Catalyst

Regeneration process (washing with solvent, calcination temperature)

FAME yield [%]

Ref.

CaO from mud clam shells

n-hexane, 900˚C

96.7 to 74.5

[28]

CaZnO

n-hexane, MeOH, 800˚C (3 h)

80 to <80

[29]

CaO from biomass

Acetone, EtOH, 600˚C - 800˚C (4 h)

75 to 50

[30]

CaO from waste cockle shells

MeOH, n-hexane, 900˚C (2 h)

>97

[31]

Modified red mud

n-hexane, 700˚C (2 h)

99.6 to 96.8

This study