Enhanced surface properties, hydrophobicity, and sorption behavior of ZnO nanoparticle-impregnated biomass support for oil spill treatment

Metallic nanoparticles (NPs) have gained significant attention in recent years due to their efficiency in the adsorption of water pollutants. Except for magnetic NPs, metallic NPs are rarely used in oil sorption studies, due to the difficulty in recovering the NPs from the treated water. This study reports for the first time the application of ZnONPs for oil spill treatment. The ZnONPs were impregnated onto Musa acuminata peel (MP) support to form a novel material (ZnOMP), which was utilized for the sorption of oil from synthetic oil spills. The as-prepared sorbents were characterized by the SEM, EDS, BET, FTIR, FE-SEM, TGA, and XRD techniques. The presence of 31.32-nm average-sized ZnONPs enhanced the oil uptake characteristics, with clear affinity for the oil phase in comparison to the pristine MP. A maximum sorption capacity of 4.146 g/g and 5.236 g/g was obtained for biosorbents MP and ZnOMP, respectively, which was higher than most reported sorbents. The Freundlich model presented the best fit for the isotherm data, while the pseudo-second-order model was most suited for the kinetics. The presence of competing heavy metal ions in solution did not have any significant effect on the oil sorption capacity onto ZnOMP. The sorption mechanism was attributed to absorption and hydrophobic interactions. ZnONPs impregnated onto the biomass enhanced the spontaneity of oil uptake at higher temperatures. Over 82% desorption of the oil contaminant from the biosorbents was achieved during recovery, using petroleum ether and n-pentane as eluents. Concisely, ZnONPs enhanced the uptake and hydrophobic characteristic of MP biomass and showed good recovery and reusability. Thus, the application of ZnONPs impregnated onto biosorbents in oil spill treatment is highly recommended.