Fabrication of a novel tantalum boride/vanadium carbide modified screen-printed carbon electrode for voltammetric determination of pimonidazole in bio-fluids

For the first time, a tumour hypoxia marker detection has been developed using two-dimensional layered composite modified electrodes in biological and environmental samples. The concept of TaB2 and V4C3-based MXene composite materials is not reported hitherto using ball-milling and thermal methods and it remains the potentiality of the present work. The successful formation is confirmed through various characterisation techniques like X-ray crystallography, scanning electron microscopy photoelectron, and impedance spectroscopy. A reliable and repeatable electrochemical sensor based on TaB2@V4C3/SPCE was developed for quick and extremely sensitive detection of pimonidazole by various electroanalytical methods. It has been shown that the modified electrode intensifies the reduction peak current and causes a decrease in the potential for reduction, in comparison with the bare electrode. The proposed sensor for pimonidazole reduction has strong electrocatalytic activity and high sensitivity, as demonstrated by the cyclic voltammetry approach. Under the optimal experimental circumstances, differential pulse voltammetry techniques were utilised for generating the wide linear range (0.02 to 928.51 µM) with a detection limit of 0.0072 µM. The resultant data demonstrates that TaB2@V4C3/SPCE nano-sensor exhibits excellent stability, reliability, and repeatability in the determination of pimonidazole. Additionally, the suggested sensor was successfully used to determine the presence of pimonidazole in several real samples, such as human blood serum, urine, water, and drugs.

Deep Eutectic Solvent Coated Cerium Oxide Nanoparticles Based Polysulfone Membrane to Mitigate Environmental Toxicology

In this study, ceria nanoparticles (NPs) and deep eutectic solvent (DES) were synthesized, and the ceria-NP's surfaces were modified by DES to form DES-ceria NP filler to develop mixed matrix membranes (MMMs). For the sake of interface engineering, MMMs of 2%, 4%, 6% and 8% filler loadings were fabricated using solution casting technique. The characterizations of SEM, FTIR and TGA of synthesized membranes were performed. SEM represented the surface and cross-sectional morphology of membranes, which indicated that the filler is uniformly dispersed in the polysulfone. FTIR was used to analyze the interaction between the filler and support, which showed there was no reaction between the polymer and DES-ceria NPs as all the peaks were consistent, and TGA provided the variation in the membrane materials with respect to temperature, which categorized all of the membranes as very stable and showed that the trend of stability increases with respect to DES-ceria NPs filler loading. For the evaluation of efficiency of the MMMs, the gas permeation was tested. The permeability of CO2 was improved in comparison with the pristine Polysulfone (PSF) membrane and enhanced selectivities of 35.43 (αCO2/CH4) and 39.3 (αCO2/N2) were found. Hence, the DES-ceria NP-based MMMs proved useful in mitigating CO2 from a gaseous mixture.

Membrane reactor for production of biodiesel from nonedible seed oil of Trachyspermum ammi using heterogenous green nanocatalyst of manganese oxide

Conventional homogeneous-based catalyzed transesterification for the production of biodiesel can be replaced with a membrane reactor that has an immobilized heterogeneous catalyst. Combining reaction with separation while utilizing membranes with a certain pore size might boost conversion process. this investigation to study the effectiveness of membrane reactor in combination with heterogeneous green nano catalysis of MnO2. Techniques such as XRD, EDX, FTIR, SEM, and TGA were used to characterize the synthesized MnO2 nano catalyst. The highest conversion of around 94% Trachyspermum ammi oil was obtained by MnO2. The optimum process variables for maximum conversion were catalyst loading of 0.26 (wt.%), 8:1 M ratio, 90 °C reaction temperature, and time 120 min. The green nano catalyst of MnO2 was reusable up to five cycles with minimum loss in conversion rate of about 75% in the fifth cycle. Nuclear magnetic resonance validated the synthesis of methyl esters. It was concluded that membrane reactor a promising technique to efficiently transesterify triglycerides into methyl esters and enable process intensification uses MnO2 as a catalyst.

Hydrothermally synthesized Ag-TiO2 nanofibers (NFs) for photocatalytic dye degradation and antibacterial activity

This work successfully utilised eco-friendly green synthesis to produce Ag-TiO₂ nanofibers (NFs). As pollution and energy limitations have become global issues, there is an ongoing need to develop more effective catalysts through straightforward and environmentally friendly methods. The Ag-TiO₂ nanofibers (NFs) XRD pattern exhibits an anatase TiO₂ and FCC crystal structure of Ag nanoparticles. The SEM investigation revealed a nanofiber-like surface morphology. The Ag-TiO₂ nanofibers (NFs) exhibits an optical band gap energy is 2.5 eV. Methylene blue (MB), malachite green (MG), Congo red (CR), and crystal violet (CV) dye aqueous solutions were used to evaluate the photocatalytic performance of the synthesized Ag-modified TiO₂ nanofibers (NFs) under direct sunlight irradiation. The effects of catalyst size on the efficient breakdown of MB dye were also investigated. The optimum catalyst concentration was found to be at 0.02 mg/mL. At 120 min of direct sunlight, the highest photosynthetic degradation efficiency (DE percentage) of 94% was achieved for MB dye. Ag-TiO₂ nanofibers (NFs) have been demonstrated to have exceptional antibacterial activity against Gram-positive bacteria such as Staphylococcus aureus and Gram-negative bacteria E-Coli. Because of these great qualities, it seems likely that the Ag-TiO₂ nanofibers (NFs) made could be a great photocatalyst for getting dye pollutants out of wastewater.

Hydrophobic ammonium based ionic liquids for efficient extraction of textile dyes from aqueous media: Extraction study and antibacterial evaluation

Alizarin red S (ARS) extraction from aqueous medium was carried out using hydrophobic ionic liquids (ILs) containing trioctylammonium cation paired with 4-tert-butylbenzoate ([TOA][Butbenz] (IL1), 4-phenylbutanoate ([TOA][PheBut] (IL2), 3-4-dimethylbenzoate ([TOA][DMbenz] (IL3), naphthoate, ([TOA][Naph]) (IL4), salicylate ([TOA][Sali]) (IL5) and nonanedioate ([TOA]2[Nona]) (IL6). The findings demonstrated that all of the tested ILs were efficient for extracting ARS, however, [TOA]2[Nona] was more effective than others. For the extraction of ARS from the aqueous phase, the effects of various parameters including the initial pH of the dye solution, contact time, ILs to dye volume ratio (VIL:VW), dye concentration, temperature, and salt effect were investigated. The spontaneity of the liquid-liquid extraction of ARS from the aqueous phase to the IL phase was confirmed by thermodynamic parameters. More than 90% of the ARS was extracted from the aqueous phase to the IL phase throughout all experiments. Interaction of selected IL with dyes were confirmed using FTIR analysis. The standard bacterial strains of Escherichia coli (E. coli) ATCC BAA-2471 (gram negative) and Methicillin-resistant Staphylococcus (MRSA) ATCC 43300 (gram positive) were used for evaluating antibacterial activity. The lower dose (250 ppm), the ILs1, 2, 3, 4, 5, and 6 inhibited 0.40, 1.50, 6.50, 1.50, 2.50, and 0.50 mm growth of E. coli, and 4.0, 2.0, 16.50, 0.40, 5.0, and 3.50 mm growth of MRSA, respectively. The experimental findings confirmed that the present ILs can be utilized as an effective solvent for ARS and other dyes extraction from aqueous media.

Energy, exergy, economic, environment, exergo-environment based assessment of amine-based hybrid solvents for natural gas sweetening

Natural gas is the cleanest form of fossil fuel that needs to be purified from CO₂ and H₂S to diminish harmful emissions and provide feasible processing. The conventional chemical and physical solvents used for this purpose have many drawbacks, including corrosion, solvent loss, high energy requirement, and the formation of toxic compounds, which ultimately disrupt the process and affect the environment. Hybrid solvents have lately been researched to cater to these liabilities and enhance process economics. This study screened eight solvents based on CO₂ selectivity viscosity, absorption enthalpy, corrosivity, working capacity, specific heat, and vapor pressure. From the screened solvents, ten cases of hybrid solvents are simulated and optimized on Aspen HYSYS®. Furthermore, 5Es (Energy, Exergy, Economic, Environmental, and Exergy-environmental) analyses were performed on optimized cases, and results were compared with the base case, MEA (30 wt%). The hybrid blend of Sulfolane and MDEA with weight percentages of 6% and 24%, respectively, showed the highest energy savings of 20% concerning the base case. In addition, it offered 93% savings in exergy destruction and 17.26% in the total operating cost of the process. It is also promising to the environment due to reduced entropy sent to the ecosystem and controlled CO₂ emissions. Therefore, the blend of Sulfolane and MDEA is proposed to Supersede the conventional solvent MEA for the natural gas sweetening process.

"Magnetic Ni-Zn ferrite anchored on g-C3N4 as nano-photocatalyst for efficient photo-degradation of doxycycline from water"

In the present work, mixed-spinel ferrite anchored onto graphitic carbon nitride (GCN) was synthesized for mineralization of antibiotic pollutant from waste water. A Z-scheme g-C₃N₄/Ni_0.5Zn_0.5Fe₂O₄ nano heterojunction was fabricated by three step procedure: pyrolysis, solution combustion and mechanical grinding followed by annealing. The prepared photocatlyst was tested for degradation of Doxycycline (DC) drug under the natural sun light. Results revealed that the prepared heterojunction has maximum degradation efficiency of 97.10% pollutant in 60 min experiment. The Z-scheme heterojunction between g-C₃N₄ and Ni-Zn ferrite improves the photoinduced charges separation and protection of redox capability and therby increases the photo degradation efficiency. The scavenging experiments suggested that O₂^-● and h⁺ as main active species responsible for degradation of the antibiotic. In addition, the dopant variation can drive the shists in band gap and energy band positiong too which makes then excellent candidates for synthesizing tunable heterostructures with organic semiconductors. The work focusses on designing and developing of saimpler but efficient magnetic heterojunctions with superior redox capability for solar powered waste water treatment.

Synthesis and Characterization of Ni Nanoparticles via the Microemulsion Technique and Its Applications for Energy Storage Devices

Herein, a unique synthetic approach called microemulsion is used to create nickel nanoparticles (Ni-NPs). SEM, TEM, EDX, and XRD techniques were employed for the investigation of morphology and structures of the synthesized material. Electrons from electroactive components are transferred to external circuits by Ni-NPs' superior electrical conductivity and interconnected nanostructures, which also provide a large number of channels for ion diffusion and additional active sites. The experimental findings showed that as a positive electrode for supercapacitors (SC), Ni-NPs had an outstanding ability to store charge, with a dominant capacitive charge storage of 72.4% when measured at 10 mV/s. Furthermore, at 1 A/g, Ni-NP electrodes exhibit a maximum capacitance of 730 F/g. Further, the Ni-NP electrode retains 92.4% of its capacitance even for 5000 cycles, highlighting possible applications for it in the developing field of renewable energy. The current study provides a new method for producing high-rate next-generation electrodes for supercapacitors.

Palladium Hydroxide (Pearlman's Catalyst) Doped MXene (Ti3C2Tx) Composite Modified Electrode for Selective Detection of Nicotine in Human Sweat

High concentrations of nicotine (40 to 60 mg) are more dangerous for adults who weigh about 70 kg. Herein, we developed an electrochemical transducer using an MXene (Ti₃C₂Tx)/palladium hydroxide-supported carbon (Pearlman's catalyst) composite (MXene/Pd(OH)₂/C) for the identification of nicotine levels in human sweat. Firstly, the MXene was doped with Pd(OH)₂/C (PHC) by mechanical grinding followed by an ultrasonication process to obtain the MXene/PHC composite. Secondly, XRD, Raman, FE-SEM, EDS and E-mapping analysis were utilized to confirm the successful formation of MXene/PHC composite. Using MXene/PHC composite dispersion, an MXene/PHC composite-modified glassy carbon electrode (MXene/PHC/GCE) was prepared, which showed high sensitivity as well as selectivity towards nicotine (300 µM NIC) oxidation in 0.1 M phosphate buffer (pH = 7.4) by cyclic voltammetry (CV) and amperometry. The MXene/PHC/GCE had reduced the over potential of nicotine oxidation (about 200 mV) and also enhanced the oxidation peak current (8.9 µA) compared to bare/GCE (2.1 µA) and MXene/GCE (5.5 µA). Moreover, the optimized experimental condition was used for the quantification of NIC from 0.25 µM to 37.5 µM. The limit of detection (LOD) and sensitivity were 27 nM and 0.286 µA µM^-1 cm², respectively. The MXene/PHC/GCE was also tested in the presence of Na⁺, Mg²⁺, Ca²⁺, hydrogen peroxide, acetic acid, ascorbic acid, dopamine and glucose. These molecules were not interfered during NIC analysis, which indicated the good selectivity of the MXene/PHC/GCE sensor. In addition, electrochemical determination of NIC was successfully carried out in the human sweat samples collected from a tobacco smoker. The recovery percentage of NIC in the sweat sample was 97%. Finally, we concluded that the MXene/PHC composite-based sensor can be prepared for the accurate determination of NIC with high sensitivity, selectivity and stability in human sweat samples.

Bismuth telluride decorated on graphitic carbon nitrides based binary nanosheets: Its application in electrochemical determination of salbutamol (feed additive) in meat samples

The design and fabrication of effective electrochemical sensor for ultrasensitive detection of feed additive and multidrug are highly significant in food analysis. In this work, we explored to develop the possibility for rapid detection of feed additive drug using bismuth telluride (Bi₂Te₃) decorated graphitic carbon nitrides (GCN) nanostructures as a modified electrode for electrochemical sensing. Herein, the modified electrode was focused on the development of electrocatalytic performances for the determination of salbutamol in food products. The electrochemical sensors are developed by bismuth telluride sheets interconnected with graphitic carbon nitrides sheets (Bi₂Te₃/GCN) on to a screen-printed carbon electrode. The binary nanosheets of Bi₂Te₃/GCN exhibited an enhanced electrocatalytic ability towards salbutamol detection owing to their selective adsorption, by the combination of electrostatic interaction of binary nanosheets and the formation of charge assisted interactions between salbutamol and Bi₂Te₃/GCN surfaces. A nanomolar limit of detection (1.36 nM) was calculated in 0.05 M phosphate buffer (PB) supporting electrolyte (pH 7.0) using differential pulse voltammetry. The linear dynamic ranges with respect to salbutamol concentration were 0.01-892.5 μM, and the sensitivity of the sensor was 36.277 μA μM^-1 cm^-2. The sensor stability and reproducibility performances were observed. However, the obtained results are highly satisfactory which suggest the application of binary nanosheets in real-time food analysis.

Hydrothermally synthesized cubical zinc manganite nanostructure for electrocatalytic detection of sulfadiazine

An electrocatalyst modified electrode has been investigated to develop the rapid detection of antibiotics. The modified electrocatalyst was intended for the determination of sulfadiazine (SFZ) in biological fluids by electrochemical methods. Nanocube of zinc manganite (ZnMn₂O₄-NC) is prepared by hydrothermal method and a glassy carbon electrode (GCE) has been modified with the zinc manganite. The ZnMn₂O₄/GCE exhibit enhanced detection performances towards SFZ drug owing to their selective adsorption ability and the combination of electrostatic attraction of nanocube with SFZ. The modified electrocatalyst shows excellent electrocatalytic interactions with antibiotic drug. Besides, the modified sensors exhibit nanomolar detection limit (0.0021 μM) in 0.05 M phosphate buffer (pH = 7.0) using differential pulse voltammetric method. The working range of the modified electrode is 0.008-1264 μM, and the sensitivity of the SFZ sensor is 11.44 μA μM^-1 cm^-2. The modified sensor stability and reproducibility performances have been examined by electrochemical method. In addition, the obtained results of real sample analysis with different concentrations of SFZ in biological fluids are satisfactory with good recovery.

An electrochemical sensing of phenolic derivative 4-Cyanophenol in environmental water using a facile-constructed Aurivillius-structured Bi2MoO6

Harmful chemicals are always found in the environment and it is necessary to construct a viable sensor to detect those chemicals. In order to construct an electrochemical sensing platform, designing an electrode using bismuth mixed oxides are more important and which grabbed more attention due to its high electrocatalytic ability and conductivity. In this literature, we report a facile synthesis of thorn apple like structured pure bismuth molybdate (Bi₂MoO₆) using a simple hydrothermal assisted one-step calcination method and we report a facile method to sense 4-cyanophenol by electrochemical technique. Bi₂MoO₆ modified (Glassy Carbon electrode) GCE possess two linear ranges 0.1-39.1 µM and 46.6-110.1 µM with excellent detection limit 0.008297 µM and 0.01097 µM. Also, this novel sensor is steady with good stability, repeatability, and reproducibility. Successfully, the environmental water sample is analyzed as a real sample with a feasible and quantification results which were compared with HPLC analysis.

A disposable electrode modified with metal orthovanadate and sulfur-reduced graphene oxide for electrochemical detection of

CVO@SRG composite was prepared by a hydrothermal method and the voltammetric measurement of an organic compound.