In:
Journal of Nanomaterials, Hindawi Limited, Vol. 2020 ( 2020-08-01), p. 1-11
Abstract:
Catalytic ozonation is a new method used for removal of NH 4 OH solution. Therefore, high catalytic performance (activity and selectivity) should be achieved. In this work, we report the synthesis and catalytic performance of Fe 2 O 3 -Co 3 O 4 modified dolomite in the catalytic ozonation of NH 4 OH solution. Dolomite was successfully activated and modified with Fe 2 O 3 and Co 3 O 4 . Firstly, dolomite was activated by heating at 800°C for 3 h and followed by KOH treatment. Activated dolomite was modified with Fe 2 O 3 by the atomic implantation method using FeCl 3 as Fe source. Fe 2 O 3 modified dolomite was further modified with Co 3 O 4 by precipitation method. The obtained catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N 2 adsorption–desorption (BET), and temperature-programmed reduction (H 2 -TPR). From SEM image, it was revealed that nano-Fe 2 O 3 and Co 3 O 4 particles with the size of 80–120 nm. Catalytic performance of activated dolomite, Fe 2 O 3 modified dolomite, and Fe 2 O 3 -Co 3 O 4 modified dolomite in catalytic ozonation of NH 4 + solution was investigated and evaluated. Among 3 tested catalysts, Fe 2 O 3 -Co 3 O 4 modified dolomite has the highest NH 4 + conversion (96%) and N 2 selectivity (77.82%). Selectivity toward N 2 over the catalyst was explained on the basis of bond strength M-O in oxides through the standard enthalpy Δ H ° f of oxide. Catalyst with lower Δ H ° f value has higher N 2 selectivity and the order is the following: Co 3 O 4 ( Δ H ° f of 60 kcal (mole O)) 〉 Fe 2 O 3 ( Δ H ° f of 70 kcal (mole O)) 〉 MgO ( Δ H ° f of 170 kcal (mole O)). Moreover, high reduction ability of Fe 2 O 3 -Co 3 O 4 modified dolomite could improve the N 2 selectivity by the reduction of NO 3 - to N 2 gas.
Type of Medium:
Online Resource
ISSN:
1687-4110
,
1687-4129
DOI:
10.1155/2020/4593054
Language:
English
Publisher:
Hindawi Limited
Publication Date:
2020
detail.hit.zdb_id:
2229480-6
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