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•Spherical Ag NPs of ∼8 nm dispersed on rGO layers was synthesized.•SERS sensing and photocatalytic degradation of Ag-rGO was studied on 3 dyes and TE.•Carcinogenic dye contaminants ...were observed in the SERS spectra of TE.•TE was degraded under visible light with an effective Kapp of 4.49 × 10−3/min.•Results suggest development of sensitive, scalable, stable sensing and removal substrates.
Uncontrolled volumes of textile effluents (TE) discharged into water-bodies significantly escalate the possibility of health hazards and environmental deterioration owing to the presence of hazardous dye contaminants. In this work, the toxic components in real TE were sensed on a graphene boosted silver nanoparticles (Ag-rGO) platform through surface enhanced Raman scattering (SERS) technique. Transmission electron microscopic images of Ag-rGO showed spherical Ag nanoparticles of ∼8 nm dispersed on wrinkled graphene oxide sheets. The efficiency of the substrate as a SERS sensor and photocatalytic substrate was first analyzed on commercial dyes such as rhodamine6 G, Congo red and malachite green. In TE, carcinogenic azo dye contaminants were effectively identified from the presence of NN and CN bands present in the SERS spectra. Further, removal of these dye contaminants in TE through visible light assisted photocatalysis by Ag-rGO was also evaluated. High degradation rate constant of ∼9 × 10−3/min was observed in TE after visible light assisted photocatalysis by Ag-rGO. Synergistically, the dual utility of Ag-rGO can be attributed to the enhanced electromagnetic field originating from the plasmonic nature of Ag nanoparticles and the strengthened charge transfer due to the adsorptive nature of rGO. Furthermore, the reduced particle size and suppressed fluorescence also aids the sensing and removal. These results suggest feasible development of sensitive, scalable, stable intermediate dye sensing and removal/ water recycling structures based on Ag-rGO to be incorporated at the discharge stage of textile dyeing industries.
•Indium/tungsten oxide nanocomposites synthesized by the hydrothermal route.•The conductivity of indium/tungsten oxide nanocomposite increase with roughness.•Dye absorption may boost due to the large ...surface of nano flower morphology.•Improved photovoltaic parameters due to a merger of indium in the tungsten oxide.
Tungsten oxide nanoparticles (PWNPs) and indium/tungsten oxide nanocomposites (IWNCs) were synthesized by the facile hydrothermal method. Powder X-ray diffraction (XRD) results confirmed the formation of the orthorhombic and body-centered cubic crystalline structure of PWNPs and IWNCs. An increase in roughness of IWNCs than PWNPs was evident through atomic force microscopy (AFM), which in turn increases the electrical conductivity of IWNCs. Dye-sensitized solar cells (DSSCs) for PWNPs and IWNCs were investigated as electron-transport layers in planar DSSCs. The integration of indium in the tungsten oxide layer led to enhanced power conversion efficiency (PCE) of about 4.69% due to the electron transfer and reduced back-recombination.
Bismuth sulfide nanoparticles (BiS NPs) were synthesized via the hydrothermal method, and reduced graphene oxide(rGO) and silver nanoparticles (Ag), which acted as substrates, have prepared using the ...chemical reduction method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy, and photoluminescence spectroscopy. Commercially available paracetamol-500 mg (PAM) and aspirin-300 mg (ASP) were selected for photodegradation under visible light using the as-prepared composites in an aqueous solution. Photoluminescence spectroscopy was used to detect PAM and ASP using the photo-excited electron transfer (PET) process, and the limit of detection (LOD) has obtained for PAM(8.70 ppm) and ASP(4.43 ppm) with a sensitivity of 0.9954 and 0.8002, respectively. Fourier transform infrared spectroscopy (FTIR) was used to analyze the before and after degradation products and to confirm the disintegrated products such as –COOH and –CH– both before and after disintegration.. The experimental data were found to fit well with the Freundlich isotherm, suggesting that the as-prepared nanocomposites exhibited a heterogeneous nature for PAM (5119 mg/L), and the pseudo-first-order kinetic model suggests ASP (1030 mg/L) with R2 values of 0.9119 and 0.7075. The risk assessment analysis of PAM was 9.823 μg/L(RQ > 1) and that of ASP was 0.2106 μg/L(RQ < 1), indicating that PAM has a higher potential risk than ASP. The demographic data of the participants indicated that PAM was the most stockpiled medicine at home; this work also encompasses the action of a single PAM and ASP tablet toward the environment, if it is accidently disposed of improperly could create massive water/soil pollution; hence, the care/duty of each person should follow the proper disposal of medical waste because we cannot replace this environment.
•BiSNPs@rGO/Ag composites successfully detect and degrade PAM and ASP.•Detection utilizes photo-induced electron transfer through photoluminescence spectroscopy.•PAM degradation tendency surpasses that of ASP.•Risk assessment indicates PAM poses a higher soil/water pollution risk than ASP.•Demographic data emphasizes prompt separate collection of stockpiled pharmaceutical drugs.
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) ...nanoparticles (NPs), Magnesium oxide (MgO) NPs and Zinc oxide/Magnesium oxide nanocomposites (ZnO/MgO NCs) namely 0.9 M ZnO:0.1 M MgO, 0.7 M ZnO:0.3M MgO, and 0.5 M ZnO:0.5 M MgO NCs were synthesized by simple wet chemical method and used as an effective photocatalyst for the degradation of toxic and harmful organic dye present in textile dyeing wastewater. The average crystallite sizes for the ZnO/MgO NCs were 31 nm, 30 nm, and 29 nm. The energy band gap (E
g
) for the NCs was estimated as 3.7eV, 4 eV, and 4.4eV using Tauc's plot. Uniform, flaky and porous morphology of the ZnO/MgO NCs were observed in the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The 0.5 M ZnO:0.5 M MgO NCs with textile dyeing wastewater under UV light of 254 nm and visible light irradiation showed superior photocatalytic degradation with the rate constant of 0.005/min and 0.0008/min respectively. Furthermore, they showed good antibacterial activity against Staphylococcus aureus and Escherichia coli with 7 mm and 6 mm of inhibition zone. This study suggests that ZnO/MgO NCs can serve as an ideal commercial pollutant degradation method.
Photocatalysis is a photochemical advanced oxidation process (AOP) that depends on the crystalline quality and specific surface area of the nanoparticles. Heterogeneous photocatalysts zinc ...oxide/barium oxide nanocomposites (ZnO/BaO NCs) were synthesized by a simple and low-cost hydrothermal method for the degradation of organic pollutants in wastewater. X-ray diffraction analysis (XRD) revealed the formation of hexagonal and cubic crystalline-structure phases for ZnO and BaO nanoneedles, with an average crystallite size ranging from 28–31 nm. Sphere-like morphology for the synthesized NCs was evident from the SEM analysis. BaO in ZnO significantly enhances the photocatalytic performance of ZnO with high degradation efficiency of 97% in 40 min, 96% and 93% in 90 min under UV light irradiation; and 97% in 60 min, 95% in 90 min, and 50% in 120 min under visible light irradiation for the decolorization of methylene blue (MB), malachite green (MG) and methyl orange (MO), respectively. Moreover, they showed efficient rate constants of about 25 × 10
−3
min
−1
, 23 × 10
−3
min
−1
, and 5 × 10
−3
min
−1
for MB, MG, and MO, respectively. These NCs effectively inactivated pathogenic bacteria, namely
S. aureus
and
E. coli
, by cell wall destruction with a zone of inhibition of about 6 mm and 7 mm, respectively even with small volumes of NC solutions (75 μl). Hence this study suggests that ZnO/BaO NCs can provide an efficient way toward the best pollutant degradation system commercially.
Highlights
Heterogeneous photocatalysts zinc oxide/barium oxide nanocomposites (ZnO/BaO NCs) were synthesized by hydrothermal method.
BaO in ZnO significantly enhances the photocatalytic performance of ZnO with high degradation efficiency under UV light irradiation and visible light irradiation for the decolorization of methylene blue (MB), malachite green (MG), and methyl orange (MO), respectively.
ZnO/BaO NCs effectively inactivated pathogenic bacteria, namely
S
.
aureus
and
E
.
coli
, by cell wall destruction with a zone of inhibition of about 6 mm and 7 mm, respectively, even with small volumes of NC solutions (75 μl).
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•Cu, Ni and CuNi NPs were successfully synthesized solvothermally.•CuNi bimetallic NPs showed FCC structure with particle size of 23nm.•CuNi showed zone of inhibition of 31mm & 30mm ...against S. aureus and E. coli.•Synergistic bactericidal Cu2+ and bacteriostatic Ni2+ strongly inhibit bacterium.•Smaller particle size and enzyme disruption may enhance the activity.
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 (100), (200) and (220) planes. Porous, flaky NPs with interspersed spherical cuboids were observed through scanning electron microscopy. CuNi showed zones of inhibition of 31mm and 30mm against S. aureus and E. coli respectively which was comparable to a 31mm 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.
•Ag and Au nanoparticles detected landfill leachate.•Leachate degrades in the visible region.•Solid profiles and COD ranges were achieved for crosslinked membrane.•UV/Vis spectrophometer confirms the efficiency of each process.
Surface enhanced Raman scattering (SERS), photocatalytic and antibacterial activities of Fe
3
O
4
/Ag magnetic nano particle (MNP) is reported in this work. A synthesized Fe
3
O
4
/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 Fe
3
O
4
/Ag MNP posses good magnetic response and attribute as a SERS substrate. SERS property of Fe
3
O
4
/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 Fe
3
O
4
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.
Graphic Abstract
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A novel and fresh Au@Pt nanoflower synthesised by the chemical reduction method. Au@Pt nanoflowers exhibit the Au SPR peak at 530 nm and the peak of Pt NPs at 265 nm. Transmission ...electron microscopy (TEM) analysis showed the average particle size to be 19 nm. Using Surface Enhanced Raman Scattering (SERS) the pollutants such as Poly Chlorinated Biphenyls (PCBs) were detected in the real environmental sample; river soil and it is further confirmed through Gas Chromatography and Mass Spectrometry (GC–MS) studies. The catalytic activity of Au@Pt nanoflowers was studied via the catalytic reduction of 4-nitrophenol (NP) to 4-aminophenol (AP) assisted by NaBH4. Au@Pt nanoflowers exhibit the highest catalytic activity, converting 4- NP to 4- AP in 12 min.
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•Silver and activated carbon co-doped titania nanoparticles (TAC) were synthesized.•Pure anatase phase titania, face centered cubic silver nanoparticles were observed.•Zones of ...inhibition comparable to streptomycin were observed in E. coli & S. aureus.•Adsorptive nature of activated carbon concentrates bacteria around TAC.•Oxidative stress, cell rupture and bacterial adsorption inhibit bacterial growth.
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.
