Degradation of MO and H₂O₂ on Cu/γ‐Al₂O₃ pellets in a fixed bed reactor: Kinetics and transport characteristics

Abstract

Pelletized Cu catalysts (Cu/γ-Al 2 O 3) with different diameters (d p = 1.1-4.2 mm) were prepared and examined kinetically for methyl orange (MO) degradation using a fixed bed reactor. A Cu/γ-Al 2 O 3 catalyst (d p = 2.3 mm) exhibited high degradation activity (Conv. MO > 95%) and superior leaching resistance (Cu leaching <0.6 mg/L in 200 hr). Apparent kinetics showed that both MO degradation and H 2 O 2 decomposition were mainly controlled by internal mass transfer. A plug-flow reactor model with masstransfer coefficients was developed, and a modified empirical correlation for external mass transfer (Sh = 1.5Re' 1.10 Sc 0.42) was proposed to accurately describe the species transport from/to the catalyst pellets in the low Reynolds number regime. The model was verified against conversions of pollutants degradation and H 2 O 2 decomposition separately in a fixed bed with relative errors <5% compared with experimental data; thus, it could be used as an effective tool for further design and optimization of reactor configuration and reaction conditions for the continuous catalytic wet peroxide oxidation process.

Natural magnetite as an effective and long-lasting catalyst for CWPO of azole pesticides in a continuous up-flow fixed-bed reactor

“…In particular, those based on synthesized magnetite have received major attention, which can be attributed to the presence of both Fe(II) and Fe(III) species, which significantly fasten the oxidation rate (Munoz et al 2015 ). In general, catalysts preparation involves the use of synthetic organic or inorganic supports and requires relatively complex multi-step procedures like incipient wetness impregnation followed by high-temperature calcination (di Luca et al 2018 ; Ding et al 2020 ), combination of thermal treatments and metal–organic chemical vapor deposition (Yang et al 2018 ), clay intercalation by auto-hydrolysis followed by calcination (Pinchao et al 2021 ) or chemical co-precipitation and hydrothermal treatment (Huaccallo-Aguilar et al 2021a , b ; Huaccallo-Aguilar et al 2021a , b ). There are also attempts using different kinds of wastes as carbon support precursors like PET bottles (Thirumoorthy et al 2021 ) or olive stones (Esteves et al 2022 ), but in both cases, complex multi-step procedures and carbonization at high temperatures were required.…”