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Heterogeneous catalysis has currently become an emerging tool for the design and development of sustainable manufacturing processes in order to obtain advanced intermediates, fine chemicals, and bioactive molecules. This field has been considered efficient and eco-friendly, as it investigates the utilization of non-hazardous metals for atom-economical reactions. Nanomaterials have created a significant impact on scientific and engineering advancements due to their tunable properties with superior performance over their massive counterparts. Due to the increased demand for heterogeneous catalysts in industries and academia, different transition metal oxides have been made into substantial nanostructures. Among them, titanium dioxide (TiO 2 ) nanomaterials have received more attention on account of their chemical stability, low cost, dual acid-base properties, good oxidation rate and refractive index. Different modifications of TiO 2 extend their applications as active catalysts or catalyst supports in diverse catalytic processes, such as photovoltaics, lithium batteries, pigments and others. One-dimensional (1-D) TiO 2 nanostructures such as nanotubes, nanowires and nanorods have achieved greater importance owing to the unique properties of improved porosity, decreased inter-crystalline contacts, large surface-to-volume ratio, superior dispersibility, amplified accessibility of hydroxyl (-OH) groups and presence of good concentrations of Brønsted/Lewis acid sites. Since the discovery, 1-D TiO 2 nanostructures have served good photocatalytic applications, but were less explored in organic transformations. While many articles and reviews have covered the applications of 0-D and 1-D TiO 2 nanostructured materials (NSMs) in photoelectrochemical reactions and solar cells, there are other interesting applications of these as well. In contrast to the conventional multi-step processes that utilise the stepwise formation of individual bonds, one-pot conversions based on multicomponent reactions (MCRs) have acquired much significance in contemporary organic synthesis. This paper presents a critical review on history, classification, design and synthetic utility of titania-based nanostructures, which could be used as robust solid-acid catalysts and catalyst supports for MCRs. Further, to put ideas into perspective, the introduction and applications of MCRs for various organic transformations have been discussed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In the present-day scenario, it is necessary to establish more flexible, effective and selective analytical methods that are easy to operate and less expensive. Cyclic voltammetry (CV) can be a useful technique to assess minute quantity of pollutants and in this work, an effort has been made to detect the trace quantification from the environmental samples. Herein, electrochemical sensor was fabricated using tungsten oxide nanorod (WO 3 ·0.33H 2 O) for sensitive detection of fungicide, carbendazim (CBZ). Under optimal conditions, while studying the effect of pH on peak current, the highest peak current was observed at pH 4.2. The degradation of CBZ followed the mixed diffusion-adsorption controlled and quasi-reversible processess at the WO 3 ·0.33H 2 O/GC electrode surface. Using WO 3 ·0.33H 2 O/GCE sensor in SWV provided the lowest limit of detection (LOD) and limit of quantification (LOQ) values of 2.21 × 10 -8  M and 7.37 × 10 -8  M, respectively over the concentration ranges of 1.0 × 10 -7  M to 2.5 × 10 -4  M. The proposed method demonstrates potential applicability of the fabricated sensor for soil and water samples analysis in the management of creating a benign environment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

An upsurge in global population due to speedy urbanization and industrialization is facing significant challenges such as rising energy-demand, enormous waste-generation and environmental deterioration. The waste-to-energy nexus based on the 5R principle (Reduce, Reuse, Recycle, Recovery, and Restore) is of paramount importance in solving these Gordian knots. This review essentially concentrates on latest advancements in the field of 'simultaneous waste reduction and energy production' technologies. The waste-to-energy approaches (thermal and biochemical) for energy production from the agricultural residues are comprehensively discussed in terms environmental, techno-economic, and policy analysis. The review will assess the loopholes in order to come up with more sophisticated technologies that are not only eco-friendly and cost-effective, but also socially viable. The waste-to-energy nexus as a paradigm for sustainable development of restoring waste is critically discussed considering future advancement plans and agendas of the policy-makers., Competing Interests: Declaration of competing interest All the authors declare that we don’t have any conflict of interests., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Environmental pollution by the heavy usage of pesticides has been a pandemic issue in view of the rising farming operations for increasing the crop yield to meet the requirements of food chain supply. Throughout the world, environmental pollution by the presence of pesticides, particularly the use of herbicides in large quantities to protect the crops, has posed many environmental issues. In this research, an electrochemical sensor based on tungsten oxide hydrates (WO 3 ·0.33H 2 O) nanorod modified carbon paste electrode (CPE) was developed for the detection of herbicide, amitrole (AMT) by the cyclic voltammeter. Hydrothermally synthesized and characterized WO 3 ·0.33H 2 O nanorod was found to be sensitive towards the detection of AMT due to its superior sensing property as the sensor showed enhanced current and catalytic property when used in phosphate buffer solution (PBS) of pH 5.0 by the cyclic voltammetric (CV) and square wave voltammetric (SWV) techniques. The influence of electro kinetic parameters viz., scan rate, pH, accumulation time and temperature with respect to AMT oxidation was studied using CV. The linearity range was in between 1.0 × 10 -8  M and 24 × 10 -5  M and limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 2.33 nM and 7.8 nM respectively. The proposed simple method demonstrated the potential applicability to detect AMT from the soil and water samples., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2020. Published by Elsevier B.V.)

Photodegradation of toxic pollutants is a promising approach to deal with wastewater management. In this regard, MoS 2 /g-C 3 N 4 (MSC) derived composites with varying weight-ratios were prepared via fast (30 min) one step microwave-assisted method. The materials were characterized by XRD, XPS, EDS, FESEM and HRTEM to validate their flower-like and sheet-like morphologies. The PL and UV-vis DRS spectra exhibited low recombination-rate and band-gap (1.7 eV), which is appropriate for an effective visible-light degradation. Photocatalytic performance of the catalysts was analyzed by investigating the degradation of methylene blue (MB) as well as pesticide fipronil. Best results were obtained by 5:1 MSC (98.7% degradation efficacy; rate constant 0.0261 min -1 ) in 80 min under the sunlight. The effects of solution pH, catalyst-dose, scavengers and illumination-area were also explored. The catalyst was reusable as confirmed by degradation studies (~82% efficiency) even after 5-cycles. The photocatalytic treatment of real industrial-wastewater was also conducted. The TOC and COD analysis validated that the treatment by as-prepared catalyst is more proficient for effluent-treatment than the industrial physico-chemical treatments. Electrochemical degradation of MB was also investigated using the glassy carbon electrode modified with different MSC-ratios. The electrode modified with 5:1 MSC at pH 7 manifested the maximum peak current. The plausible mechanisms for photocatalytic and electrochemical degradations were proposed, which suggested the remarkable potential the prepared nanocomposites for wastewater treatment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Environmental sustainability criteria and rising energy demands, exhaustion of conventional resources of energy followed by environmental degradation due to abrupt climate changes have shifted the attention of scientists to seek renewable sources of green and clean energy for sustainable development. Bioenergy is an excellent alternative since it can be applied for several energy-requirements after utilizing suitable conversion methodology. This review elucidates all aspects of biofuels (bioethanol, biodiesel, and butanol) and their sustainability criteria. The principal focus is on the latest developments in biofuel production chiefly stressing on the role of nanotechnology. A plethora of investigations regarding the emerging techniques for process improvement like integration methods, less energy-intensive distillation techniques, and bioengineering of microorganisms are discussed. This can assist in making biofuel-production in a real-world market more economically and environmentally viable., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The serotype-specific early detection of dengue fever is very effective in predicting the pervasiveness of fatal infections such as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). This fever results from reinfection (secondary) with a serotype of the dengue virus, which is different from the serotype involved in primary infection. Hence, the present work was aimed to develop a multiplexed electrochemical paper-based analytical device (ePAD) consisting of graphene oxide-silicon dioxide (GO-SiO 2 ) nanocomposites to detect the specific type of dengue virus (DENV). The conducting nature of GO-SiO 2 -coated multiplexed platform provided amplification in the signal response of the genosensor. The present sensor detected the target DNA of the four serotypes of the dengue virus, namely, DENV 1, DENV 2, DENV 3, and DENV 4, in a wide detection range of 100 pM to 100 μM. The sensor showed a high degree of specificity toward specific serotypes of DENV. Further, the use of such paper-based sensor had many advantages such as facile preparation, homogeneous distribution of nanoparticles onto the surface, requirement of a small quantity of sample, and low cost. To the best of our knowledge, this is the first report on the fabrication of a genosensor for predicting the pervasiveness of the dengue hemorrhagic fever or dengue shock syndrome.

In this study, dimensionally coupled Z-scheme binary nanocomposites from two-dimensional (2D) NiFe 2 O 4 nanoplates and one-dimensional (1D) ZnWO 4 nanorods are prepared for efficient degradation of an antibiotic tetracycline (TC) and organic dye rhodamine B (RhB) under solar illumination. NiFe 2 O 4 /ZnWO 4 nanocomposites were synthesized by a simple and ecological in-situ hydrothermal method without the use of surfactants. Structural and morphological studies revealed the formation of heterostructure and 1D ZnWO 4 nanorods were uniformly distributed over the surface of NiFe 2 O 4 nanoplates. Light-harvesting capability was improved and optimized by loading with different amounts of ZnWO 4 . Photoluminescence analysis demonstrated inhibited nature of the recombination of photo-excited charge carriers in the nanocomposites. Photocatalytic experiments revealed that the nanocomposite exhibited improved Z-scheme electron-transfer for the degradation of TC under solar illumination. In particular, NFZW-20 nanocomposite demonstrated superior photocatalytic degradation of TC of approximately 98% within 105 min. Furthermore, their photocatalytic performance was investigated by RhB dye under the solar irradiation to achieve 98% of degradation of RhB in 70 min. Improved photocatalytic activities are attributed to the Z-scheme electron-transfer mechanism, which could enhance the superior ability of light absorption and reduced recombination rate of the photogenerated charge carriers., Competing Interests: Declaration of competing interest The authors of this manuscript report no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This review emphasizes utilization of waste organic matters from water bodies and soil sources for sustainable energy development. These organic waste matters (including microplastics) from a variety of environmental sources have created a big challenge to utilize them for energy development for human needs, maintaining a cleaner environment and thereby, producing useful bioproducts (sustainable bioenergy or other primary metabolites). Anaerobic digestions as well as other effective wastewater treatment approaches are discussed. From the water bodies, waste organic matter reduction can be achieved by a reduction of chemical oxygen demand and biological oxygen demand after the waste treatment. Other forms of organic waste matter are available in the form of agro wastes or residues (stalk of wheat or rice, maize, corn etc.) due to crop cultivation, which are generally burnt into ashes. Such wastes can be utilized for bioenergy energy production, which would help for the reduction of climate changes or other toxic gases. Hydrogen, bioelectricity, ethanol, butanol, methane and algal diesel or other types of fuel sources would help to provide sustainable source of bioenergy that can be produced from these wastes via degradation by the biological processes. This review will discuss in depths about the sustainable nature of organic matters to produce clean energy via application of efficient biological methods to maintain a clean environment, thereby providing alternative options to fossil energy fuels., Competing Interests: Declaration of competing interest All the authors declare that we don't have any conflict of interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The energy demand has increased exponentially worldwide owing to the continuously growing population and urbanization. The conventional fossil fuels are unable to satiate this requirement causing price inflation and significant environmental damage due to unrestrained emission of greenhouse gases. The focus now has shifted towards alternative, economical, renewable and green sources of energy such as hydrogen to deal with this bottle-neck. Hydrogen is a clean energy-source having high energy content (122 kJ/g). Recently, biological methods for the hydrogen production have attracted much attention because traditional methods are expensive, energy-exhaustive and not eco-friendly. The employment of biological methods promises utilization of waste or low-value materials for producing energy and building waste-to-energy nexus. Around 94% of the waste is discarded precariously in India and waste generation is growing at an alarming rate of 1.3% per year. The "waste-to-energy" techniques follow 'Reuse, Reduce, Recycle, Recovery and Reclamation' system solving three subjects at once; waste-management, energy-demand and environmental concern. Moreover, these methods have easy operability, cost-effectiveness and they help to shift from linear to circular model of economy for sustainable development. Biological processing of waste materials like agricultural discard (lignocellulosic biomass), food-waste and industrial discharge can be used for biohydrogen production. Dark and photo fermentation are the chief biological processes for the transformation of organic substrates to hydrogen. Dark fermentation is the acidogenic fermentation of carbohydrate-rich materials without light and oxygen. Clostridia, Enterobacter and Bacillus spp. are appropriate heterotrophic bacteria for dark fermentation. Various pretreatment methods like heat treatment, acid or base treatment, ultrasonication, aeration, electroporation, etc., can be applied on inoculums to increase H 2 producing bacteria eventually improving the hydrogen yield. However, only around 33% of COD in organic materials is transformed to H 2 by this method. Photofermentation by the photosynthetic non-sulfur bacteria (PNS) converts organic substrate to H 2 and CO 2 in the presence of nitrogenase enzyme in ammonium-limited and anoxygenic conditions. Rhodobacter or Rhodopseudomonas strains have been widely examined in this regard. But these methods are only able to produce H 2 with a poor yield. Combining dark and photofermentation is a noteworthy alternative for procuring enhanced hydrogen yields. Two-stage sequential method utilizes volatile fatty acids accumulated as byproducts after dark fermentation (in the first stage) for photofermentation by suitable bacteria (in the second stage). A proper investigation of the dark fermenter effluents is required before using them as a substrate for photo-fermentation. In a single-stage dark and photofermentation, co-culture of anaerobic and PNS bacteria in a single reactor is carried out for obtaining improved yield. The single stage system is comparatively inexpensive and less laborious; moreover, a limited requirement for an intermediate dilution stage is necessary. Economic analysis of hydrogen production showed that H 2 production by the present methods, save pyrolysis, is reasonably higher than the conventional approaches of fuel production. Probable routes to make H 2 production more cost-effective are reducing the cost of photobioreactor, installing proper storage system, etc. A constructive effort in the area of research and development of biological approaches of H 2 production technologies is vital. The commercial viability of biohydrogen production is imperative for accomplishment of circular economy system and sustainable development., Competing Interests: Declaration of competing interest All the authors declare that we have not any conflict of interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Doping effect on the photoelectrochemical (PEC) water splitting efficiency and photocatalytic activities of ZrO 2 under visible light are reported. The XRD analysis revealed that pure, 0.1 and 0.3 mol% doped samples showed mixed crystal phases (tetragonal and monoclinic) and 0.5 mol% doped sample showed a pure tetragonal phase. Under visible light, 90% of methyl orange dye degradation was achieved with in 100 min. Moreover, the optimal doped sample showed a significant degradation rate constant over other samples. The doped photoelectrodes display a better PEC water oxidation performance over pure photoelectrode. Furthermore, the optimal doped (0.3 mol %) electrode shows 0.644 mAcm -2 photocurrent density, corresponding to an approximate 50-fold enhancement over pure electrode (0.013 mAcm -2 ). The optimized doped sample achieved 98% degradation of methyl orange within 100 min of light irradiation. The superior PEC water oxidation and photocatalytic activity of optimal doped samples under visible light are credited to suitable doping content, crystalline size, greater surface area, suitable bandgap, a lower charge carrying resistance, surface properties and the ability for decreasing the charge carrier's recombination rate., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Health care monitoring is an extremely important aspect of human life that can be accomplished using wearable skin-patchable sensors. Upon interfacing with the skin or epidermal surface of the body, the sensing patches can monitor the movements of human parts such joints, legs, and fingers as well as tiny vibrations caused by respiration, blood flow, and heart beat. Wearable skin patches have shown improved promise in monitoring the body temperature and fever in addition to quick measurement of blood pressure and pulse rate along with breathing rate. Sensors can also analyze the sweat contents when in contact with the skin as well as other analytes such as diabetes-based volatile organic compounds (VOCs) and organophosphate nerve stimulating agents. Hence, the sensors can be of immense help in the early prediction of malfunctions of the body organs such as heart and lungs, leading to timely and effective treatment. This review covers different important aspects of skin-patchable sensors including mechanical strength and flexibility, sensitivity, transparency, self-healing, self-cleaning, and self-powering ability as well as their latest applications in medical technology.

Iron (Fe)-doped ZrO 2 tetragonal nanoparticles were synthesized by a facile and inexpensive hydrothermal technique, that were doped with Fe 3+ ions (0.1, 0.3, and 0.5 mol%) into the host lattice without altering the morphology and crystal structure of the nanoparticles. SEM and TEM investigations indicated that the morphology of ZrO 2 nanoparticles did not change even after incorporation of Fe, while the band gap of semiconducting ZrO 2 nanoparticles was reduced from 4.97 to 1.77 eV. Such a in band gap was responsible to harvest more photons to stimulate the generation of more electrons in the valence band, thereby enhancing the photoelectrochemical (PEC) water splitting as well as photocatalytic and photoelectrocatalytic activities in the photodegradation of Rhodamine B. The 0.3 mol%-doped ZrO 2 electrode showed enhanced photocurrent density (0.07 × 10 -3 A/cm 2 ), that was 45-times greater than the pure sample. The electrochemical impedance spectroscopy (EIS) confirmed that 0.3 mol%-doped ZrO 2 exhibited the best charge transfer characteristics, which increased with PEC water splitting activity. The maximum photocurrent density and long-term photo-stability were achieved in the light on-off states., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The whole world is now facing the battle against the severe and dangerous pandemic COVID-19, which is not only physically harming, but also mentally disturbing because of the unceasingly escalating number of affected patients and deaths globally. In India, the containment strategies constitute in identifying, tracing-contacts, quarantine, social distancing, and following other health advisories. The current treatment protocols include real-time PCR test and Point-of-Care molecular diagnostic assays for its diagnosis; some states in India have begun the pool testing. Hydroxychloroquine (HCQ) is being recommended as chemoprophylaxis drug for asymptomatic healthcare personnel handling COVID-19 cases, frontline workers, and asymptomatic contacts of the confirmed cases, while hydroxychloroquine-azithromycin combination for patients with serious sickness. India has also launched 'ArogyaSetu' mobile-application for tracking the movements of the citizens and has also commenced convalescent plasma therapy to combat the deadly COVID-19. This timely article is a report on the current situation of COVID-19 in India. The discussion can throw light on the potential of a developing country such as India to deal with the pandemic and some of these can be helpful in adverse circumstances in the future., Competing Interests: The authors declare no intellectual or financial conflicts of interest., (© 2020 The Authors.)

The fight with COVID-19 pandemic seems nowhere near the end and is extremely daunting. An upsurge in cases of mental illness in India post the pandemic is a clear indicator of its scary impact. The situation of lockdown is causing the feeling of distress, agitation and helplessness among the people. Healthcare workers, poverty-stricken people, elderly, kids and persons with some pre-existing medical condition are more vulnerable to anxiety currently. Practicing a healthy lifestyle; yoga, meditation, avoiding reading too much about the pandemic and being with family are the ways to assuage stress., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper (Indians vs. COVID-19: The scenario of mental health).The authors don't have any conflict of interest in the publication of the manuscript., (© 2020 The Authors.)

Coronavirus (COVID-19) started its invasion as an epidemic from Wuhan, China and propagated to become the scary pandemic that reached more than 200 countries all over the world. High number of infected people and unfortunately high mortality are the result of this invasion. The Indian scenario is no exception to this deadly infection attack, though it started a bit late. The first case in India came into notice in January and the number of cases showed an enormous growth in mid March and still continue to grow. This timely report focuses on the current invasion scenario in India as of 11th May 2020; with total cases of 67,152, active cases of 44, 029, deaths totaling to 2206 and over-all recoveries of ∼20,917 patients., Competing Interests: The authors declare no intellectual or financial conflicts of interest., (© 2020 The Authors.)

The world has been suffering under the horrendous effects of COVID-19 both in terms of loss of human lives and numerous tangible as well as financial losses. There has been some contrast on the magnitude of its impact in various parts of the world. The most peculiar one is the impact of COVID-19 in India as compared to other developed nations. Having the second largest population along with poor health infrastructural facilities, India has fairly performed well in its initial fight against COVID-19 as compared to the far developed and equipped countries. This variance has aroused much discussion and deliberations among the academia and medical doctors to seek possible explanations. This report elaborates on factors such as dietary habits, vaccination (BCG), exposure to unsanitary surroundings, and climatic conditions, which could be the explanation for the contrasting impact of COVID-19 in India and other developed nations., Competing Interests: The authors declare no intellectual as well as financial conflict of interests., (© 2020 The Authors.)

Energy and water are the two major issues facing the modern mankind. Providing freshwater requires energy and producing energy uses water. In the present-day scenario, both these routes face growing problems and limitations. Energy crisis has risen due to the depletion of fossil fuels that cause pollution to water bodies making the water unusable for human consumption. In this regard, semiconductor nanocrystals with luminescent properties or carbon quantum dots (CQDs) are the newly developed nanomaterials whose distinctive photo-physical characteristics are focusing to a new generation of robust materials and sensors for sustainable development. In this review, advances in surface and band gap modification of CQDs to improve the activity of nanomaterials will be discussed with special reference to some specific CQDs exhibiting special optical properties for water treatment/splitting applications. Recent advances on CQDs nanocomposites including their applications in photodegradation of organic pollutants, sensing of heavy metal ions in water and water splitting are discussed critically to narrate the future prospects in this field. Challenges and limitations for further improvement are covered to provide smart choices for creating sustainability of benign environment and economic benefits., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Nano-size photocatalysts exhibit multifunctional properties that opened the door for improved efficiency in energy, environment, and health care applications. Among the diversity of catalyst Quantum dots are a class of nanomaterials having a particle size between 2 and 10 nm, showing unique optoelectrical properties that are limited to some of the metal, metal oxide, metal chalcogenides, and carbon-based nanostructures. These unique characteristics arise from either pristine or binary/ternary composites where noble metal/metal oxide/metal chalcogenide/carbon quantum dots are anchored on the surface of semiconductor photocatalyst. It emphasized that properties, as well as performance of photocatalytic materials, are greatly influenced by the choice of synthesis methods and experimental conditions. Among the chemical methods, photo-deposition, precipitation, and chemical reduction, are the three most influential synthesis approaches. Further, two types of quantum dots namely metal based and carbon-based materials have been highlighted. Based on the optical, electrical and surface properties, quantum dots based photocatalysts have been divided into three categories namely (a) photocatalyst (b) co-catalyst and (c) photo-sensitizer. They showed enhanced photocatalytic performance for hydrogen production under visible/UV-visible light irradiation. Often, pristine metal chalcogenides as well as metal/metal oxide/carbon quantum dots attached to a semiconductor particle exhibit enhanced the photocatalytic activity for hydrogen production through absorption of visible light. Alternatively, noble metal quantum dots, which provide plenty of defects/active sites facilitate continuous hydrogen production. For instance, production of hydrogen in the presence of sacrificial agents using metal chalcogenides, metal oxides, and coinage metals based catalysts such as CdS/MoS 2 (99,000 μmol h -1 g -1 ) TiO 2 -Ni(OH) 2 (47,195 μmol h -1 g -1 ) and Cu/Ag-TiO 2 nanotubes (56,167 μmol h -1 g -1 ) have been reported. Among the carbon-based nanostructures, graphitic C 3 N 4 and carbon quantum dots composites displayed enhanced hydrogen gas (116.1 μmol h -1 ) production via overall water splitting. This review accounts recent findings on various chemical approaches used for quantum dots synthesis and their improved materials properties leading to enhanced hydrogen production particularly under visible light irradiation. Finally, the avenue to improve quantum efficiency further is proposed., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Fascinating properties of ZnO nanostructures have created much interest due to their importance in health care and environmental monitoring. Current worldwide production and their wide range of applications signify ZnO to be a representative of multi-functional oxide material. Recent nanotechnological developments have stimulated the production of various forms of ZnO nanostructures such as nano-layers, nanoparticles, nanowires, etc. Due to their enhanced sensing properties, improved binding ability with biomolecules as well as biological activities have enabled them as suitable candidates for the fabrication of biosensor devices in the biomedical arena. In this review, the synthesis of ZnO nanostructures, mechanism of their interaction with biomolecules and their applications as sensors in health care area are discussed considering the biosensors for molecules with small molecular weight, infectious diseases, and pharmaceutical compounds., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Alcohols are the essential chemicals used in a variety of pharmaceutical and chemical industries. The extreme purity of alcohols in many of such industrial applications is essential. Though distillation is one of the methods used conventionally to purify alcohols, the method consumes more energy and requires carcinogenic entertainers, making the process environmentally toxic. Alternatively, efforts have been made to focus research efforts on alcohol dehydration by the pervaporation (PV) separation technique using polymeric membranes. The present review is focused on alcohol dehydration using PV separation technique, which is the most efficient and benign method of purifying alcohols that are required in fine chemicals synthesis and developing pharmaceutical formulations. This review will discuss about the latest developments in the area of PV technique used in alcohol dehydration using a variety of novel membranes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Biosensors are promising biotechnology products that can be widely used for environmental monitoring, food analysis, and healthcare diagnostics. To detect analytes of interest, the use of nanotechnology in bio-analytical devices is advantageous for increased sensitivity, device simplification, and rapid sensing with multiple capabilities. Depending on the application, biosensors can be fabricated from different materials. TiO 2 is a semiconductor material and has received significant attention for various applications such as sensors, solar cells, water splitting, etc. The wide applicability of recently developed novel composition and structure of TiO 2 materials has accelerated the development and miniaturization of biosensor devices. This study focuses on recent achievements in TiO 2 nanostructured hybrids-based biosensors for detecting various biological markers important for healthcare., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In recent years, various facile and low-cost methods have been developed for the synthesis of advanced nanostructured photocatalytic materials. These catalysts are required to mitigate the energy crisis, environmental deterioration, including water and air pollution. Among the various semiconductors explored, recently novel classes of polymeric graphitic carbon nitride (g-C 3 N 4 )-based heterogeneous photocatalysts have established much greater importance because of their unique physiochemical properties, large surface area, low price, and long service life, ease of synthesis, product scalability, controllable band gap properties, low toxicity, and high photocatalytic activity. The present comprehensive review focuses on recent achievements in a number of facile chemical synthesis methods for semiconducting polymeric carbon nitrides and their heterogeneous nanohybrids with various dopants, nanostructured metals, metal oxides, and nanocarbons, as well as the parameters influencing their physiochemical properties and photocatalytic efficiency, which are discussed with reference to various catalytic applications such as air (NO x ) purification, wastewater treatment, hydrogen generation, CO 2 reduction, and chemical transformation. The mechanisms for the superior photocatalytic activity of polymeric g-C 3 N 4 -based heterogeneous photocatalysts are also discussed. Finally, the challenges, prospects, and future directions for photocatalytic polymeric g-C 3 N 4 -based semiconducting materials are described., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Novel sensors based on carbon paste assorted with amberlite XAD-4 resin and silver-doped titanium dioxide/amberlite XAD-4 resin (Ag-TiO 2 /XAD) were designed and employed for sensitive detection of flufenamic acid (FFA). The main objective of this study is to develop novel electrochemical sensors for more sensitive and selective detection of FFA and to propose its oxidation mechanism. In this perspective, we have developed modified electrodes using amberlite XAD-4 matrix and Ag-TiO 2 /XAD-4 mixture. These sensors when used in conjunction with different voltammetric techniques to observe enhanced outcome on FFA electrode reaction in PBS of pH 7.0. Our data confirmed exceptional stability, sensitivity, and quick responses for FFA. The effect of modifier, analyte concentration, pH of buffer solution, pre-concentration time, and sweep rates on electrochemical behavior of FFA was investigated. The current intensities were linearly proportional to the concentration of FFA. From the calibration plot of different concentrations of FFA, the detection limit of 3.6 nM at XAD-CPE and 1.2 nM, respectively at AgTiO 2 /XAD-CPE were obtained. The estimation of FFA in biological as well as clinical samples was achieved using the chemically modified electrodes., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Recent advances to utilize two or more nanoparticles for developing novel sensors with superior sensitivity have spurred advanced detection limits even at low concentrations. In this research, a blend of rutheniumdoped TiO 2 (Ru-TiO 2 ) nanoparticles and multiwalled carbon nanotubes (MWCNTs) loaded into carbon paste matrix to fabricate a novel Ru-TiO 2 /MWCNTs-CPE sensor was used for the detection and quantification of flufenamic acid (FFA) and mefenamic acid (MFA) drugs. The surface morphology of Ru-TiO 2 was assessed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Sensitivity and selectivity of the electrode was improved at the Ru-TiO 2 /MWCNTs modified CPE compared to nascent CPE due to the amazing surface distinctive characteristics of the modifier at pH 5.0. The effect of concentration of the modifier, pH, pre-concentration time, sweep rate and concentration on signal enhancement of FFA and MFA was studied. The square wave voltammetry (SWV) currents are linearly related in the concentration range of 0.01 μM-0.9 μM with the detection limit values of 0.68 nM for FFA and 0.45 nM for MFA, respectively. The developed electrode assembly was used for the quantification of both the drug analytes in human urine samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A novel sensor for the determination of 5-fluorouracil was constructed by electrochemical deposition of methylene blue on surface of carbon paste electrode. The electrode surface morphology was studied using Atomic force microscopy and XRD. The electrochemical activity of modified electrode was characterized using cyclic voltammetry and differential pulse method. The developed sensor shows impressive enlargement in sensitivity of 5-fluorouracil determination. The peak currents obtained from differential pulse voltammetry was linear with concentration of 5-fluorouracil in the range 4×10(-5)-1×10(-7)M and detection limit and quantification limit were calculated to be 2.04nM and 6.18nM respectively. Further, the sensor was successfully applied in pharmaceutical and biological fluid sample analysis., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Electrochemical oxidation of acyclovir at fullerene-C(60)-modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry. In pH 7.4 phosphate buffer, acyclovir showed an irreversible oxidation peak at about 0.96V. The cyclic voltammetric results showed that fullerene-C(60)-modified glassy carbon electrode can remarkably enhance electrocatalytic activity towards the oxidation of acyclovir. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the acyclovir determination by differential pulse voltammetry. Effects of anodic peak potential (E(p)/V), anodic peak current (I(p)/μA) and heterogeneous rate constant (k(0)) have been discussed. Under optimized conditions, the concentration range and detection limit were 9.0×10(-8) to 6.0×10(-6)M and 1.48×10(-8)M, respectively. The proposed method was applied to acyclovir determination in pharmaceutical samples and human biological fluids such as urine and blood plasma as a real sample. This method can also be employed in quality control and routine determination of drugs in pharmaceutical formulations., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The voltammetric behavior of theophylline was investigated using cyclic and differential-pulse voltammetric techniques. The cyclic voltammetric results indicate that multi-wall carbon nanotube paste electrode can remarkably enhance electrocatalytic activity toward the oxidation of theophylline in pH 3.0 phosphate buffer solution than the carbon paste electrode. The oxidation of theophylline was observed to be a two-electron process, irreversible with diffusion character. Effects of anodic peak potential (E(p)), anodic peak current (I(p)) and heterogeneous rate constant (k(o)) have been discussed. Under optimal conditions, the anodic peak current was proportional to theophylline concentration in the range of 2.0×10(-6) to 1.5×10(-4)M with a detection limit of 1.97×10(-8)M using differential pulse voltammetry. The proposed method was employed to determine theophylline in pharmaceutical formulations and urine as a real sample., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A simple and rapid electrochemical method was developed for the determination of trace-level trazodone, based on the excellent properties of multi-walled carbon nanotubes (MWCNTs). The MWCNT-modified glassy carbon electrode was constructed and the electrochemical behavior of trazodone was investigated in detail. The cyclic voltammetric results indicate that MWCNT-modified glassy carbon electrode can remarkably enhance electrocatalytic activity towards the oxidation of trazodone in neutral solutions. It leads to a considerable improvement of the anodic peak current for trazodone, and allows the development of a highly sensitive voltammetric sensor for the determination of trazodone. Trazodone could effectively accumulate at this electrode and produce two anodic peaks at about 0.73 V and 1.00 V. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the trazodone determination by differential-pulse voltammetry. Under optimized conditions, the concentration range and detection limit are 0.2-10 microM and 24 nM, respectively for trazodone. The proposed method was successfully applied to trazodone determination in pharmaceutical samples. The analytical performance of this sensor has been evaluated for detection of analyte in urine as a real sample.