The escalating global water crisis demands innovative solutions. This review highlights the transformative role of metal–organic frameworks (MOFs) in wastewater treatment, integrating green, scalable synthesis (e.g., mechanochemistry, continuous-flow, supercritical fluid methods) with advanced functionalization. It covers diverse pollutants, performance in real matrices, removal mechanisms, and practical deployment platforms. Key challenges and future directions are discussed, offering a roadmap toward sustainable, industrial-scale MOF applications for water purification.

There is a growing need to address waste generated from Fused Filament Fabrication (FFF) 3D printing activities. This study explores the mechanical recycling of waste polylactic acid (PLA) accumulated from failed 3D printing operations and PLA biocomposite filaments containing nanocellulose fibres. FFF 3D printable filaments were produced via melt mixing and extrusion of virgin PLA containing varying amounts of waste PLA. The chemical, thermal and thermomechanical characterisation of each specimen was evaluated using Fourier‐transform infrared spectroscopy (FTIR), simultaneous thermal analysis (SDT), dynamic mechanical analysis (DMA), and uniaxial tensile analysis (UTA). A desktop FFF 3D printer was used to fabricate UTA and DMA test specimens. The thermal stability of the filament specimens containing waste derived from the failed 3D prints were comparable with that of the commercial filaments. However, a 11% decrease in the onset of thermal degradation is observed for the filament containing waste biocomposites. The specimens containing waste PLA exhibited higher crystallinity and storage modulus. UTA results revealed similar tensile strength and % elongation, except for the specimen containing 50% waste PLA which exhibited a 29% decrease in tensile strength. This work successfully demonstrates mechanical recycling as a viable waste management strategy for waste materials generated during FFF 3D printing.

There is a growing need for diversified material feedstock for 3D printing technologies such as fused deposition modelling (FDM) techniques. This has resulted in an increased drive in the research and development of eco-friendly biopolymer-based composites with wide applications. At present, bionanocomposites of polylactic acid (PLA), biopolymer, and cellulose nanocrystals (CNCs) offer promising technical qualities suitable for FDM 3D printing applications due to their biodegradability and wide-ranging applications. In this work, the applicability of the PLA/CNCs bionanocomposites in 4D applications was investigated by studying its shape-recovery behaviour. Tensile and dynamic mechanical analysis (DMA) was used to elucidate the mechanical and flexural properties of the 3D-printed specimens. The results revealed improvement in the deflection temperature under load (DTUL), creep deformation, and recovery of the PLA/CNCs bionanocomposites. Tensile and static 3-point bending analyses of the bionanocomposites revealed improved tensile strength and modulus of the 3D printed parts. The potential 4D application of the PLA/CNCs bionanocomposites was also investigated by successfully printing PLA/CNC bionanocomposites directly onto a nylon fabric. The PLA/CNCs-fabric prototype included a foldable cube and grid-patterned designs. Additionally, the heat-induced shape memory behaviour of these prototypes was demonstrated.