Dosage-effectiveness of modified clay flocculating red tide organisms: Mechanical mechanism and mathematical model

Abstract

Modified clay (MC) technology is the most widely used method to remove red tide organisms from seawater on a large scale. In recent years, frequent outbreaks of red tides worldwide have led to a sharp increase in MC consumption. However, the efficient application of MC for red tides control lacks theoretical basis. The study explored dosage-effectiveness of MC for microalgae (red tide organism) removal. The results showed that the effectiveness of MC for microalgae removal increased first and then decreased with the increase of MC dosage due to the self-flocculation of MC. The self-flocculation of MC was caused by the strong attractive total interaction energy between MCs at close range in seawater. A mathematical model established based on the extended Langmuir model can simulate dosage-effectiveness of MC well, and the quantitative relationship between the dosage of MC and its degree of self-flocculation was deduced based the mathematical model. These studies will help to enrich the flocculation theory of MC application, and provide significant guidance for the efficient application of MC for red tides control.