Table 9 Investigation of different catalysts in producing Methyl ester from WCO.

Copper/Zinc oxide

Magnetic stirrer

CD = 12 wt%, T = 55 °C, MWMR = 8:1, t = 50 min

97.71

³⁴

Nano CuFe₂O₄

Magnetic stirrer

CD = 3 wt%, T = 60 °C, MWMR = 18:1, t = 30 min

90.24

⁶³

SO₄/Mg-Al-Fe₃O₄

Magnetic stirrer

CD = 4 wt%, MWMR = 9:1, t = 300 min

98.5

⁶⁴

K₂O/BaFe₂O₄

Magnetic stirrer

CD = 4 wt%, T = 65 °C, MWMR = 12:1, t = 180 min

97.63

⁶⁵

CaO

Ultrasonic reactor

CD = 1 wt%, T = 60 °C, MWMR = 9:1, t = 30 min

93.5

⁶⁸

CaO

Magnetic stirrer

CD = 1.5 wt%, T = 75 °C, MWMR = 7:1, t = 360 min

94.37

⁶⁹

CaO–ZrO₂

Magnetic stirrer

CD = 10 wt%, T = 65 °C, MWMR = 30:1, t = 120 min

92.1

⁷⁰

MgO

Magnetic stirrer

CD = 2 wt%, T = 65 °C, MWMR = 24:1, t = 60 min

93.3

⁷¹

SO₄/Fe-Al-TiO₂

Magnetic stirrer

CD = 3 wt%, T = 90 °C, MWMR = 10:1, t = 150 min

96

⁷²

FeCl₃-modified resin

Magnetic stirrer

CD = 8 wt%, T = 90 °C, MWMR = 10:1, t = 120 min

92

⁷³

TiO₂/PrSO₃H

Magnetic stirrer

CD = 4.5 wt%, T = 60 °C, MWMR = 15:1, t = 540 min

98.3

⁷⁴

Walnut shell/sawdust

Ultrasonic reactor

CD = 9.76 wt%, T = 56.58 °C, MWMR = 10.31:1, t = 30.14 min

92.25

⁷⁵

KOH

Ultrasonic reactor

CD = 0.46 wt%, T = 53.2 °C, MWMR = 6.1:1, t = 10 min

97.8

⁷⁶

CaO

Ultrasonic reactor

CD = 0.96 wt%, T = 48.3 °C, MWMR = 10.9:1, t = 10 min

96.2

⁷⁶

CaO

Magnetic stirrer

CD = 1 wt%, T = 50 °C, MWMR = 8:1, t = 90 min

96

⁷⁷

NiFe₂O₄@g-C₃N₄

Ultrasonic

reactor

CD = 2.85 wt%, T = 61.17 °C, MWMR = 11.72:1, t = 31.02 min

98.83

This study