Polydopamine-clay functionalized Calotropis gigantea fiber: A recyclable oil-absorbing material with large lumens

A facile route was used for improving the oil-absorbing performance of Calotropis gigantea fiber (CGF) via a convenient oxidative polymerization of dopamine in the presence of attapulgite (APT) and subsequent instant immersion in an ethanolic solution of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFS). The scanning electron microscope (SEM) coupled with element mapping indicated that the CGF had been successfully modified by polydopamine?APT?PFS, by which a roughened surface with higher contact angle against water can be formed. Consequently, the resulting fiber showed a significant enhancement in the oil-absorbing capacity, with 99.2?g/g for blend oil, 97.7?g/g for soybean oil, and 88.4?g/g for kerosene, respectively. Compared with previous methods, this approach is convenient for the construction of a novel material with tailored morphology and functionality, and the resulting fiber shows its promising application as a highly efficient and recyclable oil-absorbing material for oily wastewater treatment.