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A facile strategy to encrust MFe 2 O 4 (M = Zn, Co and Ni) nanoparticles over CdS nanorods via two-step solvothermal method have been reported. The ferrite-CdS nanocomposites (NCs) were characterized using powder X-ray Diffraction (XRD) andFourier Transform Infrared (FT-IR) spectroscopy. A shifting in the peak corresponding to (311) plane confirmed the presence of different metal ion in the spinel ferrite lattice.However, no variation in the peak of CdS was observed which stipulate that phase and morphology of CdS nanorods remain unaltered after hydrothermal treatment. High Resolution Transmission Electron Microscopy (HR-TEM) analysis revealed the efficacious attachment of the nanoferrite on the CdS nanorods. Optical studies of the NCs samples provided the information about the fabrication of visible light responsive photocatalyst and covered the solar spectrum from 525 nm to 737 nm. On the basis of magnetic studies, CdS-CoFe 2 O 4 and CdS-NiFe 2 O 4 were found to be ferromagnetic in nature with saturation magnetization of 26.4 and 15.5 emu/g respectively. Interestingly, a transition from ferromagnetic to super-paramagnetic was observed for ZnFe 2 O 4 loaded CdS nanorods. The photo-catalytic activities of nanocomposites were studied by carrying out the photodegradation of rhodamine B and methylene blue dye under visible-light irradiation. Maximum activity was observed in case of CdS-ZnFe 2 O 4 nanocomposites. This behavior of saturation magnetization for CoFe 2 O 4 -CdS NCs is due to the strengthening of A-B interactions as the cobalt ion has a tendency to occupy octahedral B site. So, some of the Fe 3+ ions get transferred to the tetrahedral site and the magnetic moment of M B gets concerted. So, the saturation magnetization for the CoFe 2 O 4 -CdS NRs increased. However with the Zn 2+ ions substituent, A-B exchange interactions weaken as Zn 2+ ions have the tendency to occupy the tetrahedral A sites. So the magnetic moment of M A gets diluted. 29 Therefore, for ZnFe 2 O 4 -CdS NCs, the curve didn't get saturated, indicating the fabrication of super-paramagnetic nanocomposites with negligible coercivity and remanance. However NiFe 2 O 4 -CdS NCs displayed ferromagnetic behavior. This superparamagnetic behavior of ZnFe 2 O 4 -CdS NCs can be attributed to lower particle size and the presence of non-magnetic ions in the spinel ferrite structure, which would have led to single domains. 29 These results are corroborated by the presence of single domain structure in HR-TEM images (Fig. 3) A huge difference in magnetic parameters is also conspicuous from the hysteresis loops of the NCs. It is evident from the figure that the saturation magnetization value for the CdS-ZnFe 2 O 4 NCs is 4.0 emu/g. However for CdS-CoFe 2 O 4 NCs and CdS-NiFe 2 O 4 NCs saturation magnetization is 26.4 and 15.5 emu/g respectively. Similarly, a vast variation in the values of remanance and coercivity was observed. The coercivity for CdS-ZnFe 2 O 4 NCs was 8.5 Oe, which upsurged to 90 Oe and 377.2 Oe for CdS-NiFe 2 O 4 NCs and CdS-CoFe 2 O 4N...

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BACKGROUND Continual emergence of quinolones in the environment has raised concerns and the repercussions are almost unimaginable. Along with this an increase of antibiotic resistance in microbes has encouraged the pharmaceutical and food industry to create new antimicrobial agents. Nano‐range materials with exceptional antimicrobial properties synthesized via green routes for fluorescence sensing of fluoroquinolones have rarely been reported. RESULTS A facile, eco‐friendly and green approach was utilized for the synthesis of water soluble glutathione (GSH) functionalized CdS quantum dots (QDs) for the selective detection of fluoroquinolones. The prepared QDs exhibited a strong emission peak at 460 nm and the addition of fluoroquinolones caused enhancement and significant blue shift (∼ 50 nm) in the intensity, revealing sensitive and selective detection of fluoroquinolones. The limit of detection was found to be 2.2 µmol L‐1. Also, antimicrobial activities of the QDs were assessed against both Gram positive and Gram negative bacteria and the QDs were found to be effective against the Gram positive bacteria especially Bacillus species in comparison with the Gram negative bacteria. CONCLUSIONS The current study offers a green route to synthesize water soluble and stable QDs for sensing with exceptional antimicrobial properties. © 2018 Society of Chemical Industry