Table 2.

Effect of calcination time on biodiesel yield with methanol: oil of 6:1, reaction time of 3 h, catalyst load (3%wt.), and temperature at 65 °C.

Calcination time(h)	Biodiesel yield (%)
	SS-CaO (900 °C)	CaO/ZnO (500 °C)	CaO/TiO2 (500 °C)
1	40	60	80
2	40	70	80
3	80	90	95
4	80	90	95
5	80	70	80
6	50	60	60

Key: SS: snail shell.