Study On Preparation And Photocatalytic Performance For Formaldehyde Removal Of Indium Zinc Sulfide/Pulp Fiber Composite Paper

In this paper,the in-situ synthesis method was used to load nano-indium zinc sulfide(ZnIn₂S₄)on pulp fibers(PFs)to prepare ZnIn₂S₄/PFs composite paper,meanwhile ZnIn₂S₄ and polypyrrole(PPy),ZnIn₂S₄ and cadmium sulfide(CdS)were successively loaded on PFs by a two-step in-situ deposition method to prepare PPy/ZnIn₂S₄/PFs composite.paper and CdS/ZnIn₂S₄/PFs composite paper.The influence of reactant dosage,reaction temperature,reaction time and cycle times on the formaldehyde removal efficiency of composite paper under visible light irradiation was explored.The composite paper was characterized and analyzed by using scanning electron microscope(SEM),X-ray diffractometer(XRD),X-ray photoelectron spectrometer(XPS),ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS)and electrochemical impedance spectroscopy(EIS).It was found that the formaldehyde removal ratio of ZnIn₂S₄/PFs composite paper increased first and then decreased with the increase of indium nitrate dosage.The formaldehyde removal ratio of the prepared ZnIn₂S₄/PFs composite paper can reach up to 73.14%when indium nitrate dosage is 0.08 mol/L.When the ZnIn₂S₄/PFs composite paper was placed in a natural environment for 30 days,its tensile index only decreased by 2.4 N·m/g and the formaldehyde removal ratio decreased by 21.69%,indicating that the ZnIn₂S₄/PFs composite paper had good environmental stability.After three photocatalytic cycles of ZnIn₂S₄/PFs composite paper,the formaldehyde removal ratio decreased by 19.43%,indicating that the light corrosion resistance of ZnIn₂S₄/PFs composite paper needs to be improved.The formaldehyde removal ratio of the prepared PPy/ZnIn₂S₄/PFs composite paper showed an increasing trend with the increase of pyrrole dosage.The maximum formaldehyde removal ratio is 88.04%when pyrrole dosage is 1.0 mL.When the PPy/ZnIn₂S₄/PFs composite paper prepared at 0.6 mL of pyrrole was placed in the natural environment for 30 days,its tensile index only decreased by 4.88 N·m/g and the formaldehyde removal ratio decreased by 7.2%,indicating that PPy/ZnIn₂S₄/PFs composite paper prepared at 0.6 mL of pyrrole had the most excellent environmental stability.After three photocatalytic cycles of PPy/ZnIn₂S₄/PFs composite papers with different dosages of pyrrole,the decrease of formaldehyde removal ratio of PPy/ZnIn₂S₄/PFs composite paper prepared at 0.6 mL of pyrrole was the least(12.98%),indicating that the heterojunction formed by PPy and ZnIn₂S₄ could improve the light corrosion resistance of ZnIn₂S₄/PFs composite paper.The formaldehyde removal ratio of the prepared CdS/ZnInS4/PFs composite paper showed an increasing trend with the increase of Cd2+dosage.The maximum formaldehyde removal ratio is 91.02%when Cd2+ dosage is 6 mmol.The reaction temperature has a positive effect on the formaldehyde removal ratio of CdS/ZnIn₂S₄/PFs composite paper,and the maximum formaldehyde removal ratio(92.95%)is obtained when the reaction temperature is 50 ?.With the increase of reaction time,the formaldehyde removal ratio of CdS/ZnIn₂S₄/PFs composite paper gradually decreased,and the maximum formaldehyde removal ratio(91.26%)is obtained when the reaction time is 1 h.The optimal reaction conditions are temperature 50? and time 1 h.It shows that the incorporation of CdS can greatly improve the formaldehyde removal ratio of ZnIn₂S₄/PFs composite paper.When the CdS/ZnIn₂S₄/PFs composite paper was placed in a natural environment for 30 days,its tensile index only decreased by 6.71 N·m/g,and the formaldehyde removal ratio decreased by 6.46%,indicating that the CdS/ZnIn₂S₄/PFs composite paper has good environmental stability.After three photocatalytic cycles of CdS/ZnIn₂S₄/PFs composite paper,the formaldehyde removal ratio decreased by 14.15%.The SEM images showed that ZnIn₂S₄,PPy and CdS were uniformly coated on the surface of pulp fibers in the form of nanoparticles,and the fiber morphology structure was not damaged.The diffraction peaks of the XRD curves all corresponded to the standard diffraction peaks,indicating that PPy,CdS and ZnIn₂S₄ were all well loaded on the pulp fibers.Both XPS spectra and element contents proved the successful preparation of composite paper.