Used Nitrile Gloves Converted to CO2-Capturing Material in Aarhus Lab

Every year, roughly 100 billion nitrile rubber gloves are manufactured - most for single use in healthcare settings, most destined for incineration or landfill. Each glove is a synthetic polymer derived from crude oil. Burning them releases CO2 and other harmful gases. Burying them locks away material that took considerable energy to produce. Neither outcome fits neatly into a world trying to decarbonize.

Simon Kildahl, a postdoctoral researcher at Aarhus University's Department of Chemistry, has demonstrated in the laboratory that this stream of waste material can be transformed into something more useful: a material that captures CO2 from industrial exhaust gases, releases it on demand for storage or utilization, and can then be reused. The study, published in the journal CHEM, describes a process that converts shredded rubber gloves into a functional CO2 adsorbent using a ruthenium-based catalyst and hydrogen gas.

The chemistry of the conversion

The process is conceptually straightforward. Gloves are shredded into small pieces. They then react with the ruthenium catalyst and hydrogen under conditions that modify the polymer's chemical structure, introducing functional groups capable of binding CO2 molecules from a gas stream. In laboratory tests with simulated flue gas - mimicking the exhaust from a combustion source - the material captured CO2 at meaningful levels. When heated, it releases the gas in concentrated form, allowing it to be routed to underground storage or converted into fuel or chemicals via Power-to-X processes. After releasing CO2, the material regenerates and is ready to capture again.

Kildahl is part of the Skydstrup Group at the Novo Nordisk Foundation CO2 Research Center, based at Aarhus University, which brings together researchers from multiple universities working on ways to capture or convert CO2. The group has previously converted materials previously considered unrecyclable - polyurethane foam from mattresses, and epoxy and glass fibers from wind turbine blades - into useful products. Rubber gloves appear to join that list.

Why waste-derived carbon capture materials matter

Existing CO2 capture materials are typically produced from petroleum-derived precursors. To meet the IPCC's target of removing 5 to 16 billion tons of CO2 from the atmosphere annually by 2050, those materials would need to be manufactured at enormous scale, which means extracting and processing more oil - partially undermining the climate benefit. A material derived almost entirely from waste, where the carbon is already in the product rather than drawn from new fossil fuel extraction, changes that calculus.

"With the rubber glove, we can create a CO2 capture material where almost every atom in the product comes from waste, except for a small amount of hydrogen, which can ideally be obtained from water via Power-to-X," Kildahl said.

The volume of available feedstock is not a constraint. One hundred billion gloves per year represents an enormous and consistent global supply of material that is currently treated as waste. If the conversion process can be made practical at scale, the supply chain for the raw material largely runs itself.

Where the technology stands - and what remains to be solved

This is laboratory-stage research. On the Technology Readiness Level scale that runs from 1 (basic concept) to 9 (deployed commercial technology), Kildahl places the current work at level 3 or 4. The experiments use gram quantities of material. Chemical processes frequently behave differently at kilogram or ton scale, and the transition from bench to pilot plant typically surfaces engineering challenges that are invisible in small experiments.

The more immediate bottleneck is the catalyst. The ruthenium-based system used in these experiments is expensive. Ruthenium is a platinum-group metal with limited global production, and a carbon capture technology dependent on it at large scale would face cost and supply constraints. Finding a cheaper catalyst - or identifying conditions where the reaction proceeds without one - is a stated priority for the next phase of work.

Performance parameters for CO2 capture also need improvement. The material must demonstrate competitive capture capacity, selectivity, and cycling stability compared to existing adsorbents before it could be economically deployed at a power plant or industrial facility. Kildahl is optimistic that TRL 5 or 6 is achievable in the near future if scalability and economics can be addressed, but that work remains ahead of the current results.