Development of High-Performance Ethanol Gas Sensors Based on La2O3 Nanoparticles-Embedded Porous SnO2 Nanofibers

Porous pure SnO2 nanofibers (NFs) and La2O3 nanoparticles (NPs)-embedded porous SnO2 NFs were successfully synthesized via electrospinning followed by calcination. These materials were systematically evaluated as gas-sensing elements in metal-oxide-semiconductor (MOS) sensors. The La2O3 NPs embedded in porous SnO2 NFs demonstrated superior gas-sensing performance compared to pure SnO2 NFs. Specifically, the incorporation of La2O3 resulted in a 12-fold enhancement in gas-sensing response towards ethanol, significantly improving both sensitivity and selectivity by tuning the carrier concentration and modifying oxygen deficiencies and chemisorbed oxygen levels. Thus, La2O3 NPs embedded in SnO2 NFs present a promising strategy for the development of high-performance ethanol gas sensors.

Sea urchin nanostructured nickel cobaltite modified carbon cloth integrated wearable patches for the on-site detection of the immunosuppressant drug mycophenolate mofetil

Mycophenolate mofetil (MpM) is a medication used to prevent the rejection of transplanted organs, particularly in kidney, heart, and liver transplant surgeries. It is extremely important to be conscious that MpM can raise the risk of severe infections and some cancers if it exceeds the recommended dose while lower doses will result in organ rejections. So, it is essential to monitor the dosage of MpM in real time in the micromolar range. In this work, we have synthesized 3-aminopropyltriethoxysilane (APTES) functionalized nickel cobaltite (NiCo2O4) and this amino functionalization was chosen to enhance the stability and electrochemical activity of NiCo2O4. The enhanced activity of NiCo2O4 was used for developing an electrochemical sensor for the detection of MpM. APTES functionalized NiCo2O4 was coated on carbon cloth and used as the working electrode. Surface functionalization with APTES on NiCo2O4 was aimed at augmenting the adsorption/interaction of MpM due to its binding properties. The developed sensor showed a very low detection limit of 1.23 nM with linear ranges of 10-100 nM and 1-100 μM and its practical applicability was examined using artificial samples of blood serum and cerebrospinal fluid, validating its potential application in real-life scenarios.

Green synthesis of Ag2O nanoparticles using Punica granatum leaf extract for sulfamethoxazole antibiotic adsorption: characterization, experimental study, modeling, and DFT calculation

Silver oxide (Ag2O) nanoparticles (NPs) were generated by synthesizing green leaf extract of Punica granatum, and afterwards they were used as adsorbent to remove the antibiotic additive sulfamethoxazole (SMX) from aqueous solutions. Prior of their use as adsorbent, the Ag2O NPs were characterized by various methods such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy/energy-dispersive X-ray (SEM-EDX), and transmission electron microscopy (TEM). The Ag2O NPs were found to be spherically shaped and stabilized by the constituents of the extract. Further, at SMX antibiotic concentration of 100 mg L-1, the Ag2O NPs achieved almost complete removal of 98.93% within 90 min, and by using 0.8 g L-1 of adsorbent dose at pH=4 and temperature T=308 K. In addition, the experimental data were well fitted with the theoretical Langmuir model indicating homogeneous adsorbed layer of the SMX antibiotic on the Ag2O NPs surface. The maximum uptake capacity was 277.85 mg g-1. A good agreement was also found between the kinetic adsorption data and the theoretical pseudo-second-order model. Regarding the thermodynamic adsorption aspects, the data revealed an endothermic nature and confirmed the feasibility and the spontaneity of the adsorption reaction. Furthermore, the regeneration study has shown that the Ag2O NPs could be efficiently reused for up to five cycles. The geometric structures have been optimized and quantum chemical parameters were calculated for the SMX unprotonated (SMX+/-) and protonated (SMX+) using density functional theory (DFT) calculation. The DFT results indicated that the unprotonated SMX+/- reacts more favorably on the Ag2O surface, as compared to the protonated SMX+. The SMX binding mechanism was predominantly controlled by the electrostatic attraction, hydrogen bond, hydrophobic, and π-π interactions. The overall data suggest that the Ag2O NPs have promising potential for antibiotic removal from wastewater.

Determination of chloramphenicol in food using nanomaterial-based electrochemical and optical sensors-A review

Chloramphenicol (CAP) is a widely used antibiotic for the treatment of sick animals owing to its potent action and low cost. However, the accumulation of CAP in the human body can cause irreversible aplastic anemia and hematopoietic toxicity. Accordingly, development of various analytical techniques for the rapid detection of CAP in animal products and the related processed foods is necessary. Among these analytical techniques, electrochemical and optical sensors offer many advantages for CAP detection, including high sensitivity, simple operation and fast analysis speed. In this review, we summarize recent application of carbon nanomaterials, metal nanoparticles, metal oxide nanoparticles and metal organic framework in the development of electrochemical and optical sensors for CAP detection (2010-2022). Based on the advantages and disadvantages of nanomaterials, electrochemical and optical sensors are summarized in this review. The preparation and synthesis of electrochemical and optical sensors and nanomaterials in the field of rapid detection are prospected.

Hollow SnO2/CdS QDs/CdCO3 heterostructured nanocubes coupled with hollow PtPd/MnCo-CeO2 nanozyme-mediated synergistic amplification for ultrasensitive PEC immunoanalysis of lung cancer biomarker

Nowadays, lung cancer is one of the most dangerous cancers threatening human life all over the world. As a crucial biomarker, cytokeratin 19 fragment 21-1 (CYFRA 21-1) is extraordinary important for diagnosis of non-small cell lung cancer (NSCLC). In this work, we synthesized hollow SnO₂/CdS QDs/CdCO₃ heterostructured nanocubes with high and stable photocurrents, which applied to construction of a sandwich-typed photoelectrochemical (PEC) immunosensor for detection of CYFRA 21-1, integrated by in-situ catalytic precipitation strategy with home-built PtPd alloy anchored MnCo-CeO₂ (PtPd/MnCo-CeO₂) nanozyme for synergistic amplification. The interfacial electron transfer mechanism upon visible-light irradiation was investigated in details. Further, the PEC responses were seriously quenched by the specific immunoreaction and precipitation catalyzed by the PtPd/MnCo-CeO₂ nanozyme. The established biosensor showed a wider linear range of 0.001-200 ng mL^-1 and a lower limit of detection (LOD = 0.2 pg mL^-1, S/N = 3), coupled by exploring such analysis even in diluted human serum sample. This work opens a constructive avenue to develop ultrasensitive PEC sensing platforms for detecting diverse cancer biomarkers in clinic.

Healthcare waste in Bangladesh: Current status, the impact of Covid-19 and sustainable management with life cycle and circular economy framework

COVID-19 has accelerated the generation of healthcare (medical) waste throughout the world. Developing countries are the most affected by this hazardous and toxic medical waste due to poor management systems. In recent years, Bangladesh has experienced increasing medical waste generation with estimated growth of 3 % per year. The existing healthcare waste management in Bangladesh is far behind the sustainable waste management concept. To achieve an effective waste management structure, Bangladesh has to implement life cycle assessment (LCA) and circular economy (CE) concepts in this area. However, inadequate data and insufficient research in this field are the primary barriers to the establishment of an efficient medical waste management systen in Bangladesh. This study is introduced as a guidebook containing a comprehensive overview of the medical waste generation scenario, management techniques, Covid-19 impact from treatment to testing and vaccination, and the circular economy concept for sustainable waste management in Bangladesh. The estimated generation of medical waste in Bangladesh without considering the surge due to Covid-19 and other unusual medical emergencies would be approximately 50,000 tons (1.25 kg/bed/day) in 2025, out of which 12,435 tons were predicted to be hazardous waste. However, our calculation estimated that a total of 82,553, 168.4, and 2300 tons of medical waste was generated only from handling of Covid patients, test kits, and vaccination from March 2021 to May 2022. Applicability of existing guidelines, and legislation to handle the current situation and feasibility of LCA on medical waste management system to minimize environmental impact were scrutinized. Incineration with energy recovery and microwave sterilization were found to be the best treatment techniques with minimal environmental impact. A circular economy model with the concept of waste minimizaton, and value recovery was proposed for sustainable medical waste management. This study suggests proper training on healthcare waste management, proposing strict regulations, structured research allocation, and implementation of public-private partnerships to reduce, and control medical waste generation for creating a sustainable medical waste management system in Bangladesh.

Purification and thermodynamic characterization of acid protease with novel properties from Melilotus indicus leaves

A thermostable acid protease from M. indicus leaves was purified 10-fold using a 4-step protocol. We were able to isolate a purified protease fraction with a molecular weight of 50 kDa and exhibited maximal protease activity at pH 4.0 and 40 °C. Structural analysis revealed that the protease is monomeric and non-glycosylated. The addition of epoxy monocarboxylic acid, iodoacetic acid, and dimethyl sulfoxide significantly reduced protease activity while dramatically increasing the inhibition of Mn²⁺, Fe²⁺, and Cu²⁺. The activation energy of the hydrolysis reaction (33.33 kJ mol^-1) and activation energy (E_d = 105 kJ mol^-1), the standard enthalpy variation of reversible protease unfolding (2.58 kJ/mol) were calculated after activity measurements at various temperatures. Thermal inactivation of the pure enzyme followed first-order kinetics. The half-life (t_1/2) of the pure enzyme at 50 °C, 60 °C, and 70 °C was 385, 231, and 154 min, respectively. Thermodynamic parameters (entropy and enthalpy) suggested that the protease was highly thermostable. This is the first report on the thermodynamic parameters of proteases produced by M. indicus. The novel protease appears to be particularly thermostable and may be important for industrial applications based on these thermodynamic properties.

Focus on the crucial deformation region to adjust the comprehensive performance of poly (L-lactic acid) stent

The fully biodegradable polymer stent is considered as the fourth-generation vascular implant with good biocompatibility and long-term therapeutic potential. It has attracted much attention because it overcomes the disadvantage of the permanently implanted metal stent. However, compared with the metal stent, its mechanical properties are slightly inferior, which is an urgent problem. Based on previous studies, fully biodegradable polymer stents are prone to experience cracks and damage in large deformation region during the crimping and expansion process. The large deformation region is mainly located at the ring bend of the stent. We supposed that these damages are the leading causes of weakening the mechanical performance of polymer stents and are mainly affected by the crucial deformation region. For this purpose, this work studies the relationship between different crucial deformation regions and the mechanical performance of the polymer stent. Firstly, the volume of the crucial deformation region is improved by increasing the ring width. Although the radial strength of the stent is enhanced with the increase in ring width, the radial stiffness also increases, and correspondingly, the flexibility of the stent decreases. To obtain acceptable comprehensive mechanical performance, two types of slotting design in critical deformation region were proposed. The proposed slotted stent with a bulge has sufficient radial strength and low radial stiffness, having a good radial support capacity and flexibility. In other words, the proposed stent has improved the radial support without sacrificing flexibility. Overall, different crucial deformation regions cause different degrees of damage to the stent during crimping and expansion, which affects the mechanical properties of the stent. Reasonable structural design of the crucial deformation region is the key to adjust the comprehensive performance of the stent.

Enhanced Adsorption and Evaluation of Tetracycline Removal in an Aquatic System by Modified Silica Nanotubes

In the present study, a nanocomposite adsorbent based on mesoporous silica nanotubes (MSNTs) loaded with 3-aminopropyltriethoxysilane (3-APTES@MSNTs) was synthesized. The nanocomposite was employed as an effective adsorbent for the adsorption of tetracycline (TC) antibiotics from aqueous media. It has an 848.80 mg/g maximal TC adsorption capability. The structure and properties of 3-APTES@MSNT nanoadsorbent were detected by TEM, XRD, SEM, FTIR, and N₂ adsorption-desorption isotherms. The later analysis suggested that the 3-APTES@MSNT nanoadsorbent has abundant surface functional groups, effective pore size distribution, a larger pore volume, and a relatively higher surface area. Furthermore, the influence of key adsorption parameters, including ambient temperature, ionic strength, initial TC concentration, contact time, initial pH, coexisting ions, and adsorbent dosage, had also been investigated. The 3-APTES@MSNT nanoadsorbent's ability to adsorb the TC molecules was found to be more compatible with Langmuir isothermal and pseudo-second-order kinetic models. Moreover, research on temperature profiles pointed to the process' endothermic character. In combination with the characterization findings, it was logically concluded that the 3-APTES@MSNT nanoadsorbent's primary adsorption processes involved interaction, electrostatic interaction, hydrogen bonding interaction, and the pore-fling effect. The synthesized 3-APTES@MSNT nanoadsorbent has an interestingly high recyclability of >84.6 percent up to the fifth cycle. The 3-APTES@MSNT nanoadsorbent, therefore, showed promise for TC removal and environmental cleanup.

Fabrication of chitosan-MnO2‑iridium/nanoceria supported nanoparticles: Catalytic and anti-radical activities

Chitosan capped MnO₂‑iridium nanoparticles supported on nanoceria (Ch-MnO₂-Ir/CeO₂) were fabricated by using combination of colloidal solution and metal displacement galvanic methods. The oxidative degradation of acid orange 7 in aqueous solution by activated persulfate with the as-prepared nanoparticles was studied. The resulting Ch-MnO₂-Ir/CeO₂ with S₂O₈^2-, 80 % degraded 70.06 mg/L of acid orange 7 within 100 min, while at the same time, Ch-Ir, Ch-MnO₂, and Ch-Ir-MnO₂ remained inactive. CeO₂ increased the surface of the catalyst, and also improved the reactive oxygen species site of Ch-Ir-MnO₂ through the activation of S₂O₈^2- with CeO₂. The reversible redox cycle reaction, Ce (III) ↔ Ce (IV) and strong synergistic effect of MnO₂-Ir are responsible for the remarkable catalytic performance of Ch-MnO₂-Ir/CeO₂/S₂O₈^2- system. The degradation of acid orange 7 could be significantly retarded with inorganic (NO₃^- < Cl^- < SO₄^2- < H₂PO₄^- < HCO₃^-) and organic scavengers (ethanol < tertiary butanol < benzoquinone < phenol). Ch-MnO₂-Ir/CeO₂ exhibited excellent stability and reusability. Anti-radical activity of chitosan and Ch-MnO₂-Ir/CeO₂ was evaluated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. The free radical properties increase with concentration of chitosan and Ch-MnO₂-Ir/CeO₂.

Divalent metal ion removal from simulated water using sustainable starch aerogels: Effect of crosslinking agent concentration and sorption conditions

This paper evaluates corn starch aerogels, studying different crosslinking agent (trisodium citrate) concentrations (1:1, 1:1.5, and 1:2) and sorption conditions (contact time, adsorbent weight, and initial concentration) regarding the potentially toxic elements (PTEs) [Cd(II) or Zn(II)] adsorption of the aqueous systems. Besides, other properties of aerogels, such as structural properties, specific surface area, and mechanical performance, were evaluated. For adsorption results, better values were observed in adsorption capacity and efficiency for the initial concentration of 100 ppm. In addition, an adsorption time of 12 h and an adsorbent weight of 3.0 g obtained better results due to the possible balance in this time and the high specific surface area available for Cd(II) adsorption. As for the type of adsorbent, the Aero 1:1.5 sample (intermediate crosslinking agent concentration) obtained better results, possibly due to the high porosity, smaller pore sizes, high pore density, and high specific surface area (198 m²·g^-1). In addition, hydroxyl groups in the starch aerogel removed Cd(II) ions with 30 % adsorption efficiency. Lastly, Aero 1:1.5 obtained a high mechanical strength at compression and a satisfactory compressive modulus. In contrast, starch aerogels did not absorb the Zn(II) ion.

A critical review on pineapple (Ananas comosus) wastes for water treatment, challenges and future prospects towards circular economy

Each year, nearly 30 million tons of pineapple fruit are harvested for food and drinking industries, along with the release of a huge amount of pineapple wastes. Without the proper treatment, pineapple wastes can cause adverse impacts on the environment, calling for new technologies to convert them into valuable products. Here, we review the production and application of adsorbents derived from pineapple wastes. The thermal processing or chemical modification improved the surface chemistry and porosity of these adsorbents. The specific surface areas of the pineapple wastes-based adsorbents were in range from 4.2 to at 522.9 m²·g^-1. Almost adsorption systems followed the pseudo second order kinetic model, and Langmuir isotherm model. The adsorption mechanism was found with the major role of electrostatic attraction, complexation, chelation, and ion exchange. The pineapple wastes based adsorbents could be easily regenerated. We suggest the potential of the pineapple wastes towards circular economy.

A facile method for synthesis rGO/Ag nanocomposite and its uses for enhancing photocatalytic degradation of Congo red dye

The enhancing breakdown of dyes using facile, novel and eco-friendly photocatalyst without remaining any hazards secondary intermediates from the dye species regarded one of the most challenges to the healthy world. A novel facile method was used to synthesize reduced graphene oxide (rGO) with various doping ratios of silver nanoparticles (Ag NPs) and applied as photocatalyst to enhancing removal of Congo red (CR) dye using UV light irradiation from aqueous solution. Some characterization features such as UV-diffuse reflectance spectra, TEM, SEM, FTIR, X-ray diffraction, and EDX were measured to demonstrate the energy gap, morphology, size distribution, crystalline nature, phase structure, and elemental compositions of as-synthesized nanoparticles. The effect of some important factors such as pH of solution, initial CR concertation (Co), amount of rGO@Ag (g) and contact time (t) were studied to detect the optimum adsorption condition. The results indicated that, the maximum CR dye photodegradation is obtained at pH 7, 120 min, 50 mg/L initial CR concentration and 0.4 g/L photocatalyst dosage. The photodegradation data declared that, the higher the Ag doping ratio, the higher the degrading efficiency. Isotherm and kinetic studies showed that Langmuir and Freundlich models and the pseudo-second-order model are well fitting the adsorption process with maximum CR adsorption values ranging between 86.95 and 98.04 mg/L with corresponding R2 > 0.99.

Recent advances in starch-based magnetic adsorbents for the removal of contaminants from wastewater: A review

Considerable concern exists regarding water contamination by various pollutants, such as conventional pollutants (e.g., heavy metals and organics) and emerging micropollutants (e.g., consumer care products and interfering endocrine-related compounds). Currently, academics are continuously exploring sustainability-related materials and technologies to remove contaminants from wastewater. Magnetic starch-based adsorbents (MSAs) can combine the advantages of starch and magnetic nanoparticles, which exhibit unique critical features such as availability, cost-effectiveness, size, shape, crystallinity, magnetic properties, stability, adsorption properties, and excellent surface properties. However, limited reviews on MSAs' preparations, characterizations, applications, and adsorption mechanisms could be available nowadays. Hence, this review not only focuses on their activation and preparation methods, including physical (e.g., mechanical activation treatment, microwave radiation treatment, sonication, and extrusion), chemical (e.g., grafting, cross-linking, oxidation and esterification), and enzymatic modifications to enhance their adsorption properties, but also offers an all-round state-of-the-art analysis of the full range of its characterization methods, the adsorption of various contaminants, and the underlying adsorption mechanisms. Eventually, this review focuses on the recycling and reclamation performance and highlights the main gaps in the areas where further studies are warranted. We hope that this review will spark an interdisciplinary discussion and bring about a revolution in the applications of MSAs.

The Utilization of Modified Zeolite for the Removal of Cs Ions in an Aqueous Solution: Adsorption Capacity, Isotherms, Kinetics and Microscopic Studies

Nuclear energy is a double-edged technology, which has a significant role in the chemical industry, but may bring about radioactivity and destruction. The 2011 Fukushima nuclear power plant accident caused by a tsunami, which flooded and led to tens of millions of disaster debris and tsunami deposits, severely disrupted the electricity supply in Japan and induced USD 211 billion worth of direct economic losses. Cs+ was easily dissolved in this accident, had a high chemical activity, and thus required an appropriate adsorption method. Zeolite is an effective removal adsorbent, which is suitable to be investigated. The present study uses natural zeolite and three inorganic modified zeolites. Furthermore, the effects of various factors are investigated. Kinetic models and the isothermal adsorption mechanism are also conducted. For microscale studies for the adsorption mechanism, scanning electron microscope (SEM) and X-ray diffraction (XRD) were involved in the study. The results indicate that the optimal dosage is 1.1 g and the maximum adsorption rate is around 80%. An alkaline environment is more conducive to the occurrence of adsorption. As for the isotherm and kinetic studies, the data fits better with the Redlich–Peterson isothermal model and intragranular diffusion model. In this small-scale experiment, the highest adsorption capacity was for Mg-zeolite at 6.53 mg/g. Finally, Mg-Zeolite presents the best adsorption capacity.

Pseudoionone synthesis from citral and acetone in a fixed bed catalytic reactor with lanthanum modified calcium oxide

The industrial process of pseudoionone synthesis from citral uses a homogeneous catalyst with excessive acetone as a solvent-cum reactant in a stirred tank batch reactor which needs to be replaced by a better heterogeneously catalyzed, solventless, and ecofriendly flow process as shown by the current work.

Enhanced acetic acid sensing of MOF-derived α-Fe2O3/ZrO2 arising from phase junction and defects

The coexistence of phase junction, heterojunction and defects allows α-Fe2O3/ZrO2 to display an significant response towards acetic acid.

Functionalized layered double hydroxides composite bio-adsorbent for efficient copper(II) ion encapsulation from wastewater

In this study, naturally abundant and inexpensive bamboo was used to make cheaper activated charcoal for efficient encapsulation of toxic copper (Cu(II)) ion from wastewater. The functionalized bamboo charcoal-Layered double hydroxides (BC-LDHs) composite bio-adsorbent was prepared using co-precipitation method. The composite bio-adsorbent was exploited to eliminate Cu(II) ion with high sensitivity and selectivity from contaminated water. The adsorption parameters including the effect of pH, contact time, adsorbent dose, and effect of initial concentration were optimized in systematic way and the adsorption kinetics and isotherms were investigated for potential use in real sample treatment. The physicochemical properties and morphological structure of the adsorbent were examined using X-ray Diffraction, Scanning Electronic Microscopy, Fourier Transform Infrared Spectroscopy and Thermogravimetric Analysis to understand the Cu(II) ion adsorption mechanism. The adsorption results revealed that the BC-LDH could remove almost 100% of Cu(II) ion from aqueous solution at pH range between 3.0 and 6.0 within 30 min. The maximum monolayer adsorption capacity was determined to be 85.47 mg/g based on the Langmuir isotherm. The adsorption equilibrium data were well-fitted by the Langmuir isotherm model (R² = 0.998) and the experimental kinetic data were supported by the pseudo-second order model (R² = 0.999). The BC-LDH could be reused without losing its adsorption performance in several cycles after successful regeneration with 0.10 M HCl. The Cu(II) ion removal mechanism was postulated with intercalated ion exchange, surface precipitation and interaction between BC-LDH and surface functionalities. Therefore, the highly functional BC-LDH composite could be a promising adsorbent for efficient Cu(II) ion removal from wastewater.

Fabrication of stable electrospun blended chitosan-poly(vinyl alcohol) nanofibers for designing naked-eye colorimetric glucose biosensor based on GOx/HRP

In this study, designing of a stable electrospun blended chitosan (CS)-poly(vinyl alcohol) (PVA) nanofibers for colorimetric glucose biosensing in an aqueous medium was investigated. CS and PVA solutions were blended to acquire an optimum content (CS/PVA:1/4) and electrospunned to obtain uniform and bead-free CS/PVA nanofiber structures following the optimization of the electrospinning parameters (33 kV, 20 cm, and 1.2 ml.h^-1). Crosslinking process applied subsequently provided mechanically and chemically stable nanofibers with an average diameter of 378 nm. The morphological homogeneity, high fluid absorption ability (>%50), thermal (<230 °C) and morphological stability, surface hydrophilicity and degrability properties of cross-linked CS/PVA nanofiber demonstrated their great potential to be developed as an eye-readable strip for biosensing applications. The glucose oxidase (GOx) and horseradish peroxidase (HRP) was immobilized by physical adsorption on the cross-linked CS/PVA nanofiber. The glucose assay analysis by ultraviolet-visible (UV-Vis) spectrophotometry using the same enzymatic system of the proposed glucose strips in form of absorbance versus concentration plot was found to be linear over a glucose concentration range of 2.7 to 13.8 mM. The prepared naked eye colorimetric glucose detection strips, with lower detection limit of 2.7 mM, demonstrated dramatic color change from white (0 mM) to brownish-orange (13.8 mM). The developed cross-linked CS/PVA nanofiber strips, prepared by electrospinnig procedure, could be easily adapted to a color map, as an alternative material for glucose sensing. Design of a practical, low-cost, and environmental-friendly bio-based CS/PVA testing strips for eye readable detection were presented and suggested as an applicable medium for a wide range of glucose concentrations.

Photocatalytic performance, anti-bacterial activities and 3-chlorophenol sensor fabrication using MnAl2O4·ZnAl2O4 nanomaterials

A MnAl₂O₄·ZnAl₂O₄ nanomaterial was synthesized by co-precipitation and characterized by XRD, SEM, EDS, TEM, AFM, FTIR, PL, CV and EIS. The photocatalytic activity of the nanocomposite against MV dye and its MDR anti-bacterial functions were studied. The nanocomposite shows excellent photocatalytic as well as anti-bacterial activity. A MnAl₂O₄·ZnAl₂O₄ nanomaterial/Nafion/GCE electrode was fabricated and implemented as the working electrode of a 3-CP sensor. The sensor exhibited good sensitivity, with the lowest detection limit, fast response time, large linear dynamic range (LDR), and long-term stability in the chemical environment. The estimated sensitivity is 70.07 μA mM^-1 cm^-2. The LDR, limit of detection (LOD), and limit of quantification (LOQ) are 0.1 nM to 0.01 M, 0.0014 ± 0.0001 nM, and 0.004 nM, respectively. The MnAl₂O₄·ZnAl₂O₄ nanomaterial/Nafion/GCE is a promising fabricated sensor probe for the selective detection of 3-CP for the environmental safety and healthcare fields on a large scale.

Bioremediation of heavy metals from wastewater: a current perspective on microalgae-based future

Heavy metals-containing drinking water and wastewater are posing a severe threat to the environment, and living beings on land, air and water. Different conventional, advanced nanomaterials-based and biological method has been employed for the treatment of heavy metals. Among the biological methods, microalgae are an important group of micro-organisms that have numerous environmental applications and can remediate heavy metals from wastewater. Also, it has numerous advantages over conventional remediation processes. Microalgae cells can uptake the heavy metal via different physiological and biological methods and are utilized as a nutrient source to regulate its metabolic process for the production of biomass. Furthermore, the enhancement in heavy metal removal efficiency can be improved using different strategies such as immobilization of algal cells, development of algal consortia and designing of microalgae-based nanocomposite materials. Also, it can significantly contribute towards environmental sustainability and future. Thus, the review provides a critical overview of heavy metals and their existence along with their negative effects on humans. This review provides insight on recent advanced nanomaterial approaches for the removal of heavy metals, overviews of microalgae-based heavy metal uptake mechanisms and their potential for the amputation of different heavy metals. Furthermore, the special focus is on recent strategies that enhance heavy metal removal efficiency and contribute towards sustainability for the development of a microalgae-based future.

Novel micro-structured carbon-based adsorbents for notorious arsenic removal from wastewater

The contamination of groundwater by arsenic (As) in Bangladesh is the biggest impairing of a population, with a large number of peoples affected. Specifically, groundwater of Gangetic Delta is alarmingly contaminated with arsenic. Similar, perilous circumstances exist in many other countries and consequently, there is a dire need to develop cost-effective decentralized filtration unit utilizing low-cost adsorbents for eliminating arsenic from water. Morphological synthesis of carbon with unique spherical, nanorod, and massive nanostructures were achieved by solvothermal method. Owing to their intrinsic adsorption properties and different nanostructures, these nanostructures were employed as adsorption of arsenic in aqueous solution, with the purpose to better understanding the morphological effect in adsorption. It clearly demonstrated that carbon with nanorods morphology exhibited an excellent adsorption activity of arsenite (about 82%) at pH 3, remarkably superior to the two with solid sphere and massive microstructures, because of its larger specific surface area, enhanced acid strength and improved adsorption capacity. Furthermore, we discovered that iron hydroxide radicals and energy-induced contact point formation in nanorods are the responsible for the high adsorption of As in aqueous solution. Thus, our work provides insides into the microstructure-dependent capability of different carbon for As adsorption applications.

Assessing of cesium removal from wastewater using functionalized wood cellulosic adsorbent

Sustainable materials are urgently desired for treatment of radioactive cesium (Cs) contaminated water to safe-guard the public health. Apart from the synthetic ligand-based materials, the Mangrove charcoal modified adsorbent was fabricated for assessing of Cs removal from waste sample. The raw charcoal was oxidized using nitrification approach and diverse oxygen containing carboxyl, carbonyl and hydroxyl functional groups were introduced. After modification, the adsorbent characteristics were drastically changed as compared to the charcoal during the measurement of FTIR, N₂ adsorption-desorption isotherms and SEM micrographs. The data clarified that charcoal modified adsorbent was exhibited high Cs transport through the inner surface of the adsorbent based on bonding ability. The adsorbent was shown comparatively slow kinetics to Cs ion; however, the adsorption capacity was high as 133.54 mg/g, which was higher than the crown ether based conjugate materials. The adsorption data were followed to the Langmuir adsorption isotherms and the monolayer coverage was possible due to the data presentation. The presence of high amount of Na and K were slightly interfered to the Cs adsorption by the charcoal modified adsorbent, however; the Na and K concentration was 350-600 folds higher than the Cs concentration. Then the proposed adsorbent was selective to Cs for the potential real radioactive Cs contaminated water. The volume reduction was established rather than desorption and reuses advantages. More than 99% volume reduction was measured by burning of Cs adsorbed adsorbent at 500 °C for ensuring the safe storage and disposal of used adsorbent. Therefore, the charcoal modified adsorbent may open the new door to treat the Cs containing wastewater.

Potential applications of halophilic microorganisms for biological treatment of industrial process brines contaminated with aromatics

Saline wastewater contaminated with aromatic compounds can be frequently found in various industrial sectors. Those compounds need to be degraded before reuse of wastewater in other process steps or release to the environment. Halophiles have been reported to efficiently degrade aromatics, but their application to treat industrial wastewater is rare. Halophilic processes for industrial wastewater treatment need to satisfy certain requirements: a continuous process mode, low operational expenditures, suitable reactor systems and a monitoring and control strategy. The aim of this review is to provide an overview of halophilic microorganisms, principles of aromatic biodegradation, and sources of saline wastewater containing aromatics and other contaminants. Finally, process examples for halophilic wastewater treatment and potential process monitoring strategies are discussed. To further illustrate the significant potential of halophiles for saline wastewater treatment and to facilitate development of ready-to-implement processes, future research should focus on scale-up and innovative process monitoring and control strategies.