COMPETITIVE INHIBITION OF CATALYTIC NITRATE REDUCTION OVER CU–PD-HEMATITE BY GROUNDWATER OXYANIONS
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Date
2021-12
Authors
Nurlan, Nurbek
Akmanova, Ainash
Hamid, Shanawar
Lee, Woojin
Journal Title
Journal ISSN
Volume Title
Publisher
Chemosphere
Abstract
The presence of various oxyanions in the groundwater could be the main challenge for the successive application
of Cu–Pd-hematite bimetallic catalyst to aqueous NO3
− reduction due to the inhibition of its catalytic reactivity
and alteration of product selectivity. The batch experiments showed that the reduction kinetics of NO3
− was
strongly suppressed by ClO4
− , PO4
3− , BrO3
− and SO3
2− at low concentrations (>5 mg/L) and HCO3
− , CO3
2− ,
SO4
2− and Cl− at high concentrations (20–500 mg/L). The presence of anions significantly changing the end product selectivities influenced high N2 selectivity. The selectivity toward N2 increased from 55% to 60%,
60%, and 70% as the concentrations of PO4
3− , SO3
2− , and SO4
2− increased, respectively. It decreased from 55%
to 35% in the presence of HCO3
− and CO3
2− in their concentration range of 0–500 mg/L. The production of NO2
−
was generally not detected, while the formation of NH4
+ was observed as the second by-product. It was found
that the presence of oxyanions in the NO3
− reduction influenced the reactivity and selectivity of bimetallic
catalysts by i) competing for active sites (PO4
3− , SO3
2− , and BrO3
− cases) due to their similar structure, ii)
blockage of the promoter and/or noble metal (HCO3
− , CO3
2− , SO4
2− , Cl− and ClO4
− cases), and iii) interaction
with the support surface (PO4
3− case). The results can provide a new insight for the successful application of
catalytic NO3
− reduction technology with high N2 selectivity to the contaminated groundwater system.
Description
Keywords
Type of access: Open Access, Nitrate removal, Groundwater anions, Catalytic denitrification, Competitive inhibition, N2 selectivity
Citation
Nurlan, N., Akmanova, A., Hamid, S., & Lee, W. (2022). Competitive inhibition of catalytic nitrate reduction over Cu–Pd-hematite by groundwater oxyanions. Chemosphere, 290, 133331. https://doi.org/10.1016/j.chemosphere.2021.133331