Hussein H, H. Ragab A, S. Al-Radadi N. Synthesis and Characterization of Silica-Coated Oxyhydroxide Aluminum/Doped Polymer Nanocomposites: A Comparative Study and Its Application as a Sorbent

The present investigation is a comparison study of two nanocomposites: Nano-silica-coated oxyhydroxide aluminum (SiO2-AlOOH; SCB) and nano-silica-coated oxyhydroxide aluminum doped with polyaniline (SiO2-AlOOH-PANI; SBDP). The prepared nanocomposites were evaluated by monitoring the elimination of heavy metal Ni(II) ions from aquatic solutions. The synthesized nanocomposites were analyzed and described by applying scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) techniques, as well as Zeta potential distribution. In this study, two adsorbents were applied to investigate their adsorptive capacity to eliminate Ni(II) ions from aqueous solution. The obtained results revealed that SBDP nanocomposite has a higher negative zeta potential value (-47.2 mV) compared with SCB nanocomposite (-39.4 mV). The optimum adsorption was performed at pH 8, with approximately 94% adsorption for SCB and 97% adsorption for SBDP nanocomposites. The kinetics adsorption of Ni ions onto SCB and SBDP nanocomposites was studied by applying the pseudo first-order, pseudo second-order, and Mories-Weber models. The data revealed that the adsorption of Ni ions onto SCB and SBDP nanocomposites followed the pseudo second-order kinetic model. The equilibrium adsorption data were analyzed using three models: Langmuir, Freundlich, and Dubinin-Radusekevisch-Kanager Isotherm. It was concluded that the Langmuir isotherm fits the experimental results well for the SCB and SBDP nanocomposites. Thermodynamic data revealed that the adsorption process using SCB nanocomposites is an endothermic and spontaneous reaction. Meanwhile, the Ni ion sorption on SBDP nanocomposites is exothermic and spontaneous reaction.

Dual external field-responsive polyaniline-coated magnetite/silica nanoparticles for smart fluid applications

In this communication, an electromagnetorheological fluid containing Fe₃O₄/SiO₂/PANI nanoparticles is reported to demonstrate its controllable rheological properties under electric and magnetic fields.

Host-guest energetic nanocomposites based on self-assembly of multi-nitro organic molecules in nanochannels of mesoporous materials

Host-guest energetic nanocomposites have been synthesized by self-assembly of the high energy density compound HNIW in nanometer-scale channels of an ordered mesoporous material SBA-15. The complete impregnation of HNIW can be achieved in acetone solvent at ambient temperature, and the maximum amount was around 70 wt%. Structural characterizations were systematically provided by XRD, TEM, N(2) adsorption, TG, (13)C solid-state NMR and FT-IR. The tendency of multi-nitro organic molecules to self-assemble when the solvent evaporated has been described. Hydrogen bond interactions were considered as the main driving force, so the choices of matched host matrix and guest organic compounds were pivotal for implementing this process. The thermal properties of nanocomposites were measured by DSC analysis. Compared with pure HNIW and a physical mixture, the decomposition peak temperature of the confined crystals decreased about 11 °C, while the total amount of heat released slightly increased. This strategy can also be expanded to other similar host-guest systems.

Novel composite matrices modified with nanolayers of polymers as perspective materials for separation of biomolecules and bioanalysis

AIMS

A new approach for the preparation of adsorbents for one-step isolation/purification of DNA from different samples (e.g., bacterial lysates, smears and blood) has been developed.

MATERIALS & METHODS

The technique is based on the use of porous silica preliminary treated with ozone followed by grafting of polymer nanolayers on the activated carrier surface. The chemical nature of active centers, their stability and conditions for the use of the activated support as heterogeneous initiator of different macromolecular reactions were studied.

RESULTS

The adsorbents modified with thin (~3.0-7.5 nm) polytetrafluoroethylene and polyaniline layers were prepared and characterized. Sorption properties of the obtained adsorbents were demonstrated on examples of express (2-5 min) one-step DNA isolation for direct use in PCR diagnostics.

CONCLUSION

The effectiveness of the developed adsorbents used for DNA isolation and purification was confirmed in comparison with the standard methods. Thus, a facile (alternative in relation to irradiation postpolymerization or standard oxidative polymerization techniques) manufacturing method of the materials for nucleic acids sample preparation was developed.

Synthesis and characterization of conducting self-assembled polyaniline nanotubes/zeolite nanocomposite

Self-assembled conducting, paramagnetic polyaniline nanotubes have been synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in aqueous medium in the presence of zeolite HZSM-5, without added acid. The influence of initial zeolite/aniline weight ratio on the conductivity, molecular and supramolecular structure, paramagnetic characteristics, thermal stability, and specific surface area of polyaniline/zeolite composites was studied. The conducting (approximately 10(-2) S cm(-1)), semiconducting (3 x 10(-5) S cm(-1)), and nonconducting (5 x 10(-9) S cm(-1)) composites are produced using the zeolite/aniline weight ratios 1, 5, and 10, respectively. The coexistence of polyaniline nanotubes, which have a typical outer diameter of 70-170 nm and an inner diameter of 5-50 nm, accompanied by nanorods with a diameter of 60-100 nm and polyaniline/zeolite mesoporous aggregates, distinct from the morphology of microporous zeolite HZSM-5, was proved in the conducting nanocomposite by scanning and transmission electron microscopies. FTIR spectroscopy confirmed the presence of polyaniline in the form of conducting emeraldine salt and suggested significant interaction of polyaniline with zeolite. The evolution of molecular and supramolecular structure of polyaniline in the presence of zeolite was discussed.