Type of oxide

Regeneration process after filtration

Solvent (number of washing),

Temperature of drying (duration)

FAME or FAEE yield

% (1^st run to last run)

Runs number

Reference

CaO

CaO

Hexane, MeOH

>85 to 50

6

[11]

CaO

MeOH, 80˚C

83 to 65

3

[47]

CaO

Unwashed

MeOH (3)

84.5 to 68.7

82.7 to 76.7

3

[63]

CaO derivated egg shell

MeOH, tetrahydrofuran, 50˚C (overnight)

>80

8

[86]

Mixed or supported oxides

Nano Ca-Mg-Al oxide

High-speed Centrifugation, washing to 4^th reuse, EtOH

95 - 90.4 - 89.1 - 80.7 - 43.7

1-2-3-8-9

[22]

CaO/MgFe₂O₄

External magnetic stirring, MeOH, 60˚C under vacuum (10 h)

>89

3

[24]

KF/CaO-Fe₃O₄

Anhydrous MeOH, 105˚C

>90, reduced about 10 wt%

14

[26]

KF/CaO-MgO

Centrifugation, EtOH, dried

97.9 to 86.7

4

[28]

KF/Ca-Al hydrotalcite

Cyclohexane

95

2

[29]

MgO TiO₂

Centrifugation, MeOH, 120˚C

92.3 - 81.2

4

[31]

CaO + Fe₂(SO₄)₃,

Li-CaO + Fe₂(SO₄)₃

Covered with glycerol

100 to 80

3

[51]

CaO Al composite

MeOH, dried

87

7

[54]

CaO from carbide slag SiO₂, Al₂O₃

Hexane, MeOH, 100˚C (overnight)

>80

3

[56]

Li/CaO

Hexane, dried, 120˚C

98 to 84

4

[57]

CaO-La₂O₃

MeOH, calcination or mixture MeOH + NH₃ and dried (overnight)

82 with no change

2

[60]

Dolomite

Filtration under vacuum, MeOH (2), 100˚C (1 h)

98.8 to 80.97 for canola oil

96. to 84.5 for sunflower

3

[68]

Dolomite

Mixed with methanol in a reactor, ultrasonically irradiated (15 min)

96.5 to 89.5

97.1 to 88.7 (for CaO)

4

[69]

Mg₂CoAl

110˚C (overnight)

>90

7

[72]

Ca-doped Ce oxide

n-Hexane, 120˚C

85

15

[74]

CaO-MgO (8:2)/Al₂O₃

Filtration, EtOH, dried

90 with slight decrease

4

[76]

Mg-Al mixed oxides

MeOH

>91

5

[77]

LiNO₃/MgO, LiNO₃/CaO

NaNO₃ CaO, KNO₃/CaO

MeOH, 60˚C (3 h)

>90 stable

[87]

Zn/MgO

n-hexane, MeOH, 110˚C

>84%

5

[89]

MgZnAl oxides (Al₂O₃/MgZnO)

Hexane, dried (12 h)

Drop of 5%

5

[90]

MgSil-org, 3MgO・4SiO₂・2H₂O

Centrifugation, MeOH

93 - 92

5

[92]