Effects of complex agents on the anodic deposition and electrochemical characteristics of cobalt oxides

The anodic deposition rate of cobalt oxide from CoCl₂·6H₂O is strongly affected by the type of complex agents (acetate ion (AcO⁻), citrate ion, EDTA) added into the deposition solutions. The oxidation potential of CoCl₂·6H₂O, examined by linear sweep voltammetry (LSV), is negatively shifted from ca. 1.1 V to about 0.8, 0.5, and 0.2 V by adding AcO⁻, citrate ion, and EDTA, respectively. The deposition rate of cobalt oxide is found to depend not only on the coordinating strength between Co and ligands but also on the conversion rate of the Co-L complexes (L: ligand) into the oxy-hydroxyl-Co species after electron transfer. The textural and electrochemical characteristics of resultant Co oxides, examined by X-ray photoelectron spectroscopic (XPS), scanning electron microscopic (SEM), open-circuit potential versus time, and cyclic voltammetric analyses, are also influenced by varying the complex agents. The deposition rate is the highest when the Co oxide is deposited from the precursor solution containing AcO⁻, which also exhibits the highest specific capacitance of ca. 230 F g⁻¹ among all Co oxide deposits (as the oxide loading ≥0.05 mg cm⁻²), demonstrating its most promising applicability in the electrochemical supercapacitors.     

Silver-zinc electrodeposition from a thiourea solution with added EDTA or HEDTA

This paper shows the study of silver-zinc electrodeposition from a thiourea solution with added (ethylenedinitrilo)tetraacetic acid (EDTA), disodium salt and N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), trisodium salt. Voltammetric results indicated that silver-zinc alloy can be obtained applying overpotential higher than 0.495 V, in Tu solution containing 1.0 × 10⁻¹ mol L⁻¹ Zn(NO₃)₂ + 2.5 × 10⁻² mol L⁻¹ AgNO₃. This was due to silver(I) ion complexation with thiourea, which shifted the silver deposition potential to more negative value and due to silver-zinc alloy deposition, which occurred at potentials more positive than the potential to zinc deposition alone. EDTA or HEDTA did not significantly affect the silver and zinc deposition potentials, but decreased the current density for silver-zinc deposition. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the silver-zinc deposits showed that the morphology and composition changed as a function of the conditions of deposition, viz, deposition potential (E_d), deposition charge density (q_d) and solution composition (silver, EDTA and HEDTA concentrations). EDS analysis of the deposits showed sulphur (S) incorporated into the silver-zinc deposit, while SEM images showed that this sulphur content seemed to improve the silver-zinc morphology, as did the presence of EDTA and HEDTA in the solution, which enhanced the sulphur incorporation into the silver-zinc deposit. X-ray diffraction (XRD) analysis of the silver-zinc deposit showed that it was amorphous, irrespective of its composition and morphology.     

Simultaneous determination of lead, copper and cadmium onto mercury film supported on wax impregnated carbon paste electrode: Assessment of quantification procedures by anodic stripping voltammetry

The deposition and stripping processes of lead and copper and cadmium ions over the wide concentrations range of 1 × 10⁻⁵ to 5 × 10⁻⁹ M, have been studied at mercury film deposited on wax impregnated carbon paste electrode, using cyclic voltammetry, linear sweep anodic stripping voltammetry and differential pulse anodic stripping voltammetry. The carbon paste electrode modified with the mercury film was characterized for its physical and electrochemical properties. The parameters of deposition and stripping processes of the analytes have been investigated using standard solution of the metal ions at various concentrations and different supporting electrolytes and different pH. The linear sweep anodic stripping has been adopted for the determination of analytes at higher concentration whereas the analytes at lower concentrations were determined using DPASV. The DPASV behavior for the ions studied dependent on concentrations of the analyte as well as on the time used in the pre-concentration step. The method developed using standard solutions have been successfully applied for the determination of Cu(II), Pb(II) and Cd(II) in Fin Fish muscles and water samples.     

Preparation and characterization of thiocyanate-selective electrodes based on new complexes of copper(II) as neutral carriers

The complexes of hydroxycitronellal (o-aminobenzoic acid) copper(II) (Cu(II)-HXAB) and salicylaldehyde (o-aminobenzoic acid) copper(II) (Cu(II)-SHAB) were used as neutral carriers in PVC-based membrane ion-selective electrodes. The electrode based on Cu(II)-HXAB exhibited near-Nernstian potential response to thiocyanate (SCN⁻) in a linear range of 1.0 × 10^− 6 to 1.0 × 10^− 1 M with a detection limit of 8.5 × 10^− 7 M and a slope of − 57.3 mV/decade in 0.01 M phosphate buffer solution (pH 5.0). The electrode exhibited high selectivity to SCN⁻ over other tested anions with an anti-Hofmeister selectivity sequence. The selectivity behavior might be discussed in terms of UV-Vis spectrum and infrared spectrum. The transfer process of thiocyanate across the membrane interface was investigated by making use of the AC impedance technique. The electrode containing Cu(II)-HXAB could be applied to thiocyanate analysis in waste water with satisfactory results.     

Electrodeposition of bismuth telluride films from a nonaqueous solvent

The author examines Bi₂Te₃ deposition from a DMSO solution containing TeCl₄ and Bi(NO₃)₃ × 5H₂O by means of cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). Accumulated charges and related mass changes for Bi₂Te₃ deposition on working electrodes are measured in situ. The deposit composition is more dependent on Te⁴⁺ concentrations in DMSO solution than on the potential. In a DMSO solution containing 0.01 M Te⁴⁺ and 0.0075 M Bi³⁺, Bi₂Te₃ deposits were obtained in the potential range between −0.2 and −0.8 V vs. Ag/AgCl. In a DMSO solution containing 0.05 M Te⁴⁺ and 0.0375 M Bi³⁺, Te-rich deposits were formed from −0.2 to −0.8 V vs. Ag/AgCl.     

Codeposition of copper and tin from acid sulphate solutions containing polyether sintanol DS-10 and micromolar amounts of halides

Cu(II) and Sn(II) reduction in acid sulphate solutions containing polyether laprol DS-10 was investigated using voltammetric XPS and XRD techniques. Bright yellow bronze coatings can be deposited at potentials (E) that are positive than equilibrium potential () of Sn|Sn²⁺ electrode. Here, Sn(II) reduction might be treated as underpotential deposition (UPD) of tin on foreign (copper) substrate. Further incorporation of tin into integral Cu-Sn crystallic lattice yields the mixture of pure copper, α-CuSn phase and intermediate hexagonal hcp phase. The formation of free tin phase occurs at . This gives rise for strong inhibitive adsorption of sintanol that manifests itself in the development of deep voltammetric minimum.Addition of halides results in the shift of codeposition potential to more negative values and in the increase of copper content in the coatings deposited in the UPD region. The action of halides intensifies in the sequence Cl⁻ < Br⁻ < I⁻. If iodide concentration exceeds 2-3 μM, deposition of yellow bronze becomes impossible.     

The stability of an acidic tin methanesulfonate electrolyte in the presence of a hydroquinone antioxidant

The electrodeposition of tin at a (0.28 cm²) copper surface from 0.014 mol dm⁻³ SnSO₄ and 12.5 vol.% methanesulfonic acid (MSA 1.93 mol dm⁻³) at 296 K was studied. Hydroquinone concentrations of 0.005, 0.05 and 0.5 mol dm⁻³ (corresponding to a molar concentration ratio of hydroquinone to stannous ions of 0.36, 3.6 and 36, respectively) were used. Cyclic and linear sweep voltammetry served to characterise the electrochemical behaviour of tin deposition and stripping. The effects of potential sweep rate and electrode rotation speed on the voltammetry were studied. The stability of the electrolyte with storage time was quantified by changes in the limiting current density for tin deposition at a smooth rotating disc electrode and the peak current density at a static disc electrode. The influence of hydroquinone on mass transport controlled tin deposition and suppression of hydrogen evolution was evaluated.     

Role of sulphate ions on the formation of calcareous deposits on steel in artificial seawater; the formation of Green Rust compounds during cathodic protection

Cathodic protection of steel in seawater could be optimized by taking into account the calcareous deposits forming on the steel surface. The aim of this work was to study the influence of sulphate ions on the kinetics and mechanisms of formation of these deposits. The experiments were performed at 20 °C, with an applied potential of −1.0 V/saturated calomel electrode (SCE), in artificial seawater-like solutions with various SO₄²⁻ concentrations. The deposition was monitored by chronoamperometry and electrochemical impedance spectroscopy (EIS). Micro-Raman analyses were performed in situ in a specific electrochemical cell to identify the solids forming on the steel surface. It could be demonstrated that sulphate ions had an important effect on the formation of both Ca(II)- and Mg(II)-containing phases. In the solution enriched with sulphate ions, the deposition of CaCO₃ was almost totally inhibited. Experiments performed in Ca²⁺-free solutions demonstrated that the Mg-based deposit was, in contrast, favoured by the increase of the sulphate concentration. In situ Raman spectra of the solid forming at the early stages of the cathodic protection proved to be characteristic of Green Rusts (GRs). This compound was favoured by the presence of Ca²⁺ and/or Mg²⁺ cations, and is more likely a GR-like M(II)-Fe(III) hydroxysulphate, with M = Fe, Mg and Ca.     

Mass transport studies at rotating cylinder electrode: Influence of the inter-electrode gap

This study shows the effect of using two different inter-electrode gaps on the RCE mass transport characterization. The average mass transport coefficient was calculated using the limiting current technique, using the soluble reduction of triiodide (smooth RCE interface) and the copper deposition (roughness RCE interface) in KNO₃ and H₂SO₄, respectively. Based on the analysis of the Sh = aRe^bSc^0.356 correlation, the values of the constant a, associated with shape and cell dimensions, were 0.89 and 3.8, in the soluble system (I₃⁻/I⁻), for the gaps of 2.4 and 3.2 cm, respectively, indicating that this coefficient increases with inter-electrode space. While for copper deposition, these values were 0.00081 and 0.014, for the gaps of 2.4 and 3.2 cm. The constant b, associated with hydrodynamic regime, exhibits values of 0.43 and 0.33 for the gaps of 2.4 and 3.2 cm, respectively, in the system I₃⁻/I⁻, indicating that hydrodynamics on the smooth RCE diminishes according to the inter-electrode space. While for the system (Cu(II)/Cu), the values of b were 0.91 and 0.88, for the gaps of 2.4 and 3.2 cm. These values were higher for the copper deposition than for the soluble system, due to microturbulence at the roughened (and often powdery deposits) RCE interface. From the analysis performed in this paper is clear that inter-electrode gap and hydrodynamics on the smooth and roughness RCE interface (given by the nature of reduction reaction) modify the mass transport correlation.     

Studies of stoichiometry of electrochemically grown CdSe deposits

The proper deposition bath composition for electrochemical synthesis of the CdSe deposit in the hexagonal structure of the right elemental stoichiometry, and photoreacting as an n-type semiconductor which can be used as a stable photoanode is investigated. The deposits were prepared by a cyclic potentiodynamic technique and the concentration of Cd²⁺ and SeO₃²⁻ in the deposition baths varied from 10⁻⁴ M to 0.1 M, and from 10⁻⁵ M to 10⁻³ M, respectively. The electrochemical, the X-ray diffraction (EDS and XRD), and the photoactivity studies of a number of deposits have shown that application of the solution composition following Cd:Se = 5:1 results in deposition of the stoichiometric CdSe. The detected ratio of reagents is explained on the base of reaction mechanism and necessary excess of cadmium ions preventing CdSe deposit dissolution. The procedure of CdSe electrosynthesis was developed to yield of a direct semiconductor in the hexagonal structure. The necessity for cadmium cations excess is explained on the basis of the mixed electrochemical/chemical deposition mechanism.     

Electrodeposition behavior of nickel in the water- and air-stable 1-ethyl-3-methylimidazolium-dicyanamide room-temperature ionic liquid

The electrodeposition behavior of nickel was investigated at glassy carbon and polycrystalline copper electrodes in the 1-ethyl-3-methylimidazolium dicyanamide (EMI-DCA) room-temperature ionic liquid. Amperometric titration experiments suggest that Ni(II) reacted with DCA⁻ anions forming [Ni(DCA)₄]²⁻ complex anion, which could be reduced to nickel metal via a single-step electron transfer process. However, the anodic dissolution of the nickel deposits was sluggish. The electrodeposition of nickel proceeds via three-dimensional progressive nucleation with diffusion-controlled growth on both glassy and copper substrates. Scanning electron microscopy images of the nickel deposits indicated that the morphology of the nickel electrodeposits is dependent on the deposition potential. Atomic force microscopy topography illustrated that the roughness of the nickel-deposited surface increased with decreasing deposition potential. The crystalline nature of the nickel deposits was revealed by powder X-ray diffraction spectroscopy results which indicated that the grains size of the nickel deposits decreased with decreasing deposition potential.     

Anodic stripping voltammetric measurement of trace heavy metals at antimony film carbon paste electrode

The antimony film carbon paste electrode (SbF-CPE) was prepared in situ on the carbon paste substrate electrode as a “mercury-free” electrochemical sensor. Its aptitude for measuring some selected trace heavy metals has been demonstrated in combination with square-wave anodic stripping voltammetry in non-deaerated model solutions of 0.01 M hydrochloric acid with pH 2. Some important operational parameters, such as deposition potential, deposition time, and concentration of antimony ions were optimized, and the electroanalytical performance of the SbF-CPE was critically compared with both bismuth film carbon paste electrode (BiF-CPE) and mercury film carbon paste electrode (MF-CPE) using Cd(II) and Pb(II) as test metal ions. In comparison with BiF-CPE and MF-CPE, the SbF-CPE exhibited superior electroanalytical performance in more acidic medium (pH 2) associated with favorably low hydrogen evolution, improved stripping response for Cd(II), and moreover, stripping signals corresponding to Cd(II) and Pb(II) at the SbF-CPE were slightly narrower than those observed at bismuth and mercury counterparts. In addition, the comparison with antimony film electrode prepared at the glassy carbon substrate electrode displayed higher stripping current response recorded at the SbF-CPE. The newly developed sensor revealed highly linear behavior in the examined concentration range from 5 to 50 μg L⁻¹, with limits of detection (3σ) of 0.8 μg L⁻¹ for Cd(II), and 0.2 μg L⁻¹ for Pb(II) in connection with 120 s deposition step, offering good reproducibility of ±3.8% for Cd(II), and ±1.2% for Pb(II) (30 μg L⁻¹, n = 10). Preliminary experiments disclosed that SbF-CPE and MF-CPE exhibit comparable performance for measuring trace concentration levels of Zn(II) in acidic medium with pH 2, whereas its detection with BiF-CPE was practically impossible. Finally, the practical applicability of SbF-CPE was demonstrated via measuring Cd(II) and Pb(II) in a real water sample.     

Formation of PbTe nanofilms by electrochemical atomic layer deposition (ALD)

This article describes optimization of a cycle for the deposition of lead telluride (PbTe) nanofilms using electrochemical atomic layer deposition (ALD). PbTe is of interest for the formation of thermoelectric device structures. Deposits were formed using an ALD cycle on Au substrates, one atomic layer at a time, from separate solutions, containing Pb²⁺ or HTeO₂⁺ ions. Single atomic layers were formed using surface limited reactions, referred to as underpotential deposition (UPD), so the deposition cycle consisted of alternating UPD of Te and Pb. The Pb deposition potential was maintained at −0.35 V throughout the 100 cycle-runs, while the Te deposition potential was ramped up from −0.55 V to −0.40 V over the first 20 cycles and then held constant for the remaining ALD cycles. Coulometry for the reduction of both Te and Pb indicated coverages near one monolayer, each cycle. Electron probe microanalysis (EPMA) indicated a uniform and stoichiometric deposit, with a Te/Pb ratio of 1.01. X-ray diffraction measurement showed that the thin films had the rock salt structure, with a preferential (2 0 0) orientation for the as formed deposits. No annealing was used. Infrared reflection absorption measurements of PbTe films formed with 50, 65, and 100 cycles indicated strong quantum confinement.     

Effect of plating mode, thiourea and chloride on the morphology of copper deposits produced in acidic sulphate solutions

The influence of plating mode, chloride and thiourea (TU) on morphology of copper deposits has been studied. All experiments were conducted on disc electrodes rotating at 500 rpm and an average current density of 4 A dm⁻² to produce 10 μm thick deposits. In additive-free solutions, the use of pulsed current (PC) improved deposit morphology and brightness over DC plating. In the presence of thiourea (no Cl⁻), the deposits obtained by DC and PC plating were similar under most plating conditions. The presence of thiourea generally improved deposit quality over that obtained in additive-free solutions, but caused the formation of microscopic nodules and the deposits to appear slightly cloudy, resulting in lower reflectances than that of a polished uncoated copper surface. The addition of Cl⁻ to thiourea-containing solutions strongly influenced deposit morphology at both microscopic and macroscopic scales depending on chloride concentration and pulse conditions. It prevented nodule formation and created microscopically bright and reflective deposits, but caused extreme macroscopic roughness. Nevertheless, PC plating at 50 Hz in solutions containing appropriate amounts of thiourea and Cl⁻ was found to yield macroscopically and microscopically smooth deposits with reflectance similar to that of a polished uncoated copper substrate.     

Voltammetric determination of trace quantities of 6-thioguanine based on the interaction with DNA at a mercury electrode

Herein, a sensitive square wave voltammetric (SWV) method is described for the quantitative determination of an anticancer drug, 6-thioguanine (6-TG). The interaction of 6-TG with double stranded DNA (ds-DNA) in the solution phase resulted in a well amplified SWV response at the surface of hanging mercury dropping electrode (HMDE). Accumulation and stripping steps were made in the sample medium conditioned with acetate buffer (pH 4.8). Optimized conditions for the accumulation step included the deposition potential at −0.10 V, a deposition time of 30 s, a frequency of 50 Hz, a pulse amplitude of 20 mV, and a step potential of 7 mV. In the solution containing 2.0 mg L⁻¹ ds-DNA, determination was performed within a wide concentration range of 2.4 × 10⁻⁹ to 1.8 × 10⁻⁵ mol L⁻¹, and a detection limit of 2.1 nmol L⁻¹ 6-TG. An overall conclusion was that the intercalation of 6-TG into ds-DNA in a solution medium of the acetate buffer is a possible reason for the observed behavior. The method was applied for the determination of 6-TG in 6-thioguanine tablets and spiked blood serum samples. No statistically significant differences were observed between the expected and obtained concentrations. The new method is sufficiently sensitive to detect ultra trace amounts of 6-TG content.     

Mechanism of formation and electronic structure of semiconducting ZnSb nanoclusters electrodeposited from an ionic liquid

Electrocrystallization of Sb and the compound semiconductor ZnSb has been investigated by in situ SPM methods at the electrified ionic liquid/Au(1 1 1) interface at an elevated temperature of 50 °C for the first time employing the ionic liquid ZnCl₂-[C₄mim]⁺Cl⁻ (45:55). Prior to the underpotential deposition (UPD) process of Sb, ZnCl₃⁻ anions adsorb on the gold surface at the open-circuit potential (OCP). An ordered region - showing the characteristic of a Moiré-like pattern - coexists with a disordered region indicative of an interfacial phase transition. When the potential is reduced to −0.40 V versus Pt/Pt(II), 2D electrocrystallization of Sb starts showing a typical structure of the first monolayer. Further decreasing the potential to −0.5 V a second layer of Sb islands occurs. Stepping the potential from the UPD region to −0.60 V, the OPD of Sb sets in showing randomly dispersed clusters of homogeneous size. Near the ZnSb deposition potential, at ∼−0.95 V, a nearly homogeneous distribution of clusters of spherical shape with diameters up to 15 nm is found. Their corresponding STS curves exhibit an obvious semiconducting behaviour with a gap-energy of ∼0.6 ± 0.2 eV. Experiments at deposition conditions on the Sb-rich or Zn-rich side relative to the ZnSb deposition potential show an obvious doping effect - in the case of Zn excess - which is revealed by the corresponding normalized conductance (NC) spectra.     

The influence of 2,2′-dipyridyl on non-formaldehyde electroless copper plating

High electroless copper deposition rates can be achieved using hypophosphite as the reducing agent. However, the high deposition rate also results in dark deposits. In the hypophosphite baths, nickel ions (0.0057 M with Ni²⁺/Cu²⁺ mole ratio 0.14) were used to catalyze hypophosphite oxidation. In this study, additives (e.g. 2,2′-dipyridyl) were investigated to improve the microstructure and properties of the copper deposits in the hypophosphite (non-formaldehyde) baths. The influence of 2,2′-dipyridyl on the deposit composition, structure, properties, and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) have been investigated. The electroless deposition rate decreased with the addition of 2,2′-dipyridyl to the plating solution and the color of the deposits changed from dark brown to a semi-bright with improved uniformity. The deposits also had smaller crystallite size and higher (1 1 1) plane orientation with the use of 2,2′-dipyridyl. The resistivity and nickel content of the deposit were not affected by 2,2′-dipyridyl additions to the bath. The electrochemical current-voltage results show that 2,2′-dipyridyl inhibits the catalytic oxidation of hypophosphite at the active nickel site. This results in a more negative electroless deposition potential and lower deposition rate.     

Effects of specific adsorption of copper (II) ion on charge transfer reaction at the thin film LiMn2O4 electrode/aqueous electrolyte interface

This study investigated the effect of a specific adsorption ion, copper (II) ion, on the kinetics of the charge transfer reaction at a LiMn₂O₄ thin film electrode/aqueous solution (1 mol dm⁻³ LiNO₃) interface. The zeta potential of LiMn₂O₄ particles showed a negative value in 1 × 10⁻² mol dm⁻³ LiNO₃ aqueous solution, while it was measured as positive in the presence of 1 × 10⁻² mol dm⁻³ Cu(NO₃)₂ in the solution. The presence of copper (II) ions in the solution increased the charge transfer resistance, and CV measurement revealed that the lithium insertion/extraction reaction was retarded by the presence of small amount of copper (II) ions. The activation energy for the charge transfer reaction in the solution with Cu(NO₃)₂ was estimated to be 35 kJ mol⁻¹, which was ca. 10 kJ mol⁻¹ larger than that observed in the solution without Cu(NO₃)₂. These results suggest that the interaction between the lithium ion and electrode surface is a factor in the kinetics of charge transfer reaction.     

Effect of Bi(III) concentration on the stripping voltammetric response of in situ bismuth-coated carbon paste and gold electrodes

The effect of Bi(III) concentration (over the wide concentration range of 10⁻⁷ to 10⁻⁴ M) on the determination of Pb and Cd metal ions (in the 10⁻⁸ to 10⁻⁵ M range), by means of anodic stripping voltammetry (ASV) at in situ bismuth-coated carbon paste (CPE) and gold electrodes, has been studied. It is shown that in square wave anodic stripping voltammetry (SWASV) experiments the sensitivity of the technique generally depends on the Bi(III)-to-metal ion concentration ratio. It was found that, unlike the usually recommended at least 10-fold Hg(II) excess in anodic stripping experiments at in situ prepared mercury film electrodes, Bi(III)-to-metal ion ratios less than 10 are either optimal or equally effective at CPE and Au electrode substrates. Detection limits down to 0.1 μg L⁻¹ for Pb(II) and 0.15 μg L⁻¹ for Cd(II) were estimated at CPEs under conditions of small or moderate Bi(III) excess. Depending on Bi(III) concentration and deposition time, multiple stripping peaks attributed to Bi were recorded (especially in the case of Au substrates), indicating various forms of Bi deposits.     

Studies on the feasibility of electrochemical recovery of palladium from high-level liquid waste

The electrochemical behavior of palladium (II) in nitric acid medium has been studied at platinum and stainless steel electrodes by cyclic voltammetry. The cyclic voltammogram consisted of a surge in cathodic current occurring at platinum electrode at a potential of −0.1 V (vs. Pd), which culminates in a peak at −0.3 V was due to the reduction of Pd(II) to Pd. This was accompanied by a broad scant anodic peak at 0.25 V during scan reversal. Reduction of Pd(II) was irreversible and the diffusion coefficient was found to be 2.35 × 10⁻⁸ cm²/s at 298 K. At stainless steel electrode, a surge in the cathodic current occurring at −0.4 V (vs. Pd) was due to palladium deposition, which was immediately followed by a steep increase in cathodic current at −0.66 V due to H⁺ reduction. Electrolysis of palladium nitrate from 1 M to 4 M nitric acid medium at stainless steel electrode resulted in complete recovery of palladium with reasonably high Faradaic efficiency depending upon nitric acid concentration. However, the recovery and Faradaic efficiency were significantly lowered (to 40%) in the case of electrolysis from simulated high-level liquid waste due to other interfering competitive reactions.