Thermally activated palygorskites as agents to clarify soybean oil

•Palygorskite was thermally activated.•The new material was used as clarifying agent to soybean oil.•The clay was thermally activated at different temperatures.•The sample activated above 700 °C potentiated the clarification of the soybean oil.•The clay was carotenoid dye removal and other pigments.

Palygorskite, a fibrous clay mineral, exhibits excellent adsorbent properties. This study was conducted to assess the potential activation of palygorskite and to obtain thermally activated samples to use as clarifying agents for soybean oil. Previously, the palygorskite samples were thermally activated at various temperatures in the range of 100–900 °C for 24 h. The natural and activated samples were characterized using the following techniques, XRD, XRF, FTIR, SEM, SSA, CEC and thermal analysis, to observe the structural and morphologic alterations after thermal treatment. These characterizations indicated that the primary changes to the palygorskite surface referred to losses of structural water: physically adsorbed, zeolitic and coordination water molecules. The sample was activated above 700 °C, which potentiated the clarification of the soybean oil by the removal of the carotenoid dye and other pigments, and exhibited higher performance compared with the natural palygorskite.

Graphical abstractAbsorbance visible spectra of (A) neutral soybean oil and soybean oil clarified with natural and thermally activated palygorskite (B): (a) Pal-Nat; (b) Pal-100; (c) Pal-300; (d) Pal-500; (e) Pal-700; (f) Pal-900.Figure optionsDownload full-size imageDownload as PowerPoint slide