In Situ Synthesis of Exfoliated Ni(OH)2 Nanosheets and AgNPs-Embedded Functionalized Polyindole-Based Trinary Hybrid Microspheres: A Z-Scheme Photocatalyst for the Sunlight-Driven Degradation of Organic Pollutants with Enhanced Antibacterial Efficacy.

Advancing a facile one-pot synthetic approach for the fabrication of a hybrid heterojunction photocatalyst remains a significant challenge in research pursuits. Herein, a microsphere-like trinary hybrid nanocomposite has been synthesized (NH/PIn/MAA/Ag). It comprises exfoliated single- and a few-layered Ni(OH)2 (NH nanosheets), mercaptoacetate-functionalized polyindole (PIn/MAA), and Ag nanoparticles (AgNPs) through an in situ approach. The formation mechanism is based on the exfoliation of stacked Ni(OH)2 multilayers [i.e., Ni(OH)2 microflowers] and stabilization of NH nanosheets through host-guest formation of PIn/MAA, followed by the adsorption-reduction of Ag+ ions in a one-pot reaction at low temperature. Surface morphological analyses of hybrid nanocomposite microspheres have exhibited that highly dense Ni(OH)2 microflowers have been transformed into low-density layered forms (NH nanosheets) within the polymeric platform (PIn/MAA) with deposited AgNPs. An interfacial heterojunction has been developed between the components in the depletion region, leading to an improvement in photocatalytic efficiency through a synergistic effect over the components for charge separation and transfer through the heterojunction interface via solid-state mediator Ag-based Z-scheme charge transfer dynamics. The superior photocatalytic degradation of tetracycline (98.2%) by trinary hybrid microspheres can be attributed to the deteriorated recombination rate of electron-hole pairs with reduced charge transfer resistance of the heterojunction in the photocatalyst, as obvious from photoluminescence, electrochemical impedance spectroscopy, chronoamperometry, and time-resolved photoluminescence (TRPL) analyses. Moreover, the antibacterial properties of microspheres against Bacillus pumilus (Gram-positive) and Escherichia coli (Gram-negative) bacteria have validated their potential as promising materials for the overall purification of aquatic systems.

Development of a Thermoresponsive Polymeric Composite Film Using Cross-Linked ß-Cyclodextrin Embedded with Carbon Quantum Dots as a Transdermal Drug Carrier.

Polymeric nanocomposite films are used as promising transdermal drug carriers because of the improved patient compliance, easy application on skin, and noninvasiveness. A thermoresponsive polymeric composite film has been developed here through the deposition of carbon quantum dots (CQDs) on functionalized ß-cyclodextrin (ß-CD). The composite has been developed by grafting of poly(N-vinyl caprolactam) on ß-CD, followed by cross-linking of diethylene glycol dimethacrylate and subsequent deposition of CQDs. CQDs have been prepared from waste pomegranate peels via a hydrothermal method. To enlighten the thermoresponsive nature of the composite film, lower critical solution temperature, as well as temperature-dependent swelling behavior, has been studied. The composite demonstrates excellent rheological features. The developed polymeric composite film is nontoxic toward NIH 3T3 fibroblast cell lines. On the deposition of CQDs on the copolymer, the penetration power and fluorescent property have been improved, which help to track the cells in vitro. This film is worthy to be applied to the skin. It can efficiently load lidocaine hydrochloride monohydrate (LHM). In vitro and ex vivo skin permeation profiles reveal the sustained release behavior of loaded LHM at average skin temperature and pH.

Graft copolymeric flocculant using functionalized starch towards treatment of blast furnace effluent.

Herein, a novel binary graft copolymeric flocculant [St-g-(PAAm-co-PMETAC)] has been developed using starch, polyacrylamide (PAAm) and poly (2-methacryloyloxy ethyl trimethyl ammonium chloride) (PMETAC). The copolymer has been synthesised by grafting of PAAm and PMETAC chains on starch backbone using free radical polymerization. FTIR and 1H NMR spectral analyses have been used for structural confirmation of developed copolymer. Determination of molecular weight reveals that after grafting of PAAm and PMETAC on starch, the molecular weight as well as radius of gyration have been increased as compared to pristine starch. The surface morphologies of starch and St-g-(PAAm-co-PMETAC) have been assessed by FESEM analysis. TGA/DTG along with MS analyser is able to track the pre-specified compounds over the entire period of degradation temperature. The synthesised graft copolymer i.e. St-g-(PAAm-co-PMETAC) demonstrates brilliant efficiency as flocculant towards the treatment of blast furnace effluent generated in integrated steel plant.

Long-Lived Polypyridyl Based Mononuclear Ruthenium Complexes: Synthesis, Structure, and Azo Dye Decomposition.

Two mononuclear ruthenium complexes [(bpy)2RuIIL1/L2](ClO4)2 ([1]2+/[2]2+) (bpy-2,2' bipyridine, L1 = 2,3-di(pyridin-2-yl)pyrazino[2,3-f][1,10]phenanthroline) and L2 = 2,3-di(thiophen-2-yl)pyrazino[2,3-f][1,10]phenanthroline have been synthesized. The complexes have been characterized using various analytical techniques. The complex [1]2+ has further been characterized by its single crystal X-ray structure suggesting ruthenium is coordinating through the N donors of phenanthroline end. Theoretical investigation suggests that the HOMOs of both complexes are composed of pyridine and pyrazine unit of ligands L1 and L2 whereas the LUMOs are formed by the contribution of bipyridine units. The low energy bands at ∼480 nm of the complexes can be assigned as MLCT with partial contribution from ligand transitions, whereas the rest are ligand centered. The complexes have shown RuII/RuIII oxidation couples at E1/2 at 1.26 (70 mV) V and 1.28 (62 mV) V for [1]2+ and [2]2+ vs Ag/AgCl, respectively, suggesting no significant role of distal thiophene or pyridine units of the ligands. The complexes are emissive and display solvent dependent emission properties. Both complexes have shown highest emission quantum yield and lifetime in DMSO (ϕ = 0.05 and τavg = 460 ns and λmaxem at 620 nm for [1]2+; ϕ = 0.043 and τavg = 425 ns and λmaxem at 635 nm for [2]2+). Further, the long luminescent lifetime of these complexes has been utilized to generate reactive oxygen species for efficient azo dye decomposition.