Purification of olive mill wastewater through noble metal nanoparticle synthesis: waste safe disposal and nanomaterial impact on healthy hepatic cell mitochondria

The exponential increase of waste derived from different human activities points out the importance of their reuse in order to create materials with specific properties that can be used for different applications. In this work, it was showed how the typical Mediterranean organic liquid waste, namely olive mill wastewater (OMWW), obtained during olive oil production, can be turned into an efficient reactive agent for the production of noble metals gold (Au) and silver nanoparticles (Ag NPs) with very well-defined physico-chemical properties. More than that, it was demonstrated that this synthetic procedure also leads to a drastic decrease of the organic pollution load of the OMWW, making it safer for environmental disposal and plants irrigation. Then, using healthy hepatic cell line mitochondria, the biological effects induced by these green metal NPs surrounded by a polyphenols shell, with the same NPs synthetized through a standard chemical colloidal reduction process, were compared, finding out that the green NPs are much safer.

Automated summary

This study demonstrates how typical Mediterranean organic liquid waste, olive mill wastewater, can be efficiently turned into noble metal nanoparticles, while also significantly reducing its organic pollution load. The resulting nanoparticles are not only well-defined in terms of physico-chemical properties, but also safer for environmental disposal and plant irrigation. Additionally, it was found that the biological effects induced by these green metal nanoparticles are much safer compared to those synthesized through a standard chemical colloidal reduction process when tested on a healthy hepatic cell line mitochondria.