Drought, salt, heat, cold, flooding, and heavy metal toxicity are examples of abiotic stresses that drastically lower crop output by interfering with photosynthesis, nutrient uptake, water balance, and cellular homeostasis. Global food security thus depends on the development of sustainable methods to improve crop resilience. Because of their great biocompatibility, customisable surface chemistry, superior optical qualities, minimal toxicity, and environmental friendliness, carbon dots (CDs), a family of carbon-based nanomaterials, have become potential prospects for agricultural applications. The present work provides a complete summary of current developments in the use of CDs to increase plant resistance to abiotic stressors. Improved light harvesting and electron transfer, protection of chloroplast integrity, regulation of reactive oxygen species (ROS) homeostasis, activation of antioxidant defense systems, improved nutrient assimilation, maintenance of ion and water homeostasis, and modulation of stress-responsive gene expression are some of the underlying mechanisms. In addition, the review compares the common and stress-specific mechanisms of CD-mediated stress tolerance across different abiotic stresses and discusses how physicochemical properties, including particle size, surface functionalisation, and heteroatom doping, influence their biological performance. Recent breakthroughs in green synthesis, biomass-derived precursors, scalable production methodologies, and agricultural applications are also discussed. Furthermore, current challenges associated with field-scale validation, environmental fate, ecotoxicological safety, bioaccumulation, and regulatory considerations are critically discussed to provide a balanced perspective. Overall, this review provides updated mechanistic insights and future research priorities for the safe and sustainable application of carbon dots as next-generation nanomaterials for developing climate-resilient and sustainable agricultural systems.
A simple hydrothermal technique was established to synthesize carbon dots (CDs) from the peel of Garcinia indica (GI). The as-developed GI-CDs results in an emission peak at 431 nm with fluorescence quantum yield of 37.21%. Blue fluorescent GI-CDs were highly effective in detecting periodate ions (IO4−), as their fluorescence significantly decreased with the addition of IO4− via fluorescence quenching. The synthesized GI-CDs demonstrated impressive sensitivity, with a detection limit as low as 16.33 nM, and maintained a clear linear response across a wide concentration range (0.05–50 μM). This probe also proved to be stable under different pH conditions and over extended periods. When tested with real water samples, this method showed high accuracy and reliability, achieving recoveries of 98.97–99.47% for river water samples, 98.01–99.76% for tap water samples, 99.19–99.45% for canal water samples, and 98.11–99.79% for industrial water samples, with relative standard deviation of <2%. Overall, this approach presents a sustainable and cost-effective way to monitor IO4− in environmental settings using plant-based nanomaterials.
In this study, we report the synthesis and environmental safety profiles of Co/Cu co-doped ZnO nanoparticles (NPs) synthesized by sol-gel auto-combustion route. Structural and morphological studies showed the formation of highly crystalline NPs, where the particle size was increased by co-doping. BET textural characterization indicated a reduction in specific surface area from 5.53 to 2.58 m2/g, implying a transition to a coarsened macroporous structure. To demonstrate the selective cytotoxicity as a model for health impact in humans, a comparative biological evaluation was made. Pristine and 1.0% co-doped ZnO samples showed the maximum cytotoxic activity against HCT-116 cell lines with IC50 values of 18.25 ± 3.25 μg/mL and 31.22 ± 2.15 μg/mL for pristine and 1.0% samples, respectively. Nevertheless, they are still less toxic to non-cancerous HEK-293 cells. DAPI fluorescence imaging revealed chromatin fragmentation and apoptotic bodies in the human cell lines, which suggests differential cellular sensitivity. In contrast, different NPs were tested on wheat (Triticum aestivum L.) seedlings and displayed a biphasic response with growth stimulation at lower co-doping ratios (x ≤ 0.50%) and severe growth inhibition, root morphological changes and perturbation of photosynthetic parameters at higher co-doping ratios (x ≥ 0.75%). Although these systems are promising for selective biological-targeting and plant growth-promoting activities, the possible environmental hazard, especially at the higher ratios, needs further consideration for safety management and balance before real agricultural or industrial application.
Per- and polyfluoroalkyl substances (PFAS), particularly perfluorooctanoic acid (PFOA), are persistent environmental contaminants that pose significant risks to ecosystems and human health due to their widespread occurrence, chemical stability, and bioaccumulative nature. Conventional analytical methods for PFOA determination are often expensive, labor-intensive, and unsuitable for rapid on-site monitoring. In this study, a novel Cu@rGO/Nb2O5 nanohybrid-based electrochemical sensor was developed for the sensitive and selective detection of PFOA in environmental water samples. The nanohybrid was synthesized through a controlled multistep chemical approach and comprehensively characterized using UV–Visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Electrochemical performance was evaluated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and electrochemically active surface area (ECSA) measurements. The Cu@rGO/Nb2O5-modified electrode exhibited enhanced electrocatalytic activity, reduced charge-transfer resistance, and accelerated electron-transfer kinetics compared with the bare glassy carbon electrode. The sensing mechanism is primarily attributed to the synergistic effects of Cu nanoparticles, reduced graphene oxide, and Nb2O5, which facilitate PFOA adsorption through π-π interactions and promote efficient charge transfer. Under optimized conditions (pH 7.2, 0.1 M PBS), the sensor demonstrated a linear detection range of 10–50 μM, an LOD of 131 nM, and a sensitivity of 1.377 × 10−5 mA/(nM·mm2), with excellent reproducibility (RSD ≤ 1.67%, n = 5) and outstanding selectivity in the presence of common interfering species. Furthermore, successful application in river water, tap, ground, lake and wastewater samples yielded satisfactory recovery values, confirming its practical applicability in complex environmental matrices. These findings highlight the potential of the Cu@rGO/Nb2O5 nanohybrid as a promising platform for rapid, cost-effective, and reliable electrochemical monitoring of PFOA contamination in aquatic environments.
The development of multifunctional nanocomposites with enhanced environmental and biomedical performance remains a significant challenge in nanotechnology. In the present study, a clay-assisted dysprosium orthoferrite nanocomposite (CDFO) was successfully synthesized through a combined solution combustion (SCM) and reflux method for multifunctional environmental and biomedical applications. The structural, morphological, and optical properties were investigated using XRD, FTIR, Raman, UV–Vis, PL, SEM, TEM, EIS, EDS, and transient photocurrent analyses. XRD confirmed the formation of orthorhombic DyFeO₃ (DFO), while SEM revealed average particle sizes of 35.32 nm (DFO) and 29.82 nm (CDFO). UV–Vis and Tauc's plot analysis showed reduced band gap energies from 1.81 eV (DFO) to 1.69 eV (CDFO), indicating enhanced charge transfer and light absorption. The CDFO exhibited superior photocatalytic degradation of Congo red (CR) dye (88.78%) within 120 min, with a higher kinetic rate constant (0.01823 min−1) and ~ 78% TOC removal. Radical scavenging analysis confirmed h+ as the dominant reactive species. Furthermore, CDFO demonstrated enhanced DPPH antioxidant activity (IC₅₀ = 405.36 μg/mL) and excellent antibacterial activity against B. subtilis (19 ± 0.2 mm) and E. coli (24 ± 0.2 mm) at 50 μg/mL. DNA fragmentation studies further confirmed increased bacterial DNA damage induced by CDFO. The enhanced multifunctional performance is attributed to improved charge separation, increased active sites, and reactive oxygen species (ROS) generation, highlighting the promising potential of CDFO for wastewater remediation and antimicrobial applications.
In the era of advanced industry, continuous flow chemistry with catalysis is seen as a clean technology that boosts efficiency and supports sustainability. To combat this situation, the catalytically active high flux nanoparticles (NPs) illuminated nanocellulose (NC) based free-standing membranes were fabricated via mussel-inspired polymer (MIP) chemistry and a facile vacuum filtration method. In this study, spherical silver and gold NPs were uniformly decorated onto synthesized NC via in-situ reduction of metal salts, utilizing the active functional groups of poly(dopamine) and poly(norepinephrine) MIPs derived from mussel- adhesive proteins. The resulting NC derived materials were then used to fabricate advanced membranes exhibiting both high catalytic activity and excellent water permeability, demonstrating their potential for efficient and multifunctional filtration applications. The catalytic performance of the synthesized materials and corresponding membranes was evaluated under both batch and dynamic conditions using the model reduction reaction of 4-nitrophenol (4-NP). The silver NPs decorated poly(norepinephrine) modified NC (NC-PNE-AgNPs) showed high catalytic activity in batch mode, exhibiting a mass-normalized turnover frequency (TOF) value of 1.53 × 1018 molecules g−1 min−1 and the corresponding membranes based on this also demonstrated high activity in flow mode, completing the catalytic conversion after 5 cycles. For understanding the transport properties during industrial performance, the water permeation behavior of the fabricated catalytic membrane was also investigated under different pressures ranging from 0.25 bar to 0.90 bar, and it was found that NPs decorated modified membranes exhibit almost similar behavior in water permeation with a minute difference, but the permeability is less than pure NC. In addition, a minute reduction in catalytic activity in batch mode after five cycles for all NPs decorated NC based materials demonstrated strong bonding interactions between NC and NPs through functional groups of MIPs. Due to their strong catalytic and water permeation properties, these membranes are promising for industrial catalytic converters.
Cadmium contamination in drinking water poses serious health risks due to its bioaccumulation and nephrotoxicity, while conventional detection methods are often too complex and costly for routine field use in resource-limited settings. This study reports a paper-based colorimetric sensor using L-cysteine-functionalized silver nanoparticles (AgNPs-LC) for rapid Cd(II) detection. The sensor achieved a UV–Vis detection limit of 2.70 ppb, below the WHO drinking-water guideline of 3 ppb. A naked-eye detection threshold of approximately 10 ppb further supports its utility for rapid preliminary screening of elevated Cd(II) levels. Good selectivity was observed against tested environmentally relevant ions, including As(III), Sn(II), Hg(II), Fe(III), Pb(II), Cu(II), Na(I), Mg(II), Zn(II), Cr(III), and Co(II). Cd(II) binding triggered nanoparticle aggregation, producing a surface plasmon resonance red shift from 424 to 446 nm and a visible color change from reddish-brown to mauve. Density functional theory calculations at the B3LYP/LANL2DZ level confirmed preferential Cd(II) coordination with L-cysteine, revealing bond-length variations and charge redistribution consistent with the experimental observations. The AgNPs-LC ink displayed near-Newtonian viscosity (∼6.08 cP) and rapid wetting on cellulose substrates, with the contact angle decreasing from 29.1° to 0° within 300 ms, demonstrating compatibility with controlled paper deposition and potentially scalable printing methods. Spike-and-recovery experiments in municipal tap, borewell, and open well water showed excellent accuracy, with recoveries of 98.5–103.4% and relative standard deviations below 0.77%. Additionally, a support vector classifier trained on histogram-based color features attained an F1-score of up to 97% for binary classification of Cd(II) presence. Overall, this work establishes a promising foundation for accessible, decentralized Cd(II) screening in resource-limited environments.
The rising global population is substantially increasing the demand for food, exerting pressure on crop production systems to sustain and enhance yields. Environmental stresses including - salinity, drought, heavy metals, and diseases cause significant loss of yield by damaging physiological processes like photosynthesis, nutrient and water absorption, and osmotic adjustment. Stress induces oxidative damage through the production of reactive oxygen species (ROS), which inhibits growth and reduces productivity. Plants possess defense mechanisms, yet these are usually insufficient against severe stress. Conventional mitigation methods, such as selective breeding and chemical fertilizers, are limited in their efficacy, flexibility, and environmental acceptability. Nanotechnology is a potential solution to overcome these constraints. Zinc oxide nanoparticles (ZnO NPs) have the dual benefit of supplying essential zinc micronutrients and inducing plant defense by improved nutrient absorption and activation of antioxidant defense mechanisms. Furthermore, advancements in nanoparticle technology, including surface functionalization with chitosan, phytohormones (abscisic acid, kinetin, and melatonin), compatible solutes (proline and glycine betaine), arbuscular mycorrhizal fungi, Bacillus species, and plant extracts; element doping with Fe, Ni, and other micronutrients; and encapsulation using polymeric matrices, silica, mesoporous carriers, and urea coatings, make ZnO NPs more efficient under environmental stress than unmodified forms. These nano-biostimulants (i) enhance uptake and translocation of Zn and co-supplied nutrients, (ii) strongly activate antioxidant and osmolyte-based defenses, and (iii) improve ion homeostasis and membrane stability across salinity, drought, heavy metal, and disease stresses. Interdisciplinary research is required to refine field performance, biosafety, and regulatory acceptance of these nano-biostimulants for sustainable crop protection.
The high rate of industrialization and urbanization has resulted into massive release of toxic organic pollutants like synthetic dyes and pharmaceutical remnants into water bodies leading to great threats to the ecosystem and to human life. In this work, fabrication of visible-light-active BiFe2O4-based nanocomposites was employed to the degradation of Indigo Carmine (IC) dye and Tetracycline (TC). A hydrothermal process was used to synthesize pristine BiFe2O4 (BF) and its hybrids with graphitic carbon nitride (g-C3N4) and reduced graphene oxide (rGO). The synthesized materials were systematically characterized using XRD, FTIR, XPS, SEM, EDS, HRTEM, UV–Vis DRS and PL to investigate their structural, morphological, elemental, and optical properties. Among the prepared photocatalysts, the ternary BiFe2O4/g-C3N4/rGO (BFGR) hybrid showed an improved visible-light absorption, charge separation, and reduction of the electron-hole recombination due to strong interfacial interactions between the constituent phases. Photocatalytic experiments with the use of the UVA light indicated that the BFGR hybrid achieved superior degradation efficiencies of 89.2% for IC and 83.3% for TC within 100 min. The degradation process followed pseudo-first-order reaction kinetics, with apparent rate constants of 0.0216 min−1 for IC and 0.0178 min−1 for TC, which are significantly higher than those of pristine BF and other binary hybrids. Furthermore, the BFGR photocatalyst exhibited excellent stability and reusability, maintaining high degradation performance over five successive cycles with only a slight decrease in activity. Additionally, exceptional ultraviolet light photocatalytic antibacterial efficacy was also perceived by BFGR nanocomposite against E. faecalis and S. aureus bacteria.
This study reports the green synthesis of graphene oxide (GO) modified bismuth oxide (Bi2O3) nanocomposite (GO@Bi2O3) utilizing fresh leaves of Chenopodium album as a sustainable reducing agent. The nanocomposites were designed to integrate the extensive surface area of GO with the inherent catalytic and magnetic properties of Bi2O3, creating a synergistic material system. Comprehensive characterization using XRD, SEM, EDAX, UV–Vis spectroscopy, BET surface area analysis, cyclic voltammetry, and photoluminescence (PL) spectroscopy revealed significant structural and electronic modifications. Key findings include altered crystalline structure, reduced band gap energy, the presence of surface defects, an increased specific surface area, and critically, enhanced charge separation efficiency. The incorporation of GO was pivotal in augmenting the surface area and facilitating these beneficial modifications. These combined properties significantly improve the material’s capability for effective light absorption and effective separation/transmission of photogenerated charge pairs. Consequently, GO@Bi2O3 nanocomposites demonstrate highly enhanced photocatalytic performance. Furthermore, the electrochemical characterization indicates their potential suitability for electrochemical applications. The efficacious green synthesis path and subsequent collaborative enrichments underscore the competence of these GO@Bi2O3 nanocomposites as efficient, eco-friendly materials for environmental applications (photocatalysis) as well as energy-related (electrochemical) technologies.
The increasing prevalence of herbicide-resistant weeds necessitates the development of sustainable and efficient weed management strategies. In this study, we investigated the synergistic integration of allelopathy and green nanotechnology by synthesizing silver nanoparticles (AgNPs) using leaf extract of Cleome viscosa and evaluating their bioherbicidal potential against Phalaris minor. The phytochemicals present in the extract served as both reducing and stabilizing agents during nanoparticle synthesis. The biosynthesized AgNPs (Cv-AgNPs) were characterized using UV–vis spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM), confirming the formation of stable, spherical nanoparticles with an average size of 13.2 nm and a zeta potential of −13.8 mV. Comparative bioassays under in vitro (Petri plate) and in vivo (pot) conditions at varying concentrations (0.5%, 1%, 2%, and 4%) revealed that both LAE and Cv-AgNPs treatments significantly inhibited seed germination, seedling vigor index, allelopathy index, seedling growth, physiological, and biochemical parameters in a concentration-dependent manner. Maximum inhibitory effects were observed at 4% concentration, where LAE and Cv-AgNPs reduced germination by 61.29% and 74.28%, root length by 67.74% and 78.49%, and chlorophyll content by 63.74% and 73.61%, respectively. In contrast, antioxidant enzyme activities including CAT and SOD increased by 54.93% and 59.76% under 4% LAE treatment, and by 89.25% and 86.68% under 4% Cv-AgNP treatment. Furthermore, the treatments altered cell viability and induced structural changes in stomatal morphology. Overall, Cv-AgNPs exhibited stronger inhibitory effect and enhanced bioherbicidal efficacy than LAE, which may be attributed to the enhanced stability, bioavailability, and cellular penetration of allelochemicals via nanoscale delivery. These findings show that green-synthesized AgNPs can enhance allelopathic interactions and represent a promising, environmentally friendly alternative for future weed management.
Magnetic nanocomposites were synthesized by incorporating iron oxides into a lignocellulosic matrix derived from sunflower husks, an abundant agricultural residue. The synthesis was carried out by a simple coprecipitation process to obtain magnetically separable nanocomposites intended for sustainable water purification. Structural and spectroscopic analyses indicated the successful functionalization of biomass with iron oxides, with magnetite as the predominant phase. The adsorption performance was evaluated using two contaminants of contrasting chemical nature: lead (Pb2+) and arsenic (As) species. Results showed that iron oxides modulate the adsorptive behavior of the biomass rather than consistently enhancing it. While Pb2+ uptake decreased due to partial masking of organic binding sites, the Fe-based hydroxyls introduced selective affinity toward oxoanionic species. In natural water assays, the nanocomposite effectively reduced As concentrations to below the WHO drinking water limit (0.01 mg L-1) without pH adjustment. Although no iron leaching was detected, stability studies over consecutive cycles revealed a gradual release of biomass-derived organic carbon. These findings demonstrate that while iron oxide incorporation successfully tailors surface chemistry and magnetic separation, the chemical integrity of the organic support remains a key factor for long-term applications. This study provides a realistic evaluation of biomass-based nanocomposites, highlighting their potential and the necessary optimizations for the treatment of drinking water sources.
Conventional herbicide use has intensified concerns about runoff, soil and water contamination, herbicide resistance, and non-target ecological impacts. Nano-enabled herbicide systems offer a promising alternative by improving delivery efficiency, reducing application dose, and potentially limiting environmental losses in agroecosystems. However, most evidence remains laboratory-based, and real-world performance under field conditions is still insufficiently established. This review critically examines recent progress in green nanoherbicides derived from plant extracts, microorganisms, and lignocellulosic agricultural waste, with emphasis on their potential to support sustainable weed management and environmental protection. Biogenic, microwave-assisted, and lignocellulosic synthesis routes are compared in terms of sustainability, scalability, reproducibility, and process limitations. The review also discusses coating strategies, controlled release, targeted delivery, and interactions with soil and water systems, alongside current evidence on toxicity, biodegradability, and environmental fate. Although green nanoherbicide systems may reduce agrochemical inputs and off-target dispersion, their translation remains constrained by variability in synthesis, incomplete ecotoxicological assessment, limited field-scale validation, regulatory uncertainty, and techno-economic barriers. Future development should prioritize safe-by-design formulations, standardized risk evaluation, lifecycle assessment, and policy-aligned deployment frameworks. By integrating synthesis, delivery, environmental fate, and translational considerations, this review aims to clarify the opportunities and constraints of green nanoherbicides and identify priorities for responsible advancement in sustainable agriculture.
In this work, a chitosan/silica aerogel (Cs/SA) composite was developed as an effective electrode modifier for the electrochemical detection of thiomersal (THM). Comprehensive characterization confirmed the formation of an amorphous porous composite with homogeneous dispersion of chitosan within the silica aerogel network. After modification, the BET surface area decreased from 267.09 to 158.54 m2/g, indicating partial pore occupation by chitosan while preserving the mesoporous structure. Electrochemical investigations demonstrated a significant enhancement in interfacial charge-transfer properties, with the charge-transfer resistance (Rct) decreasing from 648.5 to 312.1 Ω and the electrochemically active surface area increasing from 0.078 to 0.122 cm2. Under optimized square-wave voltammetry conditions (Britton-Robinson buffer pH 2.5, deposition potential −1.2 V, deposition time 45 s, and Cs/SA coating volume 4 μL), the Cs/SA/GCE sensor exhibited a wide linear response range of 1–160 μM, a low limit of detection of 0.071 μM, and a limit of quantification of 0.238 μM, with good repeatability (RSD 2.12 %). The sensing mechanism involves protonation-induced cleavage of THM to generate electroactive thiosalicylic acid (TSA), which is subsequently oxidized on the electrode surface. The Cs/SA composite enhances the response by promoting TSA adsorption and accelerating electron transfer, leading to improved sensitivity and selectivity. In addition, the sensor was successfully applied to THM determination in commercial vaccines and ophthalmic solutions, yielding recoveries of 92.75–101.36 %. These results highlight the Cs/SA/GCE derived from rice husk silica aerogel as a promising platform for sensitive and selective electrochemical sensing of organic mercury compounds.
Natural rubber-laden wastewater is characterized by elevated concentrations of persistent pollutants are highly resistant to conventional treatment processes. In this study, a ternary Bi2WO6 mediated CeO2/MoS2 (Bi2WO6@CeO2/MoS2) photocatalyst was rationally designed and optimized to integrate adsorption with visible-light-driven photocatalysis. D-optimal mixture experimental design was employed to simultaneously optimize COD, NH3-N, and material cost. The optimal composition (0.1:0.5:0.4 mass fraction) achieved a desirability of 0.951, yielding predicted removal efficiencies of 59.78% for COD and 64.66% for NH3-N at a low cost of 0.1702 USD/g, which were experimentally validated within the 95% prediction intervals. The ternary composite consistently outperformed the pristine Bi2WO6, CeO2, and MoS2 components, achieving maximal NH3-N removal under a reaction time of 150 min, catalyst loading of 0.2 g, and temperature of 75 °C. Adsorption isotherm analysis indicated that COD and NH3-N removal conformed to the Freundlich model, reflecting heterogeneous surface interactions appropriate for multicomponent wastewater matrices. Kinetic studies revealed that the pseudo-second-order model, confirming chemisorption as the dominant mechanism, while thermodynamic analysis demonstrated that the process was spontaneous and endothermic, with elevated temperatures enhancing pollutant–catalyst interactions. Radical scavenging experiments identified superoxide radicals (•O2−) as the primary reactive species. This hierarchy provides strong evidence for a Z-scheme-mediated charge transfer pathway, which suppresses electron-hole recombination while maintaining high redox potential. The photocatalyst retained over 85% of its activity after five consecutive cycles, underscoring its stability and practical potential for the treatment of high-strength natural rubber-laden wastewater containing persistent pollutants.
The increasing abundance of nanoparticles (NPs) and microplastics (MPs) in terrestrial environments has introduced a complex and largely unregulated category of stressors for plant systems. Here, we consolidate current evidence regarding the pathways by which NPs/MPs enter plants, their movement intracellularly, as well as their accumulation and persistence within plant tissues, thereby interfering with physiological processes and the stability of cellular molecules. Through the integration of genomics, epigenomics, transcriptomics, and metabolomics tools, nanotoxicology can aid in identifying how NPs and MPs interfere with plant regulatory processes prior to producing any observable signs of toxicity. The ‘Omics trinity’ bridges the gap between particle exposure and compromised plant health in nanotoxicomics. Recent studies suggest that NPs and MPs, apart from acting as physical stressors, also function in molecular interruptions, suppressing the vital DNA repair machineries, driving epigenetic hypermethylation, and contributing co-pollutant influx through ‘Trojan Horse’ effect. This review encompasses how these ultra-microscopic contaminants harness a ‘top down’ reprogramming of plant machinery that further threatens the transgenerational fitness and agricultural resilience. It provides an up-to-date understanding of known mechanisms involved in root and leaf uptake, movement among tissues, subcellular location, and barriers to uptake that are specific to plants, as well as incorporating findings from recent genomics, epigenomics, transcriptomics and metabolomics studies.
The widespread use of Bisphenol S (BPS) and its potential to disrupt endocrine systems necessitate the development of sensitive, reliable monitoring tools for environmental safety. In this study, we report a high-performance electrochemical sensor developed by modifying a glassy carbon electrode (GCE) with a composite of carboxylated multiwalled carbon nanotubes (MWCNT-COOH) and platinum nanoparticles (PtNPs). Through a facile drop-casting approach and systematic optimization of the MWCNT-COOH/PtNPs ratio, the sensor achieves superior electrocatalytic activity at a 1:9 (v/v) composition ratio toward BPS oxidation. Morphological and structural characterization via field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) confirmed the successful nanocomposite integration. Meanwhile, electrochemical analysis via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) revealed enhanced electron-transfer kinetics driven by synergistic interactions between the high surface area of carbon nanotubes and the catalytic potency of PtNPs. Under optimized conditions, the platform exhibits a broad linear dynamic range (0.1–100 μM), and an exceptionally low limit of detection (0.01 μM) with a high sensitivity of 4.978 μA μM−1 cm−2 for BPS detection. With excellent selectivity, reproducibility (RSD < 5%), and recovery rates of 95–104%, this proposed sensor based on the MWCNT-COOH/PtNPs/GCE platform offers a robust, efficient solution for the quantitative detection of BPS in complex environmental matrices.
Discharge of dye-laden effluents into aquatic environments poses significant risks to ecosystems, living organisms, and human health. This study introduces a novel adsorbent: chitosan nanoparticles encapsulating onion peel extract (CS/OE-NPs), developed for efficient removal of both cationic [methylene blue (M. blue), crystal violet (C. violet)] and anionic [congo red (C. red), methyl orange (M. orange)] dyes from wastewater. Red onion peels, sourced from Egyptian markets, were extracted with water, and the extract was incorporated into chitosan nanoparticles (CS-NPs). The CS/OE-NPs were comprehensively characterized using DLS, TGA, FT-IR, XRD, SEM, and TEM analyses. Dye removal conditions were optimized via response surface methodology (Box-Behnken design; BBD), focusing on removal efficiency and recovery. Adsorption isotherms and kinetics were investigated to clarify removal mechanisms. CS/OE-NPs achieved high removal efficiencies, with 90% for M. blue, 80% for C. violet, 70% for C. red, and 65% for M. orange at approximately 5 g/L. Notably, encapsulating CS/OE-NPs within polyester organza fabric membranes enabled a substantial reduction in nanoparticle dosage to 1 g/L, while maintaining similar dye removal rates. This dual encapsulation approach is novel, combining the natural antioxidant properties of onion peel extract (OE) with the biocompatibility of chitosan and the practical advantages of fabric-supported deployment. The results demonstrate that CS/OE-NPs, especially when integrated into polyester organza membranes, represent a sustainable and highly effective strategy for dye remediation in wastewater. This work highlights the unique synergy and practical application potential of CS/OE-NPs for advanced water treatment technologies.
Carbon-based nanomaterials have emerged as promising tools in agriculture owing to their biocompatibility, environmental safety, and tunable physicochemical properties. Among them, Carbon Quantum Dots (CQDs) have attracted considerable interest for their potential to enhance photosynthetic performance, improve stress tolerance, and promote plant growth. However, large-scale, crop-specific, and field-level applications of CQDs remain limited. This study introduces sugar beet molasses-derived CQDs as a crop-specific and sustainable nanomaterial platform for sugar beet cultivation, providing the first comprehensive validation of their efficacy through seed priming, pot experiments, and repeated field-scale evaluations. The results demonstrated that CQDs application significantly improved seed cracking rates (∼30% to ∼60%,), chlorophyll a content in leaves (∼20% in pilot/priming but ∼8% in large-scale), and sucrose content (Pol%) by ∼%6.5 in large scale field application compared with the untreated control. Overall, detailed laboratory and field-scale studies demonstrated that sugar beet molasses-derived CQDs act as biostimulants for improving sugar beet cultivation under field conditions, while also showing potential as nano-priming agents.
In the current work, a novel green and sustainable method was developed to prepare CaO-CoO nanocomposites using onion peel extract as a stabilizing and reducing agent. A thorough characterization of structure, morphology, elemental, and optical properties of the synthesized nanocomposite was performed with the help of methods including XRD, FTIR, XPS, FESEM, EDS, as well as fluorescence spectroscopy. XRD analysis established the successful development of crystalline CaO and CoO phases, while FTIR and XPS studies verified the existence of characteristic metal‑oxygen bonds and surface functional groups. FESEM analysis revealed an agglomerated quasi-spherical nanomaterial with a mean particle size of 23 nm. The morphology and crystallinity were further confirmed by TEM and SAED analyses, revealing nanosized polycrystalline particles. Fluorescence studies demonstrated strong emission behaviour in the 350–450 nm region, with significant quenching upon the addition of Zn2+ ions. CaO-CoO nanocomposite exhibited excellent sensitivity toward Zn2+ ions detection with a concentration range 0–50 nM with a lower detection limit of 5 nM. The developed sensing platform exhibited good pH tolerance, repeatability, and stability over multiple measurement cycles and storage periods. The successful determination of Zn2+ ions in real water samples demonstrated the practical applicability and reliability of the proposed sensor for environmental monitoring. Additionally, the synthesized nanocomposite showed concentration- dependent antimicrobial activity against Bacillus sp., S. aureus, and E. coli. These results suggest that the green-synthesized CaO-CoO nanocomposite can be used as a potential multifunctional material that serves very well for environmental sensing and antimicrobial applications.
