No abstract

Pine bark, a low-cost industrial residue, has been suggested as a promising substitute for granular activated carbon in the on-site treatment of water contaminated with 2,4,6-trinitrotoluene (TNT). However, the complex organic structure and indigenous microbial community of pine bark have thus far not been thoroughly described in the context of TNT-contaminated water treatment. This two-week batch study examined the removal efficiency ofTNT from water by (1) adsorption on pine bark and (2) simultaneous adsorption on pine bark and biotransformation by specialized TNT-biotransforming microbial inocula. The bacterial community composition of experimental batches, inocula and pine bark, was profiled by Illumina sequencing of the V6 region of the 16S rRNA gene. The results revealed that the inocula and experimental batches were dominated by phylotypes belonging to the Enterobacteriaceae family and that the tested inocula had good potential for TNT biotransformation. The type of applied inocula had the most profound effect on the TNT-transforming bacterial community structure in the experimental batches. The indigenous microbial community of pine bark harboured phylotypes that also have a potential to degrade TNT. Altogether, the combination of a specialized inoculum and pine bark proved to be the most efficient treatment option for TNT-contaminated water.

This two-week anaerobic batch study evaluated 2,4,6-trinitrotoluene (TNT) removal efficiency from industrial pink water by (1) adsorption on low-cost adsorbent pine bark, and (2) adsorption coupled with TNT biotransformation by specialised microbial communities. Samples of the supernatant and acetonitrile extracts of pine bark were analysed by HPLC, while the composition of the bacterial community of the experimental batches, inocula and pine bark were profiled by high-throughput sequencing the V6 region of the bacterial 16S rRNA gene. Integrated adsorption and biotransformation proved to be the most efficient method for TNT removal from pink water. The type of applied inoculum had a profound effect on TNT removal efficiencies and microbial community structures, which were dominated by phylotypes belonging to the Enterobacteriaceae family. The analysis of acetonitrile extracts of pine bark supported the hypothesis that the microbial community indigenous to pine bark has the ability to degrade TNT.

An efficient protocol for synthesis of indenyl rhodium complexes with arene ligands has been developed. The hexafluoroantimonate salts [(η5-indenyl)­Rh­(arene)]­(SbF6)2 (arene = benzene (2a), o-xylene (2b), mesitylene (2c), durene (2d), hexamethylbenzene (2e), and [2.2]­paracyclophane (2g)) were obtained by iodide abstraction from [(η5-indenyl)­RhI2] n (1) with AgSbF6 in the presence of benzene and its derivatives. The procedure is also suitable for the synthesis of the dirhodium arene complex [(μ-η:η′-1,3-dimesitylpropane)­{Rh­(η5-indenyl)}2]­(SbF6)4 (3) starting from 1,3-dimesitylpropane. The structures of [2e]­(SbF6)2, [2g]­(SbF6)2, and [3]­(SbF6)4 were determined by X-ray diffraction. The last species has a sterically unfavorable conformation, in which the bridgehead carbon atoms of the indenyl ligand are arranged close to the propane linker between two mesitylene moieties. Experimental and DFT calculation data revealed that the benzene ligand in 2a is more labile than that in the related cyclopentadienyl complexes [(C5R5)­Rh­(C6H6)]2+. Complex 2c effectively catalyzes the reductive amination reaction between aldehydes and primary (or secondary) amines in the presence of carbon monoxide, giving the corresponding secondary and tertiary amines in very high yields (80–99%). This protocol is the most active in water.

A new protocol for the synthesis of nitriles from carbonyl compounds with elongation of the molecule with two carbon atoms was developed. It involves a reaction of ethyl cyanoacetate with different aldehydes in the presence of iron pentacarbonyl as a reducing agent. This protocol is very simple and requires only commonly available reagents, with no catalyst or complicated ligands being employed.