Greener MOF processing could make heavy metal removal from industrial wastewater cheaper and more resource-efficient, according to University of Birmingham research.
University of Birmingham scientists have shown that greener processing can reduce the estimated production cost of a novel material designed to remove heavy metals from industrial wastewater.
The research focuses on a next-generation metal-organic framework, or MOF, developed to capture metals such as lead from contaminated water.
The team found that a freeze-drying technique made the material cheaper and less resource-intensive to produce than a similar MOF processed conventionally.
The study, published in Green Chemistry, is part of wider work at the University of Birmingham on safer and more sustainable water-treatment materials.
Greener MOF processing targets heavy metals
Industrial wastewater from sectors such as mining, electronics and chemical manufacturing can contain heavy metals that are difficult to remove from complex water streams.
Exposure to metals such as lead can create serious public health risks, particularly for children.
MOFs are emerging as potential materials for water decontamination because of their cage-like molecular structures. These structures are formed from metal nodes connected by organic linkers, creating large internal pore networks that can selectively capture dissolved metals from water.
However, many MOF manufacturing and post-processing routes remain solvent- or energy-intensive. Some MOFs can also leach metals into the water being treated, creating a risk of secondary contamination.
Freeze-drying reduces estimated production cost
Researchers led by Dr Swaroop Chakraborty, a NERC Independent Research Fellow in the School of Geography, Earth and Environmental Sciences, examined a greener processing route for a copper imidazolate MOF.
The paper shows that freeze-drying increased isolated yield more than threefold and reduced estimated electricity demand per gram by around 74%.
Compared with conventional processing, the technique lowered estimated lab-scale production cost from around $19/g to just over $5/g.
The University of Birmingham’s research record says the results establish freeze-drying as a greener processing and isolation strategy for copper imidazolate nanosheets used in aqueous separations and contaminant capture.
Material retains lead-capture performance
The freeze-dried MOF retained strong lead-capture performance under environmentally relevant conditions.
The University of Birmingham said the material removed more than 90% of lead from solution in the first hour, with high removal maintained across four consecutive treatment batches.
The material also retained its principal structural features after seven days of exposure to air, freshwater-like conditions and artificial seawater.
Earlier work by the team developed a green-synthesised MOF using a scalable water-based process. University of Birmingham Enterprise has filed a patent application on the method and material, which was engineered to recover rare earth elements and heavy metals from industrial waste streams.
The material has also been tested on real-world water samples, where it showed strong lead removal from chemically complex solutions and low copper leaching.
Research team seeks industrial partners
Dr Chakraborty said: “For water-treatment materials, removing the pollutant is only half the story. We also need to understand how materials like metal organic frameworks are manufactured and how they change during use in the environment. By redesigning one processing step, we were able to recover much more of the material, lower its estimated production cost while retaining its strong lead-capture performance under environmentally relevant conditions.”
The material is produced as pellets rather than fine powder, which could make it easier to handle in practical water-treatment settings.
The researchers are now seeking industrial partners in mining, e-waste and water treatment who may be interested in licensing the technology for specific applications or co-developing pilot-scale trials in real-world settings.
Green chemistry supports wastewater treatment innovation
The work highlights how green chemistry principles can be applied not only to pollutant removal, but also to the way treatment materials are manufactured and assessed.
The paper is titled Freeze-drying enables resource-efficient isolation of copper imidazolate metal-organic framework nanosheets for transformation-aware lead capture.
For more coverage of water treatment innovation, visit H2O Global News’ Research & Development section.
Source: University of Birmingham
