It’s easy to overlook fruit waste’s potential. It typically ends up as compost or landfill. But what if this discarded biomass could serve a higher purpose, helping to clean polluted water more effectively than many high-tech materials?
That’s exactly what researchers at Chalmers University of Technology, Sweden [57.7°N, 11.9°E] have demonstrated. Their work transforms durian shell waste into a sophisticated 3D aerogel — a sponge-like structure engineered at the molecular level — that removes toxic dyes from wastewater with striking efficiency.
The aerogel is eco-friendly, made from abundant biomass, and capable of removing over 96% of Rhodamine B dye even after nine cycles of use. It is an outstanding example of science meeting circularity — and it holds particular relevance for regions like Northern Europe and Canada, where textile, food, and pharmaceutical industries continue to challenge water treatment systems.
A Soft Material with a Sharp Purpose
At the heart of the research is a deceptively simple idea: use fruit waste as a scaffold for water purification. But the outcome is anything but rudimentary.
Through a process involving hydrothermal treatment and freeze-drying, the researchers created a super-light, porous aerogel — think of it as a featherweight sponge with an enormous surface area. Then, they functionalised its surface using chitosan (from shellfish), iron oxide particles, and sodium perfluorobutanoate, tailoring the aerogel to be both superhydrophilic and oleophobic — meaning it soaks up water while repelling oil.
This unique pairing enables the material to selectively absorb waterborne dye pollutants, even when they’re surrounded by oils or other industrial contaminants.
Tackling a Hidden Pollutant
While not as headline-grabbing as microplastics or oil spills, synthetic dyes represent a persistent problem in wastewater across Europe and Canada. Used in textiles, cosmetics, printing, and pharmaceuticals, dyes such as Rhodamine B are toxic, carcinogenic, and notoriously difficult to remove.
This Swedish-developed aerogel offers a solution that is both effective and regenerative. In laboratory tests, the material consistently removed more than 96% of Rhodamine B over multiple uses — a feat that synthetic materials often struggle to match without fouling or breaking down.
The aerogel’s performance was confirmed not only by experiment but also by density functional theory (DFT) simulations. This models chemical reactions in terms of electrons, in this case the dye molecules bonding to the aerogel. This confirms that the reaction will work beyond the lab experiment and adds considerable weight to the findings.
Beyond the Lab to the Wider World
This innovation lands at a timely moment, especially for Europe. Many municipalities are rethinking how to upgrade wastewater infrastructure in the face of stricter EU and provincial discharge standards. Meanwhile, pressure is mounting to move beyond activated carbon and synthetic adsorbents — which are expensive, often non-renewable, and sometimes difficult to regenerate.
This bio-based aerogel addresses all those concerns:
- Low-cost input (fruit waste)
- Biodegradable composition
- Reusability without significant degradation
- Adaptability for various pollutants, thanks to surface chemistry that can be tuned
Moreover, it’s scalable. The durian shell in this case study could just as easily be replaced with other lignocellulosic fruit waste — apple pomace, orange peel, or even grape skins — meaning this isn’t a one-off for tropical waste streams. It can be localised to Nordic and Canadian agricultural by-products with ease.
Looking Ahead — Smarter Materials from Natural Sources
The Swedish team’s work is more than just a clever use of food waste. It’s part of a broader shift in environmental engineering: away from resource-intensive industrial materials, and toward high-performance green technologies built on circular principles.
This aerogel doesn’t just clean water. It demonstrates that waste can become infrastructure. It shows that the tools of environmental remediation don’t need to be harsh chemicals or disposable filters — they can be renewable, regenerative, and remarkably elegant.
Further Implications — Direct and Indirect Support for Recycling Textiles
Synthetic dyes like Rhodamine B are widely used in the textile industry, especially in garments made from synthetic fibres (e.g. polyester, nylon). The challenge with recycling clothing is that:
- Dyes contaminate recycled fibre streams, making it difficult to reuse the material unless it’s fully decolourised.
- Wastewater from textile dyeing is notoriously difficult to clean, often ending up in rivers or requiring expensive treatment.
Where this aerogel could help:
- Textile wastewater treatment:
The aerogel could be used at factories to remove dye from water used in clothing production, allowing the water to be reused and reducing pollution. - Fibre recovery from dyed clothes:
In the future, if this kind of aerogel or similar bio-materials are tuned to remove dyes from fibres themselves (a more complex task), they could help separate dyes from synthetic fabrics, making closed-loop textile recycling more viable.
While the current study focused on water, the technology hints at a broader toolkit for dealing with one of fashion’s thorniest problems: how to un-dye clothing to give fibres a second life, adding to other solutions to tackle mankind’s mounting use of textiles.
Source
Upcycling Fruit Waste into High-Performance 3D Porous Aerogel for Dye Removal: Experimental and Density Functional Theory Study, Case Studies in Chemical and Environmental Engineering, 2025-05-14
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