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Ten different contact, systemic and combination products of fungicides were evaluated for their effectiveness against black spot of papaya Asperisporium caricae under in vitro condition by following poisoned food technique. Among fungicides tested, trifloxystrobin 25% + tebuconazole 50% WG, propiconzole 25% EC and zineb 68% + hexaconazole 4% WP were successful in completely (100%) inhibiting the growth of A. caricae at all concentrations (50,100, 250, 500, 750, 1000 ppm) which is followed by hexaconazole 25% EC, difenconazole 25% EC, zineb 68% hexaconazole 4% WP completely inhibited the growth of the fungus at 500 ppm and above concentration. Least inhibition of fungal growth was recorded in copper oxychloride 50% WP at all concentrations. Trifloxystrobin 25% + tebuconazole 50% WG, propiconazole 25% EC and zineb 68% + hexaconzole 4% WP were most effective which completely inhibited the spore germination at all concentrations, while the copper oxychloride 50% WP was recorded the least per cent inhibition of fungal spores.

Surface enhanced Raman scattering (SERS), photocatalytic and antibacterial activities of Fe3O4/Ag magnetic nano particle (MNP) is reported in this work. A synthesized Fe3O4/Ag MNP is characterized with UV–visible, vibrational spectral studies (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). VSM reports Fe3O4/Ag MNP posses good magnetic response and attribute as a SERS substrate. SERS property of Fe3O4/Ag MNP has studied with 10–8 M, 10–10 M and 10–12 M concentrations of R6G. Photocatalytic efficiency was calculated with both R6G and environmentally ignored real (leachate) sample. The degradation takes place with rate constant ˷ 0.012 min−1. Moreover, degradation efficiency of Ag NPs has improved with Fe3O4 NPs. Also, as synthesized substrate shows an antibacterial activity against gram negative and gram positive bacteria with an inhibition zone of 5–8 mm. Both photonic and antibacterial properties make this material as promise for potential applications in environmental pollution, human medicine and contaminated drinking water.

Engineering efficient, strong and cost-effective nanoparticles with strong inhibitory activities are the growing need at present. Using the strategies of doping, Zinc oxide/Silver nanocomposites (ZnO/Ag NCs) namely 0.9 M ZnO: 0.1 M Ag, 0.7 M ZnO: 0.3 M Ag and 0.5 M ZnO: 0.5 M Ag were synthesized hydrothermally. The average crystallite sizes for the ZnO/Ag NCs were 31 nm, 29 nm and 23 nm. The band gap energy (Eg) for the ZnO/Ag NCs was estimated to be 3.09 eV, 3.12 eV and 3.18 eV using Tauc’s plot. Grain-like morphological images was observed in the Scanning Electron Microscopy (SEM), which helps in effective promotion of degrading methyl orange (MO), methylene blue (MB) and crystal violet (CV) under visible light irradiation with a rate constant of 5 × 10–3/min, 16.6 × 10–3/min and 4 × 10–3/min respectively. This superior photocatalytic decomposition of dye are ascribed to smaller particle size, high surface area, the ability to absorb visible light and the efficient charge separation associated with the synergetic effects of appropriate amounts of ZnO and Ag in the prepared samples. In addition, the antibacterial efficacy of the NCs is observed as 90 and 100% for 75 μl. These hydrothermally synthesized synergistic NCs can be designed for large-scale fabrication of NC materials for potential applications in photocatalytic and antibacterial activity.

Tungsten oxide hydrate (WO3·H2O) nanoparticle and Iron tungstate/tungsten oxide (Fe2WO6/WO3) nanocomposite have been synthesized via a facile hydrothermal route. Structural, optical, morphological and electrical properties of the synthesized samples were characterized by X-ray powder diffraction (XRD), UV-Visible spectroscopy, Field effect scanning electron microscopy (FE-SEM) with Energy-dispersive X-ray spectroscopy (EDX) and DC electrical conductivity measurement respectively. The powder X-ray diffraction (XRD) results confirm the formation of Fe2WO6/WO3 nanocomposite. Variation in the electrical conductivity and activation energy was studied by DC electrical conductivity studies. Fe2WO6/WO3 nanocomposites show a significant enhancement in the degradation of methyl blue than WO3·H2O nanoplates. The significant enhancement was due to flower-like morphology and the narrowing of the optical band gap which reduces the electron-hole pair recombination rate. The dye-sensitized solar cell (DSSC) was fabricated using WO3·H2O and Fe2WO6/WO3 films as photoanodes and it was observed that Fe2WO6/WO3 photoanode shows highest power conversion efficiency (PCE) i.e., 4.69% which can be achieved through high dye absorbing capacity.

A novel surface enhanced Raman spectroscopy (SERS) based polyvinylthiol (PVASH) and silver modified silica nanoparticles (PSA NPs) was prepared to actively concentrate different types of landfill leachate in water. PSA NPs were characterized with UV-visible spectroscopy, XRD, TEM and EDX. SERS sensitivity of the PSA NPs was proved with environmentally ignored leachate from municipal solid waste (MSW) landfill. The result shows that, SERS sensing of PSA NPs were improved with the presence of thiol group. Further, PSA NPs exhibited similar vibrational bands of MSW and tannery waste (TW) landfill leachate in their nearest homeland aquifers. Hence, this study provides a novel SERS sensor of PSA NPs in the tile to detect and analyze the environmentally ignored organic and inorganic compounds.

Textile industries utilize various toxic azo dyes that cause a hitch to all living organisms. To overcome such problem, the semiconductor photocatalysts are very much helpful. Zinc oxide (ZnO) nano...

Environmental process such as toxic dye sensing and degradation can be stepped up through photochemical process such as surface enhanced Raman scattering (SERS) and llight induced catalytic degradation. In this work, Titanium dioxide/silver/graphene oxide nanocomposites (TAG) were studied as ideal dual substrates for SERS sensing and visible light driven degradation of Congo red (CR) and crystal violet (CV). Solvothermal route of synthesize used here resulted in a narrow size distribution (6–12 nm) of TAG. A shift towards the visible spectra observed in absorption spectroscopy along with the anatase phase titanium dioxide illustrated in the X-ray diffraction pattern and Raman spectra aided the activation of TAG under visible light irradiation. On addition of TAG, typical SERS bands corresponding to the azo nature of CR were clearly exhibited by C-N symmetric bending modes and C-N stretching modes in the 1160 cm−1–1200 cm−1 region. For CV, the aryl backbone represented by C-C bridge between two phenyl molecules at 1298 cm−1 was recorded in the SERS spectra. Visible light driven degradation of CV and CR in the presence of TAG resulted in high rate constants of 1.09 × 10−2/min and 1.26 × 10−2/min respectively. The reactive oxidative radical species in the photo-degradation reaction of dye was studied by using various scavengers. The observed augmented SERS detection and photocatalytic degradation arises from the synergistic effects of plasmonic properties Ag NPs, anatase TiO2 and π-π stacking nature of GO. This study suggests that TAG can offer the right 00path way towards an ideal commercial pollutant detection and degradation system.

Surface enhanced Raman spectroscopy (SERS) based Polyvinyl thiol (PVASH) assisted Ag NPs is synthesized to exhibit both SERS detection and photocatalytic degradation of tannery waste (TW) landfill leachate. The substrate is characterized with UV- visible, XRD, TEM and EDX. Leachate of TW landfill has degraded by PVASH assisted Ag NPs as a catalyst under visible and UV light irradiation with rate constants 0.0025 min−1 and 0.0039 min−1. The result shows that, PVASH assisted Ag NPs has a potential to detect pollutants via SERS and can degrade the pollutants in the biologically compatible wavelength (visible light) proven to its bifunctional role in the promising way to make pollution free environment.

The upsurge of colored, hazardous dye pollutants has led to the excessive presence of carcinogens in the environment, thereby requiring a sensitive, rapid and facile detection method. In this study, graphene oxide mediated surface enhanced Raman scattering (G-SERS) based sensor was studied on gold/reduced-graphene oxide nanocomposites (Au/GO NCs). Typical absorptions at 261 nm and 531 nm observed in UV–visible spectroscopy, XRD peaks at 24°, 38.2°, 44.5°, 64.7°, and 77.6° along with the TEM images showed the formation of spherical Au nanoparticles incorporated rGO sheets. In this study, monoazo, diazo, triarylmethane, thyazine and xanthenes dyes were analyzed. Further, the predominant dye contaminant contributor: textile effluent (TE) collected from Erode, India was studied. From the G-SERS spectra it can be concluded that TE may me a mixture of azo, aryl and xanthenes dyes. Also the carcinogenic aromatic structures such as C N and C N were detected successfully. Synergistically, the electromagnetic enhancement from the hotspots and hot surfaces, chemical enhancement offered by rGO and effective fluorescence quenching observed result in well defined, enhanced G-SERS signals. This work suggests the feasibility of Au/GO NCs as an effective pollutant sensor in water processing and treatment plants for industrial effluents.

An improved approach for highly selective detection and removal of polychlorinated biphenyl (PCBs) and its isomers, via Surface Enhanced Raman Scattering (SERS) platform using ZnO modified gold nanocomposites (ZnO-Au NCs) as the effective substrate with the real environmental sample of reservoir soil was reported. The synthesized ZnO-Au NCs were characterized by using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). GC-MS spectra confirm the presence of PCBs in reservoir soil. The isomers of tetrachlorobiphenyl were detected by using SERS as low concentration level even at 6 mM. The high photocatalytic activity of these ZnO-Au NCs substrate can degrade the pollutants in the soil under UV irradiation. The apparent rate constant of the catalytic reaction of reservoir soil extract in the presence of ZnO-Au NCs is 0.021/min. The SERS and photocatalytic degradation experimental result show that ZnO-Au NCs is a good candidate for the detection and degradation of organic pollutants.

TiO2 modified gold nanocomposites (Au–TiO2 NCs) were synthesized as a platform for the investigation and degradation of organic pollutants in the real environmental sample, lake soil. The prepared Au–TiO2 NCs show the surface plasmon resonance band at 532 nm. The crystallinity and the formation of Au–TiO2 NCs were confirmed by using X-ray diffraction and vibrational studies. Transmission electron microscope measurement shows the core shell structure of Au–TiO2 NCs. It reveals good photocatalytic activity for degrading pollutants in the lake soil. Using surface enhanced raman scattering the pollutants were detected and it is further confirmed through gas chromatography and mass spectrometry analysis. Au–TiO2 NCs degrades the organic pollutants in lake soil and the apparent rate constant of the catalytic reaction is 0.022/min. The observed experimental results show that the high stability Au–TiO2 NCs act as good candidate, both for the detection and degradation of pollutants.

Highly active Ag modified Fe3O4 Nanoparticles (Fe3O4 NPs) were synthesized to exhibit both Surface Enhanced Raman Scattering (SERS) and Photocatalytic Degradation of landfill leachate. SERS signal of landfill leachate showed the presence of common pollutants in leachate viz., phenols, phthalate, pesticide and heavy metal (Cr (VI)). Furthermore, the obtained SERS signals from samples confirmed the landfill crisis in homeland aquifers. Ag modified Fe3O4 NPs also effectively decomposed the leachate with rate constant 0.003/min under UV irradiation. Hence, Ag modified Fe3O4 NPs may play an ideal entrant of various applications, including the recognition and removal of environmentally deleterious substances to improve the human living environment.

The growing concern about antibacterial resistance has made it imperative to engineer effective, strong and economic nanoparticles with strong inhibitory activities. copper-nickel (CuNi) bimetallic nanoparticles (NPs) have been synthesized solvothermally. X-ray diffraction analysis exhibits CuNi NPs with face-centered-cubic structure arising from (1 0 0), (2 0 0) and (2 2 0) planes. Porous, flaky NPs with interspersed spherical cuboids were observed through scanning electron microscopy. CuNi showed zones of inhibition of 31 mm and 30 mm against S. aureus and E. coli respectively which was comparable to a 31 mm zone observed for a third generation drug, Cefixime. This strong antibacterial activity is due to the synergistic bactericidal Cu2+ and bacteriostatic Ni2+ ions released from CuNi bimetallic NPs. Additively, reactive oxygen species that can be produced on the NP surface enhance the inhibitory activity of CuNi NPs. The obtained results suggest the possible utilization of CuNi NPs as antibacterial coatings and surfaces.

During the decomposition of trashes, leachate is created and leaching is gradually pollutes the surface and groundwater. Thus, the most severe ecological impact is the risk of ground water pollution because of collection of leachate from unlined insecure landfills. Due to the low biodegradable organic strength, irregular productivity and composition, the environmentally neglected landfill leachate treatment is challenging. This work was conducted on a synthetically effective bimetallic surface enhanced Raman spectroscopic (SERS) nanosensor by gold/silver-bimetallic nanoparticles (Au/Ag-NPs), and used for the specific detection of municipal solid waste (MSW) landfill leachate in groundwater. The optical study of Au/Ag-NPs led to reflections from Ag cores and small Au shells. The structural studies represent the FCC structure of Au/Ag-NPs. The core-shell nanocrevice NPs with particle size of 23 nm played an important role with plasmonic behaviour enhances the electromagnetic excitation to achieve SERS detection and plasmonic photocatalysis. Thus, obtained results clearly show that Au was successfully added to Ag-NPs, and its existence can also be confirmed by energy dispersive spectroscopy (EDAX). The prepared SERS based sensors have the potential to detect aromatic hydrocarbon, pesticides and heavy metals from environmentally ignored MSW landfill leachate. In general, the application of this new synergetic strategy of the photocatalytic degradation of leachate was irradiated by visible wavelength with the rate constant of 0.0036/min, 0.0047/min and 0.005/min by Ag-NPs, Au-NPs and Au/Ag-NPs respectively. Overall, this is the only study achieved efficiently with photocatalytic degradation and SERS detection of environmentally ignored real sample (leachate) to make pollutant free homeland aquifers.

Wastewater effluents from textile industries contain toxic chemicals, which need to be treated prior to effluent disposal. Semiconductor photocatalysis is emerging as potential technique for treating such effluents. The main advantage of this technique is the fact that organic contaminants are completely mineralized without requiring any further treatment. Titanium dioxide (TiO2) is the most efficient semiconductor photocatalyst as it is stable in aqueous media and tolerant to both alkaline and acidic solutions. Due to its wide bandgap (Eg ≈ 3.0 eV), TiO2 can absorb only the light in the UV region, and that is one of the biggest drawbacks of TiO2. Several attempts have been made recently to improve the photocatalytic performances of a TiO2 photocatalyst by extending the photoresponse of the UV-active semiconductor into the visible region through the bandgap engineering. This chapter outlines the interaction of fluorine and carbon nanotubes in TiO2 structure and the changes in photocatalytic activity of TiO2 and multiwalled carbon nanotube-fluorine-codoped TiO2 nanocomposites, which find potential applications of the nanocomposite in water treatment.

Iron oxide gold nanocomposites (Fe3O4-Au NCs) were synthesized by chemical reduction method. The band gap of synthesized Fe3O4-Au NCs was 5.37 eV. X-Ray Diffraction (XRD) pattern confirms the crystalline nature of the synthesized nanoparticles (NPs). Transmission Electron Microscope (TEM) measurement showed the formation of Fe3O4-Au NCs with average particle size of 18 nm. The size diminution enables these Fe3O4-Au NCs to easily infiltrate the bacterial crust resulting in failure of membrane reliability. The prepared Fe3O4-Au NCs reveal good antibacterial activity against gram positive and negative pathogens, which are found in water. The obtained result shows that the prepared Fe3O4-Au NCs was good anti-bacterial agent.

Development of efficient antimicrobial agents is imperative for the persistent microbial pollution and contamination. Here, we have analyzed the enhancement in the antibacterial activity of TiO2 nanoparticles when co-doped with silver nanoparticles (Ag NPs) and activated carbon (TAC). Highly active anatase phased TiO2 was observed in X-ray diffraction patterns and Raman spectra. Morphological studies revealed the formation of spherical TiO2 and Ag NPs on carbonaceous sheets. The gram negative bacterium, E. coli and gram positive bacterium S. aureus showed zones of inhibition of 7 mm which was comparable to the standard, streptomycin. This inhibitory activity is due synergistic effects of activated carbon, Ag NPs and TiO2 in the nanocomposite. The adsorption ability of activated carbon concentrates the bacteria around the nanoparticle environment. The oxidative stress and cell wall rupture brought about by Ag+ ions and TiO2 respectively inhibit the growth of the concentrated bacteria. The cost-effective and lethal nature of TAC towards both gram positive and gram negative bacterium may find numerous applications in antibacterial coatings, paints, surfaces and films.

We investigate the focusing properties of an azimuthally polarized and amplitude modulated annular multi Gaussian beam by a high numerical aperture (NA) lens based on vector diffraction theory. We observe that our proposed system generates a subwavelength focal hole of 0.46λ having large uniform focal depth of 36λ without any annular obstruction. This kind of nondiffracting focal hole is called dark channel, which may have applications in atom optical experiments, such as with atomic lenses, atom traps, and atom switches.

Pure and fluorine doped TiO 2 nanoparticles were synthesized by the chemical reaction method under ultrasonication. The prepared nanoparticles were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopic techniques (SEM). The effect of fluorine doping on crystal structure, antimicrobial activity, photocatalytic activity and photovoltaic characteristics were studied. Fluorine doped TiO 2 nanoparticles was found to be strong antibacterial agent. The phase transformations from anatase to rutile and increase in the particle size of catalysts were found in fluorine doping, which was verified by XRD patterns. FT-IR analysis indicated the involvement of hydroxyl groups on fluoride adsorption. Fluorine doped TiO 2 has higher photocatalytic activity compared to pure TiO 2 . Further, it shows strong and distinct diode characteristics in photovoltaics.

Single crystals of ferroelectric material triglycine sulpho phosphate (TGSP) have been grown by slow evaporation method. The effect of l -lysine addition on the growth of TGSP crystal has been studied for various concentrations (5, 10 and 20 mol%). Unit cell parameters were determined from powder XRD analysis. Functional groups present in the grown crystal were confirmed from the vibrational frequencies of recorded FTIR and FT-Raman spectrum. The l -lysine doping into the crystal lattice has been qualitatively confirmed by spectral analysis. Thermogravimetric studies confirm that the lysine is incorporated into TGSP crystals. Dielectric studies reveal that the incorporation of lysine into TGSP enhances its dielectric strength.

Fluorine doped TiO2 were synthesized by solid state reaction method. Optical and structural properties of fluorine doped TiO2 were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, UV-vis diffusion reflectance spectroscopy and scanning electron microscopic techniques. The prepared fluorine doped TiO2 was smaller in size with respect to pure TiO2 and it is tetragonal in crystalline structure. Nanoflakes like structure of pure and fluorine doped TiO2 was confirmed from SEM image. Fluorine doped TiO2 shows smaller band gap, high strain and dislocation density when compared to pure TiO2. It also has higher photocatalytic activity with respect to pure TiO2.

ZnO and potassium doped ZnO nanoparticles were synthesized through wet chemical method. The samples were characterized by UV, XRD, SEM, TEM and EDAX. XRD analysis reveals that the prepared nanoparticles exhibit hexagonal wurtzite structure. TEM and SEM analyses disclose that synthesized samples were porous structure with needle shape. It also confirms that potassium was dispersed on ZnO surface. The influence of potassium on ZnO surface modulates the degradation of textile dyeing wastewater by improving its rate of decomposition to 0.007 min−1 with decoloration. A better zone of inhibition of about 20 mm against Staphylococci aureus and Pseudomonas aernginosa by ZnO and potassium doped ZnO nanoparticles were measured. The findings suggest that these nanoparticles have the potential to be a good photocatalyst and applied in water treatment to inhibit the bacterial growth.

Single crystals of the organic nonlinear material gamma-glycine have been grown in the presence of phosphoric acid by slow-evaporation method. The crystal structure is confirmed by X-ray powder diffraction method. The thermal stability and decomposition of the sample have been studied by thermal analysis. The result shows that the transition temperature, i.e. transition from gamma- to alpha-glycine is enhanced from 165 degrees C to 191 degrees C. The modes of vibrations of different molecular groups present in glycine have been identified by spectral analyses. The transmittance spectrum of gamma-glycine crystal shows that the lower UV cut-off wavelength lies at 230nm. Second harmonic generation (SHG) conversion efficiency has been estimated as 125mV and the output power by the crystal was 1.3 times that of potassium dihydrogen phosphate (KDP) crystal. The dielectric and microhardness measurements have been carried out on the gamma-glycine crystal.

The effect of nitric acid (HNO3) addition on the growth of triglycine sulphate (TGS) crystal has been studied from the aqueous solution for various concentrations of nitric acid. Significant changes in the crystal size and morphology have been observed in all the grown samples. Single crystal and powder X-ray diffraction analyses confirm the structure and cell parameter values of pure and HNO3 doped TGS crystals. FT-Raman and FTIR spectra confirm the characteristics absorption bands of pure and HNO3 doped TGS crystals. The composition of TGS crystals have been confirmed by CHNS analysis. Physical properties such as thermal, dielectric and mechanical studies have been performed for the pure and HNO3 doped TGS crystals. The dielectric constants of the crystals have been studied as a function of frequency. The results suggest that the HNO3 is doped into TGS crystal and that the doping increases its dielectric constant.

Glycine usually crystallizes as the metastable alpha-polymorph from pure aqueous solution. The polymorph, gamma-form of glycine can be crystallized only in presence of additive. In the present work, gamma-glycine has been crystallized by using potassium chloride (KCl) as additive at ambient temperature by solvent evaporation method. The form of crystallization is confirmed by X-ray powder diffraction method. Spectroscopic and thermal studies have been carried out for analyzing the presence of functional groups, thermal stability and decomposition of the sample. The results indicate that the KCl is doped into the gamma-glycine. The optical transparency of the gamma-glycine in the ultraviolet-visible region has been studied by recording the optical transmission spectrum. Second harmonic generation (SHG) conversion efficiency has been estimated as 120 mV and the output power by the crystal is less than that of potassium dihydrogen phosphate crystal.