Adsorption of thallium cations on RuO2–TiO2 electrodes

Recent Advances in Thallium Removal from Water Environment by Metal Oxide Material

Thallium is widely used in industrial and agricultural development. However, there is still a lack of systematic understanding of its environmental hazards and related treatment methods or technologies. Here, we critically assess the environmental behavior of thallium in aqueous systems. In addition, we first discuss the benefits and limitations of the synthetic methods of metal oxide materials that may affect the practicality and scalability of TI removal from water. We then assess the feasibility of different metal oxide materials for TI removal from water by estimating the material properties and contaminant removal mechanisms of four metal oxides (Mn, Fe, Al, and Ti). Next, we discuss the environmental factors that may inhibit the practicality and scalability of Tl removal from water. We conclude by highlighting the materials and processes that could serve as more sustainable alternatives to TI removal with further research and development.

A low-voltage pulse electrolysis method for the degradation of anthraquinone and azo dyes in chloride medium by anodic oxidation on Ti/IrO2 -RuO2 -SnO2 electrodes

Wastewater produced by the textile industry containing azo dyes and anthraquinone dyes is significant source of pollution to the environment and is toxic for aquatic life. To overcome the high-energy cost of traditional electrochemical oxidation, a custom-built power supply device for the degradation of anthraquinone and azo dyes by low voltage of 15.0-20.0 V pulsed discharge was investigated. Titanium coated with mixed oxide (Ti/IrO₂ -RuO₂ -SnO₂ ) plates and pure titanium plates were used as the anode and cathode, respectively, for the generation of chlorine in the dye solution. For the anthraquinone dye Reactive Blue 19, 60.0% of the chemical oxygen demand (COD) and 22.0% of the total organic carbon (TOC) were removed using this system. A comparison of the direct current electrolysis and pulsed discharge revealed that using the pulsed discharge method reduced the energy cost by 68.6%. UV-visible, LC-MS, and GC-MS were used to identify the intermediate compounds formed during the degradation of Reactive Blue 19. The results indicate that in the process of oxidation by chlorine/hypochlorite, the chromophore group was first oxidized to -NH₂ , followed by decolorization via chlorination of the aromatic rings. The results confirm that low-voltage pulse electrolysis can be used for the degradation of industrial dyes in waste effluents. PRACTITIONER POINTS: Low-voltage pulse electrolysis can be used for the degradation of industrial dyes and/or dyes in waste effluents. For anionic dye Reactive Blue 19, 60.0% of COD and 22.0% of TOC were removed using low-voltage (20.0 V) pulse electrolysis. The pulsed discharge method reduced the energy cost of this degradation process by 68.6% compared with direct current electrolysis. The intermediate compounds formed during the degradation of Reactive Blue 19 were confirmed by UV-visible spectroscopy, LC-MS, and GC-MS.

Electrodeposition of TiO2-RuO2-IrO2 coating on titanium substrate

TiO₂, RuO₂, and IrO₂ transition metal oxides have many applications in the field of applied electrochemistry. In this work, the mixed solid solutions of TiO₂-RuO₂-IrO₂ coatings have been electrodeposited from aqueous-unaqueous baths. Moreover, the obtained coatings have been heated in the electric furnace at 450 °C. The microstructure of coating was characterized using scanning electron microscopy (SEM) and Atomic force microscopy (AFM). In order to investigate, the chemical composition and crystalline phases of coating, X-ray analysis, energy dispersive spectroscopy (EDS) were carried out. Furthermore, anodic polarization behavior of coating was investigated. Results show that heat treated coating at 450 °C with the chemical composition of TiO₂/RuO₂/IrO₂ with molar ratio of 70/5/25 with six layer on substrate has the highest quality, stability, adhesion strength and minimum chlorine overvoltage. However, increasing the iridium content in electrolyte enhances the coating thickness and the quality of morphology.