The oily wastewater and oil spill caused by oil leakage accidents are extremely harmful to human health and the environment. Thus, it is very important to exploit superhydrophobic separation materials and technologies for oil/water separation and oil spill cleanup. In this study, using the 1,4-conjugate addition reaction between polyethyleneimine (PEI) and 3-(trimethoxysilyl)propyl acrylate (TMSPA), hydrolysis condensation reaction of TMSPA and dodecyltrimethoxysilane (DTMS) jointly connecting to the surface of hydrophilic silica nanoparticles, and hydrogen bond interaction of the residual amino group on the surface of PEI, covalently-crosslinked rough network structures were constructed on fabric surfaces, which endow PEI/TMSPA/SiO2/DTMS fabrics with excellent superhydrophobic properties. The obtained superhydrophobic fabric not only showed excellent heat resistance and excellent stability to acid, alkali, salt and organic solvents, but also showed good mechanical stability to tape stripping and washing tests. The superhydrophobic, superoleophilic properties and porous structure of the modified fabric make it have excellent oil/water separation efficiency (98.49% after 18 cycles) and oil spill cleanup efficiency (95.35% after 9 cycles). This superhydrophobic PEI/TMSPA/SiO2/DTMS fabric has characteristics of simple preparation, environmental friendliness and scale-up, which makes it a very promising separation material for actual oil/water separation and oil spill cleanup.
Yahui Cai,Jianfei Wu,Kaili Wang,Youming Dong,Jundie Hu,Jiafu Qu,Dan Tian,Jianzhang Li,Qiliang Fu
Designing highly porous materials is of great importance for liquid separation, water purification, and disinfection, such as spill oil cleaning and recycling, seawater desalting, and oil/water separation. However, a remaining challenge is to produce porous materials with the characteristics of fast absorption, continuous directional transport, and self-release of viscous liquid. Herein, a functional cellulosic composite is reported by the chemical treatment and functionalization of wood resulting in a smart wood that can thermally self-release and separate high viscosity oil. The smart wood has a high absorption speed of 1398 mL/(m 2 ·s) (ethylene glycol) and a maximum absorption capacity of 47.2 g/g (chloroform) due to its intrinsic vertical micro/nanoscale channel structure, low tortuosity, and high porosity. Moreover, the switchable wettability is achieved by the surface coating of poly(N-isopropylacrylamide) on the porous wood, which enables the collection and removal of oil from the oil/water mixture. The high viscosity oil can be automatically released due to the passive oil release at room temperature. The release capacity of the smart wood remains above 91% after 15 cyclic tests. We envision that this functional smart wood could be extended to a wide range of applications in smart hydrogels, microfluidics, artificial drug release, and environmental restoration.