It is extremely important to develop a facile and versatile strategy for effectively separating various oil–water mixtures. Here we report that the pith of juncus (which is also known as common rushes) can serve as a versatile material for oil–water separation. Under the action of capillary force and gravity, a piece of pith automatically and continuously separates not only immiscible oil–water mixtures but also surfactant-stabilized water-in-oil emulsions with high selectivity and desirable flux. The separation strategy is cost-effective and energy-efficient because it avoids the switch of wettability, the input of additional energy, and the use of low-surface-energy chemicals or special equipment. The unique capability of the pith is mainly attributed to the presence of three-dimensionally (3D) reticular texture with highly hydrophobic and superoleophilic properties. Owing to its easy availability and high effectiveness, juncus might be a promising material aiming for oil–water separation, water treatment, and purification of solvent or fuel, and so on.
Oily wastewater and oil spills have adverse impacts on aquatic ecosystems and even the human environment. Developing highly efficient nonfluorinated superoleophilic separation materials for oil/water separation is urgently needed. Herein, a natural Juncus effusus pith was directly used as a raw material to prepare novel separation columns via a facile compression strategy. The pith possessed natural superoleophilicity (oil contact angle almost 0°) with inherent oleophilic properties and regular multilayer, porous, network structure. These pith characteristics endowed related separation columns with superior oil selectivity . The pore size of the prepared columns was controlled by adjusting the degree of compression. In this strategy, the separation efficiency the column reached up to 99.99 and 97.7% for eight types of oil/water mixtures and surfactant-stabilized emulsions under gravity, respectively. After repeated column recycling, these columns retained excellent separation performance and the separation mechanism was investigated. No new pollutants and hazardous substances were introduced into the environment in column fabrication and separation processes. Therefore, this study provided the basis for an ecofriendly, low-cost, and scalable strategy for reasonable utilization of natural biomaterials with superoleophilicity, thus exhibiting great potential for the rapid treatment of oil spillage and industrial oily wastewater.
危险品化学品经营许可证（带存储）