Study on Synthesis and Characterization of Porous Microspheres with Pendant Amine Groups

Porous microspheres of glycidyl methacrylate cross-linked with trimethylolpropane trimethacrylate were prepared with toluene as porogen by suspension–emulsion polymerization. With increasing molar ratio of the functional monomer to cross-linker, the epoxy group content increases significantly, whereas the parameters of porous structure (specific surface area and total pore volume) decrease. To obtain adsorbents bearing functional groups, the porous methacrylate network was modified by subsequent treatment with diethylenetriamine. Polymers capacity towards Cu(II), Zn(II), Pb(II) and Cd(II) was investigated

Adsorption of Uranyl Ions at the Nano-hydroxyapatite and Its Modification

Abstract Nano-hydroxyapatite and its modification, hydroxyapatite with the excess of phosphorus (P-HAP) and hydroxyapatite with the carbon ions built into the structure (C-HAP), were prepared by the wet method. They were studied by means of XRD, accelerated surface area and porosimetry (ASAP), and SEM. The size of crystallites computed using the Scherrer method was nano-hydroxyapatite (HAP) = 20 nm; P-HAP—impossible to determine; C-HAP = 22 nm; nano-HAP/U(VI) = 13.7 nm; P-HAP/U(VI)—impossible to determine, C-HAP/U(VI) = 11 nm. There were determined basic parameters characterizing the double electrical layer at the nano-HAP/electrolyte and P-HAP/electrolyte, C-HAP/electrolyte inter faces: density of the surface charge and zeta potential. The adsorption properties of nano-HAP sorbent in relation to U(VI) ions were studied by the batch technique. The adsorption processes were rapid in the first 60 min and reached the equilibrium within approximately 120 min (for P-HAP) and 300 min (for C-HAP and nano-HAP). The adsorption process fitted well with the pseudo-second-order kinetics. The Freundlich, Langmuir–Freundlich, and Dubinin–Radushkevich models of isotherms were examined for their ability to the equilibrium sorption data. The maximum adsorption capabilities (q m ) were 7.75 g/g for P-HAP, 1.77 g/g for C-HAP, and 0.8 g/g for HAP at 293 K

Hydroxyapatite composites with multiwalled carbon nanotubes

The structure of composites based on hydroxyapatite filled with multiwalled carbon nanotubes was investigated using differential scanning calorimetry analysis and X-ray diffraction spectroscopy. Hydroxyapatite was prepared by the wet synthesis in the presence of pristine and oxidised carbon nanotubes. An influence of nature of functional groups of the nanotubes boundary layer on a crystallinity of the inorganic part was evaluated using differential scanning calorimetry analysis and X-ray diffraction spectroscopy. Morphology of composites obtained was studied by nitrogen adsorption/desorption technique and scanning electron microscopy. The hydroxyapatite/nanotubes interface was characterised using electrochemical methods. The parameters of the electrical double layer: A density of surface charge versus pH, zeta potential versus pH were described. The study has shown that the synthesis of hydroxyapatite/nanotube composites by formation of inorganic part in the presence of carbon filler significantly affect the microstructure, phase composition, crystallinity, hydroxyl content, chemical composition of the mineral part, as well as thermal properties and electrokinetic properties of composite

Effect of Carbon Nanotubes Surface Modification on Structure of Forcibly Ordered Films of Filled Polystyrene

The effect of surface modification of multi-walled carbon nanotubes (MWCNTs) with different modifiers on the filler dispersibility in polystyrene and the influence of the external magnetostatic field on the structure of obtained composites have been studied. The surface modification of as-synthesised and oxidized carbon nanotubes was performed by treatment with hydrochloric acid or ammonia hydroxide solutions. The composite films were casted on glass plates with or without the influence of magnetostatic field at the desired directions of the magnetic lines. A combination of MWCNTs surface treatment and directed influence of the magnetostatic field was shown to be an effective route to change the structure of composites