Water is an important basic material in the chemical industry and indispensable for human life. The world has witnessed a lot of progress in the research on the disinfection of water, which is closely related to the human life.
Generally, sterilizers used for water disinfection and wastewater treatment contain chlorine, hydrogen chloride, chlorine dioxide, ozone, hydrogen peroxide and ferrate. These sterilizers have been degraded due to the high cost and the release of substances harmful to the human body. In addition, their low disinfection effectiveness and short duration restrict their usage.
At present, there is a worldwide research to develop new chemical water treatment reagents with a strong disinfection effect and no harm to the human body, especially with a focus on potassium ferrate, one of the green multifunctional water treatment reagents.
Currently, commonly accepted methods for producing potassium ferrate include melting, electrolysis and wet methods. Among them, the wet methods are most widely used since the electrolytic and melting methods have some disadvantages such as high production cost, high power consumption and explosion risk.
One of the most important problems arising in the production of potassium ferrate is that it is stable in dry air but very unstable in aqueous or humid environments and it is easily decomposed. It is rapidly decomposed to release oxygen in acidic solutions and slowly decomposed in neutral or weak basic solutions. The rate of decomposition decreases as the salinity of the solution increases.
The main focus of the research on the production of potassium ferrate is to maximize its stability.
Ri Su Ryon, a researcher at the Faculty of Chemical Engineering, has examined the stability of the production of potassium ferrate widely used for water disinfection by using KI, K2SiO3 and K3PO4 as stabilizers. The experimental results show that the production of potassium ferrate is stabilized most when the amounts of KI, K2SiO3 and K3PO4 are 0.1%, 0.4%, and 0.4% of the total amount of reactants, respectively. She has also found that having dimethyl sulfoxide, methanol, diethyl ether as a detergent, it is effective to dehydrate first by using dimethyl sulfoxide and, subsequently remove the impurities such as KCl and KOH by using methanol before finally removing the remaining water and methanol by using diethyl ether. It has also been proved that when the washing temperature is lower than 20℃ and the number of washing is three, the potassium ferrate can be kept for a long time.
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