Developments on Solid-Liquid Separation of Colloids

Abstract

Solid-liquid separation includes a variety of operations such as filtration, expression, centrifugation, etc., and it plays an increasingly important role in widely diversified fields ranging from industry to environmental protection. In recent years, membranes have been successfully applied also to solid-liquid separation to attain a higher level of separation. This paper describes several new topics on the developments of solid-liquid separation technologies. A method was introduced for obtaining the pressure dependences of properties of filter cake of nanocolloids from a single dead-end filtration experiment. Filtration behaviors were evaluated based on the compression-permeability data obtained from analytical centrifugation. Parallel and series resistance models were proposed for describing the membrane fouling occurring for membranes with different structures. A method has been developed for individually evaluating the mechanism and degree of membrane fouling based on a limited amount of filtration data. It was shown that ultrahigh-pressure expression combined with reversible flocculation achieved the high rate and high-degree deliquoring of excess activated sludge. Moreover, it was found that the excess activated sludge treated by ultrasonication exhibited a significantly high settling rate with the aid of inorganic salts. I believe that these results provide new insight into the developments of solid-liquid separation technologies.

Graphical Abstract