Tufail Sherazi - Academia.edu (original) (raw)
Papers by Tufail Sherazi
In this study, the biocompatibility of iron oxide nanoparticles (Fe3O4 NPs) with a concentration ... more In this study, the biocompatibility of iron oxide nanoparticles (Fe3O4 NPs) with a concentration of 75 mg/L was experimentally investigated with different organic loading rates (OLRs) in Continuous Stir Tank Reactors (CSTRs). The OLRs were started from the lowest concentration of 0.3 gVS/Ld to the highest at 1.3 gVS/Ld with an intermediate of 0.8 gVS/Ld. During this experimentation, the behavior of other parameters like pH, soluble chemical oxygen demand (sCOD), total volatile fatty acids (TVFAs) generation and degradation, total solids (TS) and VS removal were monitored along with CH4 generation. It was observed that the NPs efficiency was higher at the lowest OLR. The CH4 yield was optimal at 0.3 gVS/Ld, which was 725.9 mL/gVS and reduced to 652.02 mL/gVS in R1 (with NPs additives). However, R2 (without NPs) showed much-stabilized behavior and get increasing from 372.8 to 424.4 mL/gVS at 0.3 to 1.3 gVS/Ld of OLR, respectively. Moreover, the higher removal of sCOD, TVFAs, and TV/VS...
Turkish Journal of Chemistry, 2022
Introduction Canola oil is extracted from rapeseeds, which is a bright yellow flower of the famil... more Introduction Canola oil is extracted from rapeseeds, which is a bright yellow flower of the family Brassicaceae. It is an essential oil crop mainly grown in United States, Canada, China, Australia, India, and the European Union. In recent years, the cultivation of canola crops has significantly increased day by day [1]. In the production of oil, the quality of the oil is the main factor because it decides the approval and sales of the products which are derived from vegetable oil [2, 3]. On the other hand, the fatty acid composition and its minor components, for instance, free fatty acids (FFA), color pigments, trace metals, phenolic compounds, waxes, and phospholipids of vegetable oil often affect the stability and quality of oil [4]. For that reason, various efficient industrial processing stages are used for removing these disagreeable impurities with the minimum effect on the desired components and the low possible loss of neutral oil. The main steps of vegetable oil refining include neutralization, bleaching, and deodorization. However, refining can also cause the removal of desirable health-promoting minor components from the oil [5]. In the neutralization process, NaOH is used to eliminate the FFA level from the oil; however, in the bleaching process, bleaching clay is used to absorb the color pigments and trace metals. Deodorization is the final key step of the refining process accountable for removing targeted volatile compounds that are liable for producing unacceptable odor, color, taste, and flavor in the oil. Unfortunately, these processing stages also result in the reduction of very important bioactive components such as tocols, sterols, phenols, and aromas. The level of reduction of each bioactive component depends on processing parameters, quality, and nature of the input oil [6]. However, a significant amount of phytosterols and tocols are distilled and recovered as by-products in the form of DD, which has been considered to be a rich source of these bioactive components. It is a by-product of the vegetable oil deodorization process and is a complex mixture of FFA, glyceride, tocols, phytosterol (free and esterified), hydrocarbon, and other volatile molecules such as aldehyde, ketone, and peroxide [7-9]. Tocols are the natural antioxidants that are Abstract: Tocopherols and tocotrienols in the combined form are known as tocols. Changes of total and individual tocols and sterols concentration of canola oil and deodorizer distillate (DD) during different processing stages were evaluated with the application of gas chromatography (GC) and high-performance liquid chromatography (HPLC). For sterols analysis, GC coupled with flame ionization detector (FID) was used while tocols in canola oil samples and DD, normal phase (NP) HPLC was applied. The results of the present study indicated that levels of total and individual tocols and sterols content were decreased during processing (neutralization to deodorization). Deodorization was found to be the most effective process for the reduction of total sterols and tocols as 55.9% and 34.2%, respectively. A high amount of tocols and sterols was observed in DD. Among tocols and sterols; beta tocopherol (β-T) and β-sitosterol were found to be in greater concentration 53.97% and 31.82%, respectively. Therefore, DD could be used as a valuable byproduct in the cosmetics and food industries.
Food Additives & Contaminants: Part B, 2014
Two hundred and fifteen broiler poultry feed samples were analysed over the time period of one ye... more Two hundred and fifteen broiler poultry feed samples were analysed over the time period of one year for the co-occurrence of aflatoxins and deoxynivalenol (DON). These were determined by GC-MS and ELISA, respectively. LOD values for aflatoxins and DON were 0.5 and 5 µg/kg, respectively. From all investigated 215 poultry feed samples, aflatoxins and DON co-occurred in 100 samples (46%). DON was detected in 114 samples while 100 samples also were positive for aflatoxins. Mean concentrations of positive samples for aflatoxins and DON were 18 and 807 µg/kg, respectively. Twenty-one DON-positive and 42 aflatoxin positive samples were contaminated above the EU maximum legal limits of 1000 µg/kg and 20 µg/kg, respectively. The present study provided useful data on aflatoxin and DON contamination, which may be helpful for future strategies to control contamination and to formulate standards in poultry feeds.
Mycotoxin Research, 2014
A study was conducted to evaluate the occurrence of ochratoxin A (OTA) in complete poultry feeds ... more A study was conducted to evaluate the occurrence of ochratoxin A (OTA) in complete poultry feeds (n=80) and poultry feed ingredients (n=286) from Pakistan. All samples were first analyzed by indirect enzyme linked immunosorbent assay (ELISA), samples with OTA concentrations above the European Union maximum regulatory limit (MRL, 100 μg/ kg) were further confirmed by HPLC-FLD. Contamination frequency and mean OTA levels were 31 % and 51 μg/kg in feed ingredients, and the corresponding values for complete feeds were 38 % and 75 μg/kg. Ten samples of complete poultry feed and 19 samples of feed ingredients contained OTA at levels higher than the MRL. The results of the present study indicate that there is a strong need for a more intense monitoring programs for OTA in poultry feed.
Journal of Agricultural and Food Chemistry, 2007
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
h i g h l i g h t s " FT-IR procedure was developed using partial least square (PLS) calibration ... more h i g h l i g h t s " FT-IR procedure was developed using partial least square (PLS) calibration model. " PLS calibration was based on region from 1807 to 1461 cm À1 of ibuprofen standards. " Estimation of ibuprofen in pharmaceutical formulations and human urine samples.
Food Chemistry, 2008
Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on ... more Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on trans fatty acids (TFA) using GC-MS. Saturated, cis-monounsaturated and polyunsaturated fatty acids were present at 24.258.1, 5.735.4 and 3.837.4% of total fatty acids, ...
RSC Adv., 2016
In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid... more In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia.
Journal of the American Oil …
Deodorizer distillate is an important by-product obtained during deodorization in the edible oil ... more Deodorizer distillate is an important by-product obtained during deodorization in the edible oil industries. It is a complex mixture of many health beneficial constituents like phytosterols, tocopherols and squalene. In the present study a simple gas chromatographic method with mass spectrometry was used for the separation, detection and quantification of different components present in the deodorizer distillate in a very short analysis time of 18 min. A simple saponification procedure without derivatization was used for their analysis followed by GC-MS analysis. Phytosterols concentration (21.27-25.53%) was the most abundant in canola and palm distillate samples whereas, squalene and tocopherol were present in concentration ranges of 2.89-13.21% and 1.29-5.81%, respectively. The present study revealed that the unsaponifiable fraction of deodorizer distillate could be used in cosmetic preparations due to its appreciable amount of bioactive constituents.
Sensors
Highly stable, small-sized and evenly distributed solid mercury nanoparticles capped with ibuprof... more Highly stable, small-sized and evenly distributed solid mercury nanoparticles capped with ibuprofen (Ibu-HgNPs) were prepared via reduction with hydrazine and capped with ibuprofen as a stabilizing agent. Characterization of Ibu-HgNPs was carried out by UV-Vis spectrophotometry and transmission electron microscopy (TEM). The prepared Ibu-HgNPs were immobilized onto a glassy carbon electrode (GCE) and used for the first time as the sensing element for voltammetric determination of low concentrations of acrylamide (AA) in aqueous solutions. Various parameters such as the type of supporting electrolyte, voltammetric mode, frequency, deposition time, stirring rate and initial potential were optimized to obtain the highest peak current of AA. The sensor delivered the best results in combination with the square wave voltammetry (SWV) mode, with good repeatability (relative standard deviation (RSD) of 25 repetitions was 1.4% for 1000 ppb AA). The study further revealed that Ibu-HgNPs are s...
International Nano Letters
Flavour and Fragrance …, 2009
In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SF... more In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SFME) and hydrodistillation (HD) methods from Laurus nobilis leaves and determined their antioxidant and antimicrobial activity. Extraction time was reduced by about 43% in SFME at 622 W and 67% in SFME at 249 W compared to hydrodistillation. Essential oil of laurel was extracted by SFME at 622 W (100%) and 249 W (40%) power levels and HD inhibited oxidation generated by ABTS radical by 93.88%, 94.13% and 92.06%, respectively. Trolox equivalent antioxidant capacities (TEAC) of essential oils were 0.18 mM/mL oil for SFME at 622 W, 1.36 mM/mL oil for SFME at 249 W and 2.40 mM/mL oil for HD (p < 0.05). Essential oils of L. nobilis were extracted by SFME at 100% and 40% power levels and HD inhibited linoleic acid peroxidation by 70.57%, 63.53% and 89.18% respectively. Inhibition effects of laurel essential oils obtained by SFME at different power levels and HD on DPPH radical cation oxidation were not significantly different. The strongest antioxidant activity against DPPH radical was found in the essential oil obtained by SFME at 100% power level. Essential oils displayed antimicrobial activity against Staphylococcus aureus 6538P, Escherichia coli O157:H7 and Salmonella typhimurium NRRL E 4463 except for Listeria monocytogenes. The inhibitory effect on Staphylococcus aureus 6538P survival of laurel oil obtained from SFME by using lower power level was found to be lower than that obtained from SFME at 100% power level and HD (p < 0.05).
Journal of Food Science and Technology
TURKISH JOURNAL OF CHEMISTRY
In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal m... more In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal method with ranolazine as a shape-directing agent. Ranolazine-functionalized CuO NPs were characterized by various analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The SEM pattern confirmed the morphology of ranolazine-functionalized CuO NPs with well-defined rice-like structures. FTIR spectroscopy confirmed the interaction between CuO NPs and ranolazine. The XRD analysis indicated that the structure of ranolazine-functionalized CuO NPs was monoclinic crystalline and the size ranged between 9 and 18 nm with an average particle size of 12 nm. The smaller size range of CuO NPs gave a large surface area that enhanced the efficiency of these catalysts employed for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the H 2 O system. In homogeneous catalysis, results showed that 50 µ L of CuO NPs was required in the presence of NaBH 4 for 99% reduction of 4-NP in 240 s. On the other hand, for heterogeneous catalysis, 0.5 mg of CuO NPs was used in the presence of NaBH 4 for 99% catalytic reduction of 4-NP to 4-AP in 320 s. The rate of reaction for homogeneous catalysis and heterogeneous catalysis was determined from the plots of In(C t /C 0) of 4-NP versus time (s), which showed good linearity with values of 1.3 × 10 −2 and 8.8 × 10 −3 s −1. respectively. The high-quality catalytic efficiency, good reusability, nontoxic nature, and low cost are favorable properties of the synthesized CuO NPs for use as efficient catalysts for reduction of 4-AP to 4-NP in both homogeneous and heterogeneous media.
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
Waste and Biomass Valorization
Journal of The Electrochemical Society
Journal of Electronic Materials, 2016
This study describes, the synthesis of cobalt oxide nanostructures using ascorbic acid as a growt... more This study describes, the synthesis of cobalt oxide nanostructures using ascorbic acid as a growth directing agent by the hydrothermal method. Ascorbic acid is used for the first time for the synthesis of cobalt oxide nanostructures and a unique morphology is prepared in the present study. The cobalt oxide nanostructures were characterized by scanning electron microcopy, x-ray diffraction, and x-ray photoelectron spectroscopy techniques. These analytical techniques demonstrated well defined morphology, good crystalline quality, and high purity of as prepared cobalt oxide nanostruc-tures. The glassy carbon electrode was modified with cobalt oxide nanos-tructures for the development of a sensitive and selective electrochemical hydrazine sensor. The developed hydrazine sensor exhibits a linear range of 2–24 lM. The sensitivity and limit of detection of presented hydrazine sensors are 12,734 lA/mM/cm 2 and 0.1 lM respectively. The developed hydrazine sensor is highly selective, stable, and reproducible. The proposed sensor is successfully applied for the detection of hydrazine from different water samples. The present study provides the development of an alternative tool for the reliable monitoring of hydrazine from environmental and biological samples.
In this study, the biocompatibility of iron oxide nanoparticles (Fe3O4 NPs) with a concentration ... more In this study, the biocompatibility of iron oxide nanoparticles (Fe3O4 NPs) with a concentration of 75 mg/L was experimentally investigated with different organic loading rates (OLRs) in Continuous Stir Tank Reactors (CSTRs). The OLRs were started from the lowest concentration of 0.3 gVS/Ld to the highest at 1.3 gVS/Ld with an intermediate of 0.8 gVS/Ld. During this experimentation, the behavior of other parameters like pH, soluble chemical oxygen demand (sCOD), total volatile fatty acids (TVFAs) generation and degradation, total solids (TS) and VS removal were monitored along with CH4 generation. It was observed that the NPs efficiency was higher at the lowest OLR. The CH4 yield was optimal at 0.3 gVS/Ld, which was 725.9 mL/gVS and reduced to 652.02 mL/gVS in R1 (with NPs additives). However, R2 (without NPs) showed much-stabilized behavior and get increasing from 372.8 to 424.4 mL/gVS at 0.3 to 1.3 gVS/Ld of OLR, respectively. Moreover, the higher removal of sCOD, TVFAs, and TV/VS...
Turkish Journal of Chemistry, 2022
Introduction Canola oil is extracted from rapeseeds, which is a bright yellow flower of the famil... more Introduction Canola oil is extracted from rapeseeds, which is a bright yellow flower of the family Brassicaceae. It is an essential oil crop mainly grown in United States, Canada, China, Australia, India, and the European Union. In recent years, the cultivation of canola crops has significantly increased day by day [1]. In the production of oil, the quality of the oil is the main factor because it decides the approval and sales of the products which are derived from vegetable oil [2, 3]. On the other hand, the fatty acid composition and its minor components, for instance, free fatty acids (FFA), color pigments, trace metals, phenolic compounds, waxes, and phospholipids of vegetable oil often affect the stability and quality of oil [4]. For that reason, various efficient industrial processing stages are used for removing these disagreeable impurities with the minimum effect on the desired components and the low possible loss of neutral oil. The main steps of vegetable oil refining include neutralization, bleaching, and deodorization. However, refining can also cause the removal of desirable health-promoting minor components from the oil [5]. In the neutralization process, NaOH is used to eliminate the FFA level from the oil; however, in the bleaching process, bleaching clay is used to absorb the color pigments and trace metals. Deodorization is the final key step of the refining process accountable for removing targeted volatile compounds that are liable for producing unacceptable odor, color, taste, and flavor in the oil. Unfortunately, these processing stages also result in the reduction of very important bioactive components such as tocols, sterols, phenols, and aromas. The level of reduction of each bioactive component depends on processing parameters, quality, and nature of the input oil [6]. However, a significant amount of phytosterols and tocols are distilled and recovered as by-products in the form of DD, which has been considered to be a rich source of these bioactive components. It is a by-product of the vegetable oil deodorization process and is a complex mixture of FFA, glyceride, tocols, phytosterol (free and esterified), hydrocarbon, and other volatile molecules such as aldehyde, ketone, and peroxide [7-9]. Tocols are the natural antioxidants that are Abstract: Tocopherols and tocotrienols in the combined form are known as tocols. Changes of total and individual tocols and sterols concentration of canola oil and deodorizer distillate (DD) during different processing stages were evaluated with the application of gas chromatography (GC) and high-performance liquid chromatography (HPLC). For sterols analysis, GC coupled with flame ionization detector (FID) was used while tocols in canola oil samples and DD, normal phase (NP) HPLC was applied. The results of the present study indicated that levels of total and individual tocols and sterols content were decreased during processing (neutralization to deodorization). Deodorization was found to be the most effective process for the reduction of total sterols and tocols as 55.9% and 34.2%, respectively. A high amount of tocols and sterols was observed in DD. Among tocols and sterols; beta tocopherol (β-T) and β-sitosterol were found to be in greater concentration 53.97% and 31.82%, respectively. Therefore, DD could be used as a valuable byproduct in the cosmetics and food industries.
Food Additives & Contaminants: Part B, 2014
Two hundred and fifteen broiler poultry feed samples were analysed over the time period of one ye... more Two hundred and fifteen broiler poultry feed samples were analysed over the time period of one year for the co-occurrence of aflatoxins and deoxynivalenol (DON). These were determined by GC-MS and ELISA, respectively. LOD values for aflatoxins and DON were 0.5 and 5 µg/kg, respectively. From all investigated 215 poultry feed samples, aflatoxins and DON co-occurred in 100 samples (46%). DON was detected in 114 samples while 100 samples also were positive for aflatoxins. Mean concentrations of positive samples for aflatoxins and DON were 18 and 807 µg/kg, respectively. Twenty-one DON-positive and 42 aflatoxin positive samples were contaminated above the EU maximum legal limits of 1000 µg/kg and 20 µg/kg, respectively. The present study provided useful data on aflatoxin and DON contamination, which may be helpful for future strategies to control contamination and to formulate standards in poultry feeds.
Mycotoxin Research, 2014
A study was conducted to evaluate the occurrence of ochratoxin A (OTA) in complete poultry feeds ... more A study was conducted to evaluate the occurrence of ochratoxin A (OTA) in complete poultry feeds (n=80) and poultry feed ingredients (n=286) from Pakistan. All samples were first analyzed by indirect enzyme linked immunosorbent assay (ELISA), samples with OTA concentrations above the European Union maximum regulatory limit (MRL, 100 μg/ kg) were further confirmed by HPLC-FLD. Contamination frequency and mean OTA levels were 31 % and 51 μg/kg in feed ingredients, and the corresponding values for complete feeds were 38 % and 75 μg/kg. Ten samples of complete poultry feed and 19 samples of feed ingredients contained OTA at levels higher than the MRL. The results of the present study indicate that there is a strong need for a more intense monitoring programs for OTA in poultry feed.
Journal of Agricultural and Food Chemistry, 2007
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
h i g h l i g h t s " FT-IR procedure was developed using partial least square (PLS) calibration ... more h i g h l i g h t s " FT-IR procedure was developed using partial least square (PLS) calibration model. " PLS calibration was based on region from 1807 to 1461 cm À1 of ibuprofen standards. " Estimation of ibuprofen in pharmaceutical formulations and human urine samples.
Food Chemistry, 2008
Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on ... more Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on trans fatty acids (TFA) using GC-MS. Saturated, cis-monounsaturated and polyunsaturated fatty acids were present at 24.258.1, 5.735.4 and 3.837.4% of total fatty acids, ...
RSC Adv., 2016
In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid... more In this study, NiO nanostructures were synthesized via a hydrothermal process using ascorbic acid as doping agent in the presence of ammonia.
Journal of the American Oil …
Deodorizer distillate is an important by-product obtained during deodorization in the edible oil ... more Deodorizer distillate is an important by-product obtained during deodorization in the edible oil industries. It is a complex mixture of many health beneficial constituents like phytosterols, tocopherols and squalene. In the present study a simple gas chromatographic method with mass spectrometry was used for the separation, detection and quantification of different components present in the deodorizer distillate in a very short analysis time of 18 min. A simple saponification procedure without derivatization was used for their analysis followed by GC-MS analysis. Phytosterols concentration (21.27-25.53%) was the most abundant in canola and palm distillate samples whereas, squalene and tocopherol were present in concentration ranges of 2.89-13.21% and 1.29-5.81%, respectively. The present study revealed that the unsaponifiable fraction of deodorizer distillate could be used in cosmetic preparations due to its appreciable amount of bioactive constituents.
Sensors
Highly stable, small-sized and evenly distributed solid mercury nanoparticles capped with ibuprof... more Highly stable, small-sized and evenly distributed solid mercury nanoparticles capped with ibuprofen (Ibu-HgNPs) were prepared via reduction with hydrazine and capped with ibuprofen as a stabilizing agent. Characterization of Ibu-HgNPs was carried out by UV-Vis spectrophotometry and transmission electron microscopy (TEM). The prepared Ibu-HgNPs were immobilized onto a glassy carbon electrode (GCE) and used for the first time as the sensing element for voltammetric determination of low concentrations of acrylamide (AA) in aqueous solutions. Various parameters such as the type of supporting electrolyte, voltammetric mode, frequency, deposition time, stirring rate and initial potential were optimized to obtain the highest peak current of AA. The sensor delivered the best results in combination with the square wave voltammetry (SWV) mode, with good repeatability (relative standard deviation (RSD) of 25 repetitions was 1.4% for 1000 ppb AA). The study further revealed that Ibu-HgNPs are s...
International Nano Letters
Flavour and Fragrance …, 2009
In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SF... more In this study, laurel essential oils were obtained by using solvent-free microwave extraction (SFME) and hydrodistillation (HD) methods from Laurus nobilis leaves and determined their antioxidant and antimicrobial activity. Extraction time was reduced by about 43% in SFME at 622 W and 67% in SFME at 249 W compared to hydrodistillation. Essential oil of laurel was extracted by SFME at 622 W (100%) and 249 W (40%) power levels and HD inhibited oxidation generated by ABTS radical by 93.88%, 94.13% and 92.06%, respectively. Trolox equivalent antioxidant capacities (TEAC) of essential oils were 0.18 mM/mL oil for SFME at 622 W, 1.36 mM/mL oil for SFME at 249 W and 2.40 mM/mL oil for HD (p < 0.05). Essential oils of L. nobilis were extracted by SFME at 100% and 40% power levels and HD inhibited linoleic acid peroxidation by 70.57%, 63.53% and 89.18% respectively. Inhibition effects of laurel essential oils obtained by SFME at different power levels and HD on DPPH radical cation oxidation were not significantly different. The strongest antioxidant activity against DPPH radical was found in the essential oil obtained by SFME at 100% power level. Essential oils displayed antimicrobial activity against Staphylococcus aureus 6538P, Escherichia coli O157:H7 and Salmonella typhimurium NRRL E 4463 except for Listeria monocytogenes. The inhibitory effect on Staphylococcus aureus 6538P survival of laurel oil obtained from SFME by using lower power level was found to be lower than that obtained from SFME at 100% power level and HD (p < 0.05).
Journal of Food Science and Technology
TURKISH JOURNAL OF CHEMISTRY
In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal m... more In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal method with ranolazine as a shape-directing agent. Ranolazine-functionalized CuO NPs were characterized by various analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The SEM pattern confirmed the morphology of ranolazine-functionalized CuO NPs with well-defined rice-like structures. FTIR spectroscopy confirmed the interaction between CuO NPs and ranolazine. The XRD analysis indicated that the structure of ranolazine-functionalized CuO NPs was monoclinic crystalline and the size ranged between 9 and 18 nm with an average particle size of 12 nm. The smaller size range of CuO NPs gave a large surface area that enhanced the efficiency of these catalysts employed for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the H 2 O system. In homogeneous catalysis, results showed that 50 µ L of CuO NPs was required in the presence of NaBH 4 for 99% reduction of 4-NP in 240 s. On the other hand, for heterogeneous catalysis, 0.5 mg of CuO NPs was used in the presence of NaBH 4 for 99% catalytic reduction of 4-NP to 4-AP in 320 s. The rate of reaction for homogeneous catalysis and heterogeneous catalysis was determined from the plots of In(C t /C 0) of 4-NP versus time (s), which showed good linearity with values of 1.3 × 10 −2 and 8.8 × 10 −3 s −1. respectively. The high-quality catalytic efficiency, good reusability, nontoxic nature, and low cost are favorable properties of the synthesized CuO NPs for use as efficient catalysts for reduction of 4-AP to 4-NP in both homogeneous and heterogeneous media.
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
Waste and Biomass Valorization
Journal of The Electrochemical Society
Journal of Electronic Materials, 2016
This study describes, the synthesis of cobalt oxide nanostructures using ascorbic acid as a growt... more This study describes, the synthesis of cobalt oxide nanostructures using ascorbic acid as a growth directing agent by the hydrothermal method. Ascorbic acid is used for the first time for the synthesis of cobalt oxide nanostructures and a unique morphology is prepared in the present study. The cobalt oxide nanostructures were characterized by scanning electron microcopy, x-ray diffraction, and x-ray photoelectron spectroscopy techniques. These analytical techniques demonstrated well defined morphology, good crystalline quality, and high purity of as prepared cobalt oxide nanostruc-tures. The glassy carbon electrode was modified with cobalt oxide nanos-tructures for the development of a sensitive and selective electrochemical hydrazine sensor. The developed hydrazine sensor exhibits a linear range of 2–24 lM. The sensitivity and limit of detection of presented hydrazine sensors are 12,734 lA/mM/cm 2 and 0.1 lM respectively. The developed hydrazine sensor is highly selective, stable, and reproducible. The proposed sensor is successfully applied for the detection of hydrazine from different water samples. The present study provides the development of an alternative tool for the reliable monitoring of hydrazine from environmental and biological samples.