Abstract
The global challenge of oil pollution calls for the efficient selective recovery of oil or organics from oil-water mixtures. A pH-responsive carbon foam (CF) made from liquefied larch sawdust (LLS) with switchable wettability was fabricated in this work. After grafted with poly 4-vinyl pyridine (P4vp), the CF obtained a switchable wettability surface, which allowed the CF to exhibit superhydrophilicity and superhydrophobicity at different pH levels, respectively. The results revealed that the pH-responsive CF possessed a three-dimensional (3D) spongy-like skeleton and porous structure with a diameter between 50 and 200 µm. Thus, the pH-responsive CF could absorb 15-35 g/g of oil/organics in a neutral aqueous solution at pH = 7 and desorb all the absorbate within 40 s after immersion in an aqueous solution at pH = 1. Moreover, only about 2.8% loss was observed for organic (chloroform) absorption and recovery after reusing up to 15 cycles, which indicated promising prospects in oil and organic recovery.