Facile and green synthesis of Melamine-Formaldehyde@rGO foam with enhanced superhydrophobicity for oil removal application

Abstract

This research presented a more effective method to synthesize superhydrophobic melamine-formaldehyde (MF) foam coated with reduced graphene oxide (MF@rGO) by a conventional heating process. This is a facile and green method based on the use of graphene oxide, GO, as a precursor, and vitamin C as a reductant. The effect of recoating GO onto MF@rGO to form MF@rGO-recoat foam on superhydrophobicity was also investigated. Then, pristine GO, rGO, MF and as-synthesized MF@rGO foams were analyzed and their structures confirmed by several techniques including FTIR, Raman, SEM, TEM, and water contact angle (WCA). The results indicated that the WCA values of MF@rGO and MF@rGO-recoat foams were increased from 144.1° to 156.9°, respectively. Furthermore, the adsorption capacity (Qe), oil removal performance, and recyclability of MF@rGO-recoat foam were investigated. The adsorption capacity of MF@rGO-recoat foam was higher than 103.8 g.g-1 for all the oils tested (palm oil, gasoline, diesel and lubricant oil), and the highest value was 115.9 g.g-1 for lubricant oil. Besides, MF@rGO-recoat foam can be easily recycled up to 10 times for removal of all oils tested. Thus, this work provides a new alternative eco-friendly way to synthesize MF foam coated with rGO sheets and the synthesized MF@rGO foam can be applied and reused for the removal of oil spillages from water or wastewater.