Fig. 9
From: Valorization of marble sludge waste in biodiesel production using a central composite design
Response surface plots of the interactive parameters: a–c effect of reaction time and temperature: d–f effect of reaction time and (M/O) molar ratio: g–i effect of reaction time and catalyst concentration: j–l effect of reaction temperature and (M/O) molar ratio: m–o effect of catalyst concentration and reaction temperature: p–r effect of catalyst concentration and (M/O) molar ratio.
