Moringa is thought to have been used by Ancient Egyptians to sterilise water.
A millenia-old purification technique could be the cure for Europe’s microplastic-riddled drinking water.
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In a recent study, seeds from the ‘miracle’ moringa tree were found to match or outperform their chemical counterpart in filtering out aged PVC microplastics – one of the most harmful plastic types for human health. The findings could pave the way for a greener alternative for treatment plants.
Tiny plastic particles released from car tyres, paint, textiles and degraded plastic packaging have been building up in global water systems for decades, creating a silent but growing health risk.
In 2024, the EU ramped up monitoring protocols for microplastics in drinking water. But last year, researchers warned that tiny particles, which are more likely to pass through the intestine into the blood and organs, could be slipping through the net.
The use of moringa for purification is as old as it is innovative: it is thought to have been used by Ancient Egyptians to remove bacteria and reduce turbidity of water.
With its fast growth, drought resistance, and low water requirements, the perennial crop not only requires minimal inputs – it acts as a carbon sink, thrives in arid, degraded soils, and supports biodiversity.
Moringa’s wide range of uses, from treating malnutrition and diseases to water purification and anti-ageing products, have earned it the nickname of the ‘miracle tree’.
Why are microplastics and their filtration methods dangerous?
Beyond the immediate health impacts of microplastics, which could be linked to cancer, heart attacks and reproductive problems, these tiny plastic particles – less than five millimetres in length – can absorb and transport other hazardous pollutants throughout ecosystems and into the food chain.
Currently, European countries use both physical and chemical methods to remove microplastics from wastewater.
Aluminum sulfate, often referred to as alum, is an inorganic salt commonly used as a coagulant in water treatment, separating microplastics and other contaminants for removal.
While effective at purification, improper use can lead to raised aluminium levels in water, which have been linked to potential neurological disorders, including Alzheimer’s disease.
Alum also produces large volumes of sludge in the coagulation process, which is difficult to manage and dispose of – typically going to landfill, where it can leach toxins into soil and waterways.
The production of alum is also harmful, requiring strip-mining for bauxite in tropical regions like Australia, Brazil, Guinea, Guyana and Jamaica, which can lead to deforestation and habitat loss. Refining and processing raw materials into the finished product requires significant thermal energy, releasing planet-heating emissions.
‘Miracle tree’ seed could remove 98% of microplastics from water
The recent study, led by Gabrielle Batista at São Paulo State University (UNESP), Brazil, and published in scientific journal ACS Omega, reveals the promise of so-called ‘miracle tree’ moringa as a plant-based, non-toxic alternative.
It compares alum with a salt-based extract made from moringa. Both coagulants work by neutralising the negative electrical charge that causes microplastic particles to repel each other and evade filters. Once neutralised, the particles clump together into larger aggregates – called flocs – that can be caught by a sand filter.
Both alum and its moringa counterpart successfully removed over 98 per cent of PVC particles in water, with moringa proving to be more consistently reliable across a wider pH range.
The particles were around 15 micrometres – small enough to slip through standard filters.
Moringa was found to be as effective for in-line filtration as direct filtration, meaning it could cut out the costly and energy-consuming flocculation process, which binds coagulated particles together.
One drawback that the researchers say needs further scrutiny is the leaching of dissolved organic carbon during the process, which could complicate downstream treatment processes. Moringa also needs to be tested for efficacy at scale.
