Fabrication Of Two Kinds Of Superhydrophobic Functional Ecomaterials And Its Oil/Water Separation Performance

With the rapid development of world economy and global industry, the demand of oil and its oil derivatives are increasing all the time. However, oil spillage and organic pollutants has caused serious and irrecoverable damage to environment and ecosystems, and oil/water separation has become a worldwide challenge. Therefore, how to address the above problems effectively and recover oil spill from water surface has become an urgent problem.Superhydrophobic surfaces exhibit the properties of self-cleaning and superhydrophobicity, which were date back to 1950’s and have being widely studied with great potential. Inspired by superhydrophobic phenomena, bionic investigation revealed that the self-cleaning of a lotus leaf was attributed to the hierarchically combined micro/nano structures and the low surface-energy substances covered on the surface, which presents a high water static contact-angle and a small sliding angle; it’s called self-cleaning or lotus effect. In general, two ways can be used for the fabrication of superhydrophobic surface:one is to create a rough structure on a hydrophobic surface, and the other is to modify a rough surface with some low surface-free-energy substances. Recently, various superhydrophobic /superoleophilic materials have been wildly researched and reported, because they can absorb oil selectively and simultaneously resist water completely. However, some disadvantages such as high cost, complicated reaction procedure and difficult scale-up limit their further application. Therefore, it is important and urgent to develop multifunctional absorbent materials to solve these problems effectively. Based on the lotus effect, two kinds of superhydrophobic functional ecomaterials were designed and their hydrophobicity and oil/water separation properties were analyzed.The functional hydrophobic air-laid paper composite was fabricatied by immobilizing carbon black via a repeated dipping-and-drying method and modifying the hydrophobic substances on the surface via chemical vapor deposition(CVD). The water contact angle was applied to study its hydrophobic/oleophiic performance at room temperature. After the fourth adsorption, carbon black accounts for 16%, by weight percent and the contact angle reaches a maximum of 147.4±1.1°, suggesting the best hydrophobic/oleophilic properties of the as-prepared composite. Furthermore, the composite shows excellent oleophilic properties and high water repellency by imitating the experiment process of the oil-water separation of the oil-water mixture and underwater organic pollutants.To achieve higher oil absorbtion capability and controllable oil-water separation, superhydrophobic/superoleophilic magnetic polyurethane sponge composite was fabricated. Motivated by adhesive proteins in mussels, strategies using dopamine to anchor magnetic iron oxide particals on the skeleton of sponge was developed via the self-polymerization of sticky dopamine, followed by modification of low-surface-energy substances such as fluoroalkylsilane (FAS) on the compostie to endow the superhydrophobicity. The as-prepared sponge shows excellent elasticity and high water repellency with the water contact angle of 153.7±2.7°; it exhibits stable wettabilty towards corrosive liquids. In addition, it can expeditiously absorb a broad variety of oils and organic solvents from oil-water mixtures with excellent absorption capacity (up to 10-35 times of its own weight) because of the porous structure. More favorably, it exhibits attractive magnetic responsivity and can absorb floating oils from the polluted regions by simply manipulating the movement of the sponge using a magnet, achieving a magnetic-actuated method for oil-water separation. Finally, the absorbed oils in the sponge could be collected by simple mechanical squeezing because of the great elasticity of the sponge. To investigate the reusability, the recycling experiments of benzene adsorption were carried out. Results show that the k of the sponge kept stable after ten successive cycles, suggesting the excellent reusability.