Making CO₂ sorbents without the mess: Why high-speed shear mixing matters

Carbon capture materials often look elegant in journal articles but become complicated when it comes to real-world preparation. Lots of solvents, long preparation steps, delicate powders, and scale-up headaches that quietly kill otherwise good ideas. Our recent work takes aim at that bottleneck, not by inventing a new molecule, but by rethinking how we make amine-based CO₂ adsorbents in the first place.

The method is called high-speed shear mixing, and its strength lies in its simplicity.

Comparison of time and energy requirements for conventional (WET) and high-speed shear mixing (DRY) methods

Instead of dissolving amines in solvents and impregnating porous supports through slow, waste-heavy processes, we use mechanical shear as the driving force. Intense mixing disperses liquid or semi-liquid amines directly onto solid supports, creating uniform, accessible amine layers without solvents, washing, or drying steps. Think of it as letting physics do the work chemistry usually complicates.

Why does solvent-free approach matter?

Because amine-supported sorbents are already one of the most promising materials for CO₂ capture, especially at low concentrations relevant to flue gas treatment or even direct air capture.  Traditional impregnation routes are energy-intensive, generate chemical waste, and scale poorly outside the lab.

Demonstration of high-speed shear mixing preparation method

High-speed shear mixing changes that equation. Preparation times are reduced from hours to around one minute. Solvents are completely eliminated. Amine loading remains high and well distributed, and the resulting materials show CO₂ adsorption capacities on par with—or better than—those made by conventional methods. Even more importantly, the sorbents hold up during repeated adsorption–desorption cycles, suggesting that the amines are mechanically stabilized rather than loosely “painted on.”

Applying green principles to sorbent preparation

From a sustainability perspective, this is where things get interesting. Eliminating solvents does not just make the process greener; it simplifies everything downstream. No solvent recovery. No energy-hungry drying. No safety overhead for handling volatile organics. The overall material footprint shrinks, and the process starts to look less like a chemistry trick and more like something industry already knows how to do.

This work does not aim to present a definitive solution to carbon capture, nor does it focus on record-setting uptake values or novel materials. Instead, it highlights a different priority: manufacturing strategy. A sorbent that is slightly less “perfect” but vastly easier to produce, scale, and deploy may win in the real world.

In a field largely driven by chemistry, this serves as a reminder that mechanics, processing, and practicality play an equally critical role. Sometimes progress is not about inventing something new. It is about removing everything that did not need to be there in the first place.

For more details visit the full-version of the work at: High-speed shear mixing: Versatile strategy towards the sustainable design of amine-supported CO2 adsorbents.