**Permeate retention and flow**

The performance of filtration is characterized by the observed retention and permeates flow. Retention is expressed as follows [40]:

$$Y(\text{@}) = \left(1 - \frac{C\_p}{C\_o}\right) . \mathbf{100} \tag{1}$$

Cp: Concentration in permeat and C0: Concentration in feed.

This parameter characterizes the effectiveness of the treatment. It quantifies the retention of a target compound.
