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A chitosan-based composite named poly(1-vinylimidazole)-chitosan (PVI-CS) was fabricated employing a microwave-assisted protocol to be used as a novel composite for CdII contaminated water. The prepared PVI-CS composite was evaluated using SEM-coupled EDX, FTIR and zeta potential analyses. Under certain experimental conditions of the batch process, the binding behavior of PVI-CS sorbent against CdII ions was investigated. Results demonstrate that the optimized experimental conditions for CdII ions removal by PVI-CS composite sorbent were to be pH 7.2, the PVI-CS dose 2.5 g/L and the CdII concentration 25 mg/L at 30 °C. The Langmuir qmax of the PVI-CS turned out to be 204.92 mg/g for CdII ions. The kinetics analysis revealed that the process was best-fitted for pseudo-first-order kinetics with R2 > 0.999. The CdII ions removal efficiency of PVI-CS sorbent remained satisfactory even after five cycles, which establish that PVI-CS is a sustainability composite for an effective water purification system.

Copper oxide/chitosan nanocomposite (CCNC) specimens were fabricated via a simple solvent evaporation route. The presence and intercalation of chitosan and CuO within the nanocomposites were explored using advanced analytical techniques of X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive X-ray analyses and the scanning electron microscopy. The prepared nanocomposite was then incorporated into poly(vinyl alcohol) (PVA) matrix to fabricate a tricomponent composite. The resultant tricomponent composite was characterized for various chemo–physical and mechanical properties using differential scanning calorimetry (DSC) and the mechanical testing. The DSC results indicated that the glass transition temperature of PVA decreased on incorporating the CCNC into the PVA matrix; this also enhanced the tensile strength and flexibility of the resulting films. The prepared tricomponent films may find potential applications in sensing and catalysis.

Herein, flexible, strong and optically tunable nano-CuO-loaded poly(vinyl alcohol) (PVA) composite films were fabricated by means of solution casting approach. The nanocomposite films were characterized using advanced analytical techniques. A small loading with CuO nanofiller resulted in prominent modifications of structural and optomechanical attributes of PVA-based nanocomposites. The comprehensive band structure and mechanical investigations of the prepared samples have been reported. The loading with just 0.5 wt% CuO nanofiller in PVA resulted in significant changes in direct band gap (5.29 to 3.16 eV), indirect band gap (4.91 to 2.88 eV), Urbach energy (0.22 to 1.12 eV), dispersion energy (1.45 to 1.92 eV), oscillator energy (5.74 to 3.25 eV), tensile strength (25.6 to 42.2 MPa), Young’s modulus (144 to 215 MPa), elongation at break (152.4 to 206.1%) and the flexural strength (4.1 to 32.2 MPa). The optical band gap calculated using Tauc’s relation, Wemple and DiDomenico single oscillator model and dielectric loss approach resulted in nearby values. Various theoretical models were employed to validate the experimentally determined Young’s moduli values. A possible application of such nanocomposite films might be in optoelectronic devices.

Herein, we used chemical precipitation method to synthesize cadmium sulfide (CdS) nanoparticles (NPs) with different concentrations of CdNO3. The CdS NPs of size 105 nm and the corresponding zeta potential of 42.2 mV were achieved at CdNO3 concentration of 1 mM. X-ray diffraction (XRD) analysis revealed W-type hexagonal geometry of CdS NPs. The prepared CdS NPs were introduced into poly(hydroxybutyrate) (PHB) matrix to fabricate CdS/PHB composite nanomaterial. The physicochemical characterization showed successful synthesis of a novel nanocomposite. The XRD analysis showed that CdS/PHB nanocomposite exhibited hexagonal crystal structure, i.e., crystallite orientation of nanocomposite was majorly controlled by CdS NPs. Scanning electron micrographs of CdS NPs and CdS/PHB nanocomposite revealed spherical morphology of CdS NPs and their successful placement into PHB matrix with some random aggregations. The results were further confirmed using transmission electron microscopy (TEM) and a high-resolution TEM. Thermogravimetric analysis showed improved thermal characteristics of nanocomposites after incorporation of CdS NPs into PHB matrix.

The use of nontoxic, biodegradable and biocompatible biopolymers such as chitosan and cellulose is of considerable importance particularly in uptake of metal ions from the contaminated water systems. Current study was aimed to develop a chitosan-based biosorbent in combination with cellulose to form composite adsorbent beads. The developed composite beads were chemo-physically characterized using advanced analytical techniques of scanning electron microscope, Fourier transform infrared, x-ray diffraction and thermogravimetric analysis. The point of zero charge (PZC) of the developed beads was determined using the methods of salt addition, electrokinetic potential and the mass atitration. The average value of PZC of composite beads was found to be 7.26 using the said methods. On incorporating cellulose into chitosan, the thermal properties of the composite beads were considerably enhanced. The adsorption capacity of chitosan–cellulose beads was found to be 99.8, 79.98 and 99.10 mg/g for Ni(II), Cu(II) and Cr(III), respectively. The adsorption extent showed that the developed composite beads could be employed as adsorbent for wastewater treatment.

A Taguchi design was employed to optimize the recipe for in vitro antibacterial activity of polyester fabric treated with chitosan nanoparticles (CNPs), which were prepared using sodium tripolyphosphate as cross-linker under ionic gelation method. The CNPs treated polyester fabric with recommended recipe under Taguchi design showed about 5 mm zone of inhibition against E. coli and 5.5 mm against S. aureus. Scanning electron microscopy installed with an energy-dispersive x-ray detector was used to observe the morphology and presence of CNPs on the treated fabric. Based on statistical design, it was found that optimum process conditions were 15 g/l of CNPs, 90 g/l of cross-linker and 140 °C curing temperature. Analysis of variation indicated that the concentration of CNPs and cross-linker significantly affected the antibacterial properties of polyester fabric. Finally, a validation run confirmed the authenticity of proposed recipe. The polyester fabric showed good antibacterial activity with minimum loss of its inherent textile properties.

Purpose of present study was to investigate the effect of different nanofillers doping on structural and thermal properties of poly(vinyl alcohol) (PVA)-based nanocomposite films. Herein, ZnO nanoparticles (NPs), CuO NPs, graphene oxide and reduced graphene oxide (RGO) nanosheets have been used as separate nanofillers in the formation of PVA nanocomposite films via solution casting approach. The prepared composite films were characterized using X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry and tensile strength testing. The results demonstrate the effect of various nanofillers on glass transition temperature (Tg), melting temperature (Tm), crystallization temperature (Tc), percentage crystallinity (%χc) and tensile strength of composite films. A doping with (0.02 wt%) RGO nanosheets caused significant influence on thermal properties and tensile strength of PVA composite films as compared to other test nanofillers. The doping with RGO nanosheets resulted in elevation of Tg (48.2 °C), Tm (218.3 °C), Tc (157.8 °C) and %χc (41.9%) as compared to that of pure PVA (Tg 38.4 °C, Tm 190.4 °C, Tc 115.1 °C and %χc 22.2%). Overall, the doping of PVA with graphene-based nanosheets exhibited better tensile strength and thermal stability of nanocomposite as compared with other tested nanofillers.