Consumption of fruits and vegetables is an indispensable component of human dietary preference, however; it is unfortunate that the enormous pesticide residues remain in the plant produces. ...Pesticides used to control the pests and diseases of the crops and livestock and its spill-over in the food production system has been an inevitable consequence. Researchers have been taking persistent efforts to eliminate pesticide residues in the food to make it safe for human consumption. Conventional techniques such as the washing of agricultural produces with chemicals, peeling, salting, and using different agents have not been an efficient means of pesticide removal.
In recent times, the emergence of non-thermal technology such as the ozone to degrade the pesticide residues is of great utility in the food processing industries. It is also considered as a green technology because unlike other conventional methods ozone treatment leaves little residual traces. However, some of the discrepancies and challenges in using this technology require to be addressed to increase its efficiency. The objective of the current review is to provide a comprehensive and critical view of the use of ozone in pesticide residue dissipation in various food matrixes.
Analysis of the pros and cons of ozone treatment reveals it as a potential technique for the degradation of pesticide residues. The diversity and complexity of pesticides along with the inherent differences in their chemical structures and residue levels of pesticides in agro-products are the factors that require due consideration. Furthermore, processing and operating conditions of the ozone treatment are some of the other major determinants to improve the efficiency of ozone treatment for the degradation of pesticides.
•The concept of application of ozone in degrading the pesticide residues introduced.•Ozone-based dissipation of pesticides in food matrix for quality agro-products.•Challenges and prospects of ozone in food industry are enumerated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nicotinamide Adenine Dinucleotide (NADH) is an important coenzyme in the human body that participates in many metabolic reactions. The impact of abnormal concentrations of NADH significantly causes ...different diseases in human body. Electrochemical detection of NADH using bare electrode is a challenging task especially in the presence of main electroactive interferences such as ascorbic acid (AA), uric acid (UA) and dopamine (DA). Modified electrodes have been widely explored to overcome the problems of poor sensitivity and selectivity occurred from bare electrodes. This review gives an overview on the progress of using conducting polymers, polyelectrolyte and its composites (co-polymer, carbonaceous, metal, metal oxide and clay) based modified electrodes for the sensing of NADH. In addition, developments on the fabrication of numerous conducting polymer composites based modified electrodes are clearly described.
•We review the conducting polymer and its composite materials for NADH sensing.•The detection mechanisms and the advantages of materials are emphasized.•Future perspectives and possible challenges in this area are outlined.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This article presents the effect of different calcination temperatures on the structural, morphological and capacitance of nickel phosphate (Ni
3
(PO
4
)
2
) as an electrode material for ...supercapacitor applications. Ni
3
(PO
4
)
2
was synthesized
via
a sonochemical method followed by calcination at different temperatures (300, 600 and 900 °C, denoted as N300, N600 and N900, respectively). The phase structure and purity of Ni
3
(PO
4
)
2
were confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The surface morphologies showed that the particle size increased with increasing the calcination temperatures. The electrochemical performance of N300, N600 and N900 were investigated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in a 1 M KOH electrolyte. It was found that N300 exhibited the maximum specific capacity of 620 C g
−1
at 0.4 A g
−1
, which was significantly higher than N600 (46 C g
−1
) and N900 (14 C g
−1
). Here, the enhanced electrochemical performance was obtained due to the amorphous structure and augmentation of the redox active sites of the N300 particles. Additionally, the fabricated N300//activated carbon based asymmetric supercapacitor can be cycled reversibly at a cell voltage of 1.45 V. The device exhibited an energy density of 76 W h kg
−1
and a power density of 599 W kg
−1
with life cycles of 88.5% capacitance retention after 3000 cycles.
This article presents the effect of different calcination temperatures on the structural, morphological and capacitance of nickel phosphate (Ni
3
(PO
4
)
2
) as an electrode material for supercapacitor applications.
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IJS, KILJ, NUK, UL, UM, UPUK
Herein, zinc cobaltite (ZnCo2O4) nanoparticles (synthesized via hydrothermal treatment) were blended with polyaniline (PANI) (synthesized via chemical oxidative polymerization) to form PANI-ZnCo2O4 ...nanocomposite. The structural crystallinity and phase purity of PANI-ZnCo2O4 nanocomposite were authenticated by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The morphological studies showed that the spinel structured ZnCo2O4 nanoparticles were well embedded on tubular-shaped PANI matrix, suggesting the effective connection between ZnCo2O4 nanoparticles with PANI matrix. The electrochemical performance studies of PANI-ZnCo2O4 nanocomposite for supercapacitor exhibited enhanced specific capacity of 398 C/g at a current density of 1 A/g as compared with ZnCo2O4 nanoparticles and PANI. The enhancement of electrochemical performance was contributed from the augmentation of electroactive sites for redox reaction, rapid electron transfer rate and the synergistic effect of ZnCo2O4 nanoparticles and highly conductive PANI. The fabricated PANI-ZnCo2O4//activated carbon based hybrid supercapacitor achieved high energy density (13.25 Wh/kg at 375 W/kg) as well as excellent cycling stability (∼90% retention after 3000 cycles). Furthermore, PANI-ZnCo2O4 nanocomposite was employed as a hydrazine sensor which exhibited good sensitivity of 0.43 μA μM−1 in the linear range of 0.1–0.6 mM with a low detection limit of 0.2 μM.
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•The PANI-ZnCo2O4 nanocomposite was prepared via blending process.•Dual roles of PANI-ZnCo2O4 in supercapacitor and electrochemical sensor.•High energy and power density was obtained in asymmetric supercapacitor.•PANI-ZnCo2O4 showed high sensitivity towards hydrazine.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The ternary nanocomposite of cobalt oxide (Co3O4) and silver (Ag) nanoparticles with reduced graphene (rGO) was successfully synthesized via single-step hydrothermal method and applied as a positrode ...material in supercapattery. The successful synthesis of ternary nanocomposite (rGO-Co3O4–Ag) and uniform distribution of Co3O4 nanograins over graphene matrix decorated with Ag nanoparticles was confirmed using X-ray diffraction, field emission scanning electron microscope, energy-dispersive X-ray and X-ray photoelectron spectroscopy. From electrochemical studies such as cyclic voltammetry, galvanic charge-discharge and impedance spectroscopy, it was found that the prepared ternary nanocomposite exhibited excellent performance compared to its counterparts (Co3O4, rGO-Co3O4). The rGO-Co3O4–Ag ternary nanocomposite showed a specific capacity of 94.20 C g−1 that is remarkably higher than the rGO-Co3O4 (63.98 C g−1) and Co3O4 (58.92 C g−1) in a three-electrode cell system using 1 M KOH electrolyte. The two electrodes cell assembly (supercapattery) was fabricated using rGO-Co3O4–Ag nanocomposite as a positrode and activated carbon as a negatrode. The assembled supercapattery (rGO-Co3O4–Ag/activated carbon) was able to run in a potential range of 0–1.5 V even at the higher scan rate. The two electrodes cell studies demonstrated that the assembled supercapattery at a current density of 0.6 A g−1 achieved energy density and power density of 23.63 Wh kg−1 and 440 W kg−1 respectively. It also displayed excellent cycling stability with capacity retention around 85.5% after 3000 cycles at a current density of 3 A g−1.
•A facile single step hydrothermal method was employed to synthesize rGO-Co3O4–Ag ternary nanocomposite.•A ternary nanocomposite (rGO-Co3O4–Ag) was exploited first time as an anode material in supercapattery applications.•rGO-Co3O4–Ag exhibited excellent electrochemical performance when used as an anode material in supercapattery devices.•Ternary nanocomposite, rGO-Co3O4–Ag showed good stability when examined for life cycle in supercapattery applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cobalt oxide (Co3O4) nanograins were in situ grown on chemically activated multiwall carbon nanotubes (MWCNT) and anchored with silver (Ag) nanoparticles to form a ternary nanocomposite ...(MWCNT-Co3O4-Ag) by simple single step hydrothermal route. The structural crystallinity and successful synthesis of MWCNT-Co3O4-Ag nanocomposite were confirmed by X-ray diffraction. The surface morphology, homogeneity, specific surface area and crystallinity were evaluated by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy with mapping, Brunauer Emmett Teller and X-ray diffraction analysis, respectively. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy were conducted in 1 M KOH electrolyte to analyze electrochemical performance of the prepared samples as an electrode material for supercapattery. The MWCNT-Co3O4-Ag nanocomposite witnessed the maximum specific capacity of 83.88 Cg-1 at 0.6 Ag-1 which is substantially higher than MWCNT-Co3O4 (55.33 Cg-1) and Co3O4 nanograins (39.24 Cg-1) in standard three electrode cell system. The remarkable electrochemical performance of ternary nanocomposite was associated with the effect of Co3O4 nanograins, conductive platform provided by the MWCNT and synergistic effect of Ag nanoparticles. The supercapattery devices were fabricated in a configuration of MWCNT-Co3O4-Ag//activated carbon. The hybrid device was capable to operate in stable potential window of 1.5 V even at higher scan rates. It was observed that the fabricated supercapattery showed an energy density of 16.5 Whkg−1 with power density of 297.5 Wkg-1 at current density of 0.2 Ag-1. Additionally, life cycle test revealed that supercapattery was highly stable and lost only 6.4% of its initial capacity after 3000 cycles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We investigated different molar concentrations of cobalt precursor intercalated reduced graphene oxide (rGO) as possible electrode materials for supercapacitors. Cobalt oxide (Co 3 O 4 ) nanocubes ...intercalated reduced graphene oxides (rGO) were synthesized via a facile hydrothermal method. It has been found that the Co 3 O 4 particles with a cubical shape are decorated on rGO matrix with an average size of ∼45 nm. The structural crystallinity of rGO–Co 3 O 4 composites was examined by X-ray diffraction (XRD). Raman spectroscopy confirmed the successful reduction of GO to rGO and effective interaction between Co 3 O 4 and the rGO matrix. The electrochemical performances of rGO–Co 3 O 4 electrodes were examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance (278 F g −1 ) is observed at current density of 200 mA g −1 in the C2 electrode resulting from effective ion transfer and less particle aggregation of Co 3 O 4 on the rGO matrix than in the other electrodes. C2 exhibits good rate capability and excellent long-term cyclic stability of 91.6% for 2000 cycles. The enhanced electrochemical performance may result from uniform intercalation of cobalt oxide over the rGO. These results suggest that the Co 3 O 4 intercalated rGO matrix could play a role in improved energy storage capability.
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IJS, KILJ, NUK, UL, UM, UPUK
•Different concentration of 4-tert-butyl-pyridine was added in GPE-TBP based DSSC.•TBP content shifts the quasi-fermi level of TiO2 photoanode to a higher potential.•Open-circuit voltage was enhanced ...by 21.31% after the addition of 7 wt% of TBP.•The addition of TBP resulted in decreasing of the short-circuit current of the DSSC.•GPE-TBP based DSSC achieved a maximum photovoltaic conversion efficiency of 8.09%.
Developing gel polymer electrolyte (GPE) can solve the safety issues faced by liquid electrolyte and allow easy fabrication of dye-sensitized solar cell (DSSC). However, its power conversion efficiency (η) still needs improvement by bettering any other parameters such as open-circuit voltage (VOC), short–circuit current (JSC) and Fill Factor (FF). Herein, 4-tert-butyl-pyridine (TBP) is used as an additive with different concentrations, and its effects on the GPE-TBP are studied. The addition of TBP is beneficial in DSSC employing GPE-TBP as it can adsorb on the surface of the mesoporous TiO2 photoanode, which leads to the shifting of the quasi-fermi level of TiO2 photoanode to a higher potential. This phenomenon enhances open-circuit voltage (VOC) of the DSSC from 615 to 750 mV upon addition of 7 wt% of TBP content to the GPE sample. However, taking into consideration all parameters in DSSC employing GPE-TBP, GPE sample containing 3 wt% of TBP shows the highest photovoltaic conversion efficiency (ɳ) of 8.11% under light illumination of 100 mW cm−2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The performance of a supercapattery depends on its energy density, rate capability of charge and discharge and stability of electrode. Here in, a sonochemical method followed by calcination was ...applied to synthesize nickel phosphate-silver phosphate (Ni3(PO4)2Ag3PO4) nanocomposites. Morphological studies revealed that crystalline Ag3PO4 (∼10 nm) was intimately anchored on the surface of amorphous Ni3(PO4)2, which benefits efficient charge transfer between the two metal phosphates. The optimized Ni3(PO4)2Ag3PO4 nanocomposite electrode exhibited a significant boost in rate capability from 29% (Ni3(PO4)2) to 78% capacity retention with the maximum specific capacity of 478C/g at 1 A/g in 1 M KOH electrolyte. The enhancement of rate capability originated from a more rapid electron-transfer rate and an augmentation of electroactive sites for electrolyte ion diffusion from the interfaces of porous Ni3(PO4)2 and an improvement in the electrical conductivity of crystalline Ag3PO4. The fabricated Ni3(PO4)2Ag3PO4//activated carbon-based supercapattery exhibited an energy density of 32.4 Wh/kg at 399.5 W/kg and excellent cyclic stability (∼82% capacity retention after 5000 cycles).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
With overwhelming progress in the field of electronic technology, self-healable hydrogel electrolyte-based supercapacitors are of significant interest as a power source in wearable energy storage ...devices. Self-healable hydrogel with unique three-dimensional porous microstructure, unprecedented self-healing, high capacitive energy density, low power density has been synthesized by in situ polymerization of acrylamide in the presence of exfoliated sodium montmorillonite (Na-MMT) clay as non-covalent cross-linker. Furthermore, addition of lithium trifluoromethanesulfonate (LiTF) salt converted the hydrogel into electrolyte for use in supercapacitor. Hydrogel electrolytes were prepared containing 10, 20, 30, and 40 wt% salt (AAM1, AAM2, AAM3, and AAM4), respectively. Acrylamide, clay and salt interactions were explored by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). X-ray diffraction (XRD) analysis reveals amorphous nature whereas FTIR and transference number measurements prove the complexation and presence of ionic species in the hydrogel electrolytes. Ionic conductivity and transport studies for hydrogel electrolyte containing 30 wt% of LiTF showed maximum ionic conductivity of 9.34 × 10−3 S/cm and number density of 70.7 × 10 20 cm−3, diffusion coefficient of 2.16 × 10 −9 cm2/s, ionic mobility of 0.854 × 10−7 cm2/V.s among all the synthesized hydrogel electrolytes. The electrochemical performance of the fabricated device disclosed the maximum significant specific capacitance of 102 F/g at 3 mV/s and 157 F/g at 50 mA/g along with power density of 50 W/kg and energy density of 21.59 W h/Kg, respectively for hydrogel electrolyte (AAM3) containing 30 wt% of the LiTF. Self-healing properties of hydrogel electrolyte have been confirmed by its use in supercapacitor where it retained its self-healing properties. The self-healable supercapacitor was used to light up 2 V light emitting diode (LED). Hence, investigations suggest the potential application of the hydrogel electrolytes with 30 wt% LiTF in the supercapacitors.
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•Synthesis of self-healable and flexible poly (acrylamide) hydrogel electrolytes.•Deconvolution of FTIR spectra to find out free ions and contact ions.•Crystallite size and % crystallinity measurements through XRD.•Fabrication of self-healable supercapacitor device to power up light emitting diode.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
