3
METHODOLOGY
The study assessed the foaming characteristics, microflo-
tation, and performance in the Dever lab cell of various
biosurfactants at different dosages and pH levels. These
biosurfactants were compared with traditional industry
reagents such as Amine, MIBC, and pine oil, either in
combination with them or as replacements. Detailed infor-
mation regarding the experimental setup and analytical
procedures is provided in the following sections.
Foam Analyzer
Foaming experiments were performed using the Kruss
Dynamic Foam Analyzer (DFA100) shown in Figure 2.
The apparatus measures the foamability of liquids and
quantifies foam stability based on precise measurements of
the foam height. Optional modules determine the liquid
content within the foam and analyze its structure concern-
ing bubble size and distribution. The comprehensive list of
measured variables is described in Table 3.
Figure 1. Examples of glycolipid biosurfactants demonstrating the structural diversity of naturally produced molecules: (a) a
rhamnolipid, (b) a mannosylerythritol lipid and (c) a sophorolipid
Figure 2. Kruss Dynamic Foam Analyzer DFA100 (Source:
Kruss-scientific.com)
Table 3. Dynamic Foam Analyzer Measurements
Measurement Description
R32 Sauter mean radius [µm]
(bubble size characteristics) R32 R
R
i i
i i
1
3
1
2 =
=
=/n
/n
FVS Foam volume stability [%]Foam volume remaining with respect to the maximum foam volume after
foaming has stopped
FLS Foam liquid stability [%]Liquid volume remaining in foam with respect to maximum liquid volume
after foaming has stopped
Time Time elapsed after measurement
start [s]
Coincides with the start of foaming
LC Liquid content of [%]Measured at the seven sensors (S1 to S7) of the
conductivity electrode from the bottom to the top
Vfoam Volume of the foam
column [mL]
Calculated from the measured foam height and the measuring column’s inner
diameter
METHODOLOGY
The study assessed the foaming characteristics, microflo-
tation, and performance in the Dever lab cell of various
biosurfactants at different dosages and pH levels. These
biosurfactants were compared with traditional industry
reagents such as Amine, MIBC, and pine oil, either in
combination with them or as replacements. Detailed infor-
mation regarding the experimental setup and analytical
procedures is provided in the following sections.
Foam Analyzer
Foaming experiments were performed using the Kruss
Dynamic Foam Analyzer (DFA100) shown in Figure 2.
The apparatus measures the foamability of liquids and
quantifies foam stability based on precise measurements of
the foam height. Optional modules determine the liquid
content within the foam and analyze its structure concern-
ing bubble size and distribution. The comprehensive list of
measured variables is described in Table 3.
Figure 1. Examples of glycolipid biosurfactants demonstrating the structural diversity of naturally produced molecules: (a) a
rhamnolipid, (b) a mannosylerythritol lipid and (c) a sophorolipid
Figure 2. Kruss Dynamic Foam Analyzer DFA100 (Source:
Kruss-scientific.com)
Table 3. Dynamic Foam Analyzer Measurements
Measurement Description
R32 Sauter mean radius [µm]
(bubble size characteristics) R32 R
R
i i
i i
1
3
1
2 =
=
=/n
/n
FVS Foam volume stability [%]Foam volume remaining with respect to the maximum foam volume after
foaming has stopped
FLS Foam liquid stability [%]Liquid volume remaining in foam with respect to maximum liquid volume
after foaming has stopped
Time Time elapsed after measurement
start [s]
Coincides with the start of foaming
LC Liquid content of [%]Measured at the seven sensors (S1 to S7) of the
conductivity electrode from the bottom to the top
Vfoam Volume of the foam
column [mL]
Calculated from the measured foam height and the measuring column’s inner
diameter