25 research outputs found
Cross‐Linked Multilayers of Poly(vinyl amine) as a Single Component and Their Interaction with Proteins
No full text
Versatile nanostructured \protect \text{SiO}_2/cross-linked polyelectrolyte composites for emerging pollutants removal from aqueous media
No full textLinear and branched poly(ethyleneimines) and poly(acrylic acid) have been used in the construction of nanostructured thin multilayer organic shell onto silica microparticles. After glutaraldehyde selective crosslinking of part of the amino groups, the polyanionic chains were removed on strong basic media. The core/shell microparticles, with amino groups active sites, could interact with anionic charged species dissolved in aqueous media. Batch/column experiments show that the polyanion extracted composites present the best performance toward gallic acid sorption (30 mg/g composite), as compared to the non-extracted samples (6 mg/g). The multiple sorption/desorption studies demonstrated the reusability of the composites for water/wastewater treatment applications in at least 10 consecutive cycles without significant loss of sorption capacity
Cross-linked multilayer films deposited onto silica microparticles with tunable selectivity for anionic dyes
No full textPolymer/Enzyme Composite Materials—Versatile Catalysts with Multiple Applications
No full textA significant interest was granted lately to enzymes, which are versatile catalysts characterized by natural origin, with high specificity and selectivity for particular substrates. Additionally, some enzymes are involved in the production of high-valuable products, such as antibiotics, while others are known for their ability to transform emerging contaminates, such as dyes and pesticides, to simpler molecules with a lower environmental impact. Nevertheless, the use of enzymes in industrial applications is limited by their reduced stability in extreme conditions and by their difficult recovery and reusability. Rationally, enzyme immobilization on organic or inorganic matrices proved to be one of the most successful innovative approaches to increase the stability of enzymatic catalysts. By the immobilization of enzymes on support materials, composite biocatalysts are obtained that pose an improved stability, preserving the enzymatic activity and some of the support material’s properties. Of high interest are the polymer/enzyme composites, which are obtained by the chemical or physical attachment of enzymes on polymer matrices. This review highlights some of the latest findings in the field of polymer/enzyme composites, classified according to the morphology of the resulting materials, following their most important applications
Poly(N,N-dimethylamino)ethyl methacrylate/sodium alginate multilayers and their interaction with proteins/enzymes
No full textSingle polyelectrolyte multilayers deposited onto silica microparticles and silicon wafers
No full textSilica-Based Composite Sorbents for Heavy Metal Ions Removal from Aqueous Solutions
No full textWeak polyelectrolyte chains are versatile polymeric materials due to the large number of functional groups that can be used in different environmental applications. Herein, one weak polycation (polyethyleneimine, PEI) and two polyanions (poly(acrylic acid), PAA, and poly(sodium methacrylate), PMAA) were directly deposited through precipitation of an inter-polyelectrolyte coacervate onto the silica surface (IS), followed by glutaraldehyde (GA) crosslinking and extraction of polyanions chains. Four core–shell composites based on silica were synthesized and tested for adsorption of lead (Pb2+) and nickel (Ni2+) as model pollutants in batch sorption experiments on the laboratory scale. The sorbed/desorbed amounts depended on the crosslinking degree of the composite shell, as well as on the type of anionic polyelectrolyte. After multiple loading/release cycles of the heavy metal ions, the maximum sorption capacities were situated between 5–10 mg Pb2+/g composite and 1–6 mg Ni2+/g composite. The strong crosslinked composites (r = 1.0) exhibited higher amounts of heavy metal ions (Me2+) sorbed than the less crosslinked ones, with less PEI on the surface but with more flexible chains being more efficient than more PEI with less flexible chains. Core–shell composites based on silica and weak polyelectrolytes could act as sorbent materials, which may be used in water or wastewater treatment
Polyelectrolyte Multilayers: An Overview on Fabrication, Properties, and Biomedical and Environmental Applications
No full textPolyelectrolyte multilayers are versatile materials that are used in a large number of domains, including biomedical and environmental applications. The fabrication of polyelectrolyte multilayers using the layer-by-layer technique is one of the simplest methods to obtain composite functional materials. The properties of the final material can be easily tuned by changing the deposition conditions and the used building blocks. This review presents the main characteristics of polyelectrolyte multilayers, the fabrication methods currently used, and the factors influencing the layer-by-layer assembly of polyelectrolytes. The last section of this paper presents some of the most important applications of polyelectrolyte multilayers, with a special focus on biomedical and environmental applications
Design of silica microparticles with oligopeptide brushes and their interaction with proteins
No full text
