4 research outputs found
Salix viminaliswood as a new precursor for manufacturing of carbon molecular sieves for effective methane/nitrogen separation
Nanoscale Phenomena Occurring during Pyrolysis of Salix viminalis Wood
Selective utilisation of unique properties of Salix viminalis wood enables preparation of materials of nanotechnologic properties. Thermal decomposition of lignin-cellulose organic matter results in the formation of a nanostructured porous carbon matrix (charcoal). Narrowed pore size distribution (PSD) in the subnanometer range allows to consider the charcoals as carbon molecular sieves (CMSs), which are capable of separating even chemically inert gases like neon, krypton, and nitrogen. High tolerance of Salix viminalis to heavy metal ions enables enriching living plant tissues with metal ions like lanthanum and manganese. Such ions may later form LaMnO3 with parallel transformation of plant tissues (organic matter) to carbon matrix using a heat treatment. In this way, one gets a hybrid material: a porous carbon matrix with uniformly suspended nanocrystallites of LaMoO3. The crystallites are in the catalytically active phase during the conversion of n-butanol to heptanone-4 with high yield and selectivity
Effect of Salix viminalis Pyrolysis Derived Antioxidants on Oxidative Stability of Diesters and DiesterâPoly-α-olefin Mixtures
The fabrication of molecular sieves and carbon-based
adsorbents
by pyrolysis of lignocellulosic material, such as Salix
viminalis wood, generates a considerable amount of
pyrolysis oil which has no specific application. In the present paper,
we investigate phenolic components of S. viminalis derived pyrolysis oil with regard to their potential application
to the oxidative stabilization of synthetic lubricating oils. Two
phenolic fractions were isolated through solvent extraction (extract
A was ether soluble; extract B was methylene chloride soluble) and
characterized by chromatographic analysis. High levels of 2,6-dimethoxyphenol
and its para-substituted derivatives were attributed to a rather atypical
composition of S. viminalis lignin.
The antioxidative effect of pyrolysis-derived polyphenols on diesters
and their blends with poly-α-olefins was studied by means of
a high temperature oxidation test combined with spectroscopic (NMR
and FT-IR) product analysis. The test proved that the antioxidant
capacity of each extract is high, at the level of ca. 1000 ppm. Extract
A had the highest increase in the induction period (170 h), and compared
with the commercial BHT antioxidant, it prolonged the lag phase ca.
3.3 times. The effect of the <i>o</i>-methoxy and para substituents,
intramolecular hydrogen bonding of the hydroxyl H atom, and synergetic
interactions on the antioxidant activity is discussed
The Origin of Amphipathic Nature of Short and Thin Pristine Carbon NanotubesâFully Recyclable 1D WaterâinâOil Emulsion Stabilizers
Abstract Short and thin pristine carbon nanotubes (CNTs) emerge as 1D emulsion stabilizers capable of replacing aquatoxic lowâmolecular surfactants. However, inconsistencies in understanding of waterâsolid interfaces for realistic CNTs hamper their individualizationâdriven functionalities, processability in benign media, and compatibility with a broadâscale of matrices. Pristine CNT processing based on water and inexpensive nâalkanes within a low energy regime would constitute an important step toward greener technologies. Therefore, structural CNT components are quantitatively assessed, placing various CNTs on the scale from hydrophobicity to hydrophilicity. This structural interweave can lead to amphipathicity enabling the formation of waterâinâoil emulsions. Combining experiments with theoretical studies, CNTs and CNT emulsions are comprehensively characterized establishing descriptors of the emulsifying behavior of pristine and purified CNTs. They emerge as having hydrophilic openâends, small number of oxygenâfunctionalized/vacancy surface areas, and hydrophobic sidewalls and full caps. The interplay of these regions allows short and thin CNTs to be utilized as fully recyclable 1D surfactants stabilizing water/oil emulsions which, as demonstrated, can be applied as paints for flexible conductive coatings. It is also shown how the amphipathic strength depends on CNT size, the pristineâtoâoxidized/vacancy domains and the oilâtoâwater ratios