Scientists at the University of Sharjah in the United Arab Emirates (UAE) have patented a new carbon capture technology that uses spent coffee grounds to absorb carbon dioxide emissions from industrial sources.
The method, published in August 2025, aims to tackle both carbon pollution and solid waste by transforming discarded materials into a high-performance CO2 adsorbent.
The patented process combines used coffee grounds, polyethylene terephthalate (PET) – a common plastic used in packaging – and potassium hydroxide to produce a porous, activated carbon material capable of capturing carbon dioxide from flue gases before they enter the atmosphere.
Globally, an estimated 8 million tons of coffee waste are produced every year, most of which end up in landfills, releasing methane and other greenhouse gases as they decompose.
By repurposing this waste stream alongside plastic packaging, the Sharjah researchers say their approach not only curbs emissions but also creates value from materials that would otherwise contribute to pollution.
From Coffee Cup to Carbon Capture
“What begins with a Starbucks coffee cup and a discarded plastic water bottle can become a powerful tool in the fight against climate change through the production of activated carbon,” said Dr. Haif Aljomard, the lead inventor of the technology.
The team’s process involves co-pyrolyzing spent coffee and PET waste, while using potassium hydroxide as an activating agent. This chemical treatment produces a highly porous form of activated carbon with an enhanced surface area that binds effectively with carbon dioxide molecules.
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According to Dr. Aljomard, the resulting material shows strong adsorption capacity for CO2 and could be deployed in fossil fuel-based energy systems or industrial exhaust streams to reduce air pollution.
“This invention repurposes two abundant waste streams – coffee and plastic – into a high-performance adsorbent,” he said. “The resulting activated carbon shows strong potential for capturing carbon dioxide from fossil fuel-based energy systems, contributing to the reduction of air pollution.”
The innovation reflects a broader trend in carbon capture research toward circular, low-cost materials, where waste is transformed into a resource for climate mitigation.
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