How to comment on the physical and chemical functions of industrial sterilants?
1. Broad spectrum
When evaluating the function of a fungicide, it depends on its killing status of various microorganisms (including bacteria, fungi and algae mainly), that is, to check its broad spectrum. Because many growth and reproduction of bacteria will increase the corrosion of equipment and pipelines, it is prominently manifested as pitting corrosion and stress surface corrosion. The fungi and algae often form a lot of slime and cover the surface of the metal wall, and then increase the mass and heat transfer resistance.
2. Habitual pH planning
The function of bactericide will be affected by the change of pH value. The change of pH value will lead to changes in the structure, condition and nature of the agent, and affect its application planning. The pH value of industrial circulating water is generally 5.5~9.5. Select several levels in this pH domain, conduct sterilization rate tests on the sterilant at different concentration levels, make a pH-sterilization rate connection curve, and find the optimal pH value plan. In practice, choosing a suitable water quality system with the best pH plan will not only increase the effect but also reduce the cost.
3. Corrosive to metals
When the bactericide is added to the industrial circulating water, its aqueous solution molecules directly contact the metal surface, which will more or less cause corrosion. Therefore, the corrosion function of the sterilant will be directly linked to the service life of the equipment. During the test, the corrosion rate of the sterilant to different materials can be measured by the coupon weight loss method, and the corrosion level can be judged.
4. Biodegradability
After the fungicide is used, its biological or natural degradability is the basic condition for its use, which is of great significance to environmental protection and human health. At present, there are many test methods to determine the degradability of sterilants, mainly including ATP method, closed container test method (CBT method), modified CBT method, OECD method and CUT method.
5. Compatibility with other water treatment agents
As a kind of water treatment agent, fungicides are generally used together with water quality stabilizers such as corrosion inhibitors and scale inhibitors. Therefore, the degree of their mutual influence (ie compatibility) is directly related to the generalized application effect. In practice, a comparison test with the blank is conducted to check the compatibility of the product. If the sterilization rate of the sample is lower than that of the blank, it will have a certain effect; otherwise, it will be considered as no effect and the compatibility is better. In addition, the water solubility and slackness of the sterilant are better, so that the operation is simple, no more feeding is required, and it is generally required to not foam. For the disinfectant with external activity, it is recommended to properly participate in the defoamer when using it.
6. Economy
The price of the fungicide includes the cost of the fungicide and the transportation cost. Its review guidelines are generally determined by the price. The lower the price of the fungicide, the more competitive it is in the market.
