关键词： Computer simulation   Tool design   Electrochemical machining   Process monitoring   Process control   Equipment behavior  

摘要： Electrochemical machining process of curvilinear surfaces with a shaped electrode is still considered one of basic operations within this technology. In a case of machining such complex surfaces it is difficult to design constant values of this process for the whole of the machining time and additionally ensure high production efficiency. This paper presents a system for controlling and monitoring the electrochemical machining process in a way which allows a suitable modification of parameters related to the kinematics of a tool electrode, including the frequency of its vibrations and tool design stage verification and optimization of machining equipment behavior. The parameters are modified according to designed criteria. The article also presents the research station which was used for verification of the presented system, as well as the effects of this verification. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Anodic oxidation   EF/BDD process   Waste water treatment   Textile industry  

摘要： Textile manufacturing is the one responsible for water bodies' contamination through the discharge of colored wastes. This work presents the study of reactive yellow HF (RYHF) dye degradation under two different electrochemical advanced oxidation processes (EAOP), namely anodic oxidation (AO) and electro-Fenton (EF)/boron-doped diamond (BDD) process. For the AO, 100 and 300 mg/L solutions using Pt and BDD as anodes in a 100 mL stirred tank cell were used, with a supporting electrolyte of 0.05 mol/L of Na2SO4 at pH 3 under 30 and 50 mA/cm(2) current density. The EF/BDD process was carried out in a flow reactor at 4 and 7 L/min to degrade 100, 200, and 300 mg/L RYHF solutions under 50 and 80 mA/cm(2). UV-Vis determinations were used for decolorization evaluation, while high-performance liquid chromatography (HPLC) method provided information on dye degradation rate.

关键词： Benzoic Acid   Electrocoagulation   Electrochemical Fenton   Optimization   Sludge Analysis  

摘要： Benzoic acid containing synthetic solution was pretreated by acid precipitation at various pH (1-3) and temperature (15-60 A degrees C). Pre-treated solution was further treated by electrocoagulation (EC) and electrochemical Fenton (EF) processes using iron anode and graphite cathode. Optimization of independent operating parameters, namely, initial pH: (3-11), current density (A/m(2)): (15.24-76.21), electrolyte concentration (mol/L): (0.03-0.07) and electrolysis time (min): (15-95) for EC process and pH: (1-5), current density (A/m(2)): (15.24-76.21), H2O2 concentration (mg/L): (100-500) and electrolysis time (min): (15-95) for EF process, was performed using central composite design (CCD) in response surface methodology (RSM). Maximum removal efficiencies of BA- 76.83%, 88.50%;chemical oxygen demand (COD) - 69.23%, 82.21% and energy consumption (kWh/kg COD removed) - 30.86, 21.15 were achieved by EC and EF processes, respectively, at optimum operating conditions. It was found that EF process is more efficient than EC process based on removal of BA and COD with lower energy consumption. The sludge obtained after EC and EF treatments was analyzed by XRD, FTIR, DTA/TGA and SEM/EDX techniques.

关键词： zinc   Electrodes   Liquid interface   metal electrode   Glow discharge   Vapors   Electrochemical processes   atomic fluorescence spectroscopy   Anodes  

摘要： In this study, a novel high efficiency vapor generation strategy was proposed on the basis of solution anode glow discharge for the determination of Cd and Zn by atomic fluorescence spectrometry. In this approach, a glow discharge microplasma was acted as a gaseous cathode to initiate the plasma electrochemical vapor generation of Cd and Zn: Cadmium/zinc ions could be converted into molecular species efficiently at the plasma-liquid interface from a supporting electrolyte (HCl, pH = 3.2), It was found that the overall efficiency of the plasma electrochemical vapor generation (PEVG) system was much higher than the conventional electrochemical hydride generation (EcHG) and HCl-KBH4 system. With no requirement for other reducing reagents, this new approach enabled us to detect Cd and Zn with detection limits as low as 0.003 mu g L-1 for Cd and 0.3 mu g L-1 for Zn. Good repeatability (relative standard deviation (RSD), n = 5) was 2.4% for Cd (0.1 mu g L-1) and 1.7% for Zn (10 mu g L-1) standard. The. accuracy of the proposed method was successfully validated through analysis of cadmium in reference material of stream sediment (GBW07311), soil (GBW07401), rice (GBW10045), and zinc in a simulated water sample (GSB 07-1184-2000). Replacing a metal electrode with a plasma offers the advantage of eliminating potential interactions between the species in liquid and the electrode, which solves the issues associated with electrode encountered in conventional EcHG. The ability to initiate electrochemical vapor generation reactions at the plasma-liquid interface opens a new approach for chemical Vapor generation based on interactions between plasma gas-phase electrons and solutions.

关键词： Anodic oxidation   Electra-Fenton   Photoelectro-Fenton   Synthetic wastewaters   Real wastewaters  

摘要： Over the last decades, research efforts have been made at developing more effective technologies for the remediation of waters containing persistent organic pollutants. Among the various technologies, the so-called electrochemical advanced oxidation processes (EAOPs) have caused increasing interest. These technologies are based on the electrochemical generation of strong oxidants such as hydroxyl radicals ((OH)-O-center dot). Here, we present an exhaustive review on the treatment of various synthetic and real wastewaters by five key EAOPs, i.e., anodic oxidation (AO), anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF), alone and in combination with other methods like biological treatment, electrocoagulation, coagulation and membrane filtration processes. Fundamentals of each EAOP are also given. (C) 2016 Elsevier B.V. All rights reserved.

关键词： MASS spectrometry   ELECTROCHEMICAL analysis   ELECTRODES   ELECTROLYTES   ELECTROLYTIC oxidation   MICROFLUIDIC devices  

摘要： The in situ molecular characterization of reaction intermediates and products at electrode electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability, we report the first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode electrolyte interface.

关键词： Electric field   Fouling rate   Bound extracellular polymeric substances (bEPS)   Soluble microbial products (SMP)   Transparent exopolymeric particles (TEP)   Sludge hydrophobicity  

摘要： Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO4-P) and ammonia nitrogen (NH4-N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

关键词： Gear   Finishing   ECH   PECH   Honing  

摘要： Part 1 of this review discussed conventional gear surface finishing processes and their advantages and limitations, and introduced the electrochemical honing (ECH) process (and its extension of pulsed electrochemical honing (PECH)), to improve the surface characteristics of different types of gears, working principles, mechanism of material removal and equipment details. Part 2 gives a review of past work, and discusses effects of various process parameters on surface characteristics and finishing productivity (i.e. material removal rate), advantages and limitations, and its other applications. The objective of this review paper is to present ECH/PECH as one emerging alternative, economical, productive and sustainable gear finishing process.

关键词： Balance   Corrosion   Gravimetric Method   Hydrogen Evolution   Hydrogen Measurement  

摘要： A new method to measure the amount of hydrogen generated from the surface of an immersed electrode is presented in this work. The method consists of a mechanical balance with a horizontal arm attached to two hydrogen-collecting containers that are submerged in two independent electrochemical cells. One of the two cells (the test cell) contains the electrode of interest, generating an unknown amount of hydrogen, whereas the other cell (the measurement cell) contains an inert electrode that is used to evolve an amount of hydrogen equal to that generated in the test cell, such as the mechanical equilibrium between the sides of the balance is constantly maintained. Adequate electrical connections and circuitry ensures that, as hydrogen is evolved from the electrode of interest in the test cell, the displacement of the balance arms activates an electrical contact, which triggers the hydrogen evolution in the measuring cell. Once a sufficient amount of hydrogen is evolved from the measuring cell, the horizontal arm is displaced in the opposite direction and the electrical contact to the measuring cell is interrupted. The measurement of the current flowing through the measuring cell enables precise estimation of the amount of hydrogen generated in the test cell. (C) The Author(s) 2017. Published by ECS. All rights reserved.

关键词： silicon anode   poly(acrylic) acid neutralization   anode calendering   lithium ion battery  

摘要： Silicon is a promising anode active material for lithium ion batteries due to improvements to overcome the volume expansion problem and preserve the electrode structural integrity during the lithiation and delithiation processes. Significant studies have been performed to overcome this problem and make silicon available for commercial applications. In this study, we developed a facile and functional method to demonstrate the possibility of widespread usage of silicon anode. Here, two methods were investigated;neutralization of poly(acrylic) acid (PAA) and calendering process during electrode production. PAA without neutralization is commonly used in silicon based anodes. Calendering is a typical process for cathode preparation. However, it is not generally utilized for making silicon anodes. This study aims to show the effect of PAA neutralization and anode calendering on the electrochemical performance of cells in comparison to anodes prepared by conventional processes. Furthermore, a high mass loading is a critical step for the use of Si anode commercially. The electrode was successfully loaded in this study as 1 mg/cm(2). Electrochemical performance measurements showed that 1370 mAh/g specific capacity was achieved after neutralization of PAA and calendering of the electrode at the 100th cycle. Meanwhile, the calendered electrode prepared with PAA polymer showed a specific capacity of 511 mAh/g after 100 cycles. Traditionally, graphite is used as anode material in commercial batteries and theoretical specific capacity is 372 mAh/g. Our observations with quite high specific capacity achieved by the process applied in this study show an important promise for the use of silicon based anode materials in the future utilization of Li ion batteries. (C) 2016 Elsevier Ltd. All rights reserved.