At night, surfactant has obvious effect on increasing dissolved oxygen in water

2021-05-19 16:07:25

The solubilization of surfactant makes oxygen molecules supersaturated in water solution, which is equivalent to increasing the saturation solubility of oxygen in water. The saturated solubility of oxygen in aquaculture water is not more than 9mg / L. when surfactant is added to the aquaculture water, the saturation solubility of oxygen in the aquaculture water can be increased. According to hydrate formation theory and double membrane theory, because oxygen solubility in water is very small, water oxygen complex in water generally forms at gas-liquid interface first, then slowly spreads from gas phase to liquid phase. In water containing surfactants, due to the solubilization of surfactants, a large amount of oxygen is dissolved in the micelles of surfactants formed in the aqueous solution. Thus, the formation of water oxygen complex in surfactant aqueous solution can occur not only at the gas-liquid interface, but also in the water body, which reduces the formation time of water oxygen complex, The solubility of oxygen in water was improved.  

At present, surfactants can be used as fungicides and disinfectants in aquatic industry, and some surfactants are used in the improvement of the bottom, but few reports on the effect of surfactants on dissolved oxygen in water are reported.     

There are many kinds of surfactants, with more than 20000 trade names and an output of 12 million tons. It is widely used, involving various fields of industry and agriculture and people's life, and has the reputation of "industrial MSG". But there are few of them applied in aquaculture, and there are less papers about surfactant application in aquaculture.      

Surfactant has a good foaming effect in water. Because the foam is dispersed in the gas and dispersed in the liquid, the gas is a dispersed phase and the liquid is a dispersed meson. Many bubbles will be produced in water body with surfactant under the action of wind, water flow and aquatic animal swimming. Because surfactant molecules can be adsorbed on the gas-liquid interface, a solid film is formed in directional arrangement to keep the bubbles stable, and the dispersibility of surfactant can make bubbles evenly dispersed in the liquid. During the process of foam disturbance, a large number of air bubbles with abundant oxygen are added into the water body to accelerate the dissolution of oxygen in the water body, resulting in a higher level of dissolved oxygen in the water body.

Especially in the night without light, surfactant has obvious effect on the improvement of dissolved oxygen in water. If there is stirring by oxygen aerator and convection of upper and lower water layers, the water body will not consume oxygen at the bottom and biology and suffer from acute hypoxia, so as to prevent the pond of breeding opposite.