Synthesis of Polyvinyl Alcohol/Coal Fly Ash Hybrid Nano-Fiber Membranes for Adsorption of Heavy Metals in Diesel Fuel

Some studies have shown that the heavy metal emissions (HMEs) emitted from diesel engines can seriously threaten human health. HMEs are mainly related to the content of heavy metal ions in diesel fuel. Therefore, in order to reduce HMEs from diesel engines, a nano-fiber membrane filtration technology for diesel fuel was investigated. Herein, coal fly ash (CFA) from coal-fired power plants combined with polyvinyl alcohol (PVA) was successfully fabricated into nano-fibrous membranes using green electrospinning technology. In order to evaluate the adsorption properties, various hybrid membranes with different mixing ratios (PVA/CFA = 10/0, 10/1, 10/3, 10/5, and 10/7 by weight) were fabricated. The results show that eight metal ions with different concentrations are found in the diesel fuel, including Pb, Cu, Zn, Al, Fe, Cr, Ba, and Ni. All PVA/FA membranes have different adsorption capacities for metal ions, following the order: Cu > Fe > Pb > Al > Zn > Cr > Ba > Ni. In addition, the adsorption capacity of CFA3 (PVA/CFA = 10/3) is the largest. The super lipophilicity of the PVA/FA membranes also provide more adsorption sites for the contact of HMs with the membranes. The above research results provide guidance for development of ultra-fine filters in the future.

Peptide-based Nanomaterials: Self-assembly and Applications

The self-assembly behavior of polypeptides is common in nature. Compared with monopeptides, polypeptide-based self-assembled nanomaterials with ordered structures have good thermal stability, mechanical stability, semi-conductivity, piezoelectric and optical properties. In recent years, the self-assembly of polypeptides has become a hot topic in the material science and biomedical field. By reasonably adjusting the molecular structure of the polypeptide and changing the external environment of the polypeptide, the polypeptide can be self-assembled or triggered by non-covalent bonding forces such as hydrogen bond, hydrophobicity, and π - π accumulation to form specific polypeptide assemblies such as nanoparticles, hydrogels, nanofibers, and micelles. Due to good biocompatibility and controllable degradability, polypeptide-based self-assembled nanomaterials have been widely used in the fields of nanotechnology, imaging technology, biosensor, and biomedical science. As a new drug delivery system, the polypeptide-drug conjugate has the advantages of low toxicity, high efficiency, enhanced drug stability, and avoiding side effects. This paper reviews the research progress of polypeptide-drug self-assembly nanostructure in recent years. Several structural models of polypeptide self-assembly technology and the mechanism of polypeptide self-assembly are introduced. Then the assembly form of polypeptide-drug self-assembly and the application of selfassembly compound therapy is described.