To evaluate the photocatalytic and antibacterial activity of a biologically synthesized AgNPs mediated by palm (
Silver-based nano compounds are used in chemical
In this work, the synthesized AgNPs from
Pure
10ml of Pathaneer was taken into two different flask and 90ml of 5mM aqueous AgNPs was added carefully in each flask. It was enclosed with aluminum foil and then the solution was heated in the water bath at 60oC for 30 min
The purified silver nanoparticles were frozen, and dried to evaluate their crystalline structure, the crystallite size of the nanoparticles using X-ray diffractometer (Bruker D8 Advance, Germany) equipped with CuKα radiation (λ = 1.5418 Å) in the 2θ range from 20o to 80o . The crystalline size of these silver nanoparticles was calculated by using the Debye Scherer’s equation. FT-IR analysis of the material was carried out by JASCO 460 PLUS FT-IR spectrometer in the range of 4000–400 cm−1. The synthesized AgNPs sample was dried and ground with KBr pellets and analyzed. The various modes of vibrations were identified to determine the different functional groups present in the AgNPs. The particle morphology, shape and size of synthesized AgNPs were analyzed by Field Emission Scanning electron microscope (SIGMA HV –Carl Zeiss with Bruker Quantax 200- Z10 EDS Detector). In this experiment, the thin film of the sample was deposited on the carbon-coated copper grid. EDAX was carried out to confirm the elements present in the biosynthesized silver nanoparticles. The surface morphology, shape and size of the synthesized AgNPs were measured by HRTEM (Jeol/JEM 2100, LaB6, 200kV). The size distribution of bioreduced silver nanoparticles was measured using DLS (Micromeritics, Nano Plus). Biosynthesized AgNPs were analyzed by using UV–Vis spectrum recorded by Perkin Elmer Lambda35 in the range 190-1100nm. The fluorescence spectrum was measured on a Perkin Elmer Lambda 45 in the range of 200-900 nm.
The antibacterial activities of AgNPs were tested against both gram positive and gram negative bacteria. Medical isolates of
Each value is the mean of three replications each (n = 3). Statistically, the means of the three experiments were not significantly different (P˂0.05). Means in the same column with different letters are significantly different at (P˂0.05) in accordance with Fisher’s least significant difference test. The statistical result shows that the synthesized silver nanoparticles are the potential candidate for enhancing antibacterial property.
The photo catalytic activities of synthesized AgNPs were evaluated using methyl blue under sunlight irradiation. 2.5mg of prepared AgNPs was added to 100mL of a1mg/L MB aqueous solution. Stirring the solution for 30 min in a dark to bring the AgNPs to constant equilibrium in the mixture. Then kept the mixture in sunlight for 2-2.30 h. The sample was collected at regular intervals (for every 30 min). The collected sample were filtered and centrifuged to ensure photo of the dye.
The crystalline nature of the newly prepared AgNPs was confirmed using powder XRD analysis as shown in
For FCC structure of the lattice parameter (a) can be calculated by the measured values of the d spacing of the (111) planes using the following equation.
Where, a is a lattice parameter h, k, and l are Miller indices of the crystalline graphic plane. The calculated value of a = 4.080Ǻ is very well agreed with the standard JCPDS File no: 04-0783 for silver nanocrystal. The average crystallite size (D) was calculated using Debye-scherrer’s formula. The average crystalline size is around 27nm.
Willamson- Hall method (W-H) is suggested to calculate the microstrain of the prepared AgNPs using the modify Scherer’s equation
The non zero slope of the strain (
The dislocation density (δ) is calculated using the relation.
The number of unit cells (n) is estimated from
Where V is the volume of the unit cell.
The Morphology Index (MI) is calculated from full wave half width maxima [FWHM] of powder XRD. MI is obtained using the relation
Where FWHMh was the greatest FWHM value achieved from peaks, FWHMp was the value of particular peak’s FWHM. The calculated Morphology index values are given in
The Relative Percentage Error (RPE)
Where ZH is the experimental d-values in the XRD pattern and Z is the standard d-values in JCPDS data. The calculated RPE values are shown in
2θo degree | d-spacing (Ǻ) | Crystalline size D (nm) | Dislocation Density (x1014 lines/m2) | Number of unitcells (x106) | Morphology index (MI) | Relative Percentage error (RPE) |
---|---|---|---|---|---|---|
38.55 | 2.3528 | 14.274 | 4.900 | 7.8824 | 0.5 | 0.7 |
44.43 | 1.9557 | 34.9156 | 8.911 | 11.8545 | 0.8364 | 0.1 |
64.29 | 1.5229 | 27.021 | 9.801 | 8.8294 | 0.6666 | 0.4 |
The stretching vibrations are generally absorbed in the spectral range of 3500cm-1 to 500cm-1 by FTIR spectrum (
FESEM shows the morphology of silver nanoparticles (
The fluorescence spectrum of AgNPs were recorded in the range of 200 -900 nm. From the
Dynamic light scattering technique can be used to determine the average particle size of AgNPs. In the present work, the synthesized silver nanoparticles are polydispersed in nature as shown in the
Optical properties of prepared AgNPs were examined using UV-Vis absorption spectrum (
Where α is the absorption co-efficient, hν is the photon energy, Eg is the optical energy band gap and A is a constant. Where n is the parameter involved in the transition process. If n=2, it will be for directly allowed transition and n=1/2 for indirect transition. The calculated value of the energy gap is 2.92 eV which is lower compared with the result reported by Narental Budhiraja et al. (4.27 eV), particle size decreases as the bandgap increases, it may be due to the quantum effect
The mechanisms of photo catalytic degradation of methyl blue under sunlight can be as shown in the
AgNPs (e-CB) + O2 → AgNPs + O2
H2O → H+ + OH
O2+H- →HO2
Silver nanoparticles (eCB) + HO2 + H +→ H2O2
AgNPs (h+νB) + dye → degradation products
HO- +H+ → H2O2
HO2 + e - → HO2-
This indicates that the silver nanoparticles possess high photo degradation efficiency.
Antibacterial assay of synthesized AgNPs against gram +ve and gram-ve bacteria at different concentrations were showed a strong properties of antibacterial agent for both tested microorganisms(
(Platephotos of AgNPs using
Compound | E.coli | S. aureus |
---|---|---|
1-Lyzol (1 %) | Nil | 12b |
2-Negative control | Nil | Nil |
3-KM | 9a | 15a |
4-SKM | Nil | Nil |
Each value is the mean of three replications each (n = 3). Statistically the means of the three experiments were not significantly different (P˂0.05). Means in the same column with different letters are significantly different at (P˂0.05) in accordance with Fisher’s least significant difference test.
The synthesis of silver nanoparticles using Pathaneer was reported for the first time. In this synthesis no aggressive chemicals were used as reducing agent. Crystalline size and the structural morphology of the sample were analyzed using several types of instrumentation like XRD, Field Emission Scanning Electron Microscopy with Energy-dispersive X-ray spectroscopy and Dynamic light scattering. From the FTIR analysis, AgNPs were formed due to the biomolecular interaction. HRTEM exhibits the morphology distribution of AgNPs the optical band gap energy was derived from UV-Vis and fluorescence spectroscopy. The prepared AgNPs were proved as an effective photo catalytic degradation of MB dye under sunlight irradiation. Then it is found that the combination of Pathaneer with AgNPs enhances the antibacterial activity for Gram + ve and Gram –ve bacteria. It can be used as nanomedicine for constipation and Gastric ulcer etc.