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The release of anaerobically digested dairy wastewater (ANDDW) without a treatment can lead to severe environmental pollution, prompting the exploration of effective and sustainable treatment methods. Amidst various wastewater treatment approaches, the electro-oxidation (EO) process is considered as a promising, clean, and adaptable solution. In this study, the major operational parameters viz. current density, electrolyte concentration, treatment time, and mixing speed of an EO comprising Ti/PbO2 anode and stainless-steel cathode, were optimized using response surface methodology (RSM) for efficient removal of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total phosphorus (TP), orthophosphate (OP), total nitrogen (TN), and total Kjeldahl nitrogen (TKN) from ANDDW. Optimal conditions were identified as a current density of 90 mA cm−2, 0.08% electrolyte concentration, 180 min treatment time, and 400 rpm mixing speed. Under the optimum conditions, the COD, NH3-N, TP, OP, TN, and TKN removal efficiencies were 78.36, 63.93, 87.41, 92.39, 67.01, and 81.42%, respectively. Furthermore, the reaction rate followed the first-order kinetic model for the pollutants removal with correlation coefficients (R2) close to 1. The findings highlight the potential of using the EO process to treat high pollutant-laden ANDDW and encourage further studies to confirm the corresponding outcomes on a pilot scale. [ABSTRACT FROM AUTHOR]

In this work, Ti/PbO2‐MWCNTs anodes modified with different amount with different amount of Tween 80 (0.0–2.0 g/L) were prepared by the direct current electrodeposition method used as anode materials for Zinc electrowinning. The MWCNTs were dispersed in a lead nitrate solution with Tween 80, and the effects of the amount of added Tween 80 on the morphology, phase composition and electrocatalytical performance of lead dioxide coating were investigated. Physical characterizations show that with the increase of the amount of Tween 80, both grain size of PbO2 and carbon content in PbO2 layer firstly increased and then decreased, the preferential orientation and crystallinity of the PbO2 grain growth in the deposition process changed. Electrochemical tests demonstrate that the optimal modified electrode achieved the minimum Eo value and maximum j0 of 2.038 V and 3.781×10−4 A, respectively, an increase of capacitance to 368.8 μF cm−2, and a decrease of charge transfer resistance to 92.74 Ω cm2, which is mainly attributed to the PbO2 electrode modified with Tween 80, coupled with the synergistic effects of MWCNTs doping. [ABSTRACT FROM AUTHOR]

The electrocatalytic degradation method with PbO2/rGO electrode (anode) was chosen to treat Safranine-O waste because it was cheap and environmentally friendly. This research aimed to study the electrocatalytic efficiency of PbO2/rGO working electrode in Safranine-O removal. In this research, rGO and PbO2/rGO electrodes were synthesized and applied to Safranine-O removal through electrochemical degradation. The characterization results of the morphology of rGO are in the form of a layered structure and have the atomic composition of C (82.87%) and O (17.13%). The characterization results of PbO2/rGO are uniform particles with gaps/pores that appear relatively large. The rGO particles in the form of sheets (layers) seem to be distributed on the surface of PbO2. PbO2/rGO electrode has the atomic composition of C (87.24%), O (9.03), and Pb (3.73). The application of PbO2/rGO anode to the electrochemical degradation of Safranine-O showed good performance. It was able to perform dye removal (DE%), as well as a decrease in BOD and COD values up to >95% within 10 minutes at a concentration of 20 ppm. Application on real waste also showed the ability of dye removal, COD, and BOD reduction up to >95%. Coating or modifying the PbO2 anode with rGO can reduce the dissolution of Pb2+ ions in the solution during the electrochemical degradation. This study concluded that the PbO2/rGO electrode has improved the efficiency in Safranine-O degradation. [ABSTRACT FROM AUTHOR]

The sensitivity of lead dioxide coating properties to the deposition conditions and electrolyte composition has allowed the preparation of coatings with different properties for different applications. In this study, the effects of electrolyte additives on the electrodeposition process were investigated using electrochemical measurements such as cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The results showed that the presence of fluoride ions significantly reduces the possibility of TiO2 formation. The addition of copper ions not only prevents lead loss at the cathode but also leads to the formation of copper oxide on the surface at the initial stages, which hinders nucleation of PbO2. The presence of sodium dodecyl sulfate (SDS) also interferes with the nucleation process as it occupies active nucleation sites. The a-PbO2 interlayer prevents copper oxidation and solves the problem of lead dioxide nucleation. Finally, it was found that the simultaneous use of all additives together with the a-PbO2 interlayer has a positive effect on the coating process. [ABSTRACT FROM AUTHOR]

The electrochemically active lead dioxide (β-PbO2) contains the hydrogen (H) species inside the bulk and on the surface. The loss of the surface H species is proposed to be one of the factors in lead-acid battery failure. In this study, water adsorption on β-PbO2 has been investigated using theoretical approaches to reveal the chemical forms of the surface H species and identify a probable cause of H loss mechanisms. For the single water–β-PbO2, density functional theory (DFT) calculations present intact water molecular adsorption on β-PbO2 (100) and dissociative water adsorption on β-PbO2 (110), (101), and (001) surfaces. The geometric distances and the number of hydrogen bonds contribute to the adsorption energy reduction of single water adsorption. For the liquid water–β-PbO2 slab models, DFT-based molecular dynamics simulations observe that the surface lead sites are fully occupied by a hydroxyl group or intact water molecule, and some of the surface oxygens are protonated at 300 K. On the β-PbO2 (110) termination, dissociative water adsorption and intact molecular water adsorption occur competitively, leading to about 50% dissociation of adsorbed water molecules. On the β-PbO2 (100), (101), and (001) terminations, the water molecules adsorb preferably in the dissociative form. The surface dependence of water dissociation is explored in terms of hydrogen bonding interactions relevant to adsorbed aqueous species. It is indicated through the Wulff crystal shape that the increase in the β-PbO2 crystallite size may be one of the H loss mechanisms associated with the electrochemically inactive β-PbO2. [ABSTRACT FROM AUTHOR]

2,4-Dinitrotoluene (2,4-DNT) is a broadly applied nitroaromatic compound with multiple applications, and its simple production has resulted in its extensive utilization in producing explosives, dyes, and rubber. This substance is hazardous and induces genetic mutations in humans, fish, and microorganisms. Thus, this research was done to assess the effectiveness of the three-dimensional electro-Fenton (3D/EF) process employing magnetic activated carbon particle electrodes (GAC/Fe3O4) in eliminating 2,4-dinitrotoluene from water-based solutions. In this experimental investigation, Fe3O4 nanoparticles were created using the chemical co-precipitation technique. The G/β-PbO2 anode was fabricated by electrochemically depositing PbO2 layers on graphite sheets. G/β-PbO2 and stainless steel were utilized as the anode and cathode, respectively. The structure, particle size, and properties of the GAC/Fe3O4 nanocomposite were analyzed using FESEM, XRD, and EDX. The morphology of the G/β-PbO2 electrode was also examined using SEM. The Taguchi experimental design method was employed to identify the optimal conditions. The outcomes demonstrated that higher reaction time and current density, as well as lower pH and pollutant concentration, resulted in improved 3D/EF efficiency. Accordingly, the optimum values of parmeters were identified to be a concentration of 2,4-DNT = 50 mg/L, pH = 3, electrolysis time = 100 min, and current density = 8 mA/cm2. With these parameters, the degradation efficiency of 2,4-DNT through the examined system was 98.42 %, alongside removal efficiencies of 84.69 % for COD and 79.67 % for TOC. Additionally, the results indicated an increase in the average oxidation state (AOS) (from 1.27 to 1.95) and carbon oxidation state (COS) (from 1.27 to 2.75) in the 3D/EF process, along with a decrease in the COD/TOC ratio (from 1.81 to 1.36), indicating the effectiveness of the 3D/EF system in enhancing the biodegradability of 2,4-DNT. Overall, the combined 3D/EF process with a G/β-PbO2 anode has relatively high efficiency in degrading solutions containing DNT and can be considered a viable treatment option for wastewater containing substances such as 2,4-DNT. [ABSTRACT FROM AUTHOR]

2,4-Dinitrotoluene (2,4-DNT) is a broadly applied nitroaromatic compound with multiple applications, and its simple production has resulted in its extensive utilization in producing explosives, dyes, and rubber. This substance is hazardous and induces genetic mutations in humans, fish, and microorganisms. Thus, this research was done to assess the effectiveness of the three-dimensional electro-Fenton (3D/EF) process employing magnetic activated carbon particle electrodes (GAC/Fe3O4) in eliminating 2,4-dinitrotoluene from water-based solutions. In this experimental investigation, Fe3O4 nanoparticles were created using the chemical co-precipitation technique. The G/β-PbO2 anode was fabricated by electrochemically depositing PbO2 layers on graphite sheets. G/β-PbO2 and stainless steel were utilized as the anode and cathode, respectively. The structure, particle size, and properties of the GAC/Fe3O4 nanocomposite were analyzed using FESEM, XRD, and EDX. The morphology of the G/β-PbO2 electrode was also examined using SEM. The Taguchi experimental design method was employed to identify the optimal conditions. The outcomes demonstrated that higher reaction time and current density, as well as lower pH and pollutant concentration, resulted in improved 3D/EF efficiency. Accordingly, the optimum values of parmeters were identified to be a concentration of 2,4-DNT = 50 mg/L, pH = 3, electrolysis time = 100 min, and current density = 8 mA/cm2. With these parameters, the degradation efficiency of 2,4-DNT through the examined system was 98.42 %, alongside removal efficiencies of 84.69 % for COD and 79.67 % for TOC. Additionally, the results indicated an increase in the average oxidation state (AOS) (from 1.27 to 1.95) and carbon oxidation state (COS) (from 1.27 to 2.75) in the 3D/EF process, along with a decrease in the COD/TOC ratio (from 1.81 to 1.36), indicating the effectiveness of the 3D/EF system in enhancing the biodegradability of 2,4-DNT. Overall, the combined 3D/EF process with a G/β-PbO2 anode has relatively high efficiency in degrading solutions containing DNT and can be considered a viable treatment option for wastewater containing substances such as 2,4-DNT. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation is an efficient and pollution-free technology that belongs to the advanced oxidation process. The anode with excellent characteristics is a key factor that affects the electrocatalytic oxidation system. To explore the difference of performance between the PbO2 electrode and RuO2-IrO2 electrode, the morphology, microstructure, and other electrochemical properties were tested respectively. The scanning electron microscopy (SEM) shows that the PbO2 film is a typical pyramid shape with a compact structure while many cracks appear on RuO2-IrO2 film. The PbO2 and RuO2-IrO2 crystallize sizes are 22.7 nm and 31.3 nm, respectively. The oxygen evolution overpotential of the PbO2 electrode is 1.33 V (vs. SCE) a little lower than the RuO2-IrO2 electrode of 1.41 V (vs. SCE). The phenol and crystal violet (CV) are applied as the target contaminants to check the electrocatalytic performance of the two electrodes. The experiment results show that the RuO2-IrO2 electrode is fit for the degradation of crystal violet and the PbO2 electrode is fit for the degradation of phenol. The better electrocatalytic performance on the degradation of crystal violet by RuO2-IrO2 electrode can be attributed to the higher oxygen evolution overpotential. [ABSTRACT FROM AUTHOR]

Singly‐linked aromatic [22]smaragdyrin BF2 complex dimer was synthesized by the reductive coupling of 16‐brominated [22]smaragdyrin BF2 complex, which was oxidized to a stable diradical with PbO2. As the first example of fused smaragdyrin dimer, a fused [22]smaragdyrin BF2 complex dimer was synthesized by the oxidation of a CuCl‐BF2 complex dimer with FeCl3 and subsequent reduction with NaBH4. After removal of the BF2 group, the singly‐linked and fused aromatic dimers were oxidized to the corresponding antiaromatic [20]smaragdyrin free base dimers. The first oxidation and reduction potentials of these dimers are split depending upon the intramolecular electronic interactions, which are larger for the fused dimers. Despite the large electronic interactions, the aromatic and antiaromatic characters are well preserved in the fused dimers. [ABSTRACT FROM AUTHOR]

The electro-Fenton oxidation process was used to treat organic pollutants in industrial wastewater as it is one of the most efficient advanced oxidation processes. The novel cell in this process consists of a prepared PbO2 electrode by electrodeposition on graphite substrate and carbon fiber modified with graphene as a cathode. X-ray diffraction, fluorescence, analysis system, atomic force microscopy, and scan electron microscopy were used to characterize the prepared anode and cathode. XRD patterns clearly show the characteristic reflection of the mixture of α - and β phases of PbO2 on graphite and carbon fiber, and AFM results for cathode and anode present that PbO2 on graphite substrate and graphene on carbon fiber surface are on a nanoscale. Contact angle measurement was determined for the carbon fiber cathode before and after modification. The anodic polarization curve showed a higher anodic current when utilizing the PbO2 anode than the graphite anode. Phenol in simulated wastewater was removed by electro-Fenton oxidation at 8 mA/cm² current density, 0.4 mM of ferrous ion concentration at 35 °C up to 6 h of electrolysis. Chemical oxygen demand for the treated solution was removed by 94.02% using the cell consisting of modified anode and cathode compared with 81.23% using modified anode and unmodified cathode and 79.87% when using unmodified anode and modified cathode. [ABSTRACT FROM AUTHOR]

The discharge of the zinc–perchloric acid–lead dioxide electrochemical system at temperatures from –50 to +50°C was studied. Zinc coatings, including those subjected to chromate passivation, can be used as anode materials for fast-activated reserve chemical power sources. The tests of pilot batches confirmed that the power sources met the activation time requirements (no more than 50 ms). The power sources of the given system are characterized by increased discharge voltage (the maximum voltage of one cell is 2.12–2.44 V) compared with that of the lead–perchloric acid–lead dioxide system (1.50–1.86 V). The disadvantages of the zinc–perchloric acid–lead dioxide system were revealed: instability of discharge characteristics and possible cell polarity reversal as a result of side reactions, which may have a significant negative impact on the reliability of reserve power sources. [ABSTRACT FROM AUTHOR]

Lead (Pb2+), due to its non‐biodegradable property and biological accumulation, would have adverse effects on human body. In this study, a poly(pyrrole thiourea) modified electrode was developed using the electropolymerization of pyrrole and thiourea. Compared with drop‐casting method, the immobilization of the modified material with fixator and the modification efficiency of an electrode was improved. The poly(pyrrole thiourea) electrode was applied for the in‐situ determination of Pb2+ in water coupled with an electrochemical flow analysis device. Several experimental parameters were optimized and the interference of the common co‐existing ions were evaluated. The precision and the repeatability of the electrode‐modified method were also examined. The relative standard deviation of response currents to 20 μg L−1 Pb2+ was found to be 4.6 % (n=90) and the recoveries varied from 91.6 % to 110.2 % in the determination of tap water and lake water samples obtained from laboratories and the university campuses. The limit of detection (3σ/Slope) of 0.03 μg L−1 for Pb2+ within the range of 0.1–100 μg L−1. Finally, the continuous monitoring of Pb2+ in water was successfully done by this developed method. [ABSTRACT FROM AUTHOR]

The aim of this study is to intensify the process of in situ leaching of uranium with saturation of the working solution with oxygen using a Venturi tube. One of the ways to increase the efficiency of underground leaching is to saturate the leaching solution with oxygen. However, this oxidizer has not found application due to the complexity and high cost of oxygen saturation in the solution. The results of the study showed that saturation of the leaching solution with oxygen using a Venturi tube leads to a decrease in the concentration of divalent iron and an increase in the concentration of trivalent iron. Thus, this leads to an increase in the average uranium content in the pregnant solution by 21.3% compared with the technology being used. The dependence of changes in the concentration of trivalent iron and the uranium content in the pregnant solution on the leaching time was obtained when the solution was saturated with oxygen. The application of the proposed technology of oxygen saturation in the solution will increase the uranium content in the pregnant solution and thereby shorten the time required to mine uranium reserves in the technological block. [ABSTRACT FROM AUTHOR]

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Although Mn(III) complexes with organic ligands have been previously identified, the information about their stability and reactivity is scarce. In the present study, we analyzed the formation and stability of three different complexes: Mn(III)-citrate, Mn(III)-tartrate, and Mn(III)-humic acid (HA), as well as their reactivity toward an element of high environmental concern, lead (Pb). Our results indicate that the stability of studied complexes is highly dependent on pH. The Mn(III) complexes with citrate and tartrate degrade below pH 8, due to the electron transfer reaction between Mn(III) and the ligand, while the Mn(III)-HA complex's degradation is slower and less sensitive to pH. At pH 4, less than 40% of the initial Mn(III)-HA was found to be stable. The reactivity of the complexes was different depending on the ligand and its concentration. The Mn(III)-citrate and Mn(III)-tartrate complexes effectively reduced PbO2 and releases aqueous Pb2+, although significant differences were found with increasing ligand concentration. There was no evidence of the reduction of PbO2 by Mn(III) when it forms a complex with HA. This is likely due to the large size of HA moieties that prevent the Mn(III) component of the complex from getting close enough to the PbO2 surface to initiate electron transfer and lead to the reduction of Pb(IV) by HA itself. [ABSTRACT FROM AUTHOR]

Polyimide (PI) film with hydrophilic greatly limits their application in the field of microelectronic device packaging. A novel hydrophobic PI film with sag structure and improved mechanical properties is prepared relying on the reaction between anhydride‐terminated isocyanate‐based polyimide (PIY) containing a seven‐membered ring structure and the amino‐terminated polyamide acid (PAA) via multi‐hybrid strategy, this work named it as hybrid PI film and marked it as PI‐PIY‐X. PI‐PIY‐30 showed excellent hydrophobic properties, and the water contact angle could reach to 102°, which is 20% and 55% higher than simply PI film and PIY film, respectively. The water absorption is only 1.02%, with a decrease of 49% and 53% compared with PI and PIY. Due to that the degradation of seven‐membered ring and generation of carbon dioxide led to the formation of sag structure, the size of sag structures is ≈16.84 and 534.55 nm for in‐plane and out‐plane direction, which are observed on surface of PI‐PIY‐30. Meanwhile, PI‐PIY‐30 possessed improved mechanical properties, and the tensile strength is 109.08 MPa, with 5% and more than 56% higher than that of pure PI and PIY film, showing greatly application prospects in the field of integrated circuit. [ABSTRACT FROM AUTHOR]

MXene has excellent capacitive properties as a two-dimensional material, but its cycling stability is poor. β-PbO 2 is one of the common crystalline forms of lead dioxide, and it has excellent electrochemical properties and cyclic stability and has potential as a capacitor electrode material. However, the capacitive performance of β-PbO 2 as a capacitor electrode material is not ideal. Therefore, CF/MXene/β-PbO 2 (CMP) composites were prepared in this study by combining β-PbO 2 with CF/MXene (CM) using a constant current electrodeposition method, and their electrochemical energy storage properties were investigated. The ordered structure of interwoven CF is used to fix MXene, which has metallic properties and large layer spacing, as the matrix material. This utilization enables faster ion transport and electron storage. The electrochemical advantages of β-PbO 2 and CM can be unified by the synergistic effect of the composites, which results in a high specific capacity (399.42 F g−1) of the CMP electrode at 0.2 A g−1. In addition, the CM//CMP asymmetric supercapacitor constructed in 1 M Na 2 SO 4 solution has a wide potential window of 2.0 V and a high specific capacitance of 193.8C g−1, and the capacity remains 54.3% of the initial value after 5000 cycles at a charge/discharge rate of 40 mA g−1. This work provides important research ideas and clues for the application of β-PbO 2 composite electrode materials in supercapacitors. [ABSTRACT FROM AUTHOR]

The oxidation of 1,4-diiodo-2,3,5,6-tetramethylbenzene (diiododurene) and 1,4-dibromo-2,3,5,6-tetramethylbenzene (dibromodurene) with lead dioxide (PbO2) in a mixture of hydrogen fluoride and pyridine (Olahʼs reagent) and methylene chloride as co-solvent at room temperature for 96 h afforded the corresponding monofluorination products of one methyl group. This reaction is the first example of using the oxidative system PbO2–HF–Py–CH2Cl2 for the side-chain monofluorination of methylbenzenes. [ABSTRACT FROM AUTHOR]

The oxidation of 1,4-diiodo-2,3,5,6-tetramethylbenzene (diiododurene) and 1,4-dibromo-2,3,5,6-tetramethylbenzene (dibromodurene) with lead dioxide (PbO2) in a mixture of hydrogen fluoride and pyridine (Olahʼs reagent) and methylene chloride as co-solvent at room temperature for 96 h afforded the corresponding monofluorination products of one methyl group. This reaction is the first example of using the oxidative system PbO2–HF–Py–CH2Cl2 for the side-chain monofluorination of methylbenzenes. [ABSTRACT FROM AUTHOR]

Mineralization of benzene, toluene, and xylene (BTX) with high efficiency at room temperature is still a challenge for the purification of indoor air. In this work, a foam Ti/Sb-SnO 2 /β-PbO 2 anode catalyst was prepared for electrocatalytically oxidizing gaseous toluene in an all-solid cell at ambient temperature. The complex Ti/Sb-SnO 2 /β-PbO 2 anode, which was prepared by sequentially deposing Sb-SnO 2 and β-PbO 2 on a foam Ti substrate, shows high electrocatalytic oxidation efficiency of toluene (80%) at 7 hr of reaction and high CO 2 selectivity (94.9%) under an optimized condition, i.e., a cell voltage of 2.0 V, relative humidity of 60% and a flow rate of 100 mL/min. The better catalytic performance can be ascribed to the high production rate of ⋅OH radicals from discharging adsorbed water and the inhibition of oxygen evolution on the surface of foam Ti/Sb-SnO 2 /β-PbO 2 anode when compared with the foam Ti/Sb-SnO 2 anode. Our results demonstrate that prepared complex electrodes can be potentially used for electrocatalytic removal of gaseous toluene at room temperature with a good performance. [Display omitted] [ABSTRACT FROM AUTHOR]

The influence of the positive electrode properties on the activation time of the reserve chemical power sources based on the lead–perchloric acid–lead dioxide system is studied. Coatings of cathodes with lead dioxide obtained under various conditions are characterized by scanning electron spectroscopy, X-ray spectral microanalysis, X-ray photoelectron spectroscopy, and standard contact porosimetry. The improvement of the performance characteristics of the power sources including the ensuring of a short time of their activation at a low temperature is shown to be possible with the use of a lead dioxide nanoporous coating. To evaluate the applicability of cathodes for the manufacturing of power sources with a minimal activation time, a diagnostic principle is used that it based on the testing of the cathodes by chronopotentiometric measurements during their galvanostatic discharge. Pilot industrial samples of small-sized reserve power sources of the above-mentioned electrochemical system with unprecedented short activation time (less than 30 ms at temperature –50°С) were manufactured and tested. [ABSTRACT FROM AUTHOR]

The relationship between the discharge characteristics of reserve chemical power sources of the lead–perchloric acid–lead dioxide system and the physicochemical properties of electroplated cathode coatings with lead dioxide, including phase composition and microstructure, has been studied. The study reveals that the discharge characteristics of power sources can be enhanced by employing a two-layer lead dioxide coating consisting of a porous outer layer and a denser inner layer. The findings have been validated through the production and testing of industrial prototypes of pilot miniature reserve power sources, which exhibit improved performance even at low temperatures (activation time, less than 30 ms; discharge capacity, ~200 mA min/cm2; discharge voltage per cell, 1.8–1.2 V at –50°C). [ABSTRACT FROM AUTHOR]

The purpose of this research is to improve the performance and reduce the activation time of reserve power sources based on lead-acid systems at lower temperatures, down to –50 °C. Physico-chemical factors affecting the activation speed of reserve power sources based on Pb–HClO4–PbO2 and Zn–HClO4–PbO2 systems are investigated using chronopotentiometry, scanning electron microscopy, and standard contact porosimetry. Two approaches to the improvement of the low-temperature performance of power sources are used. The first one is based on the substitution of lead as anodic material with zinc. This allows the increase in discharge voltage and simultaneous decrease in activation time, but brings about the instability of discharge characteristics and, finally, deteriorates the reliability of power sources. The second approach is based on the use of PbO2 cathode material with enhanced nanoporosity. The chronopotentiometric method in galvanostatic mode is applied to the quality estimation of cathodes. The criterion of applicability of cathodes for reserve power sources consists in the low discharge overvoltage (0.1–0.2 V). Efficient performance of reserve power sources possessing the stable discharge voltage (1.5–1.8 V per cell) and the unprecedentedly short activation time (under 30 ms) even at lower temperatures (down to –50 °C) is achieved. The results are verified by fabrication and testing of pilot batches of miniaturized reserve power sources having microcells’ volume of 0.02 ml. The second approach to the improvement of power sources is transferred into the industrial production.

The assessments of a novel electrochemical advanced oxidation process are presented, where PbO 2 anode and H 2 O 2 electrosynthesis cathode are simultaneously used in one system. The anode is β-PbO 2 coated on a titanium substrate. The cathode is fabricated by rolling the activated Vulcan XC-72R carbon catalyst and PTFE binder on the titanium current collector as the catalyst layer and water-repellent layer, according to different carbon/PTFE ratios. Different electrolysers are used to evaluate the synergistic contributions of the PbO 2 anode and H 2 O 2 generated cathode on the pollutant degradation process. The contributions of both direct anodic oxidation and indirect oxidation can be observed. The synergy of the PbO 2 anode and H 2 O 2 on-site generated cathode can significantly enhance the oxidation ability and COD removal. Almost all COD in the real pesticide wastewater and dye wastewater can be removed using a PbO 2 -H 2 O 2 batch electrolyser, which is run at a cell voltage of 3.0 V and at room temperature. The reaction mechanisms in both chloride-containing and sulfate-containing wastewater are discussed particularly. [ABSTRACT FROM AUTHOR]

In this study, a method for determining the lead components in waste lead paste was proposed, using simulated and spent lead paste as research objects. To compare the effectiveness of different determining methods, we selected three methods for comparison and investigated the reasons for measurement deviation. The results indicate that the measurement deviation in the current method primarily stems from the following three factors: (1) Pb is soluble in an acetic acid solution under certain conditions; (2) Pb and PbO2 undergo redox reactions; and (3) hydrogen peroxide can undergo redox reactions with Pb. It is feasible to determine the lead content using the kinetic rules of Pb and PbO2 in the acetic acid-hydrogen peroxide system. The method of determination proposed in this paper is as follows. Firstly, lead dioxide is dissolved in hydrogen peroxide under acidic conditions. Subsequently, the concentration of lead dioxide is determined, and the quantity of hydrogen peroxide consumed is recorded. Then, a new sample is taken, and the lead oxide is dissolved in an acetic acid solution. The concentration of lead oxide is determined using the EDTA·2Na titration method. The residue of lead sulfate in the filtrate is dissolved in a sodium chloride solution, and its concentration is determined using the EDTA·2Na titration method. Based on the previously recorded volume of hydrogen peroxide, the remaining lead dioxide in the residue is dissolved in a mixture of acetic acid and hydrogen peroxide. The remaining lead dioxide is then removed from the new sample employing kinetic principles. Finally, the residual metallic lead in the sample is dissolved in a nitric acid solution, and its concentration is determined using the EDTA·2Na titration method. [ABSTRACT FROM AUTHOR]

The immense applications of titanium dioxide nanoparticles (TiO2 NPs) in consumer products have raised concerns about their health effects especially because TiO2 NPs can interact with various biomolecules. Out of these, proteins are more prone to alterations owing to their dynamic nature. Different protein conformers co-exist in cellular systems, and studying the interaction of protein conformers with nanoparticles becomes crucial for mechanistic understanding and therapeutic applications of TiO2 NPs. In the present study, the effect of TiO2 NPs on native, unfolded, and misfolded luciferase has been investigated. TiO2 NPs were found to destabilize native luciferase, interfere with the spontaneous refolding of unfolded luciferase, and promote luciferase misfolding; however, minor structural alterations were observed indicating weak interactions between the TiO2 NPs and luciferase. Morphological analysis of TiO2 NPs showed an average size of 24.57 ± 4.94 nm that increased to 50.52 ± 16.71 nm upon adsorption of luciferase on to TiO2 NPs. This study provides an understanding on the implication of nanoparticle-protein interaction on structural and conformational changes in various protein conformers. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) is of crucial importance to sustainable energy and environmental engineering, and layered double hydroxides (LDHs) are among the most active catalysts for OER in alkaline conditions, but the reaction mechanism for OER on LDHs remains controversial. Distinctive types of reaction mechanisms have been proposed for the O-O coupling in OER, yet they compose a coupled reaction network with competing kinetics dependent on applied potentials. Herein, we combine grand-canonical methods and micro-kinetic modeling to unravel that the nature of dominant mechanism for OER on LDHs transitions among distinctive types as a function of applied potential, and this arises from the interplay among applied potential and competing kinetics in the coupled reaction network. The theory-predicted overpotentials, Tafel slopes, and findings are in agreement with the observations of experiments including isotope labelling. Thus, we establish a computational methodology to identify and elucidate the potential-dependent mechanisms for electrochemical reactions. The mechanisms for oxygen evolution reaction on layered double hydroxides remain controversial. Here, the authors use a computational methodology by combining grand-canonical methods and microkinetic modeling to unravel the potential-dependent transitions mechanisms for electrochemical reactions. [ABSTRACT FROM AUTHOR]

The textile industry contributes significantly to environmental pollution through dyeing and finishing processes that release dyes into wastewater. Even small amounts of dyes can have harmful effects and cause negative impacts. These effluents have carcinogenic, toxic, and teratogenic properties and can take a long time to be naturally degraded through photo/bio-degradation processes. This work investigates degradation of Reactive Blue 21 (RB21) phthalocyanine dye using anodic oxidation process with PbO2 anode doped with iron III (0.1 M) (marked as Ti/PbO2-0.1Fe) and compared with pure PbO2. Ti/PbO2 films with and without doping were successfully prepared by electrodeposition technology on Ti substrates. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS) was used to characterize the electrode morphology. Also, linear scanning voltammetry (LSV) and cyclic voltammetry (CV) tests were conducted to investigate the electrochemical response of these electrodes. The influence of operational variables on the mineralization efficiency was studied as a function of pH, temperature, and current density. Doping Ti/PbO2 with Fe3+ (0.1 M) could reduce the particle to a smaller dimension and slightly increase the oxygen evolution potential (OEP). A large anodic peak was found for both electrodes prepared in the CV test, indicating that oxidation of the RB21 dye was easily achieved on the surface of the prepared anodes. No significant effect of initial pH on the mineralization of RB21 was observed. RB21 decolorization was more rapid at room temperature and increases with increasing current density. A possible degradation pathway for the anodic oxidation of RB21 in aqueous solution is proposed based on the identified reaction products. In general, it can be said that from the findings it was observed that the Ti/PbO2 and Ti/PbO2-0.1Fe electrodes show good performance on RB21 degradation. However, it was noted that the Ti/PbO2 electrode tends to deteriorate over time and exhibits poor substrate adhesion, while the Ti/PbO2-0.1Fe electrode displays superior substrate adhesion and stability. [ABSTRACT FROM AUTHOR]

The influence of the ultrasonic field on lead dioxide electrodeposition from nitrate electrolyte was studied. The adsorption of electroactive particles and the amount of nucleation on the electrode surface were found to have increased as well as the formation of OH-radicals accelerated under the influence of the ultrasonic field. Fine-crystalline deposits of lead dioxide were formed, which contributed to obtaining high current yield of lead dioxide, coefficient increasing of the electrode active mass and increasing of the discharge capacity of the emergency current generator cell layout. It was shown that the application of ultrasound in producing a lead dioxide electrode made it possible to reduce the time of the technological procedure.

To compare between the effect of partial substitution of lead ions (Pb4+ and Pb2+) at thallium (Tl) site in Tl0.8-xHg0.2PbxBa2Ca2Cu3O9−δ superconductor; two different compounds, lead (II) oxide (PbO) and lead (IV) oxide (PbO2), were used for the synthesis of the superconducting samples. Samples with nominal compositions Tl0.8-xHg0.2PbxBa2Ca2Cu3O9−δ, with x = 0.00, 0.05, 0.10, 0.15, and 0.20, were synthesized via solid state reaction technique. The x-ray diffraction (XRD) results showed that the partial substitution of both lead ions has not affected the tetragonal structure. Moreover, the volume fraction was increased from 75.95% to 90.38% and 89.41% as x increased up to 0.20 for PbO and PbO2 substitutions, respectively. The scanning electron microscopy (SEM) images demonstrated better grain connectivity and rectangular-shaped plates, supporting the phase formation of (Tl,Hg)-1223. The energy-dispersive x-ray (EDX) analysis revealed good agreement between the nominal and real compositions. Moreover, the elemental composition and oxidation states were proved by x-ray photoelectron spectroscopy (XPS). Both the superconducting transition temperature (Tc) and critical current (Jc) showed enhancement at x = 0.5 and 0.1 for PbO and PbO2 substituted samples, respectively. Vickers microhardness (Hv) measurements were used to examine the mechanical properties of the composites under a range of applied loads (0.49–9.8 N). All the prepared composites revealed the normal indentation size effect. The proportional sample resistance model proved to be the best model for interpreting the experimental data for the prepared samples. [ABSTRACT FROM AUTHOR]

In this study, we fabricated a blue-TiO 2 /PbO 2 -carbon nanotube (CNT) electrode in which blue TiO 2 nanotube arrays (blue-TNA) served as the substrate for PbO 2 -CNT eletrodeposition. Scanning electron microscope (SEM) showed compact surface structure of the electrode. The β-PbO 2 crystal structure was detected by X-ray diffraction (XRD). The distribution of Pb, O, C, and Na elements on the electrode surface have been confirmed by X-ray photoelectron spectroscopy (XPS). Blue-TiO 2 /PbO 2 -CNT electrode had higher response current (213.12 mA), larger active surface area and lower charge transfer resistance (2.22 Ω/cm2) than conventional TiO 2 /PbO 2 -CNT electrode. The influences of current density, initial phenol concentration, initial solution pH, and Na 2 SO 4 concentration on the electrochemical oxidation of phenol have been analyzed. The results showed that the 100 mg/L phenol could be destroyed completely after 210 min, and chemical oxygen demand (COD) removal rate was 89.3% within 240 min. Additionally, the electrode showed long actual lifetime (5468.80 hr) and low energy consumption (0.08 kWh/gCOD). A phenol degradation mechanism was proposed by analyzing the intermediate products with high-performance liquid chromatography-mass spectrometry (HPLC-MS). Importantly, the blue-TiO 2 /PbO 2 -CNT electrode exhibited superior stability and high degradation efficiency after 15 times reuse, demonstrating its promising application potential on phenol-containing wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

The anode material is one of the determining factors for the success of the electrowinning process. This study aims to coat the graphite substrate with β-PbO2 to produce an inert graphite/β-PbO2 composite material with low cost and good quality. The graphite/β-PbO2 synthesis is expected to be used as an anode for inert composites for electrowinning processes. The β-PbO2 deposition layer was prepared on the surface of the graphite substrate by an electrodeposition process using a sulfuric acid electrolyte. The effect of electrolyte concentration and voltage on graphite/β-PbO2 synthesis was investigated using a potentiodynamic polarization test through Tafel analysis. Experimental data have shown that there is an increase in the current density value at the beginning of the process and then a decrease due to passivation; this is due to anodic polarization in the graphite/β-PbO2 synthesis process. Suitable conditions can effectively increase the rate of formation of β-PbO2. The results of scanning electron microscopy with energy-dispersive X-ray spectroscopic analysis of the formed crystal structure showed that the β-PbO2 deposition layer obtained had a well-formed tetragonal structure at a voltage of 9 V. [ABSTRACT FROM AUTHOR]

In this paper, the thermodynamic properties of the PbO-ZnO-FeO-Fe2O3-SiO2-CaO six-component slag system were studied by using the molecular-ion coexistence theory, and the influence of slag composition changes on the activity of each structural unit was analyzed. The results show that the calculated value of the activity model is in good agreement with the measured value of the experiment, and the activity of each structural unit is greatly affected by the composition of the slag, but less affected by the temperature. High temperature is conducive to the decomposition of lead silicate and the formation of calcium-containing compounds, but the activity of ZnO will decrease. When the mass fraction of PbO increases, the main reaction is to combine with PbO·SiO2 to form 2PbO·SiO2. Increasing the mass fraction of ZnO and CaO is beneficial to the decomposition of lead silicate and an increase in PbO activity. When the iron-silicon ratio increases, it will promote the decomposition of lead silicate and the formation of ZnO·Fe2O3, so the activity of PbO will increase and the activity of ZnO will decrease. When the calcium-silicon ratio is low, the binary combination product of CaO and SiO2 is mainly CaO·SiO2, and when the calcium-silicon ratio rises above 0.5, the activities of 2CaO·SiO2 and 3CaO·2SiO2 will increase rapidly. [ABSTRACT FROM AUTHOR]

The in situ electrochemical oxidation process has received considerable attention for the removal of dye molecules and ammonium from textile dyeing and finishing wastewater. Nevertheless, the cost and durability of the catalytic anode have seriously limited industrial applications of this technique. In this work, the lab-based waste polyvinylidene fluoride membrane was employed to fabricate a novel lead dioxide/polyvinylidene fluoride/carbon cloth composite (PbO2/PVDF/CC) via integrated surface coating and electrodeposition processes. The influences of operating parameters (pH, Cl− concentration, current density, and initial concentration of pollutant) on the oxidation efficiency of PbO2/PVDF/CC were evaluated. Under optimal conditions, this composite achieves a 100% decolorization of methyl orange (MO), 99.48% removal of ammonium, and 94.46% conversion for ammonium-based nitrogen to N2, as well as an 82.55% removal of chemical oxygen demand (COD). At the coexistent condition of ammonium and MO, MO decolorization, ammonium, and COD removals still remain around 100%, 99.43%, and 77.33%, respectively. It can be assigned to the synergistic oxidation effect of hydroxyl radical and chloride species for MO and the chlorine oxidation action for ammonium. Based on the determination of various intermediates, MO is finally mineralized to CO2 and H2O, and ammonium is mainly converted to N2. The PbO2/PVDF/CC composite exhibits excellent stability and safety. [ABSTRACT FROM AUTHOR]

The features of the formation of a hidden lead-silicate insulating layer in silicon substrates are considered. To do this, ions of molecular oxygen and lead are sequentially implanted into them in an atomic ratio of 75 : 1 then annealing is carried out at a temperature of 1150°C in an environment of dry oxygen. The distribution of the implanted ions in the experimental samples is recorded by the method of secondary ion mass spectrometry. It is shown that the latent insulator is formed in the process of the spinodal decomposition of a solid solution of SiOx–PbOx in the form of a three-layer structure. Its middle part is silicon dioxide doped with lead ions and the side parts consist of a lead-silicate phase. A relaxation diffusion model is proposed to analyze the distribution profile of lead. [ABSTRACT FROM AUTHOR]

In this paper, electrochemical degradation of Reactive Black 5 (RB5) textile azo dye was examined in regard to different synthesis procedures for making PbO2–graphitic carbon nitride (g-C3N4) electrode. The reaction of Pb OH 3 - with ClO− in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium phosphate (TBAP), under conventional conditions, resulted in the formation of PbO2 with varying morphology. The obtained materials were combined with g-C3N4 for the preparation of the final composite materials, which were then characterized morphologically and electrochemically. After optimizing the degradation method, it was shown that an anode comprising a steel electrode coated with the composite of PbO2 synthesized using CTAB as template and g-C3N4, and using 0.15 M Na2SO4 as the supporting electrolyte, gave the best performance for RB5 dye removal from a 35 mg/L solution. The treatment duration was 60 min, applying a current of 0.17 A (electrode surface 4 cm2, current density of 42.5 mA/cm2), while the initial pH of the testing solution was 2. The reusability and longevity of the electrode surface (which showed no significant change in activity throughout the study) may suggest that this approach is a promising candidate for wastewater treatment and pollutant removal. [ABSTRACT FROM AUTHOR]

Fe3S4, commonly known as greigite, is a transition metal chalcogenide and has attracted enormous attention in the field of energy storage and environmental remediation. Herein, a graphitic carbon nitride (g-C3N4) encapsulated zero-dimensional Fe3S4 nanostructure was synthesized by a solvothermal strategy. The nanocomposite material was characterized in detail by FTIR, PXRD, TGA, FE-SEM, TEM, HRTEM, BET, and XPS techniques. The highly active adsorption and catalytic centers in Fe3S4-g-C3N4 facilitate (a) the mineralization of methylene blue (MB) dye, (b) electrochemical sensing of Pb2+ and UO22+ ions, and (c) reductive adsorption of UO22+ ions from aqueous system. Almost complete (>98%) photo-Fenton degradation of MB dye was achieved at pH = 6.0 and by using direct sunlight with the least input of H2O2. A glassy carbon electrode (GCE) modified with Fe3S4-g-C3N4 was fabricated to sense micromolar concentrations of Pb2+ and UO22+ ions in the aqueous medium. The limit of detection for Pb2+ and UO22+ ions was 0.71 and 0.22 μM in the linear concentration range of 1–7 μM and 0.05–8 μM, respectively. Finally, the nanocomposite material was tested for the removal of uranyl ions. The removal of uranyl ions was very rapid, with >95% removed within 30 min of contact time. The adsorption of uranyl ions was described by the Langmuir model with a maximum monolayer adsorption of 185.20 ± 4.3 mg g−1. XPS analysis of U4f and S2p spectra confirmed the charge transfer from the sulfide ion to the uranyl ion, resulting in the reduction of U(VI) to U(IV). The magnetically recoverable Fe3S4-g-C3N4 nanocomposite showed excellent stability and reusability over multiple catalytic and adsorption cycles. [ABSTRACT FROM AUTHOR]

Lead dioxide-based electrodes have shown a great performance in the electrochemical treatment of organic wastewater. In the present study, modified PbO2 anodes supported on stainless steel (SS) with a titanium oxide interlayer such as SS/TiO2/PbO2 and SS/TiO2/PbO2-10% Boron (B) were prepared by the sol–gel spin-coating technique. The morphological and structural properties of the prepared electrodes were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that the SS/TiO2/PbO2-10% B anode led to a rougher active surface, larger specific surface area, and therefore stronger ability to generate powerful oxidizing agents. The electrochemical impedance spectroscopy (EIS) measurements showed that the modified PbO2 anodes displayed a lower charge transfer resistance Rct. The influence of the introduction of a TiO2 intermediate layer and the boron doping of a PbO2 active surface layer on the electrochemical degradation of ampicillin (AMP) antibiotic have been investigated by chemical oxygen demand measurements and HPLC analysis. Although HPLC analysis showed that the degradation process of AMP with SS/PbO2 was slightly faster than the modified PbO2 anodes, the results revealed that SS/TiO2/PbO2-10%B was the most efficient and economical anode toward the pollutant degradation due to its physico-chemical properties. At the end of the electrolysis, the chemical oxygen demand (COD), the average current efficiency (ACE) and the energy consumption (EC) reached, respectively, 69.23%, 60.30% and 0.056 kWh (g COD)−1, making SS/TiO2/PbO2-10%B a promising anode for the degradation of ampicillin antibiotic in aqueous solutions. [ABSTRACT FROM AUTHOR]

Fe3+ and/or carbon black-doped Ti/PbO2 electrodes were successfully synthesized via electrodeposition technology. The morphology and crystal structure of the electrodes were characterized by Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM/EDS) and X-ray Diffraction (XRD), respectively. Furthermore, Linear Sweep Voltammetry, Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy tests were also performed to analyze the electrochemical performance of the electrodes. The electrocatalytic activity of electrodes was examined by electrocatalytic oxidation of Reactive Yellow 14 (RY14) azo dye's model pollutant. The SEM showed that the morphology and size of PbO2 particles are strongly affected by doping with Fe3+ and carbon black. The EDS confirmed the existence of Fe and C elements. The XRD patterns show that samples were composed of higher content of β-PbO2. Ti/PbO2-0.1Fe (0.1 M Fe3+ + 0 g C) electrode exhibits the highest oxygen evolution potential (1.64 V/SCE). The CV test indicated that the presence of the anodic peak at 1.45 V/SCE means that the oxidation of RY14 dye was easily achieved on the surface of all prepared electrodes. The Nyquist plots show the presence of two semicircles, one in the high-frequency domain describes the electron transfer process, while the second in the low-frequency domain explains the adsorption of the intermediate. Ti/PbO2 and Ti/PbO2-0.1Fe electrodes showed the best performance on degradation of RY14. [ABSTRACT FROM AUTHOR]

Silicon is one of the most monitored elements in extractables and leachables studies of pharmaceutical packaging systems and related components. There is a need to review and evaluate toxicological thresholds of silicon because of its direct contact with drug products (DP) especially a liquid form of DP with the widely used pharmaceutical packaging systems made of silicon materials like glass and silicone. It is required by regulatory authorities to test silicon content in DP; however, there are no official guidelines on the toxicology of silicon that are currently available, yet the knowledge of toxicological thresholds of silicon is critical to justify the analytical limit of quantification (LOQ). Therefore, we reviewed the toxicity of silicon to derive a toxicological threshold by literature review of toxicity studies of both inorganic and organic silicon compounds. Oral toxicity is low for inorganic silicon like silicon dioxide or organic silicon polymers such as silicone tube/silicone oil (polydimethylsiloxane, or namely, PDMS as the major ingredient). In comparison, inhalational toxicity of silicon dioxide leads to pulmonary silicosis or even lung cancer. When orally administered, the toxicity of silicon dioxide, glass, polymers, or PDMS oligomers varies depending on their morphology, molecular weight (MW), and degrees of polymerization. PDMS with high MW has minimal toxic symptoms with non-detectable degradation/elimination by both intraperitoneal and subcutaneous administration routes, while exposure to either PDMS or small molecule dimethyl silicone compounds by the intravenous administration route may lead to death. We here determined a general parenteral permitted daily exposure (PDE) of 93 μg/day for inorganic silicon element and 100 μg/day for organic silicon element by reviewing toxicological data of both forms of silicon. In conclusion, this work provides evidence for pharmaceutical companies and regulatory agencies on the PDEs of silicon elements in pharmaceutical packaging and process components through a variety of administration routes. [ABSTRACT FROM AUTHOR]

Two series, A and B, of PVC based nanocomposite polymer membranes (nCPMs) were prepared using PbO only and PbO/graphite mixture as a filler by solution casting method. Seven samples with varying compositions (5–35%) of filler particles were prepared for each series and were compared by thickness measurements, porosity, water uptake, swelling degree, ionic conductivity, ion exchange capacity (IEC), membrane potential and transport number. The maximum values for these characteristics were observed as 0.402 mm, 0.77, 141.3%, 0.11, 0.0033 Scm−1, 8.6 milli-eq.g−1, 0.19 V and 0.01391 for series-A composites whereas that of 0.367 mm, 0.83, 63.4%, 0.019, 0.00981 Scm−1, 5.21 milli-eq.g−1, 0.13 V and 0.0108 for series-B nCPMs respectively. The SEM images of membranes showed greater voids produced in the series-B compared to series-A composites. The maximum Ionic conductivity, IEC, membrane potential and transport number were observed for membrane with 25% PbO/graphite, 20% PbO and 35% PbO particles respectively. [ABSTRACT FROM AUTHOR]

• A PbO x @C/GF electrode was manufactured to remove dye from water. • Doping with PbO improved the adsorption of oxygen and the degradation of the dye. • Active oxygen on the surface of the electrode promoted the degradation of the dye in the water. • The PbO x @C/GF showed strong electrocatalytic performance and stability. • The PbO x @C/GF system reached 100 % COD removal with 24.44 kW·h/kg-COD for industrial wastewater. Electro-assisted catalytic wet air oxidation (ECWAO) is an environmentally-friendly pollutant removal process with energy-saving and mild reaction properties. However, it requires an electrode with high catalytic capacity and stability, and the catalytic mechanism behind the process still needs to be further clarified. Herein, we report a graphite felt (GF)-supported PbO x catalyst which can chemically adsorb oxygen and activate it into free radicals by an anodic electric field to promote wet air oxidation. XRD, SEM, EDS, XPS, BET and TG measurements indicated that PbO and PbO 2 were successfully doped and loaded onto the GF, increasing the specific surface area and number of active sites. The best RhB degradation efficiencies achieved were 91.26 % over 15 min and 96.68 % over 90 min. The PbO x @C/GF maintained good catalytic performance over eight cycles in the pH range of 3–11 with negligible metal leaching. The RhB degradation pathway of RhB was analyzed through GC–MS results. A free radical quenching experiment, a contrast experiment, and an electrochemical test revealed the process of oxygen being adsorbed by Pb(II) and activated to degrade organic matter was revealed. Five kinds of dyes were degraded by the electrode via the ECWAO process, and the degradation rate reached over 93.7 % within 90 min. The degradation specific energy consumption (SEC) of probe pollutant RhB is 48.70 kW·h/kg-COD. The industrial practical dye wastewater COD removal rate was close to 100 %, and the SEC was 24.44 kW·h/kg-COD. Therefore, it can be concluded that a graphite felt (GF)-supported PbO x catalyst can act as an anode for ECWAO to chemically adsorb oxygen and activate it into free radicals using an anodic electric field to promote wet air oxidation. [ABSTRACT FROM AUTHOR]

This work presents the mathematical modeling, simulation, and experimental validation of a paired metal ions recovery process in a rotating cylinder electrode (RCE) electrochemical reactor in a continuous mode of operation. The process involves the recovery of copper, Cu(II), and silver, Ag(I), ions cathodically with the simultaneous recovery of lead, Pb(II), ions anodically. The experimental process was implemented in a traditional RCE electrochemical reactor, with a stainless-steel cylinder working as a cathode and six-dimensional stable plate anodes (DSA) concentric to the cathode. The experimental scheme consisted of a central composite design (CCD) with three response variables, the Cu(II), Ag(I), and Pb(II) conversion as a function of the rotating speed (rpm), current density (A m−2), and flow rate (cm3 min−1). Second-order empirical polynomials were fitted to the Cu(II) and Ag(I) conversion experimental data, while for Pb(II) conversion, a first-order polynomial was fitted. The hydrodynamics and tertiary current distribution phenomena were modeled and simulated numerically using the commercial computational fluid dynamics (CFD) software COMSOL Multiphysics. The CFD models obtained were validated with the experimental information from the experimental design. Low deviation values of the theoretical approximation to the experimental values were obtained. Also, empirical models were developed from the experimental design, which are useful for predicting the response variables in the space design, while the validated CFD models can predict the RCE electrochemical reactor behavior at any operation condition. [ABSTRACT FROM AUTHOR]

Water scarcity is becoming a serious threat for the implementation of energy storage devices based on hydrogen in the inland of dry regions, because of the difficulties in finding appropriate sources of water and the important environmental problem associated with the discharge of rejection saline streams produced during the purification of water. This becomes an opportunity for chloralkaline technology in which the quality of water used is lower than the required in other hydrogen production technologies. This work compares the performance of chloralkaline electrolyzers fed with different solutions of NaCl (from brackish water to brines) with that obtained feeding two natural water samples (seawater and porewater) and three processed waters (rejections streams of the electrodialysis, reverse osmosis of the porewater and a real rejection of the reverse osmosis of a vineyard). All tests were made with a lab-scale 3-D printed cell where, in addition, the performance of Ti/RuO 2 and Pb/PbO 2 anodes were compared, being always better the results obtained in the tests made with the Ti/RuO 2 electrode. Results obtained indicate that efficiencies reached using these alternative sources are lower than those which can be reached using synthetic brines that, in turn, were very near to the standards reached in the chloralkaline industry. In the case of hydrogen production, the maximum values were obtained for seawater, reaching efficiencies proximate to 8.0 mg H 2 (Wh)−1. Rejection streams of desalination processes were found to be less efficient, attaining values in the range 2 and 4 mg H 2 (Wh)−1. Regarding the production of chlorine and caustic soda, better performances were reached again with seawater (161.7 mg Cl 2 (Wh)−1 and 0.092 mg OH− (Wh)−1) and with the rejection of the electrodialysis, which also reached sound values of 90.4 mg Cl 2 (Wh)−1 and 0.107 mg OH− (Wh)−1. Results obtained are promising and indicate a path that must be further worked for the implementation of a greener water management strategy in the hydrogen -based energy storage technology. • Different types of water can be successfully used to fed chloralkaline electrolyzer. • Important influence of the composition & concentration and necessity of concentration. • Performance of electrolyzers with Ti/RuO 2 electrodes better than with Pb/PbO 2. • Electrolysis of seawater reaches 8 mg H 2 (Wh)−1,161.7 mg Cl 2 (Wh)−1 and 0.092 mg OH− (Wh)−1. • Among the concentration technologies, better results are reached by electrodialysis. • Necessity to improve performance of membranes against crossover of chlorine. [ABSTRACT FROM AUTHOR]