In this work, tannic acid (TA)-functionalized carbon nanotubes (CNT@TA) were synthesized by hydrogen bond and π−π stacking interactions. CNT@TA embedded with silver nanoparticles (Ag-CNT@TA) was obtained by in situ reducing silver ammonia ions in the pore channels of CNT@TA. CNT@TA and Ag-CNT@TA were added into the polyamide (PA) layer by interfacial polymerization to fabricate high-performance nanocomposite reverse osmosis membranes. The results show that the functionalized CNTs can be uniformly distributed in the PA matrix with random orientations. A loose PA separation layer was obtained by introducing CNT@TA. Correspondingly, abundant new water channels were formed. Compared with the pure PA membrane, the water permeability (4.81 L m −2 h −1 bar −1 ) of the nanocomposite membrane is enhanced by 49.8% without any loss in NaCl rejection (99.3%). The membrane exhibits satisfactory chemical-and bio-fouling resistances to bovine serum albumin and Escherichia coli as model foulants. The high bactericidal rate should be ascribed to the formation of the TA coating and confined Ag nanoparticles in CNT channels. The confined structure effectively avoids the leaching out of the Ag nanoparticles and keeps the persistence of the antibacterial property. The excellent compatibility between the CNTs and the polyamide matrix endows the membrane with long-term performance stability.

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Source of materialThe Schiff base ligand was synthesized by condensation 5-bromo-2,3-diaminopyridine and 2-hydroxy-3-methoxybenzaldehyde with the ratio 1:2inethanol. The synthesis of the title complex was carried out by reacting Ni(ClO 4 ) 2 · 6H 2 Oand the schiff base ligand (1:1, molar ratio) in methanol. After stirring, the process was continued for about 30 min at room temperature. The mixture was filtered and the filtrate was allowed to partially evaporate in air for sevral days to produce red-brown crystals suitable for X-ray diffraction with ayield about 60 %. DiscussionSchiff-bases have played an important role in the development of coordination chemistry as they readily form stable complexes with most of the transition metals, in which some could exhibit interesting properties [1][2][3][4].The coordination sphere for the Ni(II) ion in the title crystal structure is aslightly distorted square planar, in which the four positions are occupied by two Natoms and two Oatoms of the Schiffbase ligand. The mean deviation from the plane formed by the two Natoms, two Oatoms and the Ni ion is only 0.035 Å,indicative of that these five atoms can form aperfect plane. The bond lengths of Ni-Na re 1.874(3) Å and 1.929(3) Å,a nd Ni-O 1.861(2) Å and 1.905(2) Å,respectively, are consistant with the corresponding distances in 6,6'-dimethoxy-2,2'-(ethane-1,2-diyl-bis(nitrilomethylidyne)diphenolato)nickel(II) [5].

In title complex, [Co(C28H22N2O2)(C5H5N)2]ClO4·1.5H2O, the CoIII ion is in a slightly distorted octa­hedral coordination environment with the pyridine ligands in a trans arrangement. In addition to the cation and anion, the asymmetric unit also contains three half-occupancy solvent water mol­ecules and all components are connected via inter­molecular O—H⋯O hydrogen bonds.

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Key indicatorsSingle-crystal X-ray study T = 298 K Mean (C-C) = 0.011 Å R factor = 0.056 wR factor = 0.138 Data-to-parameter ratio = 16.6For details of how these key indicators were automatically derived from the article, see