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Highlights • Biodegradable ZIF-8@CNF@cellulose foams were prepared by in situ green growth method. • The ZIF-8 crystals significantly improved the adsorption ability of composite foams. • The CNF immobilized ZIF-8 crystals and improved the mechanical strength of foams. • ZIF-8@CNF@cellulose foams showed high adsorption capacity for gases and heavy metals. Abstract The excess emission of toxic gases in atmosphere and heavy metal ions in drinking water is still a serious threat to human health. In this paper, a lightweight and porous zeolitic imidazolate frameworks-8@cellulose nanofiber@cellulose foam (ZIF-8@CNF@cellulose foam) with excellent gas adsorption and heavy metal ions removal properties was prepared using a simple in situ green growth method. The nitrogen adsorption property of ZIF-8@CNF@cellulose foam was 30 times higher than pure cellulose foam. Furthermore, the adsorption testing demonstrated that the composite foam showed high adsorption capacity for fluorescent dyes (24.6 mg g−1 for rhodamine B), heavy metal ions (35.6 mg g−1 for Cr (VI)) and organic solvents (45.2 g g−1 for DMF). Additionally, the ZIF-8/cellulose-based foam with 40 wt.% CNF exhibited an excellent mechanical performance, reaching a compressive strength value of 1.30 MPa. Herein, this work provides a feasible method to prepare ZIF-8@CNF@cellulose foam composite materials, which could adsorb gas molecules and heavy metal ions and show a great potential in atmosphere and water treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel Ag-MOFs@CNF@ZIF-8 cellulose-based air filters were designed and fabricated. • The Ag-MOFs were employed to endow filters with excellent antibacterial activity. • The ZIF-8 nanocrystals were used to endow filters with high gas adsorption ability. • The introduction of CNF significantly improved the mechanical strength of filters. • The composite filter exhibited 94.3% removal efficiency for PM 2.5. Abstract A biodegradable cellulose-based air filter (Ag-MOFs@CNF@ZIF-8) with multi-layer structure was fabricated by in situ generation of double-component metal-organic frameworks (MOFs) and reinforcement of cellulose nanofiber (CNF). It exhibits good filtration performance, gas adsorption, antibacterial activity and mechanical property. The presence of MOFs could enhance the interaction between the filter and particulate matter (PM) and significantly improve the specific surface area of the composite filter. Thus, the filtration efficiency of the composite filter could reach 94.3% for PM 2.5 and the nitrogen adsorption capacity increased to 109 cm3 g−1. Furthermore, the Ag-MOFs@CNF@ZIF-8 filter exhibited excellent antibacterial activity against Escherichia coli with an inhibition zone diameter of 18.1 mm. The compressive strength of the composite filter could be up to 501 kPa, approximately 3.8 times higher than that of pure cellulose filter. Herein, this composite filter has a great application potential in PM 2.5 removal, toxic gas adsorption and healthcare fields. [ABSTRACT FROM AUTHOR]

The scale-up preparation of aramid nanofiber (ANF) and cellulose nanofiber (CNF), still faces serious challenges such as extreme production cost and lengthy preparation cycle. Herein, a feasible top-down strategy was proposed to achieve the efficient reclamation of waste resources, further realizing the large-scale production of high value-added nanofibers. The ANF/CNF as nanoscale building blocks and their reinforcement effects on the mechanical performances of carbon fiber/phenolic composites were investigated. Related strength and modulus of ANF/CNF-enhanced composites in the tensile, bending, shear and nano indentation tests, increased by 118.1% (tensile strength), 141.2% (tensile modulus), 142.2% (flexural strength), 354.4% (flexural modulus), 38.8% (shear strength) and 94.4% (elastic modulus), respectively. Our work offers a valuable reference in the fabrication of low-cost ANF/CNF derived from waste resources, which would facilitate the wide application of nanofibers in fabricating high-performance advanced functional materials. [Display omitted] [ABSTRACT FROM AUTHOR]