The effects of solid-liquid interfacial tension on the settlement of sediment flocs

In this paper, the effects of interfacial tension between the sediment solid particle and liquid on the settlement of sediment flocs are investigated. After a discussion of mechanical and physical chemistry, we give a settling velocity expression including such dynamical information of the floc growth as interfacial tension and primary particle size \textit{etc.}. The resulting expression indicates the average settling velocity of sediment flocs increases with increasing solid-liquid interfacial tension in a form of power law and deceases with the primary particle size. We report on a general method for analyzing settling behaviors of sediment flocs under different flocculation conditions and verify the rationality of the assumption of tension-induced flocculation by fitting typical experimental data to the electrolyte concentration-dependent sedimentation model which can follow from the relationship between interfacial tension and electrolyte concentration.