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The in situ electrochemical oxidation process has received considerable attention for the removal of dye molecules and ammonium from textile dyeing and finishing wastewater. Nevertheless, the cost and durability of the catalytic anode have seriously limited industrial applications of this technique. In this work, the lab-based waste polyvinylidene fluoride membrane was employed to fabricate a novel lead dioxide/polyvinylidene fluoride/carbon cloth composite (PbO2/PVDF/CC) via integrated surface coating and electrodeposition processes. The influences of operating parameters (pH, Cl− concentration, current density, and initial concentration of pollutant) on the oxidation efficiency of PbO2/PVDF/CC were evaluated. Under optimal conditions, this composite achieves a 100% decolorization of methyl orange (MO), 99.48% removal of ammonium, and 94.46% conversion for ammonium-based nitrogen to N2, as well as an 82.55% removal of chemical oxygen demand (COD). At the coexistent condition of ammonium and MO, MO decolorization, ammonium, and COD removals still remain around 100%, 99.43%, and 77.33%, respectively. It can be assigned to the synergistic oxidation effect of hydroxyl radical and chloride species for MO and the chlorine oxidation action for ammonium. Based on the determination of various intermediates, MO is finally mineralized to CO2 and H2O, and ammonium is mainly converted to N2. The PbO2/PVDF/CC composite exhibits excellent stability and safety.

In the study, the waste polyvinylidene fluoride (PVDF) membranes were recovered and the micropowders of this polymer were obtained by solvent recovery method. Moreover, the new direction for applying waste PVDF membranes to the field of tribology were developed. Thus, a novel PVDF-based tribological composite (PAO@PSF/PVDF) was fabricated with recycled PVDF micropowders acted as the matrix polymer and PAO@PSF microcapsules with the configuration of polysulfone (PSF) capsuling lubricant oil (PAO) served as the filler. The self-lubricating and wear properties of PAO@PSF/PVDF composite were tested under dry sliding condition using a ball-on-disc configuration. In particular, this kind of composite with the inclusion of 20 wt% PAO@PSF microcapsules exhibited the best tribological properties, i.e., the lowest friction coefficient (0.077) and the smallest wear rate (2.34×10-15 m3/Nm). The filling of PAO@PSF microcapsules greatly improved the antifriction and wear resistance of PVDF, guaranteeing the self-lubricating feature of this polymer. The tribological properties of PAO@PSF/PVDF composite can reach close to those under the condition of dripping lubricating oil, and the prepared PAO@PSF/PVDF self-lubricating composite can be applied to a large range of friction conditions. Furthermore, without any doubt, it will facilitate the reutilization of waste polymers.

In the study, the waste polyvinylidene fluoride (PVDF) membranes were recovered and the obtained resin powders by a solvent recovery method were employed for the fabrication of a novel PVDF-based tribological composite.Herein, a new strategy was developed for applying the waste PVDF membranes to fabricate a self-lubricant composite, where the recycled PVDF powders acted as the polymer matrix and microcapsules with the configuration of polysulfone (PSF) capsuling lubricant oil (PAO) served as the filler. The morphologies, crystal phases, chemical components and groups as well as thermal stabilities of fabricated PAO@PSF/PVDF composites were characterized, and the self-lubricating and wear properties of fabricated composites were tested under the dry sliding condition using a ball-on-disc configuration. Experimental results suggest that the PAO@PSF/PVDF composite with an addition of 20 wt% PAO@PSF microcapsules exhibits the best tribological properties, in view of the lowest friction coefficient (0.077) and the smallest wear rate (2.34 Â 10 À15 m 3 /Nm). The incorporation of PAO@PSF microcapsules greatly reduces the friction coefficient of PVDF polymer. The tribological properties of fabricated PAO@PSF/PVDF composite will be expectable to that of the PVDF polymer with the dripping presence of lubricating oil.

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