Sodium ferrate and its properties
Sodium ferrate is a compound of iron with a valence of +6.
The decomposition of ferrates occurs gradually: passing through the oxidation stages of Fe(V) and Fe(IV) to Fe(III), the ferrate systematically collects various radicals around itself. The forces of interatomic interaction are sufficient to organize complex compounds, making the ferrate ion simultaneously a coagulant, flocculant, and disinfectant
Traditional view of industrial water treatment. Chlorination
Today, the most common reagents for water purification are chlorine-containing substances.
Chlorine was first isolated by the Swedish chemist and pharmacist K. Scheele in 1774. Almost immediately, chlorine was recognized as an effective disinfecting agent.
Currently, for the purpose of water disinfection, reagents such as chlorine, chlorine dioxide, chloramine, chloride of lime, and sodium hypochlorite are used.
Despite the low cost and simplicity of water purification methods based on chlorination, they have serious disadvantages:
- formation of by-products (carcinogenic compounds),
- the danger of direct human contact with liquid and gaseous chlorine,
- the inadmissibility of chlorine in natural water bodies,
- the difficulty of storing chlorine in a liquid state
New approach - sodium ferrate
Alkali metal ferrates are the strongest oxidizers used in practice, and therefore, they can be used to oxidize organic compounds, their derivatives, and pollutants such as methyl tert-butyl ether and gasoline additives, purifying water.
After analyzing various methods of obtaining alkali metal ferrates, we determined that the most pragmatic approach is the electrochemical method, which is safe to implement, does not require high costs or high temperatures
What allowed a fresh look at the possibility of using sodium ferrates for water purification?
A solution of sodium ferrate is an environmentally friendly, safe, and effective method for purifying water from chemical and biological agents, including viruses. Due to their high oxidizing ability, ferrates quickly degrade during storage and transportation, meaning they must be produced at the point of use. The technology we have developed for producing sodium ferrate solution is aimed at application in water treatment plants without the need to restructure existing processes.
Biological methods of treating wastewater and other waters are economically efficient and environmentally acceptable for removing so-called macro-pollutants. However, they are less effective in removing hard-to-degrade chemical compounds and require further treatment to remove bacteriological contamination with strong oxidizers. Therefore, there is an urgent need to find inexpensive and environmentally friendly technologies for further treatment of effluents without chlorine-containing reagents, which are not inferior to the technologies using hypochlorite (chlorine) in terms of effectiveness and cost, and also solve the problem of meeting the purity requirements for effluents in the absence of chlorine
Our reagent, sodium ferrate, is the strongest known oxidizer, also possessing pronounced coagulant and flocculant properties. Ferrates (VI) are capable of decomposing many toxic chemical substances into low-toxicity products (oxidizing action) and causing the death of microorganisms (disinfecting action). During the purification process, the ferrates themselves convert into iron (III) hydroxide with high coagulating ability and further clean the water environment by combining dispersed particles (coagulating action). The technology for producing ferrates at the point of use is the most cost-effective compared to the production of hypochlorite, ultraviolet treatment, and ozonation, both in terms of capital expenditures and operating and maintenance costs per liter of reagent.