In this work, the influence of coordination environment on the electrochemical sensing performance of Zn(II) Schiff base complexes toward nitrite detection is investigated. Two complexes, Zn(SB1)I₂ and Zn(SB2)I₂, with different coordination geometries were synthesized and used to modify screen-printed carbon electrodes. Zn(SB1)I₂ exhibited superior sensing performance, with a wide linear range up to 5 mM, a detection limit of 1.82 μM, and good repeatability, relative standard deviation (RSD: 5.26%), whereas Zn(SB2)I₂ showed a weaker response. This difference highlights the critical role of coordination structure in controlling sensor behavior. Computational studies, including density functional theory (DFT), molecular electrostatic potential (MEP), and frontier molecular orbital (FMO) analysis, suggest that nitrite interaction at the Zn center induces electronic redistribution and facilitates charge transfer, more effectively in Zn(SB1)I₂. These findings demonstrate that the coordination environment of the metal center governs sensing performance, providing insight for the rational design of electrochemical sensors.

This study investigates the design, fabrication, and manufacturing/mechanical characterization of 3D-printed polylactic acid (PLA) cylindrical filter supports developed as substrates for subsequent hydrochar functionalization. Filters with an outer diameter of 30 mm, a height of 20 mm, and a wall thickness of 3 mm were manufactured by material extrusion additive manufacturing and internally filled with gyroid architectures generated in Bambu Studio at three density levels, namely 10%, 15%, and 20%. The printed filters were first evaluated in terms of weight and compressive response. The main focus of the work was the manufacturing consistency and mechanical response of the gyroid supports, while hydrochar deposition was considered as an initial functionalization screening step. The results showed that increasing gyroid density led to higher maximum compressive stress, while mass-normalized analysis revealed a trade-off between absolute mechanical resistance and material efficiency. Surface-treatment screening trials were then carried out on flat PLA specimens to evaluate whether algae-derived hydrochar could be retained on PLA after alkaline activation. Visual and SEM observations showed partial and heterogeneous hydrochar-related surface coverage, with localized agglomerates and partial masking of the original printing lines, but without the formation of a homogeneous coating. EDX analysis of selected agglomerates revealed C and O together with Na, Cl, K, and Ca, supporting the presence of hydrochar-related/mineral-containing deposits on the treated PLA surface, although K may also be associated with residual species from the KOH activation step. FTIR analysis did not reveal clear hydrochar-related spectral features, indicating that FTIR alone was not sufficient to demonstrate effective homogeneous surface functionalization and supporting the interpretation of heterogeneous surface retention. Overall, the study provides a first manufacturing-oriented basis for PLA gyroid filter supports intended for hydrochar deposition and highlights the need for improved surface activation strategies before subsequent functional validation.

In this work, we report for the first time a simple, green, and economical one-step hydrothermal carbonization (HTC) route for synthesizing highly fluorescent hydrochar bulk (HC) from the aqueous extract of Lavandula multifida (Lamiaceae). The hydrochars prepared at 180 degrees C, 240 degrees C, and 300 degrees C were extensively characterized using TEM, FTIR, XRD, UV-Vis, and photoluminescence spectroscopy to elucidate the influence of temperature on their morphological, microstructural, and optical properties. Among the synthesized materials, the Lm 180 hydrochar exhibited the strongest fluorescence emission which was attributed to its richer content of oxygenated surface functional groups and organic chromophores. Excitation-dependent photoluminescence revealed the coexistence of multiple fluorophores, giving rise to blue, yellow, and green emission bands. Leveraging these unique optical features, Lm 180 was explored as a fluorescent probe for heavy-metal ion detection. Remarkably, it showed high selectivity for Hg2+ over Pb2+, Cd2+, Mn2+, Ni2+, and Co2+, displaying a dual-mode detection mechanism: a fluorescence turn-off response at 436 nm at low Hg2+ concentrations (1-10 nM) and a turn-on response at 530 nm at higher concentrations (1-10 mu M). This dual emission behavior enabled the development of a robust ratiometric fluorescent sensor based on the F436/F530 ratio, achieving excellent linearity (R2 = 1.00) and an ultralow limit of detection (LOD) of 0.21 nM Overall, this study demonstrates that Lavandula multifida hydrochar, produced via a sustainable one-step process, is a highly effective and low-cost ratiometric fluorescent sensor for trace mercury detection in aqueous solutions, with strong potential for application in real environmental samples.

This review provides a unified and critical perspective on the sustainable production of pharmaceutical building blocks from lignocellulosic biomass, bridging advances across hemicellulose and lignin valorization pathways. The classification of lignocellulosic residues and methods for their processing are outlined, and the composition and potential of different types of feedstocks are discussed. Methods for obtaining key building blocks from hemicellulose are examined, with an emphasis on effective technological approaches such as the use of heterogeneous catalysts. The emerging role of lignin as an underutilized aromatic resource is also discussed. Recent progress in the valorization of H-, G-, and S-derived phenolic building blocks is highlighted, demonstrating their potential in the synthesis of active pharmaceutical ingredients, lead compounds, and nanoscale drug delivery systems. Importantly, this review moves beyond conventional summaries by critically comparing biomass-derived and petrochemical routes using green chemistry metrics and by identifying key limitations in current assessment approaches for complex processing chains. Strategies for wastewater treatment are also discussed as an integral component of sustainable pharmaceutical production. By integrating catalytic, synthetic, and sustainability perspectives, this work defines key challenges and opportunities, positioning lignocellulosic biomass as a viable platform for next-generation pharmaceutical manufacturing.

Aluminum-doped ZnO nanopowders were synthesized via a sol-gel method at Al/Zn atomic ratios of 0, 0.02, and 0.04. The structural, morphological, and optical properties of the materials were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV-visible spectroscopy, and X-ray diffraction (XRD). Structural analysis confirmed that both pure and Al-doped ZnO samples crystallize in the hexagonal wurtzite structure, with no detectable secondary phases. Slight lattice distortions and variations in crystallite size were observed as the Al concentration increased. Thick-film chemoresistive sensors were fabricated by depositing the synthesized nanopowders onto alumina substrates with interdigitated platinum electrodes. The sensor based on ZnO:Al-2% exhibited the best performance, with the highest response and faster response-recovery dynamics at an operating temperature of 250 degrees C. The improved sensing behavior is attributed to increased charge-carrier concentration and to oxygen vacancies formed by Al doping. These results demonstrate that moderate aluminum incorporation significantly improves the CO2 sensing performance of ZnO nanoparticles under controlled dry conditions, highlighting their potential as low-cost CO2-sensitive materials for preliminary environmental monitoring and smart agriculture applications. However, further selectivity and humidity-dependent tests are required to assess their performance under real operating conditions.

Recently, metal-organic frameworks (MOFs) have attracted significant attention due to their remarkable properties, which make them up-and-coming candidates for sensing applications. In this work, we report the solvothermal synthesis of MIL-101(Fe), which was successfully drop-cast onto screen-printed carbon electrodes (SPCEs) without the need for any binders or surfactants. The resulting sensor was evaluated for the simultaneous electrochemical detection of three environmentally hazardous dihydroxybenzene isomers: hydroquinone (HQ), catechol (CC), and resorcinol (RS). Electrochemical techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) demonstrated that MIL-101(Fe) exhibits high electrocatalytic activity and excellent selectivity toward the target analytesThe sensor achieved wide linear response ranges of 1-700 mu M for HQ and CC, and 0.1-290 mu M for RS, with low detection limits of 0.2 mu M (HQ), 1.0 mu M (CC), and 0.1 mu M (RS). Furthermore, the sensor was applied to real water samples (tap, mineral, and seawater) using the standard addition method. Satisfactory recovery rates ranging from 89.26% to 105.08%, with relative standard deviations (RSD) between 0.77% and 5.64%, confirmed its practical applicability. These results highlight the potential of MIL-101(Fe)-based sensors as reliable and low-cost platforms for environmental monitoring of phenolic contaminants. Synthesis of MIL-101(Fe) via solvothermal method.Analysis of MIL-101(Fe)'s high surface area and water stability.Modified carbon electrode with MIL-101(Fe) for dihydroxybenzene detection.Linear response for Hydroquinone, Catechol, Resorcinol, with LODs of 0.2-1 mu M, and recovery in water samples: 89.26%-105.08%.

Metal oxide semiconductors are widely employed to enhance the performance of hydrogen sensors. In this work, a simple sol-gel method was used to synthesise TiO2 followed by heat treatment (400, 600, or 800 °C.) to obtain materials with predominantly tetragonal (anatase-rutile), mixed tetragonal-orthorhombic, and mixed tetragonal-tetragonal (anatase-rutile) crystal structures, respectively. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV-visible diffuse reflectance spectroscopy (UV-visible DRS). The results show that TiO2 annealed at 600 °C exhibits the best H2 sensing performance, ensuring a sensor response (Ra/Rg) of approximately 3.7 at 3000 ppm and fast response and recovery times of 3.5 and 11.9 s, respectively.

Enhancing crop drought resilience is essential for sustainable agriculture in a changing climate. Among potential strategies, hydrochar (HC), a carbon-rich product of hydrothermal carbonization, represents a promising soil amendment. We hypothesized that HC enhances drought tolerance in Helianthus annuus L. through coordinated soil–plant–gene interactions that modulate water retention, plant hydraulics, and drought-responsive gene networks. Using a multiscale approach combining soil physicochemical analyses, plant physiology, and transcriptomics, we assessed the effects of garden waste-derived HC on H. annuus under well-watered and water-limited conditions.HC application improved soil water retention without altering key chemical parameters and enhanced plant hydraulics. Across irrigation regimes, HC-treated plants showed greater biomass accumulation and photosynthetic capacity. During drought, HC mitigated stress by maintaining leaf water potential and membrane integrity, and by promoting a more negative turgor loss point via osmotic adjustment and increased cell wall stiffness. Transcriptomic analysis revealed that HC modulated drought-responsive genes, including transcription factors (e.g., WRKY51, bZIP11) and genes involved in osmotic regulation, antioxidant defense, and hormonal signaling. The distinct molecular signature in HC-treated plants under drought suggests a priming effect that sustains physiological function under stress.This study provides novel evidence linking HC-induced soil enhancement to molecular drought responses in crops, highlighting HC’s potential as a circular input for improving adaptation and productivity in climate-resilient agroecosystems.

Biomass-derived nanoengineered carbon materials have emerged as key platforms in environmental technologies due to their high surface area, electrical conductivity, chemical stability, and sustainable synthetic route starting from renewable feedstock. This broad family comprises dimensionally nanoscale materials, such as carbon dots, carbon nanofibers, and graphene-based structures, as well as biochars, hydrochars, activated carbons, and related porous carbonaceous materials whose pore architecture, surface chemistry, or defects are deliberately engineered at the nanometer scale. Beyond their traditional role as passive supports, these materials can actively regulate adsorption phenomena, charge transport, and catalytic microenvironments through precise control of heteroatom doping, graphitic domains, and hierarchical porosity. Among current environmental priorities, carbon dioxide (CO2) management represents one of the most pressing challenges. Biomass-derived nanocarbons offer tunable adsorption sites for selective CO2 capture while simultaneously serving as active matrices for catalytic conversion. Tailored doped-carbon frameworks can stabilize key reaction intermediates, suppress competing pathways such as hydrogen evolution, and promote selective transformation into fuels and high-value chemicals. In addition, these materials are excellent hosts for atomically dispersed metals, dual-site catalysts, and semiconductor hybrids used in electrochemical and photocatalytic CO2 reduction. By combining renewable sourcing with nanoscale control of reactivity, carbon materials create a bridge between environmental remediation and carbon valorization. This review critically examines recent progress in biomass-derived nanoengineered carbon materials for integrated CO2 capture and conversion, with emphasis on structure-property-performance relationships, mechanistic roles, scalability, and sustainability. Particular attention is also devoted to catalytic conversion and electrochemical CO2 sensing, where carbon-based and hybrid interfaces enable the transduction of CO2 recognition into measurable electrical responses. These materials represent a promising yet underexplored pathway toward circular carbon management and the development of next-generation low-carbon chemical technologies.

In this paper, a study on the development of indium-doped CuxS heterojunction-based conductometry sensors is presented. To fabricate the sensors, thick films of In-CuxS heterojunctions were sprayed directly on the alumina sensing platform provided with interdigitated Pt electrodes. The effect of the doping level with different nominal amounts of InCl3 additive (0%, 3%, and 5%) on the structural, morphological and optical properties of CuxS films was first studied by XRD, AFM, UV-Vis and Raman spectroscopy. Moreover, the electrical and sensing characteristics towards low concentrations of hydrogen sulfide (H2S) in air were investigated. The tests carried out clearly demonstrated the positive effect of In doping on the H2S sensing performance of CuxS. The 5%-doped CuxS sensor showed the highest sensitivity to the target gas compared to the other sensor, as well as good stability and selectivity properties.

This study reports the valorisation of almond shells waste as a sustainable feedstock for the development of a cellulose-based electrochemical sensor for tetracycline detection. Cellulose from almond shells was functionalized with zinc oxide nanoparticles (ZnO) and multiwalled carbon nanotubes (MWCNTs), to form an hybrid AS-ZnO@MWCNTs Composite with enhanced physicochemical and electrochemical properties. The resulting material was characterized by scanning electron microscopy coupled with energy -dispersive X-ray spectroscopy (SEM-EDX), and Fourier-transform infrared spectroscopy (FT-IR) confirming the successful integration of ZnO and MWCNTs within the cellulose matrix. The improved electrochemical performance arises from the complementary contributions of the composite components: ZnO-containing domains provide electroactive sites for tetracycline oxidation, MWCNTs establish conductive pathways that improve electron-transfer kinetics, and the cellulose matrix supports their structural and interfacial integration. The AS-ZnO@MWCNTs/SPCE sensor exhibited excellent analytical performance toward tetracycline detection with a high sensitivity of 24.8 μA·μM−1·cm−2 and a low detection limit of 0.16 μM based on the second oxidation peak (A2). The sensor also demonstrated good selectivity in the presence of potential interfering species, as well as satisfactory repeatability, stability and reproducibility. The proposed platform was successfully applied to the detection of tetracycline in real samples, including milk and honey, showing reliable recovery values. The findings highlight the potential of cellulose recovered from agro-industrial waste as a renewable functional matrix for the development of electrochemical sensing platforms for food-safety monitoring.

In this study, kaolin waste was functionalized with sulfonic groups to enhance its textural and chemical properties, resulting in a high-performance heterogeneous catalyst. The functionalized material was thoroughly characterized using various techniques, including FTIR, XRD, TGA, BET (N2-physisorption), and TEM-EDX. The incorporation of sulfonic groups introduced active sites that significantly increased the ion exchange capacity, thereby enhancing the catalytic performance. When employed as a catalyst in the acetalization of benzaldehyde, the functionalized kaolin waste achieved a remarkable conversion rate of 98 % under optimized conditions. The successful transformation of kaolin waste into a highly effective catalyst demonstrates its potential for broader applications in green chemistry, particularly in sustainable synthesis. Acetals, the target products, are crucial intermediates in organic synthesis and the pharmaceutical industry. The catalytic process proposed in this study offers an efficient and environmentally friendly approach to acetal formation, advancing the field of heterogeneous catalysis. Additionally, extending the application of this functionalized material to other challenging reactions could further highlight its versatility and potential as a sustainable catalyst in various industrial processes.

Porphyrin/sulphonated polyetheretherketone (sPEEK) composites are successfully obtained at different dye/polymer weight/weight percentage taking advantage of electrostatic interactions among the protonable nitrogen atoms of 5,10,15,20‐tetrakis(4‐pyridyl)‐21H,23H‐porphyrin porphyrin (TPyP) and anionic sulphonated groups of the polymer with 65% of sulfonation degree. These supramolecular adducts(TPyP‐sPEEK) are drop‐casted onto a commercial screen‐printed carbon substrate (SPCE) to fabricate new modified TPyP‐sPEEK /SPCE sensors for the detection of heavy metal ions such as Pb 2+ , Cd 2+ , and Hg 2+ . Sample at different porphyrin loads has been analyzed by electrochemical techniques. sPEEK composite with 5% porphyrin/polymer w/w% is identified as the optimal one in terms of stability and high percentages of recovery of the tested heavy metal ions in seawater environment.

A novel β-cyclodextrin-aza[5]helicene conjugate as theranostic platform for anticancer agents delivery in cancer cells is here reported. The carrier was synthesized via monotosylation of hydroxyethyl-β-cyclodextrin (HE-β-CD), followed by reaction with the synthesized aza[5]helicene, yielding the corresponding ammonium tosylate salt. The system was characterized by NMR, FTIR, UV-vis, and PL measurements, demonstrating favorable optical properties. The suitability of the fluorescent system to act as smart drug delivery system for cancer therapy was investigated by choosing gemcitabine (GMC) as a model drug. The GMC inclusion inside the system was evaluated by experimental and computational studies which confirmed the formation of a 1:1 complex between β-CD and GMC. The inclusion of GMC within the β-CD cavity led to a marked enhancement in its water solubility. Biological tests conducted on A549 cells revealed high cell internalization (∼80 %) and low cytotoxicity (IC50 = 262.7 µg mL-1) of the β-CD-aza[5]helicene conjugate. The results obtained by exploiting the host-guest chemistry of β-cyclodextrin combined with the unique photophysical properties of aza[5]helicene could pave the way for new anticancer therapies, by increasing the therapeutic index of anticancer agents endowed with poor solubility in water and characterized by systemic toxicity and, thanks to the fluorescent properties of the inserted probe, following their release into biological pathways.

In this work, Aluminum-doped ZnO nanopowders with [Al]/[Zn] atomic ratios of 0, 0.02, and 0.04 were synthesized using a sol-gel method and examined using Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction. Both undoped and Al-doped ZnO samples, based on characterization data, exhibit a hexagonal wurtzite structure with slight deformation of the ZnO lattice. Chemo-resistive devices based on a thick layer of synthesized Al-doped ZnO nanoparticles were fabricated, and their electrical and sensing properties toward CO2 were investigated. The ZnO: Al2%-based sensors had a greater response than the other samples, enabling CO2 detection at the operational temperature of 250°C.

Carbon dots (CDs) have emerged as promising nanomaterials for optical sensing due to their outstanding photoluminescence, chemical stability, and biocompatibility. In recent years, the development of sustainable CDs derived from biomass—particularly cellulose—has attracted increasing interest as a green alternative to conventional synthetic routes. This review offers a comprehensive overview of recent advances in synthesis, functionalization, and application of cellulose-based carbon dots for environmental sensing. We examine key synthetic approaches—including hydrothermal, microwave-assisted, and pyrolytic methods—and discuss how the structure and origin of cellulose influence the physicochemical properties of the resulting CDs. The mechanisms underlying their sensing performance are analyzed in detail, with a focus on the detection of heavy metals, organic pollutants, and other environmental contaminants. Challenges related to reproducibility, scalability, and long-term stability are critically addressed. Finally, we outline future directions involving hybrid nanomaterials, real-time sensing platforms, and strategies aligned with circular economy principles. This review aims to serve as a valuable resource for researchers in the fields of sustainable nanomaterials, green chemistry, and environmental sensor development.

Hydrochars (HCs) are carbonaceous nanomaterials derived from many renewable sources, including biomass and various natural products such as plant matter, agricultural waste, and other organic derivatives. This study introduces a straightforward, sustainable, and cost-efficient hydrothermal method to synthesize HCs, utilizing an aqueous extract of Lavandula multifida’s aerial parts harvested from the Kerkennah islands, Tunisia. The HCs synthesis was performed in water at three different temperatures (180 ℃, 240 ℃, and 300 ℃) for 1 h. Comprehensive morphological and microstructural analyses of the obtained solid fractions were conducted using XRD, TEM and UV–Vis spectroscopy and PL techniques. The PL emission spectra of the different synthesized HCs were recorded at varying excitation wavelengths. Out of the three materials produced, Lm180 hydrochar stood out as the optimal choice for detecting metal ions. The remarkably low limit of detection (LOD) of 0.78 nM achieved by Lm180 hydrochars demonstrates their performances for the detection of mercury ions at trace levels.

In this work, TiO2 semiconductor junctions were investigated to improve the performance of hydrogen sensors. To develop TiO2 homojunction with tetragonal (anatase), tetragonal-orthorhombic, and tetragonal-tetragonal (anatase-rutile) structures, we used a simple sol-gel method followed by heat treatment at different temperatures such as 400 °C, 600 °C, and 800 °C. The samples were characterized using X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV-visible DRS) and used to develop efficient conductivity sensors for H2 monitoring. The obtained results showed that the tetragonal orthorhombic TiO2 homojunction obtained at 600 °C annealing temperature exhibited good H2 performance (sensor response Ra/Rg of about 5.3 at 5000 ppm and fast response/recovery of 4 s and 14 s, respectively).

In this study, fluorescent probes were developed using carbon nanodots (CNDs) derived from hydrochar obtained through the hydrothermal carbonization of beer bagasse. Beer bagasse is a by-product of the beer industry and offers several advantages as a lignocellulosic source for carbon material synthesis. The raw materials and the resulting CNDs were characterized using various techniques. The synthesized CNDs displayed small dimensions, intriguing fluorescence behaviour, high stability, and remarkable water solubility due to the presence of hydroxyl and carboxyl functional groups. Leveraging these properties, the CNDs were utilized in the development of highly sensitive fluorimetric probes for iron ions, exhibiting a high response and low limit of detection.

Addressing the major challenge of global warming by implementing a circular carbon cycle involving CO2 conversion is currently an urgent priority for a more sustainable future. The design of efficient, stable, cheap and eco-friendly systems for such purpose is a remarkable challenge. This study reports an unprecedented metal -free, co -catalyst -free orange peel waste-derived carbon nanodot highly active and selective system for the photoreduction of CO2 into methanol. The waste -derived photocatalyst exhibited a maximum methanol production rate of 416.6 mu molMeOH.gcat -1 .h- 1 and a highly stable methanol production rate of 12.9 mu molMeOH.gcat -1 .h- 1 after 72 h. This work proposes a successful waste -to -fuel strategy that combines the valorization of orange peel waste and CO2 conversion for the synthesis of green methanol.