Browsing by Author "Pantuzza, Gabriel F."
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- Assisted hydrothermal carbonization of agroindustrial byproducts as effective step in the production of activated carbon catalysts for wet peroxide oxidation of micro-pollutantsPublication . Díaz de Tuesta, Jose Luis; Saviotti, Marcus Chamahum; Roman, Fernanda; Pantuzza, Gabriel F.; Sartori, Hiram J.F.; Shinibekova, Assem A.; Kalmakhanova, Marzhan; Massalimova, Bakytgul Kabykenovna; Pietrobelli, Juliana Martins Teixeira; Lenzi, Giane G.; Gomes, HelderThis work deals with the valorisation of bagasse of sugarcane – BC, bagasse of malt – BM and seed of chia – SC, through its transformation into pyrochars, hydrochars and activated carbons (ACs) by pyrolysis, hydrothermal carbonization (HTC) and sequential HTC and pyrolysis, respectively. The HTC process was carried out in the presence of H2O, FeCl3 and H2SO4 solutions. The materials resulting by HTC in the presence of FeCl3 revealed the highest burn-off, but the contents of carbon released into the liquid phase, measured as total organic carbon, and to the gaseous phase, determined by carbon balance, depend strongly on the carbon precursor. In this sense, BC generates more volatile organic compounds (up to 34% of the initial carbon content), followed by BM (< 15%) and SC (< 5%) in their HTC and pyrolysis (70%). The pyrochars, hydrochars and ACs prepared from BC also show the highest specific surface areas (SBET < 447 m2⋅g-1) when compared to the specific surface areas of the materials prepared from BM and SC. The carbon-based materials prepared with FeCl3 show the highest catalytic activity, but iron leaching into solution is observed. On the other hand, the materials prepared with H2SO4 show high activity, enabling its application in successive cycles and the complete degradation of caffeine in concentrations ranging from 1 to 100 mg⋅L-1, after 5–60 min of reaction.
- Catalysts prepared with matured compost derived from mechanical-biological treatment plants for the wet peroxide oxidation of pollutants with different lipophilicityPublication . Díaz de Tuesta, Jose Luis; Pantuzza, Gabriel F.; Silva, Adrián; Praça, Paulo; Faria, Joaquim; Gomes, HelderThe current work proposes a strategy for the valorization of compost obtained from municipal solid waste, through its activation with H2SO4 and thermal treatment at 400–800 C to produce low-cost catalysts for wet peroxide oxidation. All the developed materials were catalytically active for the aqueous solution oxidation of 2-nitrophenol (C2-NP,0 = 0.5 g L1) and 4-nitrophenol (C4-NP,0 = 5.0 g L1). In particular, using the catalysts prepared by thermal activation of the compost (with and without subsequent treatment with H2SO4), complete removal of both model pollutants was achieved after 24 h (at 50 C, initial pH 3, Ccat = 2.5 g L1, and employing a stoichiometric quantity of H2O2 needed for the total mineralization of the pollutants). In a cyclohexane–water mixture (simulating biphasic oily wastewater), 4-nitrophenol is also completely removed by the catalyst not treated with H2SO4. In contrast, the removal of 2-nitrophenol decreased to 93% due to its higher lipophilic character. Thus, this work demonstrates that active catalysts for wet peroxide oxidation can be obtained by using as a precursor a matured compost derived from municipal solid waste.