The electrocatalytic activity of several materials for the nitrate reduction reaction was studied by cyclic voltammetry on a rotating ring disc electrode in solutions with different concentrations of sodium bicarbonate. Copper exhibited highest catalytic activity among the materials studied. Nitrate reduction on copper was characterized by two cathodic shoulders on the polarization curve in the potential region of the commencement of hydrogen evolution. In this potential range an anodic current response was observed on the Pt ring electrode identified as nitrite to nitrate oxidation. This indicates that nitrite is an intermediate product during nitrate reduction. These conclusions were verified by batch electrolysis using a plate electrode electrochemical cell. Copper and nickel, materials representing the opposite ends of the electrocatalytic activity spectra, were used in batch electrolysis testing.
"the formation of nitrite and ammonia  . Vorlop and Tacke  were the first to report that a second metal, Pd, in addition to Cu could improve the N 2 selectivity during the electrochemical reduction of nitrate. "
[Show abstract][Hide abstract] ABSTRACT: Cu and Pd–Cu (Pd = 40 wt%) electrodes supported on stainless steel (Cu/SS and Pd–Cu/SS) were prepared using electrodeposition methods and characterized by X-ray diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. The electrocatalytic reduction of nitrate on Cu/SS and Pd–Cu/SS electrodes was studied in sodium perchlorate electrolyte. By tuning the applied potential, nitrate was found to be selectively reduced to different products, indicating a strong dependence of nitrate reduction reaction on the applied potential. Moreover, the effect of electrode material on nitrate reduction was studied also. Results showed that the nitrate reduction over the two electrodes was different due in part to distinct surface morphology. Results demonstrated a novel avenue to improve the selectivity of nitrate reduction products through controlling the applied potential and selection of electrode material. Results also showed strategy warrant further studies on nitrate conversion to harmless nitrogen gas.
"For this purpose, on the one hand, according to the literature, nitrate electroreduction has been widely studied using several electrodes materials such as Pt, Pb, Ni, Zn,Pd, Cu, Ag and Au. Among these materials, Copper (Cu) is known to exhibit the highest electrocatalytic activity for the nitrate reduction by mainly producing ammonia as final product . On the other hand, many researchers focused on the use of inorganic ammonium (NH 4 + ) as a potential nitrogen source for biological hydrogen production     ; and the use of cheap inorganic nitrogen source appears relevant from an economical point of view, contrarily to organic nitrogen sources such as yeast extract   and polypepton   which are often more expensive. "
[Show abstract][Hide abstract] ABSTRACT: The main objective of this work was to examine the feasibility of coupling electrochemical and biological processes to destroy nitrate ions (NO3−) while producing biohydrogen. In this integrated process NO3− was firstly converted to ammonium using an electrochemical flow cell. After only one pass of concentrated nitrate solutions (3 g NO3− L−1) through the flow cell, ammonium ions selectivity of 98.8%, corresponding to 0.86 g NH4+ L−1 was recorded. The obtained ammonium solution was then tested as a nitrogen source to produce H2 in a batch system involving heat-treated aerobic activated sludge.
"Inorganic by-products are also generated (Bergmann and Koparal, 2005; Bergmann et al., 2001; Gordon et al., 1998; Bouzek et al., 2001; White, 1999). Nitrites and ammonia produced by the cathodic reduction of nitrates were found to decrease the current efficiency of hypochlorite formation (Bergmann and Koparal, 2005; Bergmann et al., 2001; Gordon et al., 1998; Bouzek et al., 2001; White, 1999). This paper deals only with current losses occurring during the electrolysis of a dilute pure sodium chloride solution. "
[Show abstract][Hide abstract] ABSTRACT: A mathematical model was set up for anodic, cathodic and overall current efficiencies of an electrochemical cell for hypochlorite production acting as an ideal stirred reactor. A 0.06-0.20 mol dm−3 NaClO hypochlorite solution was obtained in the cell by the electrolysis of 0.25-0.50 mol dm−3 sodium chloride solution at a temperature of 20 °C, at a current density of 100 mA cm−2 and at 8.3 < pH < 8.7. Anodic current losses occur through hypochlorite and water oxidation at the DSA anode, and cathodic current losses result from hypochlorite reduction at the titanium cathode.
Chemical Engineering Research and Design 01/2015; 93:591-601. DOI:10.1016/j.cherd.2014.07.025 · 2.28 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.