CdO Decorated with Polypyrrole Nanotube Heterostructure: Potent Electrocatalyst for the Detection of Antihistamine Drug Promethazine Hydrochloride in Environmental Samples.

In the realm of electrochemical sensor application, the development and fabrication of semiconducting metal oxides with the integration of conducting polymers for the trace-level detection of pharmaceutical medicines garnered considerable interest. Herein, we reported facile cadmium oxide decorated with polypyrrole nanotubes fabricated on a glassy carbon electrode (CdO@PPy/GCE) for efficient determination of antihistamine drug promethazine hydrochloride (PMH). The as-synthesized CdO@PPy composite was characterized by various analytical tools like X-ray powder diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the electrocatalytic activity of the modified electrode for PMH detection was examined by voltammetry and amperometric methods, and the modified electrode exhibited lower charge transfer resistance compared to the bare GCE. Under the optimized condition, the fabricated electrode shows a wide linear range (50-550 µM), better sensitivity (0.13 µAµM-1 cm-2), low detection limit (10.83 nM) (S/N = 3), and excellent selectivity and reproducibility toward PMH detection. Moreover, the modified GCE depicted eminent practical ability for PMH detection in lake water and pharmaceutical tablets.

Developments in Titanium-Based Alkali and Alkaline Earth Metal Oxide Catalysts for Sustainable Biodiesel Production: A Review.

Biodiesel represents a biodegradable, environmentally friendly, and renewable alternative to fossil fuels. Despite more than three decades of research, significant obstacles still hinder the widespread production of biodiesel. This current review elucidates both the potential and the existing challenges associated with homogeneous and heterogeneous catalysts in catalyzing biodiesel production, with a particular focus on alkali analogues, alkaline earth metal oxides, and titania-based catalysts. In particular, a comprehensive analysis is presented concerning alkali and alkaline earth-based titania (TiO2 ) catalysts. Among these, the alkaline earth metal oxides, including lithium, calcium, and strontium when combined with titanium-based catalysts, exhibit superior catalytic activity compared to other metal oxides, owing to their heightened basicity. Consequently, this review offers a thorough and up-to-date insight into the potential of titania-based heterogeneous catalysts for advancing biodiesel production.

Gold Nanorods as an Efficient Substrate for the Detection and Degradation of Pesticides.

The rapid, ultralow detection, degradation, and complete removal of pesticides demand the design of potential substrates. Herein, we discussed gold nanorods (Au NRs) as the potential substrate for the naked eye detection and degradation of two common and broad-spectrum pesticides, chlorpyrifos (CPF) and malathion (MLT), up to 0.15 ppt concentration within 2 min. Under certain environmental conditions, both the pesticides degraded and adsorbed on the surface of Au NRs. The degraded moieties of CPF and MLT on the surface of Au NRs formed side-to-side and end-to-end interactions, respectively, leading to a long-range assembly. This shows that no external agent is required, and only CPF and MLT analytes are quite enough for the formation of assembly of Au NRs. Assembly of Au NRs is confirmed by transmission electron microscopy (TEM) analysis, and degradation is supported by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and gas chromatography-mass spectrometry (GC-MS) analyses. Au NRs were recovered and reused for four consecutive cycles. The fast and ultralow detection of pesticides demonstrates that Au NRs are a potential substrate for the detection and degradation of pesticides.

Unraveling the electrochemical properties of lanthanum cobaltite decorated halloysite nanotube nanocomposite: An advanced electrocatalyst for determination of flutamide in environmental samples.

Prostate cancer is one of the primary causes of death around the world. As an important drug, flutamide has been used in the clinical diagnosis of prostate cancer. However, the over dosage and improper discharge of flutamide could affect the living organism. Thus, it necessary to develop the sensor for detection of flutamide with highly sensitivity. In this paper, we report the synthesis of lanthanum cobaltite decorated halloysite nanotube (LCO/HNT) nanocomposite prepared by a facile method and evaluated for selective reduction of flutamide. The as-prepared LCO/HNT nanocomposite shows the best catalytic performance towards detection of flutamide, when compared to other bare and modified electrodes. The good electrochemical performance of the LCO/HNT nanocomposite modified electrode is ascribed to abundant active sites, large specific surface area and their synergetic effects. Furthermore, the LCO/HNT modified electrode exhibits low detection limit (0.002 µM), wide working range (0.009-145 µM) and excellent selectivity with remarkable stability. Meaningfully, the developed electrochemical sensor was applied in real environmental samples with an acceptable recovery range.

Lanthanum cobaltite supported on graphene nanosheets for non-enzymatic electrochemical determination of catechol.

An electrochemical sensor is described for the determination of catechol (CT) based on the nanocomposite of lanthanum cobaltite supported on graphene nanosheets (LaCo/GNS). The nanocomposite was systematically examined by various analytical and spectroscopic methods. The LaCo/GNS-modified electrode exhibites good electrochemical activity towards CT determination compared to other modified and unmodified electrodes. The electrochemical signal was acquired at a redox potential of 0.21 (Epa) and 0.17 (Epc) Volt (vs. Ag/AgCl). The proposed electrode exhibits low detection limit (1.0 nM), wide working range (0.009-132 µM), and good sensitivity (5.68 µA µM-1 cm-2). The electrochemical nanoprobe has good selectivity over potentially interfering compounds. The electrochemical sensor was applied to the analysis of environmental samples with acceptable recovery. Graphical abstractSchematic representation of electrochemical determination of catechol in the environmental sample analysis using lanthanum cobaltite supported on graphene nanosheets.

An "OFF-ON" quantum dot-graphene oxide bioprobe for sensitive detection of micrococcal nuclease of Staphylococcus aureus.

Micrococcal nuclease (MNase) is an extracellular endonuclease of Staphylococcus aureus (S. aureus). It digests single stranded nucleic acid. The presence of MNase is the gold standard to identify S. aureus and its content. The present study reports the ultrahigh sensitive and selective fluorescence platform for MNase detection, designed and developed based on the surface energy transfer mechanism. A "proof of concept" is being developed based on monoclonal antibody-conjugated quantum dots (mAb-QDs), wherein mAb-QDs act as donors and graphene oxide (GO) acts as an acceptor. mAb-QDs in close proximity to GO undergo adsorption due to weak affinity between them and this results in fluorescence quenching by the transfer of surface energy from mAb-QDs to GO. During sensing, a much stronger affinity of mAb-QDs towards MNase inhibits the energy transfer to GO and this allows the regaining of fluorescence. Immobilized mAb-QDs on nitrocellulose membrane strips were fabricated and tested for "ON-OFF-ON" sensing of MNase. The limit of detection for fluorescence based assay and strips is found to be 0.3 ng mL-1 and 0.5 ng mL-1, respectively. The developed strips were applied on real samples for the detection of S. aureus.

Fouling resistant functional blend membrane for removal of organic matter and heavy metal ions.

This study investigates the removal of heavy metal ions and humic acid using Cellulose acetate (CA) and Poly (methyl vinyl ether-alt-maleic acid) (PMVEMA) blend membranes. Antifouling properties of blend membranes were also investigated. Flat sheet membranes were prepared by phase inversion technique using different concentrations of CA and PMVEMA. The prepared membranes were characterized and their performance was evaluated by measuring pure water flux, water uptake capacity and humic acid removal. Rejection of humic acid (HA) was observed to be around 97% for all the blend membranes because of electrostatic interactions between the functional groups of HA and blends. The fouling characteristics of the membranes was assessed using HA as a foulant and the antifouling capacity of blend membranes was observed to be greater with a flux recovery ratio of almost 95% when compared to bare CA, commercial CA (TechInc) and other reported CA blends used for HA rejection. Also, the blend membranes were very effective in removing heavy metal ions (Pb2+, Cd2+ and Cr+6) and humic acid simultaneously. Overall, the PMVEMA modified CA membranes can open up new possibilities in enhancing the hydrophilicity, permeability and antifouling properties.

Photo-active float for field water disinfection.

The present study investigates the antibacterial activity of a photoactive float fabricated with visible light active N-F-TiO2 for the disinfection of field water widely contaminated with Gram positive and Gram negative bacteria like, Salmonella typhimurium (Gram negative), Escherichia coli (Gram negative), Staphylococcus aureus (Gram positive), Bacillus species (Gram positive), and Pseudomonas species (Gram negative). The antibacterial activity can be attributed to the unique properties of the photocatalyst, which releases reactive oxygen species in aqueous solution, under the illumination of sunlight. N-F-TiO2 nanoparticles efficiently photocatalyse the destruction of all the bacteria present in the contaminated water, giving clean water. The inactivation of bacteria is confirmed by a standard plate count method, MDA, RNA and DNA analysis. The purity of water was further validated by SPC indicating nil counts of bacteria after two days of storing and testing. The photocatalysts were characterized by XRD, BET measurement, SEM, EDX, UV-Vis and PL analysis.

A fluorescent chemodosimeter for Hg2+ based on a spirolactam ring-opening strategy and its application towards mercury determination in aqueous and cellular media.

A novel fluorescent chemosensor rhodamine B phenyl hydrazide (RBPH) for Hg(2+) was designed and synthesized. This probe is highly sensitive, selective, and irreversible for Hg(2+) and exhibits fluorescent response at 580 nm. RBPH also displayed detectable color change from colorless to pink upon treatment with Hg(2+). This property has been utilized as naked eye detection for Hg(2+) in various industrial samples. Fluorescence microscopic experiments demonstrated that this chemosensor is cell permeable and can be used for fluorescence imaging of Hg(2+) in cellular media. This probe can detect Hg(2+) with good linear relationships from 1 to 100 nM with r = 0.99983 and the limit of detection were found to be 0.019 nM with ± 0.91 % RSD at 10 nM concentrations.

Halide exchange mediated cation exchange facilitates room temperature co-doping of d-and f-block elements in cesium lead halide perovskite nanoparticles.

This study presents a halide exchange mediated cation exchange reaction to co-dope d- and f-block elements in CsPbX3 NPs at room temperature. Addition of MnCl2 and YbCl3 to CsPbBr3 NPs induces ion exchange reactions generating the corresponding CsPbBr3/MnCl2YbCl3 NPs. In addition to the perovskite emission, the NPs display sensitized Mn2+ and Yb3+ emissions in concert spanning the UV, visible, and NIR spectral region. Structural and spectroscopic characterizations indicate a substitutional displacement of Pb2+ by the Mn2+ and Yb3+. The identity of the host halide in modulating the ion exchange reactions was also tested. An effective perovskite host NP is presented that can be used to incorporate d-f or f-f dopant combinations to realize a gamut of dopant emission lines. A charge trapping based photophysical model is developed that focuses on rational energy alignments to predict dopant emissions semi-empirically and aids the design of optimal perovskite host-multi-dopant combinations.

Liquid- liquid (Cyclohexanone: Cyclohexanol) separation using augmented tight nanofiltration membrane: A sustainable approach.

Organic solvent nanofiltration (OSN) is an incipient technology in the field of organic liquid-liquid separation. The incomplete separations and complexity involved in these, forces many organic liquids to be released as effluents and the adverse effects of these on environment is enormous and irreparable. The work prominences on the complete separation of industrially significant cyclohexanone: cyclohexanol (keto-alcohol oil) and heptane: toluene mixtures. The separations of these above-mentioned organic liquid mixtures were carried out using the fabricated Lewis acid modified graphitic carbon nitride (Cu2O@g-C3N4) incorporated polyvinylidene difluoride (PVDF) composite membranes. These fabricated membranes showed a separation factor of 18.16 and flux of 1.62 Lm-2h-1 for cyclohexanone: cyclohexanol mixture and separation of heptane and toluene mixture (with heptane flux of 1.52 Lm-2h-1) showed a separation factor of 9.9. The selectivity and productivity are based on the polarity and size of the organic liquids. The role of Cu2O@g-C3N4 is influencing the pore size distribution, increased divergence from solubility parameters, polarity, solvent uptake and porosity of the composite membranes. The developed composite membranes are thus envisioned to be apt for a wide range of liquid-liquid separations due to its implicit nature.

Recent advances in metal organic frameworks-based magnetic nanomaterials for waste water treatment.

Magnetic nanoparticle-incorporated metal organic frameworks (MOF) are potential composites for various applications such as catalysis, water treatment, drug delivery, gas storage, chemical sensing, and heavy metal ion removal. MOFs exhibits high porosity and flexibility enabling guest species like heavy metal ions to diffuse into bulk structure. Additionally, shape and size of the pores contribute to selectivity of the guest materials. Incorporation of magnetic materials allows easy collection of adsorbent materials from solution system making the process simple and cost-effective. In view of the above advantages in the present review article, we are discussing recent advances of different magnetic material-incorporated MOF (Mg-MOF) composite for application in photocatalytic degradation of dyes and toxic chemicals, adsorption of organic compounds, adsorption of heavy metal ions, and adsorption of dyes. The review initially discusses on properties of Mg-MOF, different synthesis techniques such as mechanochemical, sonochemical (ultrasound) synthesis, slow evaporation and diffusion methods, solvo(hydro)-thermal and iono-thermal method, microwave-assisted method, microemulsion method post-synthetic modification template strategies and followed by application in waste water treatment.

A Rare Case of Low-Grade B-cell Non-Hodgkin's Lymphoma of the Lower Lip Mimicking a Mucocele.

In a clinical context, oral lymphomas are very uncommon and frequently challenging to identify. Mucosa-associated lymphoid tissue (MALT) lymphomas are a diverse category of lymphomas that were formerly believed to be formed from B-cells located in the marginal zone, which surrounds B-cell follicles and the surrounding lymphoepithelium. Extranodal organs like the stomach, thyroid, and large salivary glands are where they most frequently appear. As a result, they are accurately identified as extranodal marginal zone B-cell lymphomas (ENMZL). This report presents a case of a 53-year-old female with lower lip swelling, which was diagnosed as a case of marginal low-grade B-cell non-Hodgkin's lymphoma after clinical, histopathological, and immunological examinations. Non-Hodgkin's lymphoma diagnosis can be aided by pathological examination and biopsy performed early in the lesion's development. The dentist has a key role to play in the early diagnosis process.

Phase transferred and non-coated, water soluble perovskite quantum dots for biocompatibility and sensing.

Despite the excellent optoelectronic properties exhibited by CsPbBr3 QDs (PQDs) for sensing applications, their poor resistance to water does not allow their utilization as probes to detect analytes in aqueous media. The present work provides water soluble PQDs (dispersed in water) prepared by an appropriate phase engineering of the ligand. The dicarboxylate functional ligands at a particular pH allow the protonated state to form solvated carboxyl dimers, which interconnects PQDs, thus avoiding Ostwald ripening and enhancing the photoluminescence quantum yield (PLQY). As a proof of concept, this probe was applied to detect bioamines in water, namely histamine, hexamethylenediamine, phenethylamine, dopamine and thiamine. The probe is highly selective to histamine at concentrations below 500 nM and this selectivity of histamine over dopamine is very interesting and rarely reported. More importantly, this work offers a standard protocol for transferring PQDs from the organic to aqueous phase, for the detection of such biomolecules in water.

Review on Liquid-Liquid Separation by Membrane Filtration.

Liquid-liquid separation is crucial in the present circumstances. Substitution of the conventional types of separation like distillation and pervaporation is mandatory due to the high energy requirement of the two. The separation of organic mixtures has a huge potential in industries such as pharmaceutical, fine chemicals, fuels, textile, papers, and fertilizers. Membrane-affiliated separations are one of the prime techniques for liquid-liquid separations. Organic solvent nanofiltration, solvent-resistant nanofiltration, and ultrafiltration are a few methods through which organic liquid-liquid separation can be attained. Implementation of such a technology in chemical industries reduces the time consumption and is cost efficient. Even though a lot of research has been done, attention is needed in the field of organic-liquid separation aided by membranes. In this review, various membranes used for organic mixture separations such as polar-nonpolar, polar-polar, and nonpolar-nonpolar are discussed with a focus on membrane materials, additives, separation theory, separation type, experimental setup, fouling mitigation, surface modification, and major challenges. The review also offers insights and probable solutions for existing problems and also discusses the scope of research to be undertaken in the future.

Comprehensive Analysis of Spinel-Type Mixed Metal Oxide-Functionalized Polysulfone Membranes toward Fouling Resistance and Dye and Natural Organic Matter Removal.

Nanostructured polymeric membranes are of great importance in enhancing the antifouling properties during water filtration. Nanomaterials with tunable size, morphology and composition, surface modification, and increased functionality provide considerable opportunities for effective wastewater treatment. Thus, in this work, an attempt has been made to use spinel-structured MnCo2O4 as a nanofiller in the fabrication of nanostructured polysulfone (PSF) mixed matrix membranes and is investigated in terms of morphology, hydrophilicity, permeability, protein and natural organic matter separation, dye removal, and, finally, antifouling properties. The MnCo2O4 nanomaterials are synthesized and characterized via X-ray diffraction and field emission scanning electron microscopy and are loaded into a membrane matrix with varied concentrations (0 to 1.5 wt %). PSF nanocomposite membranes are prepared via a nonsolvent-induced phase-separation process. The results show an enhancement in hydrophilicity, porosity, and permeability with respect to the modified nanocomposite membranes because of oxygen-rich species in the membrane matrix, which increases affinity toward water. It was also found that the modified membranes display remarkably greater pure water flux (PWF) (220 L/m2 h), higher Congo red rejection coefficient (99.86%), higher humic acid removal (99.81%), higher fouling resistance, and a significant flux recovery ratio (FRR) (88%) when tested with bovine serum albumin protein when compared to a bare PSF membrane (30 L/m2 h PWF and 35% FRR). This is because the addition of MnCo2O4 nanoparticles into the polymeric casting solution yielded tighter PSF membranes with a denser skin layer and greater selectivity. Thus, the enhanced permeability, greater rejection coefficient, and antifouling properties show the promising potential of the fabricated PSF-spinel nanostructured membrane to be utilized in membrane technology for wastewater treatment.

Nitrogenated Graphene Oxide-Decorated Metal Sulfides for Better Antifouling and Dye Removal.

Nitrogenated graphene oxide-decorated copper sulfide nanocomposites (Cu x S-NrGO, where x = 1 and 2) are designed to be incorporated in polysulfone (PSF) membranes for effective fouling resistance of PSF membranes and their dye removal capacity. The developed membranes possess more hydrophilicity and an enhancement in pure water flux (PWF). Also, the highest bovine serum albumin (BSA) rejection of 89% was observed when compared to membranes with pristine PSF (5 L/m2 h PWF and 88% BSA rejection) and CuS-incorporated PSF membranes (14 L/m2 h PWF and 83% BSA rejection) because of N doping and enhanced permeability. It is also found that the Cu x S-NrGO-incorporated PSF membranes exhibited a significantly higher fouling resistance, a larger permeate flux recovery ratio (FRR) of nearly 82%, and a congo red dye rejection of 93%. Cu x S-NrGO nanoparticles thus demonstrate the potential efficacy of enhancing the hydrophilicity, leading to a better flux, dye removal capacity, and antifouling capacity with a very high FRR value of 82% because of a strong interaction between the N-active sites of the NrGO, Cu x S, and polysulfone matrix, and negligible leaching of nanoparticles is observed.

Aqueous, Non-Polymer-Based Perovskite Quantum Dots for Bioimaging: Conserving Fluorescence and Long-Term Stability via Simple and Robust Synthesis.

Perovskite quantum dots (PQDs) offer high photoluminescence quantum yields; however, due to their limited stability in aqueous media, to date their utilization in biomedical applications has been limited. The present work demonstrates highly fluorescent and stable aqueous PQDs that were synthesized using a facile engineered phase transfer method. Ligands were engineered to have a dual functionality, i.e., they could simultaneously mediate the strong binding of PQDs and the interactions with water molecules. The resultant water-soluble PQDs demonstrated robust structural and optical properties. The extracted aqueous PQDs remained stable in pellet form for 8 months, which was the entire test duration. Notably, 100% of their fluorescence was also retained. As a proof-of-concept experiment, the water-soluble PQDs were successfully tagged to polyclonal antibodies and used to image Escherichia coli cells in aqueous media. No structural or optical disturbance in PQDs was detected throughout the process. This work marks the beginning of the use of nonpolymeric aqueous PQDs and shows their strong potential to be used in biological applications.

Efficacy of Electrospun Nanofiber Membranes on Fouling Mitigation: A Review.

Despite the advantages of high contaminant removal, operational flexibility, and technical advancements offered, the undesirable fouling property of membranes limits their durability, thus posing restrictions on their usage. An enormous struggle is underway to conquer this major challenge. Most of the earlier reviews include the basic concepts of fouling and antifouling, with respect to particular separation processes such as ultrafiltration, nanofiltration, reverse osmosis and membrane bioreactors, graphene-based membranes, zwitterionic membranes, and so on. As per our knowledge, the importance of nanofiber membranes in challenging the fouling process has not been included in any record to date. Nanofibers with the ability to be embedded in any medium with a high surface to volume ratio play a key role in mitigating the fouling of membranes, and it is important for these studies to be critically analyzed and reported. Our Review hence intends to focus on nanofiber membranes developed with enhanced antifouling and biofouling properties with a brief introduction on fabrication processes and surface and chemical modifications. A summary on surface modifications of preformed nanofibers is given along with different nanofiller combinations used and blend fabrication with efficacy in wastewater treatment and antifouling abilities. In addition, future prospects and advancements are discussed.

Recent case studies on the use of ozone to combat coronavirus: Problems and perspectives.

Coronavirus pandemic has created havoc in the world. COVID-19 is now officially labeled as Severe Acute Respiratory Syndrome-related Coronavirus-SARS-CoV-2. Therefore, it is equally important to combat the virus both inside the human body as well as in the environment. These viruses, being RNA viruses, are found to be susceptible to ozone. Ozone being an unstable molecule can breakup into its split products namely reactive oxygen species and ozonides creating a toxic environment for these viruses. Ozone mainly prevents the membrane fusion with the host cell, thus interfering with their replication. With vast applications of the gas, it has created a new spark in the field of medicine in combating these viruses and many other organisms. In this context, this article provides insights from recent clinical and research studies on the problems and possibilities in employing the ozone to combat the coronaviruses.