Degradation of Acid Blue 40 dye solution and dye house wastewater from textile industry by photo-assisted electrochemical process

In this paper, electrochemical and photo-assisted electrochemical processes are used for color, total organic carbon (TOC) and chemical oxygen demand (COD) degradation of one of the most abundant and strongly colored industrial wastewaters, which results from the dyeing of fibers and fabrics in the textile industry. The experiments were carried out in an 18L pilot-scale tubular low reactor with 70% TiO2/30% RuO2 DSA. A synthetic acid blue 40 solution and real dye house wastewater, containing the same dye, were used for the experiments. By using current density of 80 mA cm(-2) electrochemical process has the capability to remove 80% of color, 46% of TOC and 69% of COD. When used the photochemical process with 4.6 mW cm(-2) of 254nm UV-C radiation to assist the electrolysis, has been obtained 90% of color, 64% of TOC and 60% of COD removal in 90 minutes of processing; furthermore, 70% of initial color was degraded within the first 15 minutes. Experimental runs using dye house wastewater resulted in 78% of color, 26% of TOC and 49% of COD in electrolysis at 80 mA cm(-2) and 90 min; additionally, when photo-assisted, electrolysis resulted in removals of 85% of color, 42% of TOC and 58% of COD. For the operational conditions used in this study, color, TOC and COD showed pseudo-first-order decaying profiles. Apparent rate constants for degradation of TOC and COD were improved by one order of magnitude when the photo-electrochemical process was used.42142131213

Thirty minutes laser calcination method for the preparation of DSA (R) type oxide electrodes

In this paper, a new approach for the preparation of dimensionally stable anodes DSA(R) type oxide electrodes, using a CO2 laser as a heat source, is proposed. Commercial composition of (TiO2)(0.7)(RuO2)(0.3) was used for this feasibility study in which thermal decomposition of precursor chlorides, for the growth of a coating 2-3 mum thick, is carried out in 30 min. The resulting oxide layer presented the usual cracked-mud morphology that lasted 8 h in an accelerated service life test at 400 mA cm(-2), in a H2SO4 1 M solution. The results involving the effects of laser beam power and scan rate are examined. Voltammetric anodic charge was maximized by the combination of 15 W beampower, focal distance of 210 mm and beam scan rate of 35 mm s(-1). By cycling potential between 0.2 and 1.1 V vs SCE the oxide coating behaved as a capacitor capable of being charged and discharged reversibly and the cathodic/anodic charge ratio remained close to one. Currents related to oxygen evolution reaction were observed after 1.37 V vs SCE. (C) 2002 Elsevier Science B.V. All rights reserved.4213914

Titanium coated with high-performance nanocrystalline ruthenium oxide synthesized by the microwave-assisted sol-gel procedure

Ruthenium oxide coating on titanium was prepared by the sol-gel procedure from well-defined colloidal oxide dispersions synthesized by the microwave (MW)-assisted hydrothermal route under defined temperature and pressure heating conditions. The dispersions were characterized by dynamic light scattering (DLS) measurements and scanning electron microscopy (SEM). The electrochemical properties were analyzed as capacitive performances gained by cyclic voltammetry and electrochemical impedance spectroscopy and as the electrocatalytic activity for oxygen evolution from acid solution. The obtained dispersions were polydisperse and contained regular particles and agglomerates of increasing surface energy and decreasing particle size as the MW-assisted heating conditions were intensified. Owing to these features of the precursor dispersions, the obtained coatings had considerably improved capacitive performances and good electrocatalytic activity for oxygen evolution at high overpotentials