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Frequent oceanic oil spill incidents and the discharge of industrial oily wastewaters have caused serious threats to environments, food chains and human beings. Lignin wastes with many reactive groups exist as the byproducts from bioethanol and pulping processing industries, and they are either discarded as wastes or directly consumed as a fuel. To make full use of lignin wastes and simultaneously deal with oily wastewaters, porous lignin-based composites have been rationally designed and prepared. In this review, recent advances in the preparation of porous lignin-based composites are summarized in terms of aerogels, sponges, foams, papers, and membranes, respectively. Then, the mechanisms and the application of porous lignin-based adsorbents and filtration materials for oil/water separation are discussed. Finally, the challenges and perspectives of porous lignin-based composites are proposed in the field of oil/water separation. The utilization of abundant lignin wastes can replace fossil resources, and meanwhile porous lignin-based composites can be used to efficiently treat with oily wastewaters. The above utilization strategy opens an avenue to the rational design and preparation of lignin wastes with high-added value, and gives a possible solution to use lignin wastes in a sustainable and environmentally friendly way. [ABSTRACT FROM AUTHOR]

An anisotropic aerogel hot-extrusion strategy is designed to convert polyimide aerogels into aerogel-based paper. The multilayer interconnected aerogel-based paper exhibits excellent thermal stability and mechanical properties, and the mechanical properties remain great at high temperatures. This aerogel-based paper has huge application potential in the aerospace field. [Display omitted] • Multi-layer interconnected aerogel based paper was successfully prepared by anisotropic aerogel hot extrusion strategy. • Aerogel-based papers exhibit excellent thermal stability and stable mechanical properties (PI-1: 216.28 MPa at 25 °C). • The tensile strength of PI-1 was 3 times that of commercial polyimide paper and 24 times that of aramid paper at 400 °C. • Aerogel-based paper maintain stable mechanical property after 5000 cycles. The continuous improvement of papermaking technology has attracted widespread attention. However, the prevention of high-temperature decomposition and a subsequent decline in mechanical strength is still a significant challenge with current papermaking technology. Herein, a newly developed multilayer interconnected polyimide aerogel-based paper was successfully prepared via an anisotropic aerogel hot-extrusion strategy. Precursor solutions of highly rigid benzimidazole units containing intermolecular hydrogen bonds and linear rod-like benzimide units were first prepared. Anisotropic precursor polyimide (PAAS) aerogels with a thickness of 3 mm were then manufactured by unidirectional freeze-drying. Then, aerogel-based papers with a thickness of 40 μm and microstructure multilayer interconnected properties were obtained by a hot extrusion strategy and a thermal imidization process. This polyimide structural paper exhibited excellent thermal and mechanical properties. Through the design of micro and macro structures, the tensile strength of the aerogel-based paper was much higher than that of commercial paper at both room temperature and 400 ℃. This aerogel-based paper also exhibited high-temperature cycle stability, high flexibility, and good stretchable bending properties. The successful preparation of this aerogel-based paper demonstrates the feasibility of the hot extrusion strategy. This work provides a new papermaking technology method and broadens the application field of paper. [ABSTRACT FROM AUTHOR]