usually do?

Makoto Koike:Intellectual Property Division is an organization to support Sony's business activities by handling intellectual property rights, such as patents, designs, and trademarks. The main mission is to protect Sony’s business by gaining the competitiveness with its own intellectual property rights and by competing to reduce business risks in terms of external intellectual property rights.

──Of all those activities, what specific role do you play in the Triporous project?

Koike:By evolving the tasks I just mentioned, IP Incubation & Investment Department, where we belong, aims to provide a new functional value as an organization that is responsible for intellectual property within a company (the corporate IP division). In the case of Triporous, our goal is to create a licensing business that leverages its intellectual property rights. Even if the results of R&D investment are not utilized in Sony's existing businesses, I believe that we can provide a new functional value to create a different opportunity for utilizing the results by making use of its intellectual property rights.

I myself have been involved in the Triporous project since January 2018. As management, I support the Triporous project team, including Yamanoi-san as the project leader and Tabata-san as the technical leader. Triporous aims to create a licensing business using intellectual property rights as I mentioned. That may sound very different from the conventional Sony business model, but Sony has lots of experience in the licensing business. For example, in the recording media business, such as CD, DVD, and Memory Stick, Sony has promoted licensing to create a market for products that Sony has manufactured and sold. We also made a great success in MPEG2 Video as the licensing business, which aimed to promote the technology Sony adopts.

If there is anything special about the Triporous project, it would be that we actively promote and appeal this novel material to the public ourselves, in a similar manner to IT industry platformers. This allows us to be engaged with interested companies and organizations, and gives us an opportunity to promote an open innovation, where we can collaborate with others to strengthen our ideas for the project. We are also creating our licensing business in a "co-creative innovation" style. In other words, we seek ways to co-create with people outside of Sony and form a business ecosystem from which we can receive license fees. We expect that this kind of scheme will lead to a new functional value as the corporate IP division.

──What challenges did you face in the mass production of Triporous, and how did you solve them?

Shun Yamanoi:When we tried the same method as a lab experiment in a mini-plant, we failed in the process of removing silica by etching, which is the process of stirring carbonized rice husks in reaction liquid. When I tried to separate the water from the rice husks after the reaction, the resistance of the rice husks was unexpectedly large, which caused the filter to get clogged. Furthermore, in the final activation process where water vapor was applied to make a reaction in an environment of ca. 1000 degrees C, light rice husks flew away when exposed to wind, resulting in a very low yield As a result of trial and error, we developed a method to process rice husks into pellets before going to mass-production. The development of this method enabled us to successfully produce several tons of Triporous. Although we faced a series of unexpected events, I was very happy to see it produced in tons, instead of grams when we did in Atsugi's laboratory.

Since Sony did not have much know-how in the mass production of materials, we had a great amount of support from chemical and activated carbon manufacturers to mass-produce Triporous. This collaboration enabled us to combine Sony's Triporous technology and their expertise to bring realization. Even now, our technology is advancing everyday thanks to their knowledge.

How will Triporous be implemented in society?

──What is Triporous currently used for?

Yamanoi:Triporous was adopted by Rohto Pharmaceuticals Co., Ltd. into their body soaps and by EDIFICE for their apparel products in 2019, and the products containing Triporous have started to be available in the market. Triporous can be adjusted in its shape, granularity, and quality to suit various uses. In addition to skin cleansers and deodorant fibers which are already sold in the health care and apparel fields, we are planning to expand implementations to water filters for the water purification field and air filters for the air purification field. We have met the food additive and medicinal carbon standards as well, so we are also looking forward to developing this technology for food and pharmaceuticals sectors.

Koike:We are currently proceeding the commercialization for B-to-C markets, but we also expect that we will be able to enter B-to-B markets where large amounts of Triporous powder can be consumed, in order to reduce production costs. We'd also like to expand our brand licensing business. And for this, we'd like to support the companies who have adopted Triporous for B-to-C by publishing information so that they can easily appeal the environmental value of sustainable materials using excess biomass, and by promoting commercialization in various fields so that it will be easier to conduct marketing across industries.

Tabata:It may sound unusual, but Triporous can also be used to preserve art and craft works. For the long-term storage of cultural properties, air quality control is required at a higher level than normal indoor environments. Because air purification devices and sheets using processed Triporous can efficiently remove gaseous contaminants, Triporous has started to be used in a variety of places where important cultural properties are stored, including the World Heritage Byodoin Temple.

Triporous helps to preserve Sony's Founding Prospectus displayed in the lobby of Sony's headquarters building

──So, you are exploring applications as well as researching and developing how to process it.

Tabata:Yes. Since the development at the lab level is almost completed, we are preparing to implement them into variety of areas the world.

Koike:It is both difficult and interesting that we must tailor our products to each customer's needs. We are developing processed products in cooperation with partner companies.

Yamanoi:In the case of textiles, for example, it has been found that mixing Triporous enhances deodorizing power, but Sony has little knowledge of how to mix it into textiles. Therefore, we need the help of textile specialists. By the way, if Triporous is mixed into textiles at a few percent of the weight of the clothes, its deodorant effect starts appearing. We have also confirmed the conditions under which the deodorant effect can be actually felt, and only the fibers that satisfy those conditions are tagged as Triporous FIBER.

Tabata:As we considered various business models, we found out that we couldn't do everything on our own. This reality was hard for us, but we never gave up on our dream, and thanks to our business partners' support, we stand where we currently are.

Sustainable growth and open innovation

──Sustainable growth is an essential aspect of the times, and open innovation is critical for large companies to survive.

Koike:Yes. When a large company like Sony tries to create its own product, it would often be proceeded with development in a closed manner, but I feel the trend is shifting towards open innovation, in a manner to seek a platform for more open knowledge creation. I think that the Triporous project has shifted from the "enclosure style" as conducted in the manufacturing industry to the "co-creation style" as many IT companies do.

In my opinion, Triporous could be used for many things and we shouldn't narrow down targets at this point. If we focus on something, we may or may not succeed. I would rather like to collaborate with more people and proceed with development without selecting areas. In this way, we will be able to find answers to our challenges as to where we can make business and whether it can grow sustainably.

Currently, Triporous is not produced as much as the ordinary activated carbons, but if it becomes more widespread and can be produced at a similar level as the conventional activated carbons, the cost will be dramatically decreased and it can generate applications where the cost used to be a bottleneck even if the performance is good from the user's point of view. We expect the Triporous business to grow even further.

Tabata:We are often asked from other companies, why Sony is using rice husks to make carbon. Sony is famous for offering cool, cutting-edge products, but now it uses low-tech rice husks to clean up the environment—this gap seems to be gaining a good reputation among people. We believe that Triporous can also contribute to the Sustainable Development Goals (SDGs) in Sony's unique way.

Purifying Water and Air

──What existing things do you imagine will be replaced by Triporous if the manufacturing cost largely drops and its use is widely spread?

Koike:Currently, millions of tons of coconut shells and wood-based activated carbons are used. So, in the beginning of the Triporous project, we thought Triporous could be used as a replacement of them. But since Triporous is a new material, I think it's going to create a new application. I believe it will be developing in a different way from the idea of just a replacement of something.

For example, in the case of water purification, activated carbon is used to clean water, but since Triporous has three different sizes of pores—large, medium, and small—it can adsorb substances more quickly. In that sense, Triporous can be used as a replacement when water needs to be purified during a short contact time. But this is a special case. I think there would be off chance to simply replace commonly-used items by Triporous.

Yamanoi:I hope that "Triporous" will be a common word in our daily lives. "Use Triporous when drinking water." "Clean the air in the room with Triporous." "Wash yourself with Triporous” and “Go out in Triporous clothes." If we could hear such conversations here and there, I think it means we had great success. We'd like to create a whole new world, rather than aiming to replace existing things.

Koike:In terms of purifying water and air, emerging countries might come across your mind. If water and air can be purified by using Triporous in a place where development is still progressing and purification solutions are yet to be provided, it would be wonderful.

Tabata:If you calculate the quantity of rice husks generated worldwide, there are more than 100 million tons per year. Some are used for power generation, but many are discarded. If a significant portion of such waste can be transformed into Triporous, we will be able to deliver various values to those who are suffering in the world. There are so many ways to utilize Triporous, and we are continuing discussions for ideas. Purifying water and air in regions where the infrastructures are not available is what we want to pursue, and we also want to contribute to the community by realizing a circular economy.

Yamanoi:Triporous alone cannot filter seawater, but it may be possible to reduce the load on the RO membrane (reverse osmosis membrane) and extend its life by attaching a Triporous filter as the prefilter of the RO membrane. In this way, there could be many ways in which Triporous can achieve maximum performance when combined with other components.

Koike:I anticipate that water and air purification will become a part of our business, and I'd like to make every effort to realize it. But, of course, it will take time, so until then, we are going to make our business stable in other areas, such as Triporous FIBER and WASH brand business, and steadily increase areas where we can make the best use of Triporous' unique pore structure. And if water and air purification we are jointly working on with other partners finally blooms as business, it will be a very desirable scenario.

As with Triporous, we'd like to continue to explore new ways to protect and enhance the value of technologies developed by many people in the R&D of Sony.

Sony Outstanding Engineer Award 2018 - The most valuable award given to individual engineers in the Sony Group (October 31, 2019)
Triporous An Innovative New Material for Purifying Water and Air
Triporous™, contributing to a clean world

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