Assisted hydrothermal carbonization of agroindustrial byproducts as effective step in the production of activated carbon catalysts for wet peroxide oxidation of micro-pollutants. Issue 1 (February 2021)

• Record Type: Journal Article
• Authors: Diaz de Tuesta, Jose L.; Saviotti, Marcus C.; Roman, Fernanda F.; Pantuzza, Gabriel F.; Sartori, Hiram J.F.; Shinibekova, Assem; Kalmakhanova, Marzhan S.; Massalimova, Bakytgul K.; Pietrobelli, Juliana M.T.A.; Lenzi, Giane G.; Gomes, Helder T.
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 1(2021)
• Publication Date: 2021-02
• Subjects: Activated carbons -- Hydrothermal carbonization -- Wet peroxide oxidation -- Micro-pollutants -- Caffeine; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2020.105004
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: This 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 H2 O, FeCl3 and H2 SO4 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 ( S BET < 447 m 2 ·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 H2 SO4 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. Graphical Abstract: ga1 Highlights: Hydrochars are produced by FeCl3 - and H2 SO4 -assisted hydrothermal carbonization. Activated carbons (ACs) are produced from pyrolysis of the hydrochars. Hydrochars and ACs show high catalytic activity in the CWPO of caffeine. ACs show better textural properties and higher catalytic activity. ACs prepared from hydrochars with H2 SO4 are stable in consecutive reuses.