Commercial activated carbons, produced from non-renewable coal, petroleum residues and from plant by-products like wood and coconut shells, are used to clean up wastewaters via the removal and recovery of chemical pollutants. The technology of adsorbing the pollutants works when the high surface area, porous and chemically active surfaces of the activated carbons come into contact with the pollutant molecules in aqueous medium. In this context, it is worth mentioning that the grape pomace generated as a waste by-product from the wineries is an interesting and inexpensive medium for the development of activated carbons. Constituting about 20% of the input grape in a typical winery, the pomace has an estimated annual generation of 14.5 million tons in Europe. Such solid wastes have practically no utility except for its use as a cattle feed or as a fertilizer; but prolonged use as a fertilizer has resulted in germination problems due to the toxicity associated with the high levels of polyphenols in the waste matrices.
Considering grapes to be the world´s largest fruit crop with maximum production in the European countries of France, Spain and Portugal and considering the large scale generation of the grape pomace from the wineries of such countries, the pomace may be effectively utilised as a cheap alternative source for water clean-up activities. Research work under the Marie Curie funded “ValoWaste” project hosted at IRIS, Barcelona has developed effective low cost activated carbons from the grape pomace for the water clean-up activities. (Blog post: Marie Curie funded VALOWASTE: Relevance to agrofood industries, environment and society).
The process of turning the bio-waste into activated carbons involves grinding the waste materials into a fine powder that is subsequently heated in an oxygen-free furnace at 1,300 to 1,500 degrees Fahrenheit, creating a completely sanitized product. The results of the initial findings have been published in ¨Development of a green and sustainable clean up system from grape pomace for heavy metal remediation, Journal of Environmental Chemical Engineering 4(2016)4342-4353¨