Metal-organic frameworks (MOFs), an emerging class of porous organic-inorganic hybrid materials, have shown great potential for water and wastewater treatment applications. However, pure MOF powders have limited practical applications in water treatment due to their insolubility, poor processability, brittleness, safety hazard from dust formation, and difficult separation from aqueous solutions. Thus, exploring potential MOFs composites with improved separation performance is of great importance. The marriage of MOFs with electrospun nanofiber with forethought into the final product's morphology, structure, and chemistry has opened up new opportunities for efficient wastewater treatment. The present review exhaustively summarizes the strategies to integrate MOFs into nanofibers via electrospinning to remove various pollutants (i.e., organic dyes, heavy metal ions, pharmaceuticals, personal care products, oily compounds, organic solvents, etc.) via adsorption, photodegradation, and membrane filtration. Besides, the most recent advances of electrospun MOF nanofibers for wastewater treatment and their current challenges and future outlook are delineated.

Piezoelectric nanogenerators (PENGs) provide a viable solution to convert the mechanical energy generated by body movement to electricity. One-dimensional yarns offer a platform for flexible wearable textile PENGs, which can conform to body for comfort and efficient energy harvesting. In this context, we report a flexible piezoelectric yarn, assembled by one-step cocentric deposition of cesium lead halide perovskite decorated polyvinylidene fluoride (PVDF) nanofibers, on a stainless-steel yarn. Perovskite crystals were formed in situ during electrospinning. Our work demonstrates a nanofiber morphology in which perovskite crystals spread over the nanofiber, leading to a rough surface, and complementing piezoelectric nanocomposite formation with PVDF for superior stress excitation. We investigated how the halide anions of perovskite affect the piezoelectric performance of PENG yarns by comparing CsPbBr 3 and CsPbI 2 Br. Effects of the perovskite concentration, annealing temperature, and deposition time on the piezoelectric properties of PENG yarns were investigated. Devices assembled with a single yarn of CsPbI 2 Br decorated PVDF nanofibers yield the optimal performance with an output voltage of 8.3 V and current of 1.91 μA in response to pressing from an actuator and used to charge capacitors for powering electronics. After aging in the ambient environment for 3 months, the device maintained its performance during 19,200 cycles of mechanical stresses. The excellent and stable electrical performance can be ascribed to the optimized crystallization of CsPbI 2 Br crystals, their complementing performance with PVDF, and formation of nanofibers with uniformity and strength. The flexibility of piezoelectric yarns enables them to be bent, twisted, braided, and woven for different textile integrations while harvesting energy from body movements, demonstrating the potential for wearable mechanical energy harvesting.