Facile fabrication of carbon/attapulgite composite for bleaching of palm oil

• The chitosan/attapulgite composites were calcined for the bleaching of palm oil.
• Carbon species/attapulgite composites were formed after being calcined.
• Effect of calcination on structure and decoloration efficiency was studied.
• A feasible approach to improve the decoloring efficiency of palm oil was found.

A series of carbon/attapulgite (C/APT) composites were fabricated by calcining chitosan/attapulgite (CTS/APT) composite and used as adsorbents for the efficient bleaching of palm oil. The effects of the dosage of CTS and calcination temperature on the structure characteristics of C/APT composites were investigated by FTIR, XRD, TGA, TEM and N2 adsorption–desorption isotherm techniques. It was found that the specific surface area, pore size distribution, and surface morphology of C/APT composites were affected by the calcination process. The CTS macromolecular chains attached on the surface of APT were transformed into carbon after being calcined at above 280 °C, which facilitate to enlarge the pore size of the composite and create the new active adsorption sites. The bleaching efficiency of the composite for palm oil was greatly improved after in situ introducing carbon on APT. After decolored by the as-prepared composites, the Red value and the content of peroxide and phospholipid decreased by 57.36%, 76.34% and 43.11%, respectively; but the commercial bleaching earth can only decrease these values by 38.76%, 71.59% and 10.15%, respectively. The composite adsorbents derived from low cost and eco-friendly raw materials show excellent bleaching efficiency, and can be used as promising eco-friendly decolorizer for refining of edible oils.