Chuanhui Xu

Adsorption of Cu(II), Zn(II), and Pb(II) from aqueous single and binary metal solutions by regenerated cellulose and sodium alginate chemically modified with polyethyleneimine

In this paper, crosslinked cellulose/sodium alginate (SA) was modified with polyethyleneimine (PEI) as an adsorbent (PEI-RCSA) for comparative and competitive adsorption of Cu(II), Zn(II), and Pb(II) in single and binary aqueous solutions. FTIR, SEM, TGA and specific surface area analysis were used to characterize the structural characteristics of PEI-RCSA. The effects of initial pH of solutions, contact time and initial concentration of heavy metal ions on the adsorption capacity of PEI-RCSA were investigated. The experimental results revealed that the removal of metal ions on the PEI-RCSA was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 5–6. The adsorption kinetics were followed by a pseudo-second-order kinetics model, and the diffusion properties played a significant role in the control of the adsorption kinetics. Meanwhile, adsorption isotherms were successfully described by the Langmuir model in a single aqueous solution system. The maximum adsorption capacities of PEI-RCSA for Cu(II), Zn(II), and Pb(II) in a single system were 177.1, 110.2 and 234.2 mg g−1, respectively. The binary-component system was better described with the Langmuir competitive isotherm model. The removal efficiencies didnt change significantly when three adsorption–desorption experimental cycles were conducted. All the above results indicated that PEI-RCSA has promising applications in the treatment of toxic metal pollution.

Preparation and characterization of individual chitin nanofibers with high stability from chitin gels by low-intensity ultrasonication for antibacterial finishing

AbstractIndividual chitin nanofibers with high stability were feasibly prepared from chitin gel via low-intensity ultrasonication. The morphology of the treated gel could be controlled from nanoparticles to nanofibers by simply adjusting the ultrasonic time. The nanofibers had a nanoscaled width and an average length of 650xa0nm. Compared with original chitin gel, the chemical structure, α-chitin crystalline structure and thermo stability of chitin nanofibers were well maintained after the treatment. TGA results proved that nanofibers were obtained by hydrogen bonding structure’s reorganization of chitin gel which was driven by ultrasonication. These nanofibers had high suspension stability and were used as finishing agent for cotton fabric. The SEM result showed that chitin nanofibers had good compatibility to cotton fabrics. The finished cotton fabric had a low color difference of 4.88 to raw cotton fabric and an antibacterial activity with 99% bacterial reductions. Our results indicate that this cost-effective and eco-friendly product holds immense potential value in textile industry for antibacterial finishing application.n