This manufacturing process for iron nanoparticles, developed and patented at the University of Alicante, allows an important waste, alpechín, to be converted into a value-added product: iron nanoparticles. The technology at the heart of this process is called “hydrothermal carbonization.” It is in an autoclave reactor that works at temperature and pressure. As raw material for the production of nanoparticles, alpechín (waste water from the olive oil industry) and metal salts are used. The nanoparticles obtained have a cost 25 times lower than those on the market.
The use of nanoparticles as an additive in biodigesters makes it possible to energetically valorize the biogas produced and reduce maintenance costs in the elimination of hydrogen sulfide. Thanks to this technology, two environmental problems are solved: valorizing the alpechín and generating a valuable product to be used as an additive in the biodigesters of wastewater treatment plants and biogas plants.
Iron nanoparticles have numerous applications: elimination of heavy metals in water and soil, elimination of sulfur compounds, elimination of drugs and pesticides, etc. One of the main lines of use of these nanoparticles is the improvement of biogas and the elimination of hydrogen sulfide within the biodigesters common to treatment plants, biogas plants and some landfills. Iron nanoparticles improve biogas production by up to 20% and increase methane yield by up to 40%. They have a high capacity to eliminate hydrogen sulfide (>90%), a corrosive and toxic gas generated during anaerobic digestion. In addition to this, they allow the biodigesters to be stabilized in the face of high organic loads, inhibiting excessive acidification with a high C/N ratio. They mitigate ammonia inhibition in case of high waste loading with nitrogen (N/C). They eliminate COD and TOC by 12% and 10% respectively. They allow phosphorus to be captured and reduced in the form of vivianite. Iron nanoparticles are an ideal solution for the energy recovery of biogas within anaerobic digesters, allowing for reduced maintenance costs and extending the useful life of the combustion engine.
This process has been presented for the innovation award at the first #RenewableGas Show.
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