Eco-friendly foams of castor oil based-polyurethane with Artemisia residue fillers for discarded vegetable oil sorption

In this article, a new approach is applied to reuse Artemisia residue (AR) as filler in polyurethane (PU) foam for vegetable oil sorption for discarded cooking oil applications. The pristine PU and PU/X%AR foams (X stands for AR content of 5–20%wt/wt) were characterized by SEM, density, contact angle (CA), thermogravimetric analysis, and Fourier transform infrared spectroscopy. The influence of two experimental factors, such as contact time (30–180 s) and initial vegetable oil concentration (20–200 g/L), was investigated in vegetable oil and vegetable oil/mineral water systems. The AR loading of the foams increased the foams' density and influenced the morphological, physical, thermal, and sorption properties. The PU/20%AR sample presented the highest CA (122.5°) and the best sorption capacity and efficiency in both systems due to the small pores size and higher frequency of pores. Langmuir and Freundlich isotherm models well defined the sorption mechanisms. The Langmuir model represented the best fit of experimental data for PU/20%AR with a maximum adsorption capacity of 16.86 g/g. The PU/20%AR presented reusability of 7 cycles, conserving their hydrophobicity after the process. Therefore, AR is an innovative route as fillers in PU foams for discarded vegetable oil sorption, and the circular economy can benefit from the reuse of discarded vegetable cooking oil.