Activated carbons from waste biomasses for water purification.

Abstract

This thesis focused on the synthesis, characterization, and testing of activated carbons derived from second-generation biomasses for the treatment of water contaminated by herbicides such as atrazine and terbuthylazine. The chosen biomass for the preparation of activated biochars includes hazelnut shells and rice husks, that are agricultural wastes from crops in which Italy is among the world leaders in annual production. The process involves the initial slow pyrolysis of each biomass at 700 °C, followed by physical activation with steam at 850 °C. The carbons, in both their natural and activated states, were characterized using various techniques such as FTIR spectroscopy, nitrogen physisorption, programmed temperature desorption (TPD), iodine number, elemental analysis, and scanning electron microscopy (SEM). The adsorption capacity of the biochars were tested with model molecule, to determine their maximum adsorption capacity of the pollutant. Trichloroethylene was selected as the model molecule due to its ability to replicate the adsorption mechanism of triazine herbicides. Adsorption tests of atrazine and terbuthylazine were performed on the activated biochar with the highest adsorption capacity. This thesis proved the viability of using activated biochar derived from second-generation waste biomass to purify water from herbicides, offering an alternative to traditional commercial activated carbons.