Pore-Mouth Structure of Highly Agglomerated Detonation Nanodiamonds

Detonation nanodiamond aggregates contain water that is removed by thermal treatments in vacuo, leaving available pores for the adsorption of target molecules. A hard hydrogel of detonation nanodiamonds was thermally treated at 423 K for 2 h, 10 h, and 52 h in vacuo to determine the intensive water adsorption sites and clarify the hygroscopic nature of nanodiamonds. Nanodiamond aggregates heated for long periods in vacuo agglomerate due to the removal of structural water molecules through the shrinkage and/or collapse of the pores. The agglomerated nanodiamond structure that results from long heating periods decreases the nitrogen adsorption but increases the water adsorption by 40%. Nanodiamonds heated for long times possess ultramicropores <0.4 nm in diameter in which only water molecules can be adsorbed, and the characteristic mouth-shaped mesopores adsorb 60% more water than nitrogen. The pore mouth controls the adsorption in the mesopores. Long-term dehydration partially distorts the pore mouth, decreasing the nitrogen adsorption. Furthermore, the nitrogen adsorbed at the pore mouth suppresses additional nitrogen adsorption. Consequently, the mesopores are not fully accessible to nitrogen molecules because the pore entrances are blocked by polar groups. Thus, mildly oxidized detonation nanodiamond particles can show a unique molecular sieving behavior.

Phylogeny and diversity of Bjerkandera (Polyporales, Basidiomycota), including four new species from South America and Asia

Four new species of Bjerkandera, viz. B. ecuadorensis, B. fulgida, B. minispora, and B. resupinataspp. nov., are described from tropical America and Asia. B. ecuadorensis is characterised by dark grey to black pore surface, a monomitic hyphal system, hyaline to yellowish-brown generative hyphae, and ellipsoid basidiospores measuring 3.9–4.5 × 2.7–3 μm. B. fulgida is distinguished from the other species in the genus by clay buff to pale brown and shiny pore surface. B. minispora is characterised by white tomentose pore mouth and small basidiospores measuring 3.1–4.2 × 2–2.8 μm. B. resupinata is characterised by resupinate basidiomata, pinkish buff to pale brownish pore surface, and ellipsoid to broadly ellipsoid basidiospores measuring 4.5–6 × 3.2–4.1 µm. All these new species grow on angiosperm trunks or rotten wood, and cause a white rot. The closely related taxa to four new species are discussed. An identification key to the ten accepted species of Bjerkandera is provided, and a phylogeny comprising all known Bjerkandera species is provided.

Entropy driven preference for alkene adsorption at the pore mouth as the origin of pore-mouth catalysis for alkane hydroisomerization in 1D zeolites

This work presents a theoretical basis for a pore-mouth catalysis model developed to explain the positional selectivity of skeletal isomerization on bifunctional metal acid-zeolite catalysts.