Abstract
The influence of different coupling agents and coupling times on the wettability of a polyurethane (PU) sponge surface were optimized. Octadecyltrichlorosilane (OTS) was selected as the optimal coupling agent to prepare the superhydrophobic sponge. The superhydrophobic sponge was prepared in one step, which has the advantages of simple operation and enhanced durability. The superhydrophobic sponge was characterized by scanning electron microscopy, Teclis Tracker tensiometry, and Fourier transform infrared (FT-IR) spectrophotometry. The water contact angle increased from 64.1° to 151.3°, exhibiting ideal superhydrophobicity. Oils and organic solvents with different viscosities and densities can be rapidly and selectively absorbed by superhydrophobic sponges, with an absorption capacity of 14.99 to 86.53 times the weight of the sponge itself, without absorbing any water. Since temperature affects the viscosity and ionic strength of oil, and influences the surface wettability of the sponges, the effect of temperature and ionic strength on the oil absorption capacity of the superhydrophobic sponges was measured, and its mechanism was elucidated. The results showed that the absorptive capacity retained more than 90% of the initial absorptive capacity after repeated use for 10 times. Low-cost, durable superhydrophobic sponges show great potential for large-scale oil-water separation.
Highlights
With the economic growth, the development of the petroleum industry and marine transportation have made marine oil spills a frequent and severe environmental challenge [1,2]
Fifty mg of hydroxylated Multi-walled carbon nanotubes (MWCNTs) were slowly added to 50 mL of toluene, and the carbon nanotubes were dispersed by ultrasonication for 20 min
Since oil and organic solvent spills usually occur under complex environmental conditions, it is crucial to elucidate the performance of superhydrophobic sponges under various conditions [44,45]
Summary
The development of the petroleum industry and marine transportation have made marine oil spills a frequent and severe environmental challenge [1,2]. Due to its simple operation and easy separation, the absorption method is usually used for oil-water separations Traditional absorbent substances such as cellulose [10,11], activated carbon [12,13] and zeolites [14], are mostly microporous materials. 3D adsorbent materials possess the characteristics of large pores and large specific surface area, which can absorb oil on the material surface and realize oil-water separations [15]. They are inexpensive, and have a large absorption capacity [16]. Several oils and organic solvents were adopted as model pollutants, and the absorption mechanism was identified and discussed
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