Synthesis and Photocatalytic Application of Magnetic CoFe2O4/Conjugated Poly(vinyl chloride) Derivative Nanocomposite

CoFe₂O₄ has potential for application as a magnetically recoverable visible-light photocatalyst, but its photocatalytic activity is encumbered by the high recombination probability of its photogenerated holes (h⁺) and electrons (e^-). This work was undertaken to boost the photocatalysis of CoFe₂O₄ through coupling with conjugated poly(vinyl chloride) derivative (CPVC). An easily implementable solvothermal-liquid solid mixing-evaporation of the solvent-pyrolysis method was exploited to synthesize CoFe₂O₄/CPVC nanocomposites. The photocatalytic capabilities of the products were assessed through photocatalyzing the reduction of Cr(VI) under visible-light (λ > 420 nm). The results demonstrate that the optimal CoFe₂O₄/CPVC nanocomposite (CoFe₂O₄/CPVC-2) has markedly heightened photocatalytic activity (3.6 times that of CoFe₂O₄) and competent reusability and is magnetically recoverable. Furthermore, CoFe₂O₄/CPVC-2 also shows superior performance toward photocatalytic treatment of the diluted Cr(VI)-containing passivation solution of copper alloys. It is deduced based on the photoelectricity measurement results that the increased photocatalysis of CoFe₂O₄/CPVC-2 is chiefly attributed to its p-n heterojunction structure, which greatly elevates the h⁺-e^- separation and transfer efficiency. When waste PVC plastic films (replacing the new pure PVC powder) were utilized for the synthesis, the obtained CoFe₂O₄/CPVC nanocomposite exhibited even better photocatalytic activity (4 times that of CoFe₂O₄). This work not only has made a new magnetically recoverable, efficient visible-light photocatalyst for decontamination of Cr(VI) in water but also is inspirational for recycling PVC plastic waste to produce high-valued visible-light photocatalysts.