Cellulose is the most abundant natural polymer derived from various plant sources. A valuable source of cellulose is the bamboo plant. Bamboo cellulose contains "Bamboo Kun," which is crucial for the targeted research application due to the antibacterial properties it imparts to the cellulose; hence, bamboo cellulose was utilized in this study. Through chemical modification, bamboo cellulose derivatives, such as Dialdehyde Bamboo Cellulose (DABC), can be synthesized to endow the cellulose with unique properties. Dialdehyde cellulose possesses extensive applications in food packaging, heavy metal adsorption from water, nanoparticle synthesis, an‎d more. The utilization of dialdehyde cellulose for nanofiber production has received limited attention to date. This research investigates the feasibility of electrospinning bamboo cellulose nanofibers. Initially, aldehyde groups were introduced into the structure of delignified bamboo cellulose using sodium periodate. The successful synthesis was confirmed via Copper Number eva‎luation an‎d FTIR analysis. Subsequently, silver nanoparticles (AgNPs) were synthesized in-situ in the presence of dialdehyde bamboo cellulose using silver nitrate, confirmed by X-ray Diffraction (XRD) patterns. Electrospinning of pure dialdehyde bamboo cellulose nanofibers was not feasible; therefore, Polyacrylonitrile (PAN) was employed as a co-spinning polymer. A solution comprising 12.5% PAN an‎d 7.5% dialdehyde cellulose was used, yielding uniform an‎d defect-free nanofibers with an average diameter of 508 nm. Electrospinning of the polymer solution containing silver nitrate resulted in a viscosity reduction from 1420 to 1310 cP. According to Scanning Electron Microscopy (SEM) images, the addition of 10% an‎d 15% silver nitrate to the polymer solution reduced the nanofiber diameter to 435 nm an‎d 372 nm, respectively. To eva‎luate the photocatalytic capability of the nanofibers, Methylene Blue dye was used. The photodegradation efficiency for pure PAN, PAN containing DABC, an‎d PAN/DABC containing 10% an‎d 15% silver was found to be 26%, 35%, 55%, an‎d 50%, respectively. The effect of photocatalyst dosage an‎d dye concentration on the performance of the optimum sample (nanofibers containing 10% silver nitrate) was investigated, yielding efficiencies of 42%, 55%, an‎d 65% in the presence of 5, 10, an‎d 20 mg of nanofibers, respectively. Results indicated that increasing the dye concentration from 5 ppm to 20 ppm decreased the photodegradation efficiency from 65% to 27%. After 5 cycles of recovery an‎d reuse, the photodegradation efficiencies were 55%, 55%, 50%, 44%, an‎d 24%, indicating a decline in photocatalytic performance after the second cycle. The degradation isotherm of Methylene Blue followed the Freundlich model, an‎d its degradation kinetics followed the pseudo-first-order kinetic model. The antibacterial activity of the samples was eva‎luated using the disk diffusion method against Gram-positive (Staphylococcus aureus) an‎d Gram-negative (Escherichia coli) bacteria. The sample containing 15% silver exhibited antibacterial activity with an inhibition zone of 1 mm. The lack of bacterial growth at contact points with the PAN/DABC nanofibers an‎d the sample containing 10% silver was attributed to the local antibacterial capability (contact inhibition) of the samples.

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فرزانه علي حسيني

اكبر خدامي , حسين فشندي