Purification of degummed crude sunflower oil with selected metal-organic frameworks as adsorbents

The aims of this study were to investigate the effectiveness of seven metal-organic frameworks (MOFs) as adsorbents for the purification of crude degummed sunflower oil, and to compare their effectiveness with three natural clays. The oil was treated with two different addition levels (0.05% and 0.3%, w/w), and two different treatment times (0.5 h and 3.0 h) under constant temperature (25 degrees C). The results indicated that all adsorbent treatments improved the oil's physico-chemical properties. Most importantly, the oil's free fatty acid, peroxide and p-anisidine values were significantly reduced by Ti-MOF and gamma-CD-MOF in comparison with the control sample. The oil showed no contamination by the metals during the MOF treatments. There were no significant changes in the fatty acid or sterol composition of the treated oil, while a-tocopherol contents decreased to some extent. This study proved the possibility of MOF as adsorbents for crude oil purification, and showed the great potential of Ti-MOF and gamma-CD-MOF as promising adsorbents.