Electrodegradation of Acid Mixture Dye through the Employment of Cu/Fe Macro-Corrosion Galvanic Cell in Na2SO4 Synthetic Wastewater.

Traditional wastewater purification processes are based on a combination of physical, chemical, and biological methods; however, typical electrochemical techniques for removing pollutants require large amounts of electrical energy. In this study, we report on a process of wastewater purification, through continuous anodic dissolution of iron anode for aerated Cu/Fe galvanic cell in synthetic Na2SO4 wastewater solution. Electrochemical experiments were conducted by means of a laboratory size electrolyzer, where electrocoagulation along with electrooxidation phenomena were examined for wastewater containing Acid Mixture dye. The above was visualized through the employment of electrochemical (cyclic voltammetry and ac impedance spectroscopy techniques) along with instrumental spectroscopy analyses.

Electrochemical Degradation of Industrial Dyes in Wastewater through the Dissolution of Aluminum Sacrificial Anode of Cu/Al Macro-Corrosion Galvanic Cell.

This paper reports on the process of industrial-type wastewater purification carried-out through continuous anodic dissolution of aluminum alloy sacrificial anode for artificially aerated Cu-Al alloy galvanic (macro-corrosion) cells and synthetically prepared wastewater solutions. Electrochemical experiments were performed by means of a laboratory size electrolyzer unit, where the electrocoagulation process along with surface-induced electrooxidation phenomena were examined for wastewater containing Acid Mixture and Disperse Red 167 dyes. Final reduction of the dyes concentrations came to 32 and 99% for Acid Mixture and Disperse Red 167, correspondingly. The above was visualized through the employment of electrochemical (cyclic voltammetry and a.c. impedance spectroscopy techniques) and instrumental spectroscopy analyses.

Electrodegradation of Resorcinol on Pure and Catalyst-Modified Ni Foam Anodes, Studied under Alkaline and Neutral pH Conditions.

This work reports on the kinetics of electrochemical degradation of the resorcinol molecule, examined on nickel foam-based electrodes in contact with 0.1 M NaOH and 0.5 M Na2SO4 supporting electrolytes. The electrooxidation of resorcinol was examined on as-received, as well as on Pd-modified, nickel foam catalyst materials, produced via spontaneous deposition of trace amounts of palladium element. Electrochemical (cyclic voltammetry and a.c. impedance) experiments were carried out by means of a three-compartment, pyrex glass electrochemical cell, whereas continuous resorcinol electrooxidation tests were conducted galvanostatically (or potentistatically) with a laboratory-size, single-cell electrolyzer unit. In addition, quantitative determination of resorcinol and its possible electrodegradation products was performed by means of instrumental HPLC: High-Performance Liquid Chromatography/MS: Mass Spectrometry methodology. Also, SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray spectroscopy) techniques were employed for Ni foam (Pd-modified Ni foam) surface characterizations.

A novel automatic flow method with direct-injection photometric detector for determination of dissolved reactive phosphorus in wastewater and freshwater samples.

The novel automatic flow system, direct-injection detector (DID) integrated with multi-pumping flow system (MPFS), dedicated for the photometric determination of orthophosphates in wastewater and freshwater samples is for the first time described. All reagents and the sample were injected simultaneously, in counter-current into the reaction-detection chamber by the system of specially selected for this purpose solenoid micro-pumps. The micro-pumps provided good precision and accuracy of the injected volumes. For the determination of orthophosphates, the molybdenum blue method was employed. The developed method can be used to detect orthophosphate in the range 0.1-12 mg L-1, with the repeatability (RSD) about 2.2% at 4 mg L-1 and a very high injection throughput of 120 injections h-1. It was possible to achieve a very small consumption of reagents (10 µL of ammonium molybdate and 10 µL of ascorbic acid) and sample (20 µL). The volume of generated waste was only 440 µL per analysis. The method has been successfully applied, giving a good accuracy, to determination of orthophosphates in complex matrix samples: treated wastewater, lake water and reference sample of groundwater. The developed system is compact, small in both size and weight, requires 12 V in supply voltage, which are desirable for truly portable equipment used in routine analysis. The simplicity of the system should result in its greater long-time reliability comparing to other flow methods previously described.

Modelling the structure of sludge aggregates.

The structure of sludge is closely associated with the process of wastewater treatment. Synthetic dyestuff wastewater and sewage were coagulated using the PAX and PIX methods, and electro-coagulated on aluminium electrodes. The processes of wastewater treatment were supported with an organic polymer. The images of surface structures of the investigated sludge were obtained using scanning electron microscopy (SEM). The software image analysis permitted obtaining plots log A vs. log P, wherein A is the surface area and P is the perimeter of the object, for individual objects comprised in the structure of the sludge. The resulting database confirmed the 'self-similarity' of the structural objects in the studied groups of sludge, which enabled calculating their fractal dimension and proposing models for these objects. A quantitative description of the sludge aggregates permitted proposing a mechanism of the processes responsible for their formation. In the paper, also, the impact of the structure of the investigated sludge on the process of sedimentation, and dehydration of the thickened sludge after sedimentation, was discussed.

Electrocoagulation of synthetic dairy wastewater.

This study compares the effectiveness of pollutant removal from synthetic dairy wastewater electrocoagulated by means of aluminum and iron anodic dissolution. A method based on the cubic function (third degree polynomial) was proposed for electrocoagulant dosing. Mathematical methods for calculating the optimal electrocoagulant doses proved to be quite precise and useful for practical applications. The results of gravimetric measurements of electrocoagulant (electrode) consumption demonstrated that theoretical doses of Al determined based on Faraday's law were substantially lower than those produced by electrode weighing. The above phenomenon was also discussed in the light of the results of polarization resistance measurements for Al and Fe electrodes used in the study.