Eco method removes toxins from wastewater

October 30, 2025

Researchers from Dalhousie University have unveiled a groundbreaking technique that effectively eliminates toxic contaminants from wastewater—offering a major leap forward for sustainable water treatment and waste management.

Eco-friendly innovation turns waste into powerful water purifiers

The research introduces an eco-friendly, low-cost, and reusable method that transforms agricultural and forestry residues into magnetic materials capable of absorbing hazardous chemicals from water.

“Our goal was to create a sustainable, affordable, and reusable solution for treating wastewater contaminated with toxic substances,” explained lead researcher Tunnisha Dasgupta from Dalhousie University’s Faculty of Agriculture. “By repurposing agricultural and forestry waste, we’re not only cleaning polluted water but also giving new life to discarded materials.”

From biomass waste to magnetic carbon materials

The team developed magnetic carbon adsorbents using two abundant types of biomass waste: flax shives and eucalyptus sawdust. These materials were converted into carbon-rich solids known as hydrochars through a process called hydrothermal carbonization (HTC)—a technique that uses heat and pressure to transform organic matter into carbon-based materials.

By incorporating iron during the HTC process, the researchers created magnetic hydrochars that can be easily removed from treated water with a simple magnet, eliminating the need for expensive filtration systems.

The full findings, published in Sustainable Carbon Materials, highlight the conversion of lignocellulosic waste into magnetic bio-adsorbents for efficient wastewater remediation.

circular economy meets clean water technology

According to the research team, the introduction of iron not only enhanced the magnetic properties of the hydrochar but also enabled easy recovery and reuse. Two variants—FS-Fe-HC (flax shive hydrochar) and ES-Fe-HC (eucalyptus hydrochar)—were tested for their ability to remove pentachlorophenol (PCP), a highly toxic industrial pollutant.

“This study demonstrates how hydrothermal carbonization can turn biomass waste into valuable bio-adsorbents for wastewater purification,” the authors noted. “The approach addresses both environmental pollution and industrial waste management challenges while promoting circular economy principles.”

Impressive results in toxic pollutant removal

The new materials showed exceptional performance in removing pentachlorophenol from contaminated water. Under optimal conditions, the flax-based hydrochar achieved up to 95% removal efficiency, while the eucalyptus-based variant reached nearly 89%.

Even after six reuse cycles, both adsorbents maintained their high efficiency with minimal performance loss and no iron leaching, confirming their environmental safety and durability.

Advancing global sustainability goals

“This research demonstrates how we can transform organic waste into advanced materials that protect our ecosystems,” said senior author Dr. Quan. “Our magnetic hydrochars are scalable, highly effective, and perfectly aligned with global sustainability and water management goals.”

This pioneering work underscores the potential of biomass-based water treatment solutions to address pollution while supporting a circular, zero-waste economy.