The objectives of this study were to identify molecular features characteristic to arctic DOM from the Kolyma River basin and to elucidate structural imprints induced by a choice of the sorption technique. To achieve this goal, DOM was isolated from the Kolyma River basin with a use of three nonionic sorbents: Amberlite XAD-8 resin, PPL- and C18 - SPE cartridges, and one anion exchanging resin–diethylaminoethyl (DEAE) -cellulose. The structural studies were conducted with a use of electrospray ionization Fourier Transform Ion Cyclotron Resonance (ESI FT-ICR) mass spectrometry and liquid state ¹H NMR spectroscopy. The DOM isolates obtained with a use of PPL and C18 cartridges were characterized with higher content of aliphatic compounds as compared to XAD-8 and DEAE-isolates. In total, for all arctic DOM isolates we observed predominance of hydrogen saturated compounds with high H/C values of identified formulas from FT-ICR MS data. ¹H NMR spectroscopy studies have confirmed this trend and revealed high contribution of alkyl-chain protons into the spectral density of the arctic DOM reaching 43% for PPL isolates.

Ca–Al double-substituted strontium hexaferrites exhibit record-high coercivities up to 21.3 kOe.

Iron deficiency is a frequent problem for many crops, particularly in calcareous soils and iron humates are commonly applied in the Mediterranean basin in spite of their lesser efficiency than iron synthetic chelates. Development and application of new fertilizers using nanotechnology are one of the potentially effective options of enhancing the iron humates, according to the sustainable agriculture. Particle size, pH, and kinetics constrain the iron humate efficiency. Thus, it is relevant to understand the iron humate mechanism in the plant–soil system linking their particle size, characterization and iron distribution in plant and soil using ⁵⁷Fe as a tracer tool. Three hybrid nanomaterials (F, S, and M) were synthesized as iron-humic nanofertilizers (⁵⁷Fe-NFs) from leonardite potassium humate and ⁵⁷Fe used in the form of ⁵⁷Fe(NO₃)₃ or ⁵⁷Fe₂(SO₄)₃. They were characterized using Mössbauer spectroscopy, X-ray diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS), transmission electron microscopy (TEM) and tested for iron availability in a calcareous soil pot experiment carried out under growth chamber conditions. Three doses (35, 75, and 150 μmol pot^-1) of each iron-humic material were applied to soybean iron deficient plants and their iron nutrition contributions were compared to ⁵⁷FeEDDHA and leonardite potassium humate as control treatments. Ferrihydrite was detected as the main structure of all three ⁵⁷Fe-NFs and the plants tested with iron-humic compounds exhibited continuous long-term statistically reproducible iron uptake and showed high shoot fresh weight. Moreover, the ⁵⁷Fe from the humic nanofertilizers remained available in soil and was detected in soybean pods. The Fe-NFs offers a natural, low cost and environmental option to the traditional iron fertilization in calcareous soils.

Porous anodic aluminium oxide has a long history of practical application for corrosion protection and coloring. In the last few decades a lot of hi-tech applications of this material have been found owing to the discovery of anodization conditions leading to the formation of highly ordered porous structures with a narrow pore size distribution. Here we show that in-plane orientation of the porous system in anodic films on aluminium is fully determined by the intrinsic crystallographic orientation of the Al substrate. The anisotropy of aluminium oxidation rates on a scalloped metal–oxide interface leads to reorientation of Al spikes in certain directions, which builds up an in-plane orientational order on a macroscopic scale restricted by a crystallite size. This is a unique example of the inheritance of the substrate crystal structure by an amorphous film through a size difference of three orders of magnitude.