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Sustainable conversion of wastes into eco-friendly wearable energy storage materials is of uppermost priority when facing the rapid development of human society. Although some attempts have successfully developed wastes into activated carbon electrodes, the high energy consumption of the production process and the powder form greatly restrict their application in eco-friendly wearable supercapacitors. Here, industrial waste-flax noil was conversed into fiber-shaped supercapacitors (FSSCs) via wet spinning and in situ deposition of polypyrrole (PPy). The regenerated cellulose fibers (RCFs) collected from the ethyl alcohol coagulation bath possessed excellent tensile behaviors and multi-groove surfaces, encouraging the subsequent textile processing and ions activities. After PPy deposition, the obtained fiber electrodes yielded high specific capacitance (510.7 F g-1 at 0.5 A g-1) and excellent coulombic efficiency (99.3% at 10 A g-1). More importantly, the assembled FSSCs delivered remarkable electrochemical performances and could power the LED. The green strategy proposed in this work provides a new consideration for converting wastes into practical eco-friendly wearable devices. [Display omitted] • Flax noil was successfully converted into eco-friendly fiber supercapacitors. • ETf@PPy12 electrodes possessed high specific capacitance and coulombic efficiency. • The assembled flexible supercapacitor showed superior electrochemical performance. • The devices in series could power the LED. [ABSTRACT FROM AUTHOR]

• Pristine polypyrrole (PPy) membrane with nanotubes were prepared for Cr(VI) removal. • The flexibility and shape stability make PPy membranes easy for separation. • The maximum Cr (VI) adsorption capacity of PPy membrane was 250.31 mg/g. • The Cr (VI) adsorption capacity fell by only 8.2% after four cycles of regeneration. The effective removal of toxic Cr(VI) from wastewater remains an important environmental issue. The low adsorption capacity and the complex processes to separate the adsorbents from the treated wastewater are the main scientific and technological challenges. In this study, a flexible and free-standing pristine polypyrrole (PPy) membrane with a nanotube structure (PPy-N) was synthesized via template-assisted interfacial polymerization (TIP) for the selective removal of Cr(VI) through a simple separation and collection process. The superior Cr(VI) adsorption capacity as high as 250.31 mg/g was endowed by the unique structure of the PPy-N membrane. The Langmuir adsorption isotherm model was used to describe the adsorption behavior, with the adsorption kinetics followed a quasi-second-order kinetic model. After four adsorption-and–desorption cycles, the PPy-N membrane adsorption capacity fell by only 8.2%. The mechanism of the selective removal of Cr(VI) was proposed, including electrostatic adsorption, ion exchange and reduction. A combination of the highly attractive material properties, including mechanical processability, large surface area, superior Cr(VI) adsorption capacity and regeneration, makes the single-component PPy-N membrane a good candidate for removing Cr(VI) ions from wastewater. [ABSTRACT FROM AUTHOR]