Electrochemical-assisted photocatalytic degradation of textile washwater

Photocatalytic methods with TiO2 catalyst were successfully applied to the decomposition of many organic contaminants. In this paper the performance of an electrochemical-assisted photocatalytic degradation of textile washwater containing procion blue dye was investigated. Several operational parameters to achieve optimum efficiency of this electrochemical-assisted photocatalytic degradation system have been done. The main objective was to determine the chemical oxygen demand (COD) and colour removal of the organic pollutant. The effects of pH, current density, supporting electrolyte, the irradiation time and photocatalyst on treatment efficiency were studied. The results showed that electrochemical-assisted photocatalytic process was used efficiently with 90% COD removal and complete colour removal after 7 h treatment

Ag–TiO2 doped photo catalytic degradation of Procion blue H-B dye in textile washwater

The photocatalytic degradation of Procion blue H-B dye in biodegraded textile washwater has been investigated for the complete removal of color and maximum reduction of chemical oxygen demand (COD). Pseudomonas putida was utilized for obtaining biodegraded textile washwater. In this process, silver-doped TiO2 photocatalyst was prepared and experiments were carried out to study the effects of UV and mercury lamp irradiations on COD reduction and removal of color. The thus prepared silver-doped TiO2 catalyst was characterized by thermogravimetric and differential thermal analysis, UV-visible spectrometer, X-ray diffraction, scanning electron microscope, energy dispersive X-ray microanalysis, and BET surface area techniques. Adsorption studies were also carried out to evaluate the fitness of isotherm models. The results show that the silver-doped TiO2 has enhanced the photodegradation of Procion blue H-B dye under UV and mercury lamp irradiations. The enhanced activity of silver-doped TiO2 is due to the enrichment of electron–hole separation by electron trapping of silver particles

Photocatalytic and electrochemical combined treatment of textile wash water

Various chemical and physical processes for treatment of textile effluent are not destructive but they only transfer the contaminants from one form to another. The presence of high concentration of organic dye and total dissolved solids (TDS) in the effluent that are not removed by biological treatment must be eliminated by an alternative method to the conventional ones is the advanced oxidation process (AOP). A procion blue dye effluent was treated by photo and electrochemical oxidation process as well as by combining photocatalytic degradation using TiO2 suspensions. Chemical oxygen demand (COD) and colour removal can be used to follow the degradation of the organic pollutant. The effects of pH, current density, flow rate of effluent that passes into the reactor and supporting electrolyte were studied. Comparative studies were carried out on photocatalytic and electrochemical process to degrade the procion blue. The maximum COD reduction and colour removal were 96 and 100%, respectively. Photodegradation efficiency of dye was high when photolysis was carried out in the presence of 40 mg/l of TiO2

The induced co-deposition of Ni–Mo–W ternary alloy; Coatings for hardness and corrosion resistance applications

Ni–Mo–W ternary alloy coatings were electrodeposited on mild steel substrate using citrate electrolyte for hardness and corrosion resistance applications. The influences electrolyte pH, electrolyte temperature and sodium molybdate concentrations on deposit qualities were studied. The sodium molybdate concentrations were varied from 0.025 to 0.1 M for obtaining alloy coatings with various molybdenum (Mo) compositions. The deposition condition such as electrolyte concentration, pH and temperature were optimized for obtaining good aesthetic (bright) appearance, surface stability and microhardness properties. The maximum Mo composition (47.71 wt %) in alloy deposit was achieved is 47.71 wt % using 0.1 M sodium molybdate concentration. The microhardness properties were increased from 850 HV to 946 HV by introducing molybdenum (47.71 wt %) as third alloying element in to Ni–W alloy matrix. The obtained mechanical and corrosion resistance properties of these ternary alloy coatings were compared with binary alloy and metallic coatings viz., Ni–W and Ni–Mo and metallic Ni coatings. The superior corrosion rate was observed for Ni–Mo–W alloy deposits (5.8 mpy) compared to Ni–W (9.04 mpy) and Ni–Mo (8.89 mpy) alloy