Why Platinized Ti Electrodes are Used for Cyanide Containing Wastewater Treatment?

Jun 18, 2021

Why Platinized Ti Electrodes are Used for Cyanide Containing Wastewater Treatment?

Cyanide containing wastewater may not be disposed to the environment due to its high toxicity to people and wildlife. Electrochemical oxidation is an efficient method for cyanide containing wastewater treatment since it is a cost-effective and environmentally friendly way to utilize cyanide solutions producing no toxic side products. It is important to note that electrochemical oxidation can be used to destroy high concentration cyanide wastes at the anode and to recover dissolved metals at the cathode simultaneously.

However, it is pointed out that the direct oxidation of cyanide is a fairly slow reaction. For this reason, people try to develop a working electrode that must be the most efficient and as resistant as possible to a strong oxidizing agent such as oxygen, because the intensive discharge of water proceeds near the anode during the process of electrochemical oxidation of cyanide. Platinum, steel, lead, and nickel anodes have been used in many experiments for cyanide oxidation.

Unfortunately, these electrodes exhibit poor current efficiency or show poor resistance to corrosion or both. Better results were obtained by using graphite, but these anodes become slowly degraded during electrolysis. Recently, the effective destruction of cyanide was demonstrated by using an electrochemical reactor equipped with Ti/SnO2-Sb-Ce anodes. However, many of the proposed electrodes are too expensive or complicated in preparation.

It is likely that platinized Ti electrodes are appropriate as they have been developed for various applications. It was observed that a Ti/Pt electrode itself has higher electroactivity to the reduction of nitrate. The active surface area of the Ti/Pt electrode is 125 times larger than that of a polycrystalline Pt electrode of the same geometric area. Due to their electrocatalytic properties, Ti/Pt anodes are suitable for treating wastewaters containing dyes (methylene blue). Platinized Ti electrodes were evaluated for urea oxidation activity, and it was found that Ti/Pt surfaces are 1 900 times more active for urea oxidation than smooth Pt surfaces. It was demonstrated that platinized Ti electrodes may serve as anodes for effective electrochemical oxidation of high concentrated cyanide solutions reaching current efficiencies comparable to those obtained using pure Pt anodes. However, the lifetime of platinized Ti electrodes in cyanide destruction was not investigated elsewhere.