Japanese scientists at the Institute of Science, Meguro in Tokyo have discovered a new type of liquid that could make capturing carbon dioxide from factories and power plants faster and more efficient. Known as molten alkali-borates, these liquids can absorb large amounts of CO₂ at extremely high temperatures and release it just as quickly using steam—allowing the liquid to be reused over and over.

With most of the sorbent-based carbon capture technologies, such as using amine-based sorbents, majority of costs are related to regeneration typically comprising over 70% of the total operational costs. The high temperature regeneration of liquid sorbents such as aqueous-amines suffers from degradation, severe toxicity, corrosion, and high energy intensities. In addition, the pressure swing regeneration approaches rely on using partial vacuum or an inert gas to for recovery of the adsorbed CO2.

The research work led by Professor Takuya Harada investigated studied carbon capture performance of lithium-sodium orthoborate, its optimization and regeneration employing nitrogen and steam. These materials were able to capture and release CO2 under more realistic operating conditions, at partial pressure swing and temperature swing.

This work is published in the latest NPJ Material Sustainability journal with title ‘high-capacity carbon capture via steam-based regeneration using molten alkali borates’.

Tests show they can capture CO₂ in just 10 minutes at temperatures above 575 °C, in making them a promising alternative to today’s carbon-capturing chemicals. The liquids are also stable and adaptable, potentially working in a wide variety of industrial setups.

The research team attempted to assess the compatibility with system configurations involving both temperature swing and steam-based partial pressure swing regeneration, revealing the suitability of these sorbents for use in a large variety of CO2-emitting industries.

While large heat exchangers are still needed to recycle energy efficiently, early results suggest that molten borates could one day make carbon capture faster, cheaper, and more sustainable—offering a powerful new tool in the fight against climate change and the pursuit of net-zero targets.