Preparation of chitosan-SiO2 aerogel/cellulose/polypropylene composite spunlaced nonwovens and adsorption dye performance
Objective The cellulose fiber(CF)spunlaced nonwovens have the advantages of wide availability,low cost,excellent mechanical properties,and large specific surface area.However,as adsorption materials,cellulose and its derivatives have limited potential for intramolecular chain interactions and hydrogen bonding with organic dyes.In order to expand the application of cellulose-based spunlaced materials in the treatment of organic dye wastewater,CF/polypropylene(PP)spunlaced nonwovens with the mass ratio of 9∶1 was used as substrate material and oxidated.Then chitosan(CS)-silicon dioxide(SiO2)aerogel was prepared by sol-gel method and loaded on the surface of the oxidated CF(OCF)/PP spunlaced nonwovens to prepare CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens.Method After oxidation,the OCF/PP spunlaced nonwoven fabric was used as the substrate and reacted with a mixed solution of CS and tetraethyl orthosilicate(TEOS)with different volume fractions via the sol-gel method,and then CS-SiO2 aerogel/OCF/PP composite spunlaced nonwoven fabric was obtained by freeze drying.The optimal volume fraction of TEOS in the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwoven material was determined based on the studies of the morphology,structure,and organic dye adsorption performance of the composite spunlaced nonwovens.Additionally,the mechanical properties of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwoven material were investigated.Results When the volume fraction of TEOS increased to 25%,the pores on the surface of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwoven became smaller and more densely distributed compared to the CF/PP spunlaced nonwovens material,and many micropores generated on the pore walls,providing more adsorption sites for organic dyes.FT-IR characteristic peaks belonging to CS and SiO2 appeared on the surface of the OCF/PP spunlaced nonwovens.Compared to the OCF/PP spunlaced nonwovens,the diffraction peaks at 2θ of 14.39° and 17.22° in the XRD pattern of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)were significantly weakened,indicating a reduction in the crystallinity of the reconstituted polysaccharide structure.The CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)exhibited higher adsorption efficiency for cationic dyes than those of anionic dyes.The adsorption efficiency of CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens for MB increased when the volume fractions of TEOS increased.When the volume fraction of TEOS was 25%,the adsorption temperature was 30℃,and the pH of adsorption solution was 7,the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens exhibited the highest adsorption MB efficiency,reaching 99.63%.Compared with the pseudo-first-order adsorption model,the pseudo-second-order adsorption model showed better agreement with the experimental results,indicating that the main adsorption MB mechanism of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)was chemical adsorption.The adsorption thermodynamic analysis indicated that the adsorption MB of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)was a spontaneous process.After five cycles,the adsorption MB efficiency of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)remained around 80.59%.Compared to the CF/PP spunlaced nonwovens,the tensile strength and elongation at break of the CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens(5#)showed a slight decrease.Conclusion The CS-SiO2 aerogel/OCF/PP composite spunlaced nonwovens exhibited the highest adsorption performance(99.63%)when the volume fraction of TEOS was 25%,the adsorption temperature was 30℃,and pH was 7.The composite nonwovens demonstrated good stability and reusability.The findings of this study would be useful for expanding the application of the CF/PP spunlaced nonwovens in the water treatment industry.
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