A Sustainable Material Contributing to a Circular Economy

The origins of Triporous date back to 2007, when Tabata, a member of development team, was conducting R&D on using surplus biomass as a feedstock for producing battery electrodes. Turning their attention to silica (the primary component of glass), which is found abundantly in rice husks, Tabata successfully developed a carbon material with a new unique porous structure. Subsequent research revealed that this material possessed outstanding adsorption properties, ultimately leading to the creation of Triporous.

Triporous features a large number of pores that differ in size from those found in conventional activated carbon, including micropores with diameter of approximately 2nm, mesopores ranging from 2 to 50nm, and macropores of larger than 50nm, most of which are approximately 1μm. Yamanoi, who is involved in the development of Triporous, explains its unique characteristics: "These pore variants all exist within a single material, where mesopores and macropores in particular serve as substance pathways, enabling rapid diffusion within each grain of Triporous. As a result, Triporous can readily adsorb large organic molecules and even viruses, which are difficult for conventional activated carbon to capture. Furthermore, this adsorption occurs more rapidly than with activated carbon, and has demonstrated removal rates of over 99% for viruses and bacteria."

Triporous is produced from a feedstock of rice husks, which are produced in large quantities around the world - approximately 2 million metric tons annually in Japan alone, and more than 100 million metric tons globally each year. As approximately 100 kilograms of Triporous can be produced from one metric ton of rice husks, recycling this abundant biomass resource contributes to the realization of an environmentally friendly circular economy.

In addition, when compared to incinerating an equivalent amount of rice husks as waste, using it to instead produce Triporous measurably and significantly reduces greenhouse gas and PM2.5 emissions. As a result, the process is also expected to contribute to improvements in air quality and the mitigation of climate change.

Expanding Applications to New Fields, from Clothing to PFAS Remediation

The shape and particle size of Triporous can be readily tailored to meet specific application requirements, and the material's outstanding adsorption performance enables a wide range of functional benefits. As a result, Triporous has found applications in a number of products from a wide variety of fields, including in deodorizing and antibacterial textiles in the clothing industry, filtration systems in the field of water purification, air filters in the HVAC industry, and cleansing agents in the field of healthcare.

In the clothing industry, Triporous has been incorporated into textiles to develop products with deodorizing, antibacterial, and antiviral properties. The material's fine pores rapidly adsorb odor-producing molecules, while its larger pores help suppress the spread of bacteria and viruses on the surface of fabrics. Currently, a growing number of companies - including ISSEY MIYAKE, STYLEM IMABARI KINSEI, Aswan, and KOKUYO - are developing products that incorporate Triporous. Applications extend beyond typical clothing to include daily-use items such as handkerchiefs, as well as carpets, office furniture, and other lifestyle products that are already available on the market.

"When we were exploring potential applications for Triporous and introducing its unique properties to various industries, we were fortunate to connect with people working in clothing and skincare. Those connections ultimately led to the development of such a diverse range of products," says Giga, a member of the marketing team. "Today, Triporous is used not only in Japan but also in clothing and skincare products around the world."

Although Triporous was developed by Sony, bringing it to a wide variety of products would not have been possible without partner companies that helped explore applications and develop sales channels. By combining Triporous with the expertise of partner companies through a process of open innovation, the range of potential applications for the material has expanded significantly.

One of the most important breakthroughs within this process came when attempting to incorporate Triporous into fibers without compromising its characteristic pore structure. Reflecting on this process, Yamanoi explains: "Determining the right material that could be spun together with Triporous into fibers without compromising the pore structure, as well as identifying the optimal synthesis conditions, such as the correct Triporous ratio that would maintain fiber strength and other such qualities, was extremely challenging." To address these issues, Sony worked closely with partner companies to develop suitable material processing and manufacturing conditions. By repeatedly evaluating the performance and strength of prototype samples and making continuous improvements, the team finally succeeded in creating products with practical, commercial-grade quality. Yamanoi further explains, "Even after the fibers had been developed, we needed to classify functions such as deodorizing and antibacterial performance in accordance with industry guidelines and standards. This process also provided a valuable opportunity to learn about rules, regulations, and evaluation methods in areas where Sony had previously limited experience, greatly expanding our expertise."

Another noteworthy aspect of Triporous is its potential to help address PFAS contamination, an issue that has grown increasingly relevant in recent years. PFAS have been used in a wide variety of contexts, including clothing, cookware, and construction materials. Concerns have emerged, however, regarding the potential impact of certain PFAS compounds on human health and the environment, raising questions about the safety of drinking water. On account of its unique pore structure, Triporous has been shown to rapidly and effectively adsorb a wider range of PFAS compounds compared with conventional activated carbon, making it a promising solution for PFAS remediation.

A major factor in considering Triporous for PFAS remediation came in 2021, through discussions at the consortium for analysis and remediation of per- and poly fluoroalkyl substances (CAR-PFAS Japan), held by the National Institute of Advanced Industrial Science and Technology (AIST). There, Triporous team members were granted the opportunity to have the efficacy of Triporous evaluated by both AIST and Örebro University in Sweden. This evaluation involved testing the adsorption performance of Triporous on 25 different PFAS compounds, which when compared within a group of 15 commercially available adsorbents in Japan, demonstrated that Triporous was the most effective material at adsorbing these PFAS compounds. Validation studies are now being conducted at several other facilities to confirm this result.

Since 2024, Triporous has also been evaluated by numerous experts for its ability to remove PFAS from a range of aquatic environments in Japan, including rivers and groundwater. These studies have produced data which show that Triporous maintains excellent adsorption performance even in complex environments containing other organic substances in addition to PFAS, such as wastewater, groundwater, and soil. Tabata is optimistic about the material's future potential, stating: "Real-world environments differ greatly from the conditions assumed at a laboratory scale, with factors such as weather and location affecting PFAS concentration and composition, as well as required filter replacement rates. As PFAS represents a relatively new societal challenge, we hope to continue working closely with experts to widely consider ways of applying Triporous towards this issue."

Contributing to Solutions for the Global PFAS Challenge

PFAS contamination has become a growing concern in many locations across Japan as well as in other parts of the world. In response, efforts are underway to establish effective remediation technologies by validating promising solutions under real-world conditions. As part of these efforts, Triporous was selected to be tested in a demonstration project sponsored by Japan's Ministry of the Environment, which will evaluate Triporous using water containing PFAS concentrations higher than any previously treated with the material. The project will also involve developing processing technologies that enable Triporous to be incorporated into existing treatment systems, allowing current infrastructure to be used for PFAS remediation without major modifications.

Looking ahead, Yato, the leader of the Triporous project says: "Until now, our primary focus has been on expanding the range of applications for Triporous. Going forward, however, we would like to place greater emphasis on water purification and PFAS remediation." In the case that the Ministry of the Environment's demonstration project confirms the effectiveness of Triporous, the potential would grow for accelerated deployment of PFAS countermeasures in a wide variety of settings both in Japan and internationally. Aiming to address PFAS challenges in Japan and around the world, Sony will continue advancing the social implementation of Triporous into the future.