Effect of water composition on catalytic reduction of nitrate

Sanchis, I.; Díaz, Elena; Pizarro, A.H.; Rodrı́guez, Juan J.; Mohedano, A.F.

doi:10.1016/j.seppur.2020.117766

Cited by 16 publications

(9 citation statements)

References 54 publications

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“…+ production [15,17,[21][22][23][24]. The order of metal impregnation appeared to have a negligible effect on the catalyst activity, showing similar kinetic constants between Pd-Sn and Sn-Pd metal loading pairs.…”

Section: Catalyst Configuration Effectmentioning

confidence: 85%

“…As can be seen, the Pd 1.5 -Sn 1 /Al 2 O 3 activity remained practically constant in the experiments performed with synthetic water (W0), achieving nitrate conversion rates between 70 and 75% once the steady state was achieved after 10 h time on stream. However, when commercial drinking waters were used, a loss of activity was observed in all experiments, which can be attributed to the water composition [15]. A decrease in nitrate conversion from 60% at the beginning of the reaction to 42% at 45 h on stream, when the steady state was reached, was observed using DW2 drinking water.…”

Section: Stability Experiments In Drinking Watersmentioning

confidence: 86%

“…On the other hand, the initial nitrate conversion rates obtained with DW1 and DW3 were similar, 55 and 60%, respectively, and a continuous conversion decrease was observed to 20 and 30%, respectively, after 60 h on stream. DW1 and DW3 presented similar concentrations of HCO 3 − (255 and 244 mg L −1 , respectively), an anion that shows a negative effect on the catalyst performance due to its competitive adsorption for the active metal sites versus nitrate ions [13,15]. The difference observed in the catalyst when treating DW1 and DW3 is related to the higher Cl − concentration of DW3, which can reduce the negative influence of HCO 3 − on the catalytic reduction of nitrate [15].…”

Section: Stability Experiments In Drinking Watersmentioning

confidence: 96%

“…The main drawbacks of this treatment are the formation of NO 2 − as a reaction intermediate and NH 4 + as a by-product. In addition, the ions present in natural waters can cause catalyst deactivation, making it difficult to use for drinking water [12][13][14][15]. The catalytic reduction of NO 3 − requires the use of bimetallic catalysts, composed of a noble metal (Pd or Pt) and a promoter metal (Cu, Sn, or In), which integrate the active phase, mainly supported on metal oxides (Al 2 O 3 , SiO 2 , or TiO 2 ) and activated carbon [8][9][10].…”

Section: Nitrate (Nomentioning

confidence: 99%

“…Thus, the H spillover from the noble site to the promoter metal decreases and therefore the rate of NO 3 − reduction. On the other hand, an excess of noble metal with respect to the promoter metal increases the hydrogen spillover rate and consequently decreases the N/H ratio on the catalyst surface, favoring the formation of NH 4 + [15,17,[21][22][23][24]. One of the most important drawbacks of catalytic NO 3 − reduction is catalyst deactivation during the treatment of polluted waters, which limits the large-scale application of this technology [10].…”

Section: Nitrate (Nomentioning

confidence: 99%

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Activity and Stability of Pd Bimetallic Catalysts for Catalytic Nitrate Reduction

et al. 2022

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In this work, we study the effect of modifying the metal loading (0.5–1.5 wt.% Pd and 0.1–1 wt.% Sn or In), the impregnation order of noble or promoter metal (Pd–Sn or Sn–Pd), and the type of promoter metal (Sn or In) during the preparation process for a Pd bimetallic catalyst, supported on γ-alumina, used in the catalytic reduction of nitrate. The deposition of the noble metal over the promoter metal, especially with Pd:Sn ratios (wt.) of 1:10 and 1:2, favored the hydrogen spillover rate and increased the H concentration on the catalyst surface, enhancing NH4+ production. On the other hand, Pd–In catalysts showed higher activity than the Sn catalysts, as well as higher NH4+ selectivity. The stability of the Pd–Sn/Al2O3 (1.5–1 wt.%) catalyst was evaluated in long-term experiments for the treatment of synthetic water (100 mg L−1 NO3−) and three different commercial drinking waters. This Pd–Sn/Al2O3 catalyst achieved a stable nitrate conversion for a duration of 50 h in the synthetic water treatment. However, the catalyst showed a significant activity loss in the presence of other ions (different to NO3−) in the reaction medium, increasing slightly the selectivity to NH4+.

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Section: Catalyst Configuration Effectmentioning

confidence: 85%

Section: Stability Experiments In Drinking Watersmentioning

confidence: 86%

Section: Stability Experiments In Drinking Watersmentioning

confidence: 96%

Section: Nitrate (Nomentioning

confidence: 99%

Section: Nitrate (Nomentioning

confidence: 99%

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Activity and Stability of Pd Bimetallic Catalysts for Catalytic Nitrate Reduction

et al. 2022

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Performance and microbial response to nitrate nitrogen removal from simulated groundwater by electrode biofilm reactor with Ti/CNT/Cu5‐Pd5 catalytic cathode

Gao,

Shen,

Yinzhang

et al. 2024

Water Environment Research

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To enhance the removal of nitrate nitrogen (NO3−‐N) in groundwater with a low C/N ratio, electrocatalytic reduction of NO3−‐N has received extensive attention since its electrons can be directly produced in situ while simultaneously providing a clean electronic donor of hydrogen for denitrifying bacteria. In this study, Ti/CNT/CuPd bimetallic catalytic electrodes with different copper‐palladium (CuPd) ratios were prepared by electrodeposition onto carbon nanotube (CNT) using titanium (Ti) plates. The results showed that the NO3−‐N conversion rate by Ti/CNT/Cu5‐Pd5 electrode was the highest (53.60%) compared with other CuPd electrode ratios because of the combined role of the copper's high NO3−‐N catalytic activity and the palladium's high N2 selectivity. A new type of electrode biofilm reactor (EBR) with Ti/CNT/Cu5‐Pd5 cathode, biochar substrate was constructed to explore the removal ability of NO3−‐N in simulated low C/N groundwater. When the influent NO3−‐N concentration was 30 mg/L, under the condition of a 30 mA electronic current and hydraulic retention time (HRT) of 12 h, the removal rate of NO3−‐N could reach as high as 78.1 ± 1.2%, and the N2 conversion rate was 99.7%. The horizontal distribution of microbial communities in EBR showed that the denitrification capacity was significantly improved through the electrochemical catalytic reduction of the Ti/CNT/Cu5‐Pd5 cathode and the supply of the hydrogen electron donor to autotrophic denitrogenerating microbes such as Anaerobacillus, Thauera, and Hydrophaga. This study provides a new bimetallic catalytic cathode to enhance the removal of NO3−‐N in groundwater with a low C/N ratio.Practitioner Points The Cu5Pd5/CNTs/Ti electrode is beneficial to the adsorption and reduction of NO3−‐N to N2. The production of hydrogen electron donors by cathode promoted nitrogen degradation. Activated electrodes together with denitrifying microorganisms contributed to the improved N removal rate.

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Interference effects of oxyanions commonly found in natural waters on the catalytic reduction of nitrate in water

Sacco

Zoppas

Beltrame

et al. 2022

Environ Sci Pollut Res

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Effect of water composition on catalytic reduction of nitrate

Cited by 16 publications

References 54 publications

Activity and Stability of Pd Bimetallic Catalysts for Catalytic Nitrate Reduction

Activity and Stability of Pd Bimetallic Catalysts for Catalytic Nitrate Reduction

Performance and microbial response to nitrate nitrogen removal from simulated groundwater by electrode biofilm reactor with Ti/CNT/Cu5‐Pd5 catalytic cathode

Interference effects of oxyanions commonly found in natural waters on the catalytic reduction of nitrate in water

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