Preparation And Characteristic Research Of Superhydrophobic/Superoleophilic Corn Straw Fiber

Superhydrophobic and superoleophilic material with water contact angel larger than 150° and oil contact angle lower than 5° selectively absorb various oils while completely repelling water, which determining its widely application in the field of oil spill cleanup. In theory, the combined effect of hierarchical coarse structure and low surface free energy is a necessary condition for the acquisition of the features of superhydrophobicity and simultaneous superoleophilicity. This article selects corn straw as raw materials, through the formation of inorganic particles on the sample surface and hydrophobic modification, novel superhydrophobic/superoleophilic straw fibers were successfully fabricated. The main research content of this paper includes the following aspects:Concretely, superhydrophobic/superoleophilic corn straw was successfully prepared by the combination of the deposition of SiO2/ZnO composite particles on fiber surface through uncomplex impregnation method and hydrophobic modification of octyltriethoxysilane (OTES). The surface morphology, chemical composition and surface wettability of resulting corn straw product were studied by utilizing scanning electron microscopy (SEM), energy-dispersive x-ray analysis (EDX) and contact angle (CA) instrument, respectively. The performances of superhydrophobicity and superoleophilicity of as-prepared corn straw remained no matter in corrosive solution or after long-time storage. The maximum absorption capacity of superhydrophobic/superoleophilic corn for crude oil was 20.81 g/g, exhibiting high oil absorption capacity.The deposition of SiO2 particles on corn straw was realized via in-situ synthesis, which was responsible for the establishment of dual hierarchical structure and the incensement of surface roughness. On this basis, as hydrophobic modifier, surface decoration of silane coupling agent of hexadecyltrimethoxysilane (HDTMOS) effectively lowered the surface free energy of corn straw and further improved the hydrophobic and oleophilic performances of straw fiber. The relevant results showed that the product had water contact angle of 153° and oil contact angle of 0°. In addition, the as-prepared superhydrophobic/superoleophilic corn straw possessed noteworthy acid and alkali resistance and favorable stability in air environment. Meanwhile, the product showed high adsorption capacity for various oils and organic solvents.Homogeneous SiO2 was prepared via sol-gel process using tetraethoxysilane as silicon source, ammonia as catalyst. Superhydrophobic/superoleophilic corn straw fiber was prepared by the successful attachment of PTES-modified SiO2 particles onto fibers surfaces. The as-prepared straw product exhibited outstanding properties of superhydrophobicity and simultaneous superoleophilicity with water contact angle of 152° and oil contact angle of 0° for different oils. The microstructure, surface wetting property and chemical composition of the samples were analysed by conventional characterization techniques. The corresponding results revealed that the homogeneous deposition of SiO2 particles on fiber surface caused sufficient roughness and OTS induced low surface energy of the product, giving rise to both superhydrophobic and superoleophilic behaviors of the resulting sample.Corn straw product with superior performances of superhydrophobicity and superoleophilicity was fabricated by the deposition of ZnO particles onto corn straw surface, followed by the self-assembly of hexadecyltrimethoxysilane. The influence of pH of aqueous solution on the wettability of corn straw was inspected and the oil-water separation experiment was designed. Besides, oil absorption capability in pure oil system and oil removal efficiency in an oil-water mixture of superhydrophobic/superoleophilic corn straw were also studied. Furthermore, the reusability of superhydrophobic/superoleophilic corn straw was also investigated to provide evidences for the better utilization of corn straw in oil/water separation. Because of its intrinsic water-repellence, high sorption capacity and low density, the product floating on the surface of water after absorbing the oil was easy to transport and recycle. It was very meaningful that superhydrophobic/superoleophilic corn straw fiber broadened the possibilities for its applications in oily wastewater treatment.