Variation of Used Vegetable Oils’ Composition upon Treatment with Algerian Clays

The treatment of used vegetable oils (UVOs) with clays represents a pivotal step in their
industrial recycling process as well as one of the most challenging topics for researchers. In particular,
cheap, effective, and sustainable powders need to be explored in order to develop new processes
which produce beneficial results in relation to economic and environmental aspects. In this
context, five samples within commercial and waste vegetable oils were treated with two sodiumand
calcium-based bentonites employing a low oil/bentonite ratio (0.15 wt%). The outcomes of the
processes were monitored by FT-IR spectroscopy and compared with the data relative to the parent
commercial edible oil. In particular, treatment of FT-IR data by multivariate statistical analysis allowed
us to determine a chemical fingerprint characteristic of each sample. Important relationships
between the overall chemical composition and the specific clay employed and the treatment time (2
or 4 h) were highlighted. Finally, N2 physisorption, TEM microscopy, and FT-IR analyses of the
more efficient Na bentonite allowed us to characterize the material and thus to furnish all the information
needed to set-up a general protocol for the partial regeneration of waste vegetable oil destined
for further processing.