2 research outputs found
Supported Ionic Liquid Membranes for Removal of Dioxins from High-Temperature Vapor Streams
Dioxins and dioxin-like chemicals are predominantly produced by thermal processes such as incineration and combustion at concentrations in the range of 10–100 ng of I-TEQ/kg (I-TEQ = international toxic equivalents). In this work, a new approach for the removal of dioxins from high-temperature vapor streams using facilitated supported ionic liquid membranes (SILMs) is proposed. The use of ceramic membranes containing specific ionic liquids, with extremely low volatility, for dioxin removal from incineration sources is proposed owing to their stability at very high temperatures. Supported liquid membranes were prepared by successfully immobilizing the ionic liquids tri-C<sub>8</sub>–C<sub>10</sub>-alkylmethylammonium dicyanamide ([Aliquat][DCA]) and 1-<i>n</i>-octyl-3-methylimidazolium dicyanamide ([Omim][DCA]) inside the porous structure of ceramic membranes. The porous inorganic membranes tested were made of titanium oxide (TiO<sub>2</sub>), with a nominal pore size of 30 nm, and aluminum oxide (Al<sub>2</sub>O<sub>3</sub>), with a nominal pore size of 100 nm. The ionic liquids were characterized, and the membrane performance was assessed for the removal of dioxins. Different materials (membrane pore size, type of ionic liquid, and dioxin) and different operating conditions (temperature and flow rate) were tested to evaluate the efficiency of SILMs for dioxin removal. All membranes prepared were stable at temperatures up to 200 °C. Experiments with model incineration gas were also carried out, and the results obtained validate the potential of using ceramic membranes with immobilized ionic liquids for the removal of dioxins from high-temperature vapor sources
Hydrogel Composite Membranes Incorporating Iron Oxide Nanoparticles as Topographical Designers for Controlled Heteronucleation of Proteins
In
this study, we exploited the possibility of tuning physical–chemical
properties of hydrogel composite membranes (HCMs) surfaces, by using
iron oxide nanoparticles (NPs) as topographical designers, with the
aim of examining the effect of surface topography and wettability
on the heterogeneous nucleation of protein crystals. On the basis
of roughness and contact angle measurements, it was found that surface
structural characteristics, in addition to chemical interactions between
the surface and protein molecules, have influence on the heterogeneous
nucleation of lysozyme and thermolysin crystals to different extents.
We demonstrated that increasing the amount of NPs incorporated in
the hydrogel matrix promotes protein nucleation to a higher extent,
potentially due to the increase of local solute concentration, arising
from the enhanced wetting tendency in the Wenzel regime, and physical
confinement at rougher hydrophilic surfaces. An extensive crystallographic
analysis suggested the tendency of the growing crystals to incorporate
hydrogel materials, which allows inducement of protein conformational
states slightly different from those covered by standard crystallization
methods. Protein flexibility can be thus sampled by changing the amount
of NPs in the HCMs, with negligible influence on the quantity and
quality of X-ray diffraction data