Principle of adding surfactant into aquaculture water

2020-11-30 16:24:41

The principle of surfactant oxygenation: adding surfactant to aquaculture water can increase the saturation solubility of oxygen in aquaculture water. According to hydrate formation theory and double membrane theory, because the solubility of oxygen in water is very small, water oxygenate usually forms at the gas-liquid interface, and then slowly diffuses from the gas phase to the liquid phase. In the water containing surfactant, due to the solubilization of surfactant, a large amount of oxygen is dissolved in the surfactant micelles formed in the aqueous solution. Thus, the formation of water oxygenates in the surfactant aqueous solution can occur not only at the gas-liquid interface, but also within the water body, which reduces the formation time of water oxygenates and improves the oxygen content in water Solubility in.   

In the conventional water quality improvers, we often use a lot of flocculants, such as aluminum potassium sulfate, aluminum sulfate, polyaluminum chloride (PAC) and polymerized ferric sulfate (PFS), which have disadvantages of large dosage, unstable effect and secondary pollution. At present, polyethylenedimethylammonium chloride, polyammonium, sodium polyacrylate and acrylamide have gradually replaced the traditional water purification agent.

Polyacrylamide is a kind of linear water-soluble copolymer. The cationic polyacrylamide is a kind of solid powder, which is easy to dissolve in water. It has strong hygroscopic and flocculating effects. It is a linear polymer surfactant with positive charge, which can make the suspended organic colloid and organic compounds have the following characteristics: 1 Effective flocculation.

The flocculation mechanism is as follows: the long-chain polymer and the solid particle surface in sewage (generally negative electricity, such as clay) have multi-point adsorption; the polymer chain is very long, which can be adsorbed on several solid particles at the same time to make them bridge together; the long-chain molecules adsorbing several solid particles can also be bridged together by common adsorption of solid particles or mutual winding to form floc Agglomerate (or agglomerate).   

Traditional oxygen enhancers are often peroxides such as sodium percarbonate, calcium peroxide and Percarbamide, which have the disadvantages of low oxygen release and short action time. The research of aquatic drug developers shows that some surfactants have good properties For example, Gemini coconut oil betaine can inhibit the excessive reproduction of anaerobic microorganisms in water, and rapidly reduce the interfacial tension between water and air, so that a large amount of oxygen in the air can be introduced into the water body, and the dissolved oxygen level can reach a high level of 4-5.5 mg / L from the low dissolved oxygen level of 1 mg / L.