Fabrication of modified electrode based on titanium with metal oxidecomposites for removal of reactive black dye and COD reduction

Water is the most important material in the world. In most industries, water is the base of theproduction process and can affect the quality and quantity of the production, directly orindirectly. For example, in the textile industry for washing, dying, bleaching and other processesthe water consumption is very high. According to annual reports, ۷ × ۱۰۸ kg of dyes are used fortextile consumption while the average amount of ۲.۸× ۱۰۸ kg enters to sewage. These pollutantscontain ۸۰۰۰ types of dyes and ۶۹۰۰ types of chemicals and salts, so these dyes, together with thetoxic substances, would also bring other serious threats to the environments and human health,Therefore, it is essential to treat the wastewater before discharging to environment and returningof it to the production cycle if possible [۱-۳].In this research, the titanium electrode surface which was modified with NiCl۲.۶H۲O, SbCl۳and SnCl۲ salts by the electrodeposition was used as a working electrode. The most importantvariables for electrode modification such as the ratio of salts and time of deposition were optimized.Then constant current electrolysis in a two-electrode system was used for degradation dye. Someparameters such as current density, initial concentration, and electrolysis time were optimized andfinally the kinetics of dye degradation was investigated. Absorption spectra before and after dyedegradation were investigated and dye removal percentages evaluated.The results showed that the modified electrode could degrade ۹۵% of black dye RB-۵ from initialconcentration of ۲۰۰ mg∙L-۱ in ۶۰ min under current density of ۲۰ mA∙cm-۲. COD removal wasalso measured as high as ۵۹ percent.