Fabrication of cellulose acetate/polybenzoxazine cross-linked electrospun nanofibrous membrane for water treatment

Abstract

Herein, polybenzoxazine based cross-linked cellulose acetate nanofibrous membrane exhibiting enhanced thermal/mechanical properties and improved adsorption efficiency was successfully produced via electrospinning and thermal curing. Initially, suitable solution composition was determined by varying the amount of the benzoxazine (BA-a) resin, cellulose acetate (CA) and citric acid (CTR) to obtain uniform nanofibrous membrane via electrospinning. Subsequently, thermal curing was performed by step-wise at 150, 175, 200 and 225°C to obtain cross-linked composite nanofibrous membranes. SEM images and solubility experiments demonstrated that most favorable result was obtained from the 10% (w/v) CA, 5% (w/v) BA-a and 1% (w/v) CTR composition and cross-linked nanofibrous membrane (CA10/PolyBA-a5/CTR1) was obtained after the thermal curing. Chemical structural changes (ring opening) occurred by thermal curing revealed successful cross-linking of BA-a in the composite nanofibrous membrane. Thermal, mechanical and adsorption performance of pristine CA and CA10/PolyBA-a5/CTR1 nanofibrous membranes were studied. Char yield of the pristine CA nanofibrous membrane has increased notably from 12 to 24.7% for composite CA10/PolyBA-a5/CTR1 membrane. When compared to pristine CA membrane, CA10/PolyBA-a5/CTR1 nanofibrous membrane has shown superior mechanical properties having tensile strength and Young's modulus of 8.64±0.63MPa and 213.87±30.79MPa, respectively. Finally, adsorption performance of pristine CA and CA10/PolyBA-a5/CTR1 nanofibrous membranes was examined by a model polycyclic aromatic hydrocarbon (PAH) compound (i.e. phenanthrene) in aqueous solution, in which CA10/PolyBA-a5/CTR1 nanofibrous membrane has shown better removal efficiency (98.5%) and adsorption capacity (592μg/g).

Nanofiber-Based Materials for Persistent Organic Pollutants in Water Remediation by Adsorption

“…Hydrophobic interactions led to a contaminant removal of 97% (Table 20, N2). Cross-linking of cellulose acetate nanofibers with benzene rings by polybenzoxazine provided a hydrophobic adsorptive structure [113]. The adsorbent benzene rings further enabled π-π interactions with Phenantrene aromatic rings, thus leading to 98.5% contaminant removal ( Phenantrene via molecular filtration, by inclusion-complexation of the hydrophobic contaminants in the apolar cyclodextrin cavity [112].…”

“…Regarding the adsorption performance, engineered nanofibers yielded over 95% removal efficiency with high adsorption capacities comparable to granular activated carbons and acid-treated biomass. For example, activated carbon nanofibers against Phenol showed a capacity of 256.1 mg/g (Table 7, N20), and cross-linked cellulose acetate-polybenzoxazine nanofibers demonstrated against Phenantrene 98.5% removal (Table 20, N1) [61,113]. Such a nanofiber web presented adequate structural and chemical surface characteristics for the adsorption of organic contaminants.…”

“…The tuning of the carbon adsorbent surface chemistry to shift its isoelectric point could also be investigated to improve the contaminant adsorption by electrostatic interaction contribution. Other structures such as cellulose acetate crosslinked with polybenzoxazine lead to a highly hydrophobic surface presenting unsaturated bonds, resulting in high performance in the capture of Phenantrene [113]. Material functionalisation to reach a surface chemistry allowing the three adsorption mechanism defined above could be the focus of future research in order to yield complete contaminant removal.…”

“…Compared to hydrophobic interactions, electrostatic interactions and foremost electron interactions were shown to be more efficient adsorption mechanisms [41,113]. To this end, adsorbent isoelectric point should be systematically determined to improve the contribution of electrostatic interactions in the contaminant capture.…”

Fabrication of lightweight and flexible cellulose acetate composite nanofibers for high‐performance ultra violet protective materials

“…In the literature , electrospinning of continuous CA nanofibers without beads used by a single solvent is not reported due to a wide range of technical challenges. Therefore, a variety of binary solvents with various ratios has been used such as Ac:water (3:1 and 4:1) , acetic acid:water (3:1) , acetic acid:Ac (1:1) , Ac:dimethyl sulfoxide (DMSO) (2:1) , dichloromethane (DCM):Ac (1:1, 3:1, and 5:1) , DMAc:DMSO (55:45) , Ac:DMAc (2:1) , and DCM: methanol (4:1) . In this work, it was found that the CA solution for the first time could be continuously electrospun nanofibers using binary solvents of Ac:DMAc (3:1).…”