BACKGROUND: Cleanup of oil spills is a worldwide task needed to avoid serious environmental pollution. Recently, polyurethane (PU) sponge has been used as an oil absorbent, however, its efficacy is limited by its hydrophilic property.
RESULTS: This work describes the modification of PU sponge with ZnO microrods and palmitic acid (PA). A coating of ZnO microrods made the surface of PU sponge rough, which improved the hydrophobicity and oil-adsorption capacity of the sponge.Further immersion in PA solution reduced the surface energy, which enabled the rough surface to be superhydrophobic (water contact angle (CA) > 150 ∘ ). The contact angles of water and oil on the prepared ZnO and PA modified (ZnO-PA sponge) sponge were 168.9 ∘ and 0 ∘ , respectively. Adsorption capacities of ZnO-PA sponge varied between 33 and 44 g g −1 for different oil samples, which were higher than those of the non-modified PU sponge (21-23 g g −1 ). Adsorption equilibrium for the adsorption process of ZnO-PA sponge was achieved within tens of seconds. Additionally, the ZnO-PA sponge showed excellent selectivity for oil over water, and high reusability.CONCLUSION: These findings indicated that the superhydrophobic PU sponge was a promising oil adsorbent for large-scale oil-spill collection.
RESULTS AND DISCUSSION
Synthesis of ZnO-PA spongeThe ZnO microrods were synthesized using a combination of sol-gel (Scheme 1) and hydrothermal (Scheme 2) methods. Zn(CH 3 COO) 2 was reacted with KOH, which generated Zn(OH) 2
A molecular surface chemical treatment is introduced into a dye sensitized solar cell (DSSC) incorporating metal nanoparticles to suppress the charge recombination. Dodecanethiol molecules as a surface treatment agent are successfully anchored onto the exposed Au nanoparticle sites of the ZnO nanorods/Au nanoparticles/N719 photoanode. ATR-FTIR and Raman measurements are conducted to understand the adsorptions of different molecules (dodecanethiol, N719) on the ZnO nanorods and Au nanoparticles surface. The effects of the dodecanethiol surface treatment on the performance of the plasmon-enhanced DSSC are investigated by UV-vis absorption, incident photon-to-current conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS). The plasmon-enhanced light absorption due to the presence of Au nanoparticles is not affected by the dodecanethiol surface treatment. The charge recombination on the ZnO nanorods-dye-electrolyte interface is substantially retarded by insulating the exposed Au nanoparticle sites from the oxidized form of the electrolyte via dodecanethiol molecules. The strategy of a molecular surface chemical treatment on the photoanode of a DSSC with metal nanoparticles fully exploits the plasmon-enhanced light absorption and explores a simple method to protect the metal nanoparticles for the plasmon-enhanced DSSC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.