Forums | HES 健康与环境科学

14 November 2022, 12:11 PM

Speaker: Dr. Giovanni Cagnetta

Time: 09:45-11:00

Location: ES354

Title

Mechanochemical destruction of POPs and POPs-like pollutants by high energy ball milling and solid-state synthesis of materials for wastewater treatment by mechanochemical methods

Abstract

The presentation concerns the two main research interests of Giovanni Cagnetta. The major one is related to mechanochemical destruction of POPs by high energy milling. The approaches proposed to solve the main problems of this technology, which hamper its application at full scale, will be briefly shown. In particular, it will be explained how the combination of high energy milling with a low-cost technology like the biological treatment can improve the global degradation degree of POPs and save milling energy. The “waste-to-materials” approach will be also illustrated as a feasible way to avert using excess of conventional co-milling reagent, typically required to obtain full POPs destruction. This method is based on utilizing special co-milling reagents at stoichiometric ratios with POPs halogen content that can be converted into useful products and ensure POPs mineralization at the same time. The advances in understanding the mechanochemical destruction mechanism will be shown, especially the dioxin unintentional formation under high energy milling conditions and the mechanical activation of metal oxides. Finally, the design of a mechanochemical destruction plant, including its economic optimization, will be presented.

The second research interest regards the synthesis of materials for wastewater cleanup. A slow-corrosion Cu-C-Fe ternary composite was prepared by one-step mechanochemical synthesis to reduce nitrophenols to biodegradable hydroxyanilines. An MXene-based highly porous adsorbent for removal of organics from water was synthetized by mechanochemical exfoliation of a precursor (MAX phase). The spent adsorbent (with adsorbed pollutants) can be used to regenerate the MAX phase through mechanochemical process, thus allowing closure of the cycle. Chitosan was mechanochemically oxidized (by solid state reaction) to improve its adsorption properties toward emerging organic pollutants, as well as mechanochemically cross-linked to enhance its resistance to acid environment and produce pellets (adsorption beds) with increased mechanical resistance (compared to pristine chitosan).