Preparation and characterization of chitosan-boehmite nanocomposite membranes for pervaporative ethanol dehydration

Evaluation of the biological, physical, mechanical and chemical properties of orthodontic primer modified by nano-chitosan loaded with bioactive materials

Objective

The primary objective was to evaluate the antibacterial and remineralizing effects of modified orthodontic primer containing nano-chitosan loaded with bioactive materials (gallic acid and calcium phosphate). The secondary objectives were to assess the physical, mechanical, and chemical properties of the adhesive primer.

Materials and methods

The chitosan loaded with gallic acid and calcium phosphate was prepared and characterized by FESEM-EDX. Then it was mixed with Transbond XT primer at two different concentrations to prepare 3 groups: Control, 5 % and 10 % Nano-Chitosan/Gallic acid + Calcium Phosphate Primer (NC/GACP). The primer groups were evaluated based on their Shear Bond Strength (SBS), Adhesive Remanent Index (ARI), Wettability, Degree of Conversion (DC), Antibacterial and Remineralization properties. Statistical analysis was conducted using one-way ANOVA and Tukey's post hoc test, all significant differences were set at P < 0.05.

Results

The modified primer groups containing 5 % and 10 % NC/GACP showed a significant increase (P < 0.05) in SBS and DC compared to the control group, with no significant differences observed in wettability. The ARI scores were mainly 3 meaning all the adhesive remained on the enamel after debonding. Additionally, both modified primer groups exhibited significant antibacterial activity (P < 0.05). Furthermore, the 5 % NC/GACP primer group showed the highest calcium and phosphate weight percentages and Ca/P ratio compared to the other groups (P < 0.05).

Conclusions

The orthodontic primer modified by nano-chitosan/gallic acid + calcium phosphate can be considered a novel antimicrobial and remineralizing adhesive that enhances the physical, chemical and mechanical properties of the adhesive.

Design of chitosan/boehmite biocomposite for the removal of anionic and nonionic dyes from aqueous solutions: Adsorption isotherms, kinetics, and thermodynamics studies

This study introduces a chitosan/boehmite biocomposite as an efficient adsorbent for removing anionic Congo Red (CR) and non-ionic Bromothymol Blue (BTB) from water. Boehmite nanoparticles were synthesized using the Sol-gel method and then attached to chitosan particles using sodium tripolyphosphate through co-precipitation method. Characterized through FTIR, FE-SEM, BET, and XRD, the biosorbent displayed structural integrity with optimized pH conditions of 3 for CR and 4 for BTB, achieving over 90 % adsorption within 30 min. Pseudo second order kinetics model and Langmuir isotherm revealed monolayer sorption with capacities of 64.93 mg/g for CR and 90.90 mg/g for BTB. Thermodynamics indicated a spontaneous and exothermic process, with physisorption as the primary mechanism. The biosorbent demonstrated excellent performance and recyclability over five cycles, highlighting its potential for eco-friendly dye removal in contaminated waters.

Chitosan as a matrix of nanocomposites: A review on nanostructures, processes, properties, and applications

Chitosan is a biopolymer that is natural, biodegradable, and relatively low price. Chitosan has been attracting interest as a matrix of nanocomposites due to new properties for various applications. This study presents a comprehensive overview of common and recent advances using chitosan as a nanocomposite matrix. The focus is to present alternative processes to produce embedded or coated nanoparticles, and the shaping techniques that have been employed (3D printing, electrospinning), as well as the nanocomposites emerging applications in medicine, tissue engineering, wastewater treatment, corrosion inhibition, among others. There are several reviews about single chitosan material and derivatives for diverse applications. However, there is not a study that focuses on chitosan as a nanocomposite matrix, explaining the possibility of nanomaterial additions, the interaction of the attached species, and the applications possibility following the techniques to combine chitosan with nanostructures. Finally, future directions are presented for expanding the applications of chitosan nanocomposites.