Magnetic clay-based composites are promising materials for pollutant remediation due to their tunable surface chemistry, ion-exchange capacity and facile magnetic recovery. However, their practical deployment remains limited by poor scalability and the lack of a predictive framework linking physicochemical properties to adsorption performance. Here, we address both challenges by combining scalable spray-drying fabrication with colloidally driven design and data-driven modelling, establishing a predictive approach to multifunctional adsorption. We developed a scalable strategy to integrate Fe3O4 nanoparticles into oppositely charged clay matrices via heterocoagulation or coprecipitation, followed by one-step spray-drying to produce mechanically robust micrometre-sized granules. The resulting composites retained the intrinsic magnetic behaviour of Fe3O4 (M-H up to 1.5 T) while exhibiting strong and selective uptake across multiple pollutant classes, including heavy-metal ions (Cu2+ and Fe3+ > 15 mg g-1), oppositely charged dyes (rhodamine B ∼20 mg g-1; methylene blue and methyl orange ∼7 mg g-1) and phenols (30-40 µg g-1). The co-aggregates were highly reusable, with < 10% efficiency loss after four reuse cycles. Notably, in all cases, chemisorption governed the overall uptake, primarily driven by ion-exchange interactions with aqueous species. A machine-learning model (R 2 = 0.91) correlated adsorption capacity with material descriptors, identifying zeta potential, isoelectric point and hydrodynamic size as the dominant factors controlling performance. Together, these results moved beyond empirical material design by providing a scalable and predictive structure-property framework for magnetic clay composites, enabling their rational optimisation and practical implementation in water treatment.

Correction for ‘Characterizing nanoplastic suspensions of increasing complexity: inter-laboratory comparison of size measurements using dynamic light scattering’ by Korinna Altmann et al. , Environ. Sci.: Nano , 2025, 12 , 5242–5256, https://doi.org/10.1039/D5EN00645G.

The industrial application of essential oils (EOs) is hindered by their high volatility, instability and poor solubility. Encapsulation represents an effective strategy to overcome these limitations by enhancing protection, enabling controlled release, and improving functional properties. In this study, we developed an aqueous-based sol–gel synthesis, combined with the interfacial oil miniemulsion method, to encapsulate blends of lavender (LO), thyme (TO), and cinnamon (CO) essential oils within silica nanocarriers, in order to hinder EOs volatility and instability, as well as control their release. It was also investigated whether combining LO with other essential oils (TO and CO) could provide complementary or synergistic effects. The process was conducted predominantly in water, using TEOS as silica precursor and a non-ionic surfactant under controlled conditions, aiming to reduce solvent consumption and process-related hazards in line with Safe and Sustainable by Design approach. Physicochemical characterization (SEM, FTIR, TGA, DLS, HPLC) confirmed the formation of spherical silica nanocarriers with diameters of 55–85 nm, narrow size distributions (PdI < 0.15), and encapsulation efficiencies of 93%–94%, corresponding to loading capacities of 52 wt. %. Release studies showed a sustained behavior, with release limited to 15%–26% over 48–168 h, depending on the formulation, and kinetic modelling indicated predominantly diffusion-controlled release. Antibacterial assays against Escherichia coli and Staphylococcus aureus showed that encapsulated EO blends preserved their antibacterial activity. SiO2 nanocarriers loaded with LO showed MIC values to 25% for E. coli and 3.125% for S. aureus. Notably, the oil blends improved LO performance also within the encapsulated system, with MIC values of 6.25% and 0.78% (for LO and CO), and 6.25% and 1.56% (for LO and TO) against E. coli and S. aureus, respectively. Overall, this study demonstrates the feasibility of integrating aqueous sol–gel processing with interfacial miniemulsion to fabricate silica nanocarriers for essential oil delivery, achieving enhanced stability, controlled release behaviour, and preserved antibacterial performance, with promising implications for sustainable formulations.

Silver nanoparticles (NPs) are frequently deployed in medical devices due to their antimicrobial properties. We previously reported an eco-friendly process for preparing AgNPs by using a quaternary ammonium salt of hydroxyethyl cellulose (HEC) as a capping and reducing agent. Here, inspired by the Safe and Sustainable by Design framework, we conducted a comprehensive safety and efficacy assessment of AgHEC versus commercial uncoated AgNPs before and after their integration into wound dressings based on poly L-lactic acid fibers prepared by electrospinning (PLLA-Ag and PLLA-AgHEC). We demonstrated that the AgHEC formulation displayed an improved antibacterial efficacy compared to its uncoated counterpart. We also performed colloidal and dissolution studies in vitro using relevant biological media. Moreover, the toxicological evaluation using state-of-the-art porcine skin models and the clinically relevant dermal open flow microperfusion (dOFM) approach demonstrated negligible penetration of silver through both intact and disrupted skin while no evidence for elevated inflammatory immune responses was noted compared to the control. Taken together, our findings not only validate AgHEC as an alternative for wound healing applications but also establishes a robust methodological framework for the future evaluation of other nanobiomaterials.

Addressing water pollution issues requires innovative solutions and global cooperation for sustainable water resources. In this study, the design of calcium ferrite nanoparticles was optimised by investigating different Ca:Fe molar ratios, calcination temperatures, and synthesis methods: thermal decomposition (TD) and sol-gel combustion (SG). We evaluated the magnetic behaviour, the photocatalytic degradation of cationic/anionic dyes (methylene blue, MB; methyl orange, MO) and the adsorption of phosphates (PO₄3−). We found that only SG samples exhibited superparamagnetic behaviour, with a high value of maximum magnetisation (5–40 Am2 kg Fe−1). TD samples showed superior photocatalytic activities, up to 4.5 mg g−1 for MB and 2.0 mg g−1 for MO. The phosphate adsorption capacity of both TD and SG CaFe_1:1 samples was very promising, with values exceeding 100 mg g−1 for TD samples and ranging between 50 and 100 mg g−1 for SG samples. We systematically investigated the structural and colloidal properties to identify which design parameters most significantly affected the functional ones. Photocatalytic activity and phosphate adsorption capacity were found to be strongly dependent on the crystal phase of the samples. The samples exhibiting the highest activity were those containing brownmillerite (Ca2Fe2O5), followed by those containing hematite. The orthorhombic off-spinel phase (O-CaFe2O4) did not exhibit significant activity unless brownmillerite or hematite crystalline phases were also present. Finally, only SG samples Ca:Fe 1:2_300-750 in the presence of both cubic spinel phase (C-CaFe2O4) and brownmillerite showed relevant magnetic and photocatalytic activities, with SG sample Ca:Fe_1:2_500 exhibiting the highest photocatalytic efficiency. The other physicochemical properties had little influence on the reactivity of the investigated ferrite phases, including specific surface area, which was significantly higher for the SG samples compared to the TD samples.

Abstract As the world faces growing environmental challenges, understanding the nature of microplastics—such as Low-Density Polyethylene (LDPE) and Polyurethane (PU)—and their transformation in water-based environments is necessary for predicting and mitigating their effects. In this study, we investigated their physicochemical characteristics, presence of impurities, colloidal behavior, and sorption capacity to understand better how microplastics behave and transform in the environment, including their role in transporting heavy metals. The two types of microparticles investigated fall into distinct size ranges, approximately 70 microns for PE particles and around 5 microns for PU particles. Both samples showed a spherical morphology and an evident surface micro-roughness. The elemental and thermal analysis did not show the presence of any significant metal impurities. The zeta-potential measurements as a function of pH provided insights into the dispersion behavior of microplastics (MPs) in freshwaters, suitable for the growth of Zebrafish (Egg water) and Daphnia magna (Elendt M7 Water). Both materials showed in bidistilled water negative zeta potential (ZP) at natural pH (ZP = − 51.0 ± 4.3 mV at pH = 6.6 and ZP = − 29.5 ± 1.4 mV at pH = 5.6 for LDPE and PU, respectively), justified by the presence of surface-active charged impurities. In saline media, ZP vs. pH curves were flatter, with ZP values near 0 mV, confirming the reduced colloidal stability from higher ionic strength and double-layer compression. Finally, we assessed the metal adsorption capacity to establish the role of microplastics in the transport of heavy metals in the environment. We observed selective adsorption for Cu2⁺ ions, which was both medium-dependent (more ions adsorbed in Elendt M7) and plastic-dependent, with PU showing a stronger affinity for Cu2⁺ in MilliQ and Egg water. On the contrary, both plastics showed similar adsorption capacity for Fe3⁺ ions across all media.

In this work, we combined microalgae's sorptive properties with titania-based nanoparticles' photocatalytic capabilities to develop technologies applicable to wastewater treatment while also providing valuable insights into the innovation of adsorption technologies. The coupling of Neochloris oleoabundans biomass with an inorganic nanophase enables the formation of hybrid materials integrating heavy metal adsorption with photocatalytic action. To prepare the samples, we employed a water-based colloidal method followed by a spray freeze granulation treatment. The preparation process was followed by comprehensive physicochemical characterization from the wet precursors to the final hybrid granules. Key performance indicators, including adsorption and photocatalytic activity, were assessed using two model contaminants: copper ions (for heavy metal adsorption) and Rhodamine B (for photocatalysis). The results revealed a synergistic effect of the hybrid nanomaterials, significantly enhancing the Cu2+ adsorption capacity of the biomass, which increases from 30 mg g-1 to 250 mg g-1 when coupled with the inorganic phase and is likely due to the supporting and dispersing role of the inorganic nanoparticles on the biomass. The adsorption experimental values followed the Freundlich isothermal model and pseudo-second-order kinetic model, indicating that the adsorption occurred primarily through a multimolecular layer adsorption process, consistent with chemisorption mechanisms. The photocatalytic performance of the inorganic counterpart was preserved when coupled with the microalgae, with TiO2-SiO2/biomass achieving complete Rhodamine B degradation within 1 hour.

gamma-Valerolactone (GVL) has transpired as a precursor to valuable chemicals, a fuel additive and an eco-friendly solvent. Herein, Aquivion (R)/oxide hybrid catalysts were prepared by an innovative spray freeze-drying method, tuning acid site distribution in the materials and exploring an approach to GVL synthesis from furfuryl alcohol (FAL) by employing non-noble metals. SiO2, TiO2 and ZrO2 were selected because of their increasing Lewis acidity, a key factor in promoting catalytic transfer hydrogenation (CTH). A thorough study on thermal stability through TGA, MAS NMR, porosimetry, SEM-EDX and experimental testing unveiled their resistance to thermal treatments and its influence on catalytic performances. In this study, it is shown how the optimal thermal treatment conditions for the composite materials vary depending on the acid properties of the supporting oxide.

The increasing presence of micro- and nanoplastics in natural environments raises concerns about their interactions with biological particles such as pollen, that may act as carriers but could also undergo subtle chemical or structural changes, potentially influencing their ecological role. At the same time, the analytical and technological approaches used to investigate nanoplastic pollution mechanism can themselves raise concerns regarding their greenness. In this interdisciplinary study, we explored the interactions between multifloral bee pollen and polyethylene terephthalate nanoparticles (NanoPET) under environmentally relevant conditions using a multimodal analytical strategy combining AF4 (Asymmetrical Flow Field-Flow Fractionation) multidetection, Pyrolysis-GC-MS (py-GC-MS), Field Emission Scanning Electron Microscopy (FESEM), and dielectrophoresis-Raman spectroscopy (DEP-Raman). This approach aims to clarify nanoplastics exposure profiles and the associated potential health risk, as well as to promote more sustainable laboratory workflows. Pollen and NanoPET were first characterized individually by AF4, FESEM, and DEP-Raman, which provided their size distributions, morphology, and characteristic spectral signatures. Py-GC-MS offered detailed molecular fingerprints, especially for bee pollen, which had not been previously analysed with this technique. To assess the interaction between pollen and NanoPET, mixed samples were analysed using a "profilomic" approach based on changes in AF4 fractograms, UV/Vis and Raman spectra. Two distinct interaction mechanisms have emerged: the formation of a corona of soluble pollen-derived macromolecules around NanoPET, and the coating of pollen grains by NanoPET particles, as confirmed by FESEM imaging. DEP-Raman further confirmed the presence of interactions by separating non-interacting NanoPET particles and revealing spectra that included characteristic peaks of both pollen and NanoPET. Py-GC-MS analysis of fractions collected from AF4 processing of mixed samples also confirmed the presence of characteristic ions deriving from both components. Together, these findings highlight the formation of hybrid bio-nano structures and suggest potential ecological implications. Moreover, they demonstrate how multidimensional, low-impact analytical workflow can offer detailed insight into nanoplastics behaviour in complex biological matrices, paving the way for greener and more comprehensive environmental nanotoxicology studies.

Understanding the potential human health risks associated with micro- and nanoplastic exposure is currently a priority research area. Nanoplastic toxicity studies are complicated by the lack of available, well-characterized test and reference materials. Further, many nanoplastic test materials are inherently more polydisperse and heterogenous in shape compared to polystyrene beads, making accurate and representative size distribution measurements particularly challenging. The aim of this study was to conduct an inter-laboratory comparison of dynamic light scattering measurements, the most commonly used particle sizing method for nanomaterials. Using a published standard operating procedure, size measurements in water and a standardized cell culture medium (CCM) were generated for spherical, carboxy-functionalized polystyrene nanoparticles (PS-COOH; 50 nm; benchmark material), and for increasingly complex in-house produced spherical poly(ethylene terephthalate) (nanoPET) and irregular-shaped polypropylene (nanoPP) test materials. The weighted mean of hydrodynamic diameters of PS-COOH dispersed in water (55 +/- 5 nm) showed moderate variation between labs (coefficient of variation, CV = 8.2%) and were similar to literature reports. Measurements of nanoPET (82 +/- 6 nm) and nanoPP (182 +/- 12 nm) in water exhibited similar CV values (nanoPET: 7.3% and nanoPP; 6.8%). Dispersion of PS-COOH and nanoPET in CCM increased the CV to 15.1 and 14.2%, respectively, which is lower than literature reports (CV = 30%). We conclude with a series of practical recommendations for robust size measurements of nanoplastics in both water and complex media highlighting that strict adherence to a standard operating procedure is required to prevent particle agglomeration in CCM.

Water is one of the necessities for human survival, and clean water is essential for life. As a result, there is an increasing focus on efficient wastewater treatment methods, including advanced oxidation processes using innovative heterogeneous photocatalysts. In this context, TiO2–graphene oxide (TGO) composites offer a multifaceted approach to wastewater treatment, combining the photocatalytic properties of TiO2 with the adsorption capabilities and potential synergistic effects of graphene oxide. In this research, we intimately mixed commercial TiO2 powder with graphene oxide at different concentrations (9, 16, and 25 wt.%) by exploiting sonochemical activation. The morphological and physicochemical analyses confirmed the interfacial interactions and the successful formation of the composite. The TGO composites exhibited increased reactivity compared to both GO and TiO2 phases, during the photodegradation process of Rhodamine B (RhB), serving as a reaction model. Therefore, the photocatalytic results demonstrated the synergistic effect that occurs when a TiO2-based photocatalyst is combined with sonochemically activated GO. The Cu2+ adsorption tests, simulating the removal of heavy metals from contaminated water, revealed that TGO composites displayed intermediate capabilities compared to the pure phases’ higher (GO) and lower (TiO2) adsorption capacity. The functional characterizations revealed that the optimal design is represented by the sample containing 16 wt.% of GO. Overall, this study confirms that TGO composites are effective as photocatalysts and adsorbents for removing both organic and inorganic pollutants, making them strong candidates for wastewater treatment.

The development of advanced materials through safe and sustainable methods has become a priority in the field of material science. This study addresses this need by exploring how different design options affect the performance of nano-TiO2 granulated powders exploitable in water remediation applications. The high-shear wet granulation (HSWG) process parameters have been investigated to produce nanostructured powders that are easy to handle, disperse, and remove from liquids, while preserving their ability to adsorb and photodegrade water pollutants or encapsulate and stabilize active ingredients. We systematically examined a range of key variables, including liquid-to-solid ratio, granulation time, and impeller speed, which were identified as the primary factors affecting the size population. The percentage of the > 1000 µm granules fraction reached 100 % by increasing the liquid-to-solid ratio up to 0.6 gwater/gpowder, while an increase in granulation time and impeller speed caused a reduction of the largest fraction by approximately 30 % and 20 %, respectively. Additionally, we investigated the addition of different binder agents, followed by calcination at 600 °C. We found a correlation between tapped density, open porosity, swelling ratio and compressive strength. Maltodextrin (MD) improved the degree of compaction resulting in the highest compressive strength (9.5 ± 0.2 MPa) and lowest release of titanium when redispersed in water, whilst micro acryl emulsion (MA) improved the sample porosity (80.6 ± 0.5 %) and its capacity to adsorb water (swelling ratio. The pro-oxidative potential of the granules was evaluated using an •OH radical sensitive probe. TiO2-based granules showed a reactivity comparable to TiO2 pristine nanopowders, consuming approximately 98 % of RNO after 4 h.

This study investigates the influence of high-shear mechanical granulation parameters on the properties and distribution of a clay-based granulated powder population. The granulation parameters examined as design variables include granulation time, impeller speed, liquid addition rate, rotation mode, and binder agent incorporation. Our findings reveal significant behavioral differences across all parameters when comparing hydrophilic bentonite clays to hydrophobic synthetic hydrotalcite. For hydrophilic clays, the liquid-to-solid ratio is identified as the most critical variable, whereas it exerts minimal impact on hydrophobic hydrotalcite. This suggests the presence of a delicate balance between growth and breakage mechanisms in hydrophobic powders, involving the formation of water droplets that encapsulate particles, aligned with an increased swelling ratio. Furthermore, the addition of an acrylic binder to the bentonite mixture enhances open porosity without affecting compressive strength. These results highlight the need for tailored process modifications in the design of granulated clay-based advanced materials.

There was an error in the original publication [...]

Re-designing existing nano-silver technologies to optimize efficacy and sustainability has a tangible impact on preventing infections and limiting the spread of pathogenic microorganisms. Advancements in manufacturing processes could lead to more cost-effective and scalable production methods, making nano-silver-based antimicrobial products more accessible in various applications, such as medical devices, textiles, and water purification systems. In this paper, we present a new, versatile, and eco-friendly one-pot process for preparing silver nanoparticles (AgNPs) at room temperature by using a quaternary ammonium salt of hydroxyethyl cellulose (HEC), a green ingredient, acting as a capping and reducing agent. The resulting nano-hybrid phase, AgHEC, consists of AgNPs embedded into a hydrogel matrix with a tunable viscosity depending on the conversion grade, from ions to nanoparticles, and on the pH. To investigate the synthesis kinetics, we monitored the reaction progress within the first 24 h by analyzing the obtained NPs in terms of particle size (dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM)), Z-potential (ELS), surface plasmon resonance (UV-VIS), crystallographic phase (XRD), viscosity, and reaction yield (inductively coupled plasma-optical emission spectrometry (ICP-OES)). To explore the design space associated with AgHEC synthesis, we prepared a set of sample variants by changing two independent key parameters that affect nucleation and growth steps, thereby impacting the physicochemical properties and the investigated antimicrobial activity. One of the identified design alternatives pointed out an improved antimicrobial activity in the suspension, which was confirmed after application as a coating on nonwoven cellulose fabrics. This enhancement was attributed to a lower particle size distribution and a positive synergistic effect with the HEC matrix.

Safety aspects of chemicals/materials are transversal in all sustainability dimensions, representing a pillar at the early innovation stages of the European Commission's "safe and sustainable by design" (SSbD) framework for chemicals and materials. The first three of the five SSbD framework steps cover different safety aspects, namely, hazard assessment based on intrinsic properties (step 1), occupational health and safety (including exposure) assessment during the production/processing phase (step 2) and exposure in the final application phase (step 3). The goal of this work was to identify a set of characterization tools/procedures to support the operationalization of the first three safety steps in multi-component nanomaterials (MCNMs), applying the findings to an SiO2 core-ZnO shell MCNM. The safety of this MCNM, which is used as an additive to silicate/calcium hydroxide mortar to improve air quality through photocatalytic NOx removal, was investigated from different perspectives along its value chain. Existing and newly generated data on its hazard profile were collected, the exposure of workers during its synthesis was assessed, and potential exposure to hazardous substances during its final application phase was investigated. In step 1, physico-chemical properties, hazard classification and cytotoxicity assays were considered. In step 2, a three-tiered established methodology for evaluating occupational exposure assessment was performed. Lastly, in step 3, the release of inorganic substances from MCNM-based mortars in the final application phase was investigated. Safety assessment according to the SSbD framework was performed by selecting tools and procedures suitable for application in the early innovation stage, resulting in a preliminary hazard assessment of MCNMs and a suggestion for redesigning a step in the process.

Understanding the mechanism of toxicity of nanoparticles and their behavior in biological environments is crucial for designing materials with reduced side effects and improved performance. Among the factors influencing nanoparticle behavior in biological environments, the release and bioavailability of potentially toxic metal ions can alter equilibria and cause adverse effects. In this study, we applied two on-line Field-Flow Fractionation (FFF) strategies and compared the results with off-line benchmarking centrifugal ultrafiltration to assess a key descriptor, namely the solubility of zinc oxide (ZnO) nanoparticles. We found that, at the highest nanoparticle concentrations, the nanoparticle-ion ratio quickly reaches equilibrium, and the stability is not significantly affected by the separation technique. However, at lower concentrations, dynamic, non-equilibrium behavior occurs, and the results depend on the method used to separate the solid from the ionic fraction, where FFF yielded a more representative dissolution pattern. To support the (eco)toxicological profiling of the investigated nanoparticles, we generated experimental data on colloidal stability over typical (eco)toxicological assay durations. The Zeta Potential vs pH curves revealed two distinct scenarios typical of surfaces that have undergone significant modification, most likely due to pH-dependent dissolution and re-precipitation of surface groups. Finally, to enhance hazard assessment screening, we investigated ion-dependent toxicity and the effects of exposure to fresh water. Using an in vitro human skin model, we evaluated the cytotoxicity of fresh and aged ZnO nanoparticles (exposed for 72 h in M7), revealing time-dependent, dose-dependent, and nanoparticle-dependent cytotoxicity, with lower toxicity observed in the case of aged samples.

In recent years, multifunctional inorganic−organic hybrid materials have been widely investigated in order to determine their potential synergetic, antagonist, or independent effects in terms of reactivity. The aim of this study was to design and characterize a new hybrid material by coupling well-known photocatalytic TiO2 nanoparticles with sodium surfactin (SS), a biosurfactant showing high binding affinity for metal cations as well as the ability to interact with and disrupt microorganisms’ cell membranes. We used both chemical and colloidal synthesis methodologies and investigated how different TiO2:SS weight ratios affected colloidal, physicochemical, and functional properties. We discovered a clear breaking point between TiO2 and SS single-component trends and identified different ranges of applicability by considering different functional properties such as photocatalytic, heavy metal sorption capacity, and antibacterial properties. At low SS contents, the photocatalytic properties of TiO2 are preserved (conversion of organic dye = 99% after 40 min), and the hybrid system can be used in advanced oxidation processes, taking advantage of the additional antimicrobial SS properties. At high SS contents, the TiO2 photoactivity is inhibited, and the hybrid can be usefully exploited as a UV blocker in cosmetics, avoiding undesired oxidative effects (UV adsorption in the range between 300–400 nm). Around the breaking point (TiO2:SS 1:1), the hybrid material preserves the high surface area of TiO2 (specific surface area around 180 m2/g) and demonstrates NOx depletion of up to 100% in 80 min, together with improved adhesion of hybrid antibacterial coating. The last design demonstrated the best results for the concurrent removal of inorganic, organic, and biological pollutants in water/soil remediation applications.