Expanded spinel ZnxMn2O4 induced by electrochemical activation of glucose - mediated manganese oxide for stable cycle performance in zinc - ion batteries.

Rechargeable aqueous Zn - MnOx batteries show great potential for grid - scale storage due to cost - effectiveness and high safety. However, most of MnOx cathodes suffer from irreversible phase transformation into spinel ZnMn2O4 with reduced electrochemical activity after repeated charge/discharge cycles, leading to severe capacity decay. Herein, we reveal a strategic design utilizing glucose as the mediating agent to prepare nanostructured MnO/Mn3O4 material, which can be then transformed into lattice - expanded ZnxMn2O4 nanoparticles by electrochemical activation. The expanded structure of ZnxMn2O4 allows better accommodation of Zn2+ and H+ ions and undergoes reversible lattice expansion/contraction during charge/discharge process. Therefore, the lattice - expanded ZnxMn2O4 retains 121 mAh g-1 after 2000 cycles at 1 A g-1, exhibiting stable cycle performance in comparison with the parent MnO2 (63 mAh g-1) and well - crystalline ZnMn2O4 (58 mAh g-1). Moreover, through the comparison of MnO/Mn3O4, Mn3O4/MnO2, and pure Mn3O4 samples, MnO is found to play an important role in forming lattice - expanded spinel structure during the activation process.

Preparation of N,O-carboxymethyl chitosan nanoparticles as an insulin carrier.

The aim of this research was to develop pH-sensitive insulin-loaded NOCC (N,O-carboxymethyl chitosan) nanoparticles for the controlled release of insulin via the oral route. Thus, in this study, insulin-loaded NOCC nanoparticles were prepared by ionic gelation of NOCC with TPP (tripolyphosphate). NOCC nanoparticles were formed at conditions of 2 mg/ml of NOCC and 1 mg/ml of TPP. It was found that the encapsulation efficiency and process yield decreased with increasing NOCC to TPP weight ratio. Furthermore, the cumulative release of insulin from insulin-loaded NOCC nanoparticles decreased with decreasing NOCC-to-TPP weight ratio, but it increased with decreasing the initial concentration of insulin. The higher the pH of the phosphate buffered saline, the greater the amount of cumulative release of insulin-loaded NOCC nanoparticles, and thus they could protect insulin from acid.

Controlled release study of 5-fluorouracil-loaded chitosan/polyethylene glycol microparticles.

The aim of this research is to reduce the frequency of taking therapeutic drugs. Thus, anti-cancer drug [5-fluorourical (5-FU)] loaded chitosan/polyethylene glycol microparticles were prepared by a phase-inversion technique with tripolyphosphate (TPP) used as a cross-linking agent. The relationships between 5-FU release behavior/encapsulation efficiencies and chitosan concentrations, TPP concentrations, as well as cross-linking time were studied to identify better/superior conditions (3.5 wt% chitosan, 3 wt% TPP, and cross-linking time = 4 h) for preparing 5-FU-loaded microparticles. Furthermore, in order to ascertain the influence of their physical properties on 5-FU release performance, 5-FU-loaded microparticles were evaluated by swelling tests and scanning electron microscopy.

Adsorption and recovery of lead(II) from aqueous solutions by immobilized Pseudomonas Aeruginosa PU21 beads.

In this study, immobilized Pseudomonas aeruginosa PU21 beads were used as an adsorbent for lead(II). Different weight percentages of chitosan were added to polyethylene glycol (PEG, 0.5 wt.% in aqueous solution) and alginate (18 wt.% in aqueous solution), and then blended or cross-linked using different concentrations of epichlorohydrin (ECH) to prepare beads of different sizes and increased mechanical strength. Before blending or cross-linking, different weight percentages of P. aeruginosa PU21 were added to increase lead(II) adsorption. Subsequently the optimized bead composition (concentration of ECH, percentages of chitosan and P. aeruginosa PU21) and the optimum adsorption conditions (agitation rate and pH in the aqueous solution) were ascertained. Finally, the optimized beads adsorbing lead(II) were regenerated by 0.1M aqueous HCl solutions and the most effective desorption agitation rate was ascertained. The results indicate that the reuse of immobilized P. aeruginosa PU21 beads was feasible. In addition, the equilibrium adsorption, kinetics, changes in the thermodynamic properties of adsorption of lead(II) on optimized beads were also investigated.

Remediation of soil contaminated with the heavy metal (Cd2+).

Soil contamination by heavy metals is increasing. The biosorption process for removal of the heavy metal Cd(2+) from contaminated soil is chosen for this study due to its economy, commercial applications, and because it acts without destroying soil structure. The study is divided into four parts (1) soil leaching: the relationships between the soil leaching effect and agitation rates, solvent concentrations, ratios of soil to solvent, leaching time and pH were studied to identify their optimum conditions; (2) adsorption Cd(2+) tests of immobilized Saccharomycetes pombe beads: different weight percentages of chitosan and polyvinyl alcohol (PVAL) were added to alginate (10 wt.%) and then blended or cross-linked by epichlorohydrin (ECH) to increase their mechanical strength. Next, before blending or cross-linking, different weight percentages of S. pombe 806 or S. pombe ATCC 2476 were added to increase Cd(2+) adsorption. Thus, the optimum beads (blending or cross-linking, the percentages of chitosan, PVAL and S. pombe 806 or S. pombe ATCC 2476) and the optimum adsorption conditions (agitation rate, equilibrium adsorption time, and pH in the aqueous solution) were ascertained; (3) regeneration tests of the optimum beads: the optimum beads adsorbing Cd(2+) were regenerated by various concentrations of aqueous HCl solutions. The results indicate that the reuse of immobilized pombe beads was feasible; and (4) adsorption model/kinetic model/thermodynamic property: the equilibrium adsorption, kinetics, change in Gibbs free energy of adsorption of Cd(2+) on optimum beads were also investigated.