Antibiotics are pervasive contaminants in aqueous systems that pose an environmental threat to aq... more Antibiotics are pervasive contaminants in aqueous systems that pose an environmental threat to aquatic life and humans. Typically, antibiotics are developed to counteract bacterial infections; however, their prolonged and excessive use has provoked unintended consequences. The presence of excessive amounts of antibiotics and anti-inflammatory, anti-depressive, and contraceptive drugs in hospital and industrial wastewater poses a significant threat to the ecosystem, with groundwater containing drug concentrations of <1 mg/L to hundreds of µg/L. According to the literature, 33,000 people die directly from drug-resistant bacterial infections in Europe annually, which costs EUR 1.5 billion in health care and productivity loss. Consequently, the continuous spread of antibiotics in the ecosystem has led to greater interest in developing a sustainable method for effective antibiotic removal from wastewater. This critical review aims to present and discuss recent advances in the photocat...
This study was aimed at determining the cytotoxic efficacy of graphene oxide (GO) and thiourea-re... more This study was aimed at determining the cytotoxic efficacy of graphene oxide (GO) and thiourea-reduced oxide (T-rGO) nanosheets against human prostate cancer cells and their antibacterial activity against E. coli mastitis. X-ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, and scanning electron microscopy were used to study the physicochemical properties of the fabricated GO and T-rGO. The cytotoxicity of GO and T-rGO in human prostate cancer cells was examined using cell survival test, DNA laddering, and cell cycle analysis. The antibacterial effectiveness of GO and T-rGO was tested using E. coli mastitis. The study revealed that cell viability was lowered by GO and T-rGO in a concentration-dependent trend. The production of reactive oxygen species and hydroxyl radicals was found to increase following the treatment. DNA was harmed because of oxidative stress, causing laddering. Both GO and T-rGO demonstrated good antibacterial activity against E. coli...
The development of advanced materials for the removal of heavy metal ions is a never-ending quest... more The development of advanced materials for the removal of heavy metal ions is a never-ending quest of environmental remediation. In this study, a facile and cost-effective approach was employed to synthesize copper ferrite (CF) and copper ferrite/reduced graphene oxide (CG) by microwave assisted combustion method for potential removal of barium ions from aqueous medium. The physiochemical characterizations indicated the formation of magnetic nanocomposite with an average crystallite size of CF and CG is 32.4 and 30.3 nm and with specific surface area of 0.66 and 5.74 m2/g. The magnetic results possess multidomain microstructures with saturation magnetization of 37.11 and 33.84 emu/g for CF and CG. The adsorption studies prove that upon addition of rGO on the spherical spinel ferrite, the adsorption performance was greatly improved for CG nanocomposite when compared with the bare CF nanoparticles. The proposed magnetic adsorbent demonstrated a relatively high Ba2+ adsorption capacity ...
The current research focuses on the fabrication of water-soluble, reduced graphene oxide (rGO) em... more The current research focuses on the fabrication of water-soluble, reduced graphene oxide (rGO) employing thiourea (T) using a simple cost-effective method, and subsequently examining its anticancer characteristics. The cytotoxicity caused by graphene oxide (GO) and T-rGO is investigated in detail. Biological results reveal a concentration-dependent toxicity of GO and T-rGO in human colon cancer cells HT-29. A decrease in cell viability alongside DNA fragmentation is observed. Flow cytometry analysis confirms the cytotoxic effects. The novelty in this work is the use of raw graphite powder, and oxidants such as KMNO4, NaNO3, and 98 percent H2SO4 to produce graphene oxide by a modified Hummers method. This study demonstrates a simple and affordable procedure for utilising thiourea to fabricate a water-soluble reduced graphene oxide, which will be useful in a variety of biomedical applications.
Photochemical & Photobiological Sciences, 2017
The multifunctional catalytic activity of Co3O4 spinel nanoparticles, synthesized using Punica gr... more The multifunctional catalytic activity of Co3O4 spinel nanoparticles, synthesized using Punica granatum (pomegranate) seed extract was evaluated for its multiple applications.
... The sensitivity factor (S f ) data in the studied temperature range for all the vapors were e... more ... The sensitivity factor (S f ) data in the studied temperature range for all the vapors were employed to fit the Gaussian function. ... Parameters, CuSA1, SA, CuSA5. S BET (m 2 /g), 10.46, 77.86, 183.9.S mic (m 2 /g), 0.000, 33.96, 83.97. S meso (m 2 /g), 10.46, 43.90, 99.93. ...
Materials Science in Semiconductor Processing, 2015
Zinc doped cobalt ferrite spinel nanoparticles were prepared by the microwave combustion method. ... more Zinc doped cobalt ferrite spinel nanoparticles were prepared by the microwave combustion method. All the samples were characterized by using X-ray diffraction technique (XRD), Scanning Electron Microscopy, energy dispersive X-ray analysis, UV-visible diffuse reflectance spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry. The XRD patterns confirmed the formation of single phase CoFe 2 O 4 inverse spinel structure without impurities. The lattice parameter increased from 8.380 to 8.396 Å with increasing Zn 2 þ fraction. The average crystallite sizes obtained by a Scherrer method varied between 46.22 nm and 30.79 nm. The estimated band gap energy values increases with an increasing zinc fraction (1.88-2.10 eV). The elemental composition of Zn, Co, and Fe was qualitatively obtained from energy dispersive X-ray (EDX) analysis.
Nanosized ZSM-5 zeolite hexagonal cubic micro-blocks with different Si/Al ratios were successfull... more Nanosized ZSM-5 zeolite hexagonal cubic micro-blocks with different Si/Al ratios were successfully synthesized by using TPAOH in the presence of nonionic surfactant (Triton X-100) by a hydrothermal method. The samples prepared with the surfactant were characterized by XRD, XRF, FT-IR, N 2 adsorption, HR-TEM, HR-SEM and NH 3-TPD analysis to evaluate the particle structure, size and acid strength. Pure crystalline phase of ZSM-5 is confirmed by powder X-ray diffraction. FT-IR analysis further showed that nanosized zeolite has double five rings of the MFI-type of typical absorption at about 550 cm-1. The SEM images clearly show that all ZSM-5 zeolite samples possess the similar hexagonal spheres morphology with particle size of about 320-360 nm. The influence of Triton X-100 in the structural, textural, morphological and catalytic properties of ZSM-5 is compared with conventional ZSM-5. The catalytic activity of ZSM-5 zeolites with different Si/Al ratios (ZSM-5-WS(x) and ZSM-5-WOS(x)) is evaluated in the selective oxidation of benzyl alcohol (BzOH) using tert-butyl hydroperoxide (TBHP) as an oxidant and water as a solvent. The Triton X-100-assisted preparation yielded a zeolite exhibiting a higher conversion than the one prepared in the absence of Triton X-100. Among the catalysts, ZSM-5-WS(28) (Si/Al = 28) catalyst exhibited significantly higher conversion at optimum conditions. This catalyst can be retrieved and reprocessed for five times without a significant loss in its activity and selectivity.
The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be p... more The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be plant ceramics (PC) has been chosen as a dopant in the SnO2 matrix inview of evaluating as a new sensor material. Different compositions of the precursors were prepared to optimize for achieving high humidity sensitivity. The synthesized materials were characterized for structural behaviour, vibrational functional groups, BET surface area, surface morphology and elemental analysis from X-ray diffraction, FT-IR spectra, N2 adsorption/desorption isotherm at 77K, Scanning electron micrograph and Energy dispersive X-ray analysis respectively. The PC doped SnO2 was evidenced from the X-ray diffraction spectra. Two probe DC-electrical resistance method at different humidity levels were used to determine the sensitivity values. Of the various compositions prepared, SnO2-PC2 showed comparatively higher humidity sensitivity (Sf) value, 4013 ± 265. A fast response and recovery time of 80s and 140s respectively was also achieved indicating the suitability of the PC doped SnO2 as a good humidity sensor.
In the present paper, nanocrystalline hierarchical ZSM-5 zeolites were successfully synthesized b... more In the present paper, nanocrystalline hierarchical ZSM-5 zeolites were successfully synthesized by the hydrothermal method in the presence of tetrapropylammonium hydroxide as a single template with the gel composition of 58SiO 2 :Al 2 O 3 :20TPAOH:1,500H 2 O. The prepared zeolite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Nitrogen adsorption-desorption (BET), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) techniques. The formation of pure and highly crystalline ZSM-5 zeolite phase is confirmed by XRD. The IR vibration band at 550 cm-1 is assigned to the double 5-rings of MFI-type zeolites. N 2 adsorption-desorption isotherms showed that the synthesized product had high BET surface area and possessed composite pore structures with both micro and mesopores. The catalytic performance of hierarchical ZSM-5 zeolite was investigated in the selective oxidation of benzyl alcohol (BzOH) with hydrogen peroxide (H 2 O 2) under mild conditions. The results showed that the conversion of BzOH and the selectivity to benzaldehyde were about 94 and about 99 % respectively, when using 0.08 g ZSM-5 catalyst with acetonitrile as the solvent and H 2 O 2 as the oxidant at 90°C. This catalyst can be retrieved and reprocessed for five times without a significant loss in its activity and selectivity.
In this study, pure and Co-doped CuO nanostructures (0.5, 1.0, 1.5, and 2.0 at wt% of Co) were sy... more In this study, pure and Co-doped CuO nanostructures (0.5, 1.0, 1.5, and 2.0 at wt% of Co) were synthesized by microwave combustion method. The prepared samples were characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). Powder X-ray diffraction patterns refined by the Rietveld method indicated the formation of single-phase monoclinic structure. The surface morphology and elemental analysis of Co-doped CuO nanostructures were studied by using HR-SEM and EDX. Interestingly, the morphology was found to change considerably from nanoflowers to nanoplates then to nanoparticles with the variation of Co concentration. The optical band gap calculated using DRS was found to be 2.1 eV for pure CuO and increases up to 3.4 eV with increasing cobalt content. Photoluminescence measurements also confirm these results. The magnetic measurements indicated that the obtained nanostructures were ferromagnetic at room temperature with an optimum value of saturation magnetization at 1.0 wt.% of Co-doped CuO, i.e., 970 micro emu/g.
In the present work, we report simple and eco-friendly route to synthesise biocomposite doped nan... more In the present work, we report simple and eco-friendly route to synthesise biocomposite doped nanocrystalline MgO. The seed of Hygrophila spinosa T. Anders (HST) plant showing gelly nature in water and contain several minerals, is the chosen dopant (biocomposite). The structural parameters, functional groups, surface morphology, elemental analysis and optical behavior of the prepared samples were evaluated by using X-ray diffraction (XRD), Fourier transform-infra red (FT-IR), high resolution scanning electron microscope (HR-SEM), Energy dispersive X-ray analysis (EDX), Diffuse reflectance spectroscopy (DRS) techniques respectively. The two probe DC-electrical resistance method was used to evaluate the sensitivity factor (S(f)) of the prepared samples at different humidity levels. It was found that the appropriate ratio of dopant into MgO extensively modified the sensitivity. Compared to all the other composition of Mg:HS, the sensitivity factor (S(f)) of MH3 (0.25:0.75) is found to be higher i.e., 3,300. The MH3 sample also showed good linearity, reproducibility, stability, response and recovery time about 210 +/- 5 s and 232 +/- 4 s, respectively. The composition, crystallite size and surface area were found to have the significant effects on the sensitivity.
A series of Sr(II)-added nickel aluminate nanocatalysts with different molar ratios of Ni:Sr (1.0... more A series of Sr(II)-added nickel aluminate nanocatalysts with different molar ratios of Ni:Sr (1.0:0.0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4 and 0.5:0.5) keeping the molar ratio of aluminum constant were synthesized by modified sol-gel method using ethylenediamine and sintered at 900 degrees C. The samples were labeled as NiSA1-900, NiSA2-900, NiSA3-900, NiSA4-900, NiSA5-900, NiSA6-900, respectively. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms and tested for the catalytic oxidation of benzyl alcohol. Influence of the reaction parameters (molar ratio of Sr(II) added to nickel aluminate nanocatalyst, reaction time, reaction temperature and solvent effect) on the catalytic oxidation of benzyl alcohol were studied. It was observed that the addition of Sr(II) improves the performance of the nickel aluminate nanocatalysts towards the selective oxidation of benzyl alcohol and decreases the grain size. Higher activity was obtained for the conversion of benzyl alcohol to benzaldehyde for 0.3 molar percentage Sr(II) added nickel aluminate catalyst (NiSA4-900). Stability and reusability of the catalyst was also investigated.
A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials w... more A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials with different morphologies such as nanoflakes, spherical nanoparticles (SNPs), and nanorods. The concentration of the capping agent, Triton X-100, is a key factor in the morphological control of ZnO nanostructures. The formation of different morphologies of ZnO was confirmed by HR-SEM and HR-TEM. XRD data showed the formation of single-phase ZnO with the wurtzite crystal structure. The influence of La contents on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO SNPs was investigated systematically. The influence of the ZnO morphologies on the photocatalytic degradation (PCD) of Bisphenol A (BPA) as a model reaction is evaluated and discussed in terms of surface area, crystal growth habits, particle size, and oxygen defects. The results indicated that the particle size is an important factor for the enhancement of PCD. Furthermore, the effect of different photocatalytic reaction parameters on the resulting PCD efficiency of ZnO SNPs was investigated.
The effect of ethylenediamine addition in the sol-gel method for the preparation of nano CuAl 2 O... more The effect of ethylenediamine addition in the sol-gel method for the preparation of nano CuAl 2 O 4 spinel for the enhancement in their structural, electrical, optical and catalytic properties was investigated. The samples were prepared by two different methods: sol-gel and modified sol-gel technique using ethylenediamine. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms, temperature dependent conductance measurements, thermoelectric power (TEP) measurements and UV-visible diffuse reflectance (UV-vis-DRS) spectra were used to characterize the samples prepared. CuAl 2 O 4 prepared by modified sol-gel technique was found to possess a higher surface area, lower crystallite size, lower activation energy and high porosity than the one prepared by sol-gel method which in turn lead to the improved performance of it towards the selective oxidation of benzyl alcohol to benzaldehyde. Effect of solvent on the catalytic oxidation of benzyl alcohol by the nano CuAl 2 O 4 prepared by modified sol-gel technique was also investigated.
Antibiotics are pervasive contaminants in aqueous systems that pose an environmental threat to aq... more Antibiotics are pervasive contaminants in aqueous systems that pose an environmental threat to aquatic life and humans. Typically, antibiotics are developed to counteract bacterial infections; however, their prolonged and excessive use has provoked unintended consequences. The presence of excessive amounts of antibiotics and anti-inflammatory, anti-depressive, and contraceptive drugs in hospital and industrial wastewater poses a significant threat to the ecosystem, with groundwater containing drug concentrations of <1 mg/L to hundreds of µg/L. According to the literature, 33,000 people die directly from drug-resistant bacterial infections in Europe annually, which costs EUR 1.5 billion in health care and productivity loss. Consequently, the continuous spread of antibiotics in the ecosystem has led to greater interest in developing a sustainable method for effective antibiotic removal from wastewater. This critical review aims to present and discuss recent advances in the photocat...
This study was aimed at determining the cytotoxic efficacy of graphene oxide (GO) and thiourea-re... more This study was aimed at determining the cytotoxic efficacy of graphene oxide (GO) and thiourea-reduced oxide (T-rGO) nanosheets against human prostate cancer cells and their antibacterial activity against E. coli mastitis. X-ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, and scanning electron microscopy were used to study the physicochemical properties of the fabricated GO and T-rGO. The cytotoxicity of GO and T-rGO in human prostate cancer cells was examined using cell survival test, DNA laddering, and cell cycle analysis. The antibacterial effectiveness of GO and T-rGO was tested using E. coli mastitis. The study revealed that cell viability was lowered by GO and T-rGO in a concentration-dependent trend. The production of reactive oxygen species and hydroxyl radicals was found to increase following the treatment. DNA was harmed because of oxidative stress, causing laddering. Both GO and T-rGO demonstrated good antibacterial activity against E. coli...
The development of advanced materials for the removal of heavy metal ions is a never-ending quest... more The development of advanced materials for the removal of heavy metal ions is a never-ending quest of environmental remediation. In this study, a facile and cost-effective approach was employed to synthesize copper ferrite (CF) and copper ferrite/reduced graphene oxide (CG) by microwave assisted combustion method for potential removal of barium ions from aqueous medium. The physiochemical characterizations indicated the formation of magnetic nanocomposite with an average crystallite size of CF and CG is 32.4 and 30.3 nm and with specific surface area of 0.66 and 5.74 m2/g. The magnetic results possess multidomain microstructures with saturation magnetization of 37.11 and 33.84 emu/g for CF and CG. The adsorption studies prove that upon addition of rGO on the spherical spinel ferrite, the adsorption performance was greatly improved for CG nanocomposite when compared with the bare CF nanoparticles. The proposed magnetic adsorbent demonstrated a relatively high Ba2+ adsorption capacity ...
The current research focuses on the fabrication of water-soluble, reduced graphene oxide (rGO) em... more The current research focuses on the fabrication of water-soluble, reduced graphene oxide (rGO) employing thiourea (T) using a simple cost-effective method, and subsequently examining its anticancer characteristics. The cytotoxicity caused by graphene oxide (GO) and T-rGO is investigated in detail. Biological results reveal a concentration-dependent toxicity of GO and T-rGO in human colon cancer cells HT-29. A decrease in cell viability alongside DNA fragmentation is observed. Flow cytometry analysis confirms the cytotoxic effects. The novelty in this work is the use of raw graphite powder, and oxidants such as KMNO4, NaNO3, and 98 percent H2SO4 to produce graphene oxide by a modified Hummers method. This study demonstrates a simple and affordable procedure for utilising thiourea to fabricate a water-soluble reduced graphene oxide, which will be useful in a variety of biomedical applications.
Photochemical & Photobiological Sciences, 2017
The multifunctional catalytic activity of Co3O4 spinel nanoparticles, synthesized using Punica gr... more The multifunctional catalytic activity of Co3O4 spinel nanoparticles, synthesized using Punica granatum (pomegranate) seed extract was evaluated for its multiple applications.
... The sensitivity factor (S f ) data in the studied temperature range for all the vapors were e... more ... The sensitivity factor (S f ) data in the studied temperature range for all the vapors were employed to fit the Gaussian function. ... Parameters, CuSA1, SA, CuSA5. S BET (m 2 /g), 10.46, 77.86, 183.9.S mic (m 2 /g), 0.000, 33.96, 83.97. S meso (m 2 /g), 10.46, 43.90, 99.93. ...
Materials Science in Semiconductor Processing, 2015
Zinc doped cobalt ferrite spinel nanoparticles were prepared by the microwave combustion method. ... more Zinc doped cobalt ferrite spinel nanoparticles were prepared by the microwave combustion method. All the samples were characterized by using X-ray diffraction technique (XRD), Scanning Electron Microscopy, energy dispersive X-ray analysis, UV-visible diffuse reflectance spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry. The XRD patterns confirmed the formation of single phase CoFe 2 O 4 inverse spinel structure without impurities. The lattice parameter increased from 8.380 to 8.396 Å with increasing Zn 2 þ fraction. The average crystallite sizes obtained by a Scherrer method varied between 46.22 nm and 30.79 nm. The estimated band gap energy values increases with an increasing zinc fraction (1.88-2.10 eV). The elemental composition of Zn, Co, and Fe was qualitatively obtained from energy dispersive X-ray (EDX) analysis.
Nanosized ZSM-5 zeolite hexagonal cubic micro-blocks with different Si/Al ratios were successfull... more Nanosized ZSM-5 zeolite hexagonal cubic micro-blocks with different Si/Al ratios were successfully synthesized by using TPAOH in the presence of nonionic surfactant (Triton X-100) by a hydrothermal method. The samples prepared with the surfactant were characterized by XRD, XRF, FT-IR, N 2 adsorption, HR-TEM, HR-SEM and NH 3-TPD analysis to evaluate the particle structure, size and acid strength. Pure crystalline phase of ZSM-5 is confirmed by powder X-ray diffraction. FT-IR analysis further showed that nanosized zeolite has double five rings of the MFI-type of typical absorption at about 550 cm-1. The SEM images clearly show that all ZSM-5 zeolite samples possess the similar hexagonal spheres morphology with particle size of about 320-360 nm. The influence of Triton X-100 in the structural, textural, morphological and catalytic properties of ZSM-5 is compared with conventional ZSM-5. The catalytic activity of ZSM-5 zeolites with different Si/Al ratios (ZSM-5-WS(x) and ZSM-5-WOS(x)) is evaluated in the selective oxidation of benzyl alcohol (BzOH) using tert-butyl hydroperoxide (TBHP) as an oxidant and water as a solvent. The Triton X-100-assisted preparation yielded a zeolite exhibiting a higher conversion than the one prepared in the absence of Triton X-100. Among the catalysts, ZSM-5-WS(28) (Si/Al = 28) catalyst exhibited significantly higher conversion at optimum conditions. This catalyst can be retrieved and reprocessed for five times without a significant loss in its activity and selectivity.
The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be p... more The mineral oxides derived from the plant seeds Hygrophila Spinosa T. anders (HST) termed to be plant ceramics (PC) has been chosen as a dopant in the SnO2 matrix inview of evaluating as a new sensor material. Different compositions of the precursors were prepared to optimize for achieving high humidity sensitivity. The synthesized materials were characterized for structural behaviour, vibrational functional groups, BET surface area, surface morphology and elemental analysis from X-ray diffraction, FT-IR spectra, N2 adsorption/desorption isotherm at 77K, Scanning electron micrograph and Energy dispersive X-ray analysis respectively. The PC doped SnO2 was evidenced from the X-ray diffraction spectra. Two probe DC-electrical resistance method at different humidity levels were used to determine the sensitivity values. Of the various compositions prepared, SnO2-PC2 showed comparatively higher humidity sensitivity (Sf) value, 4013 ± 265. A fast response and recovery time of 80s and 140s respectively was also achieved indicating the suitability of the PC doped SnO2 as a good humidity sensor.
In the present paper, nanocrystalline hierarchical ZSM-5 zeolites were successfully synthesized b... more In the present paper, nanocrystalline hierarchical ZSM-5 zeolites were successfully synthesized by the hydrothermal method in the presence of tetrapropylammonium hydroxide as a single template with the gel composition of 58SiO 2 :Al 2 O 3 :20TPAOH:1,500H 2 O. The prepared zeolite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Nitrogen adsorption-desorption (BET), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) techniques. The formation of pure and highly crystalline ZSM-5 zeolite phase is confirmed by XRD. The IR vibration band at 550 cm-1 is assigned to the double 5-rings of MFI-type zeolites. N 2 adsorption-desorption isotherms showed that the synthesized product had high BET surface area and possessed composite pore structures with both micro and mesopores. The catalytic performance of hierarchical ZSM-5 zeolite was investigated in the selective oxidation of benzyl alcohol (BzOH) with hydrogen peroxide (H 2 O 2) under mild conditions. The results showed that the conversion of BzOH and the selectivity to benzaldehyde were about 94 and about 99 % respectively, when using 0.08 g ZSM-5 catalyst with acetonitrile as the solvent and H 2 O 2 as the oxidant at 90°C. This catalyst can be retrieved and reprocessed for five times without a significant loss in its activity and selectivity.
In this study, pure and Co-doped CuO nanostructures (0.5, 1.0, 1.5, and 2.0 at wt% of Co) were sy... more In this study, pure and Co-doped CuO nanostructures (0.5, 1.0, 1.5, and 2.0 at wt% of Co) were synthesized by microwave combustion method. The prepared samples were characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). Powder X-ray diffraction patterns refined by the Rietveld method indicated the formation of single-phase monoclinic structure. The surface morphology and elemental analysis of Co-doped CuO nanostructures were studied by using HR-SEM and EDX. Interestingly, the morphology was found to change considerably from nanoflowers to nanoplates then to nanoparticles with the variation of Co concentration. The optical band gap calculated using DRS was found to be 2.1 eV for pure CuO and increases up to 3.4 eV with increasing cobalt content. Photoluminescence measurements also confirm these results. The magnetic measurements indicated that the obtained nanostructures were ferromagnetic at room temperature with an optimum value of saturation magnetization at 1.0 wt.% of Co-doped CuO, i.e., 970 micro emu/g.
In the present work, we report simple and eco-friendly route to synthesise biocomposite doped nan... more In the present work, we report simple and eco-friendly route to synthesise biocomposite doped nanocrystalline MgO. The seed of Hygrophila spinosa T. Anders (HST) plant showing gelly nature in water and contain several minerals, is the chosen dopant (biocomposite). The structural parameters, functional groups, surface morphology, elemental analysis and optical behavior of the prepared samples were evaluated by using X-ray diffraction (XRD), Fourier transform-infra red (FT-IR), high resolution scanning electron microscope (HR-SEM), Energy dispersive X-ray analysis (EDX), Diffuse reflectance spectroscopy (DRS) techniques respectively. The two probe DC-electrical resistance method was used to evaluate the sensitivity factor (S(f)) of the prepared samples at different humidity levels. It was found that the appropriate ratio of dopant into MgO extensively modified the sensitivity. Compared to all the other composition of Mg:HS, the sensitivity factor (S(f)) of MH3 (0.25:0.75) is found to be higher i.e., 3,300. The MH3 sample also showed good linearity, reproducibility, stability, response and recovery time about 210 +/- 5 s and 232 +/- 4 s, respectively. The composition, crystallite size and surface area were found to have the significant effects on the sensitivity.
A series of Sr(II)-added nickel aluminate nanocatalysts with different molar ratios of Ni:Sr (1.0... more A series of Sr(II)-added nickel aluminate nanocatalysts with different molar ratios of Ni:Sr (1.0:0.0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4 and 0.5:0.5) keeping the molar ratio of aluminum constant were synthesized by modified sol-gel method using ethylenediamine and sintered at 900 degrees C. The samples were labeled as NiSA1-900, NiSA2-900, NiSA3-900, NiSA4-900, NiSA5-900, NiSA6-900, respectively. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms and tested for the catalytic oxidation of benzyl alcohol. Influence of the reaction parameters (molar ratio of Sr(II) added to nickel aluminate nanocatalyst, reaction time, reaction temperature and solvent effect) on the catalytic oxidation of benzyl alcohol were studied. It was observed that the addition of Sr(II) improves the performance of the nickel aluminate nanocatalysts towards the selective oxidation of benzyl alcohol and decreases the grain size. Higher activity was obtained for the conversion of benzyl alcohol to benzaldehyde for 0.3 molar percentage Sr(II) added nickel aluminate catalyst (NiSA4-900). Stability and reusability of the catalyst was also investigated.
A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials w... more A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials with different morphologies such as nanoflakes, spherical nanoparticles (SNPs), and nanorods. The concentration of the capping agent, Triton X-100, is a key factor in the morphological control of ZnO nanostructures. The formation of different morphologies of ZnO was confirmed by HR-SEM and HR-TEM. XRD data showed the formation of single-phase ZnO with the wurtzite crystal structure. The influence of La contents on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO SNPs was investigated systematically. The influence of the ZnO morphologies on the photocatalytic degradation (PCD) of Bisphenol A (BPA) as a model reaction is evaluated and discussed in terms of surface area, crystal growth habits, particle size, and oxygen defects. The results indicated that the particle size is an important factor for the enhancement of PCD. Furthermore, the effect of different photocatalytic reaction parameters on the resulting PCD efficiency of ZnO SNPs was investigated.
The effect of ethylenediamine addition in the sol-gel method for the preparation of nano CuAl 2 O... more The effect of ethylenediamine addition in the sol-gel method for the preparation of nano CuAl 2 O 4 spinel for the enhancement in their structural, electrical, optical and catalytic properties was investigated. The samples were prepared by two different methods: sol-gel and modified sol-gel technique using ethylenediamine. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms, temperature dependent conductance measurements, thermoelectric power (TEP) measurements and UV-visible diffuse reflectance (UV-vis-DRS) spectra were used to characterize the samples prepared. CuAl 2 O 4 prepared by modified sol-gel technique was found to possess a higher surface area, lower crystallite size, lower activation energy and high porosity than the one prepared by sol-gel method which in turn lead to the improved performance of it towards the selective oxidation of benzyl alcohol to benzaldehyde. Effect of solvent on the catalytic oxidation of benzyl alcohol by the nano CuAl 2 O 4 prepared by modified sol-gel technique was also investigated.
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