Electrowashing of microalgae Arthrospira platensis filter cake

Abstract

Cake washing has been used to remove compounds trapped in the pores of a filter cake. These compounds could be desired products that should be recovered. Cake washing and electrowashing have been studied and found to present many benefits, but in some cases washing filter cakes can be a slow process. In this work, electrowashing (EW) and pressure electrowashing (PEW) were for the first time applied to enhance the liquid flowing in the the algal filter cake, which has a very high specific resistance and low washing velocity. The new EW and PEW processes were compared with conventional pressure washing (PW) of Arthrospira platensis microalgae. Washing was carried out to extract desired biocompounds (CPC, APC and proteins) from the filter cake. The study showed that the use of a constant direct current (60 A/m2) coupled with the effect of an applied hydraulic pressure was an effective way to increase the cake washing kinetics. It also demonstrated that it was possible to extract proteins and pigments by applying the washing by displacement technique.