Hydrothermal Treatment Research Articles

Scaffold microstructure evolution via freeze‐casting and hydrothermal phase transformation of calcium phosphate

AbstractExtensive research efforts have been focused on customizing the microstructure, macrostructure, and phase composition of calcium phosphate for enhanced biocompatibility and bioactivity in scaffolds for bone substitutes. Despite significant progress, achieving precise phase composition and microstructure remains a challenge, primarily due to the necessity of scaffold sintering. This study addresses the challenges in developing customized patient‐specific bone substitutes by proposing a sequential approach that reduces processing steps while providing control over the phase and morphology of the scaffolds’ structure. The methodology utilizes freeze‐casting and sintering for highly porous the scaffolds’ preparation, followed by hydrothermal treatment to modify the microstructure. The introduction of CaCO3 induces a phase transformation of tricalcium phosphate, increasing the hydroxyapatite content, while the overall macrostructure retains the characteristics of freeze‐casting. The surface morphology undergoes a transition from equiaxial grains to whiskers‐like structures and hexagonal rods, impacting compressive strength. Following hydrothermal treatment, the formation of whiskers‐like hydroxyapatite grains leads to a notable strength increase from 2.8 to 5.7 MPa. Remarkably, the scaffolds undergo nearly complete phase transformation, shifting from 100% tricalcium phosphate to 99% hydroxyapatite, all while conserving the macrostructure.

Multi-component attached carbon matrix composites with superior electromagnetic wave absorption performance and multifunctional applications

The preparation of highly absorbing and high-performance electromagnetic wave-absorbing materials remains a significant challenge. In this paper, carbon matrix composites modified with sodium inorganic salts (CMS) have been successfully prepared by using the solvent evaporation method in combination with the hydrothermal treatment and high temperature carbonization processes. The composition of the product can be manipulated by varying the material ratios, which in turn affects the interface and dielectric properties of the material. Sodium carbonate (Na2CO3) was produced as a transition phase between sodium silicate and carbon matrix due to high temperature. According to differential charge density a significant charge accumulation found between the interfacial of Na2CO3 and carbon layer is helpful to polarization. The synergistic effect of polarization and conduction loss due to the formation of multiple heterogeneous interfaces and carbon matrix results in excellent electromagnetic wave absorption performance. The minimum reflection loss (RLmin) is −55.49 dB when the thickness is 3.1 mm. Furthermore, CMS composites exhibit notable flame retardancy and thermal insulation properties, rendering them suitable for a diverse range of applications. These remarkable achievements provide new ideas for the design and development of efficient electromagnetic wave absorption materials.

Effect of synthesis conditions on the properties of 13X zeolites for CO2 adsorption

ABSTRACT The 13X zeolites were successfully synthesized from sodium silicate and sodium aluminate via hydrothermal treatment, and applied to the adsorption of carbon dioxide (CO2). The properties of the 13X zeolites were characterized and tested by powder X-ray diffraction (XRD), N2-physisorption measurements, CO2-temperature programmed desorption (CO2-TPD) and CO2 adsorption measurements. The results demonstrate that H2O/Na2O, Na2O/SiO2, and SiO2/Al2O3 molar ratios have an important influence on the adsorption performance of CO2 because of their different physicochemical properties. The pure 13X zeolite can be obtained with the optimal H2O/Na2O, Na2O/SiO2 and SiO2/Al2O3 molar ratios of 60, 4 and 3 in the preparation process, respectively. The 13X sample prepared with suitable synthesis conditions possesses the highest crystallinity, the maximum values of specific surface area (720.8 m2/g) and pore volume (0.458 cm3/g) and moderate strength of the interaction between 13X and CO2, thus presenting the highest adsorption capacity of CO2 (118.3 mg/g).

In situ, fast constructing interface/doping-engineered NiCo bimetal-based composites boosting electrocatalytic oxygen reduction for zinc-air battery

Investigating cost-effective, high-performance, stable and durable oxygen reduction reaction (ORR) catalysts is imperative, yet it’s still a formidable obstacle in the advancement of metal-air batteries. In this research, NiCo-bimetallic oxides in situ combined with NiCo-bimetal alloy upon the surface of carbon-based matrix (reduced graphene oxide) (NiCo/Co-NiO/rGO) were synthesized by microwave hydrothermal treatment coupled with an ultrafast Joule heating shock process. The interfacial charge transfer between the bimetal alloy and metal oxide in NiCo/Co-NiO/rGO resulted in electron redistribution at the heterointerface, where *O species migrated to the NiCo alloy surface through Mn+-O-M0 (M=Ni, Co and n=2, 3) bonds, facilitating continuous electron transport between the two phases and unveiling added active sites. Introducing abundant oxygen vacancies by Ni3+ and Co3+ facilitated charge transfer between different valence states and led to forming more active sites, thus significantly enhancing ORR performance. More importantly, solid solution strengthening within the NiCo-bimetallic alloy mitigated the oxidation and corrosion of the catalyst. Therefore, the as-synthesized NiCo/Co-NiO/rGO(5 % Co) exhibited excellent ORR performance under an alkaline medium. It achieved a half-wave potential(E1/2) of 0.85 V(vs. RHE) and maintained 89.10 % of its current density after a 12-h long-term reaction. The assembled zinc-air battery (ZAB) employing this catalyst proved remarkable specific capacity (807.04 mAh·gZn−1), power density (95.54 mW cm−2) and cycling stability (over 240 h), outperforming that of commercial Pt/C+RuO2-based ZAB device. This study presents a viable approach for fabricating low-cost dual transition metal-based catalysts, thereby boosting their electrocatalytic performance and enhancing the efficiency and longevity of metal-air batteries.

Effect of Mild Alkali Treatment on the Structure and Physicochemical Properties of Normal and Waxy Rice Starches.

Mild alkali treatment can potentially be developed as a greener alternative to the traditional alkali treatment of starch, but the effect of mild alkali on starch is still understudied. Normal and waxy rice starches were subjected to mild alkali combined with hydrothermal treatment to investigate their changes in physicochemical properties. After mild alkali treatment, the protein content of normal and waxy rice starches decreased from 0.76% to 0.23% and from 0.89% to 0.23%, respectively. Mild alkali treatment decreased gelatinization temperature but increased the swelling power and solubility of both starches. Mild alkali treatment also increased the gelatinization enthalpy of waxy rice starch from 20.01 J/g to 25.04 J/g. Mild alkali treatment at room temperature increased the pasting viscosities of both normal and waxy rice starches, whereas at high temperature, it decreased pasting viscosities during hydrothermal treatment. Alkali treatment significantly changed the properties of normal and waxy rice starch by the ionization of hydroxyl groups and the removal of starch granule-associated proteins. Hydrothermal conditions promoted the effect of alkali. The combination of hydrothermal and alkali treatment led to greater changes in starch properties.

Micro/Meso-Porous Double-Shell Hollow Carbon Spheres through Spatially Confined Pyrolysis for Supercapacitors and Zinc-Ion Capacitor.

Energy storage in supercapacitors and hybrid zinc ion capacitors (ZIC) using porous carbon materials offers a promising alternative method for clean energy solutions. The unique combination of hierarchical porous structure and nitrogen doping in these materials has demonstrated significant capacity for energy storage. Nevertheless, the full potential of these materials, particularly the relationship between pore structure configuration and performance, remains underexplored. Herein, a confined pyrolysis strategy based on the polymerization characteristics of polydopamine (PDA) was developed to construction of hollow carbon spheres with microporous/mesoporous dual shell structure. The depth of micropores and cavity can be controlled by adjusting the duration of heat treatment and hydrothermal treatment, in accordance with the decomposition and polymerization characteristics of PDA. Due to the elasticity of this structure, the relationship between the micro/mesoporous depth of the prepared carbon spheres and the energy storage performance in supercapacitors and ZIC is established. Through optimizing the ion transport capacity of carbon spheres and considering the influence of its internal cavity structure on energy storage, the resulting carbon spheres exhibit high specific capacitance of 389 F g-1 in supercapacitor and specific capacitance of 260 F g-1 and excellent stability with 99.3 % retention after 30000 chare/discharge cycles in ZIC.

Safety assurance and nutritional quality enhancement of Phyllospora comosa biomass using hydrothermal treatment derived ensemble machine learning models

One of the major barriers to the mass industrial utilisation of brown seaweeds as food sources stem from the food safety risks associated with their iodine and arsenic concentrations, which typically exceed regulatory limits. Hydrothermal treatments might effectively reduce the high iodine and arsenic concentration of Phyllospora comosa below the Australian maximum residual limits (iodine = 1 mg/g and arsenic = 0.00667 mg/g; dry weight) set for brown seaweeds. The experimental hydrothermal treatments dictated that the 82 °C–250 s treatment reduced the iodine concentration from 2.76 mg/g to 0.88 mg/g (68% reduction) and arsenic concentration from 0.01693 mg/g to 0.00965 mg/g (43% reduction). Machine learning models predicted that blanching at 100 °C for ∼4 minutes will reduce the arsenic concentration below its maximum residual limit. Additive log-ratio transformations showed that around 50% (dw) of the hydrothermally treated Phyllospora comosa samples were leached out during the highest treatment intensity, 82 °C–250 s. Even though, a half of the biomass is lost, hydrothermally treated Phyllospora comosa products are safer for human consumption and thus may permit the expansion of seaweed production and consumption in Australia.

Porous frameworks can be treated more than imagined: Recent advances on post-synthetic modification of zeolites by hydrothermal treatment with the aid of pore-filler stabilization

Porous frameworks can be treated more than imagined: Recent advances on post-synthetic modification of zeolites by hydrothermal treatment with the aid of pore-filler stabilization

Nanostructured N-doped Ti3C2/TiO2 composite for high-performance supercapacitor

Herein, the N-doped Ti3C2/TiO2 nanostructure has been synthesized via hydrothermal treatment and following annealing in NH3. TiO2 nanoparticles in-situ grow on the surface of Ti3C2 spontaneously, resulting in the stable electron transport between TiO2 and Ti3C2. Besides, Ti3C2 nanosheets as conductive substrates make up for the poor conductivity of TiO2. The doping of N in Ti3C2/TiO2 composite further improves the electrical conduction. The ultimate N-doped Ti3C2/TiO2 composite achieves a higher specific capacitance of 737.4 F g−1 than Ti3C2 (324.4 F g−1) at 0.5 A g−1. More importantly, the composite displays a high specific capacitance retention of 81 % over 12,000 cycles. Besides, the assembled symmetrical supercapacitor (SSC) manifests an excellent specific capacitance of 236.4 F g−1 at 1 A g−1 and a comparable energy density of 32.8 Wh kg−1 at the power density of 500 W kg−1. This work provides promising guidance for the fabrication of durable electrodes for energy storage application.

The effect of hydrothermal pretreatment on the catalytic performance of Zn/HZSM-5 catalysts for ethylene aromatization reaction

To address the issue of coking and deactivation of Zn/HZSM-5 catalysts used for lightolefins aromatization, a high-temperature hydrothermalmethod was employed for catalyst pretreatment. The catalysts were characterized using XRD, N2 physical adsorption-desorption, NH3-TPD, Py-FTIR, XPS, and TG techniques. The effect of high-temperaturehydrothermal pretreatment on the catalytic performance and stability of the catalyst was investigated using ethylene aromatization as a probe reaction. The results showed that the Zn/HZSM-5 catalyst exhibited excellent catalytic performance after48 h of high-temperature hydrothermal pretreatment. Although the conversion of ethylene slightly decreased, the catalyst lifetime was significantly extended, increasing from 72to 216 h, while the aromatics selectivity remained above 60%. It was suggested that the hydrothermal treatment enhanced the interaction between ZnO species and Brønsted acid sites, promoting the generation of ZnOH+ species. This not only suppressed the hydrogen transfer reaction but also significantly enhanced the dehydrogenation performance of the catalyst, improving the selectivity towards hydrogen. Additionally, the catalyst exhibited increased carbon capacity and reduced carbon deposition rate after hydrothermal treatment, demonstrating excellent anti-coking properties.

Graphene-loaded nickel−vanadium bimetal oxides as hydrogen pumps to boost solid-state hydrogen storage kinetic performance of magnesium hydride

To modify the thermodynamics and kinetic performance of magnesium hydride (MgH2) for solid-state hydrogen storage, Ni3V2O8-rGO (rGO represents reduced graphene oxide) and Ni3V2O8 nanocomposites were prepared by hydrothermal and subsequent heat treatment. The beginning hydrogen desorption temperature of 7 wt.% Ni3V2O8-rGO modified MgH2 was reduced to 208 °C, while the additive-free MgH2 and 7 wt.% Ni3V2O8 doped MgH2 appeared to discharge hydrogen at 340 and 226 °C, respectively. A charging capacity of about 4.7 wt.% H2 for MgH2 + 7 wt.% Ni3V2O8-rGO was achieved at 125 °C in 10 min, while the dehydrogenated MgH2 took 60 min to absorb only 4.6 wt.% H2 at 215 °C. The microstructure analysis confirmed that the in-situ generated Mg2Ni/Mg2NiH4 and metallic V contributed significantly to the enhanced performance of MgH2. In addition, the presence of rGO in the MgH2 + 7 wt.% Ni3V2O8-rGO composite reduced particle aggregation tendency of Mg/MgH2, leading to improving the cyclic stability of MgH2 during 20 cycles.

Carbon fiber fabrics functionalized with monoclinic CuO nanostructures using seed-assisted hydrothermal growth treatment

The woven carbon fibers (WCF) fabrics were functionalized by growing copper-oxide (CuO) nanostructures using Seed-assisted hydrothermal technique. The effective growth of CuO on surface hydrolyzed WCF samples were achieved by seeding followed by growth treatment in the prepared precursor solution. The impact of hydrothermal process parameters such as number of seeding cycles, duration of growth treatment and molar concentration of growth solution were studied by performing 96 set of experiments with three repetitions. In this work detailed analysis of structural, morphological, and elemental attributes of the CuO-coated WCF fabrics samples have been done. The WCF fabrics were uniformly coated with monoclinic CuO nanostructures having nanopellets, nanoflakes, nanowires, and nanoflowers morphologies. Different characterization techniques such as field emission scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FT-IR spectroscopy and thermo-gravimetric analyzer were used to study different attributes of CuO-modified WCF samples. The number of seeding treatments and the length of growth treatment had a significant impact on growth of CuO nanostructures on WCF. The detailed analysis exhibits that the developed CuO-modified WCF samples may enhance interfacial surface area, bonding capacity and reduce void content by allowing nanostructures to cross-link together and with polymer matrix while fabricating composite materials.

CeO2/SWCNT nanocomposite coating: A novel approach for corrosion application

AbstractThe coatings were prepared by blending different concentrations of SWCNTs and CeO2 particles with an epoxy resin by hydrothermal method, which was then applied to the substrate through the doctor blade technique. The mixtures were transferred into a 1‐L capacity autoclave with a teflon‐lined flange type and subjected to hydrothermal treatment at 100°C for 3 h. The surface coatings were applied using a doctor blade. Subsequently, the coated materials were placed in an oven and dried for 12 h at 50°C under vacuum conditions. The samples' structural analysis was examined through x‐ray diffraction (XRD). XRD analysis verified the CeO2/SWCNT composite coating, and Fourier transform infrared spectroscopy (FTIR) was utilized to assess the presence of functional groups. Thermodynamic properties and thermal stability of composite coatings that were modified with SWCNTs and CeO2 particles were studied by thermogravimetric analysis (TGA). The impact of the CeO2/SWCNT composite on the anticorrosion capabilities of the epoxy coating was examined through electrochemical impedance spectroscopy (EIS), Nyquist curve, and Tafel slope characterization. Corrosion tests were conducted on the CeO2/SWCNT composite coatings in a 3.5 wt% sodium chloride (NaCl) solution at 25°C to improve corrosion resistance. The concentration of 0.4 wt% CeO2 was found to be optimal for achieving effective corrosion resistance. The composite coating CNT0.6‐C0.4 exhibited significantly higher Ecorr (−426 V) and lower Icorr (2.96 × 10−6 A cm−2) values compared to samples from the CNT0, CNT0.2, and CNT0.6 groups. The paper presents a viable solution with CeO2/SWCNT composite coating for the engineering application of corrosive‐inhibiting coatings.

Acidic process fluid from hydrothermal carbonization improves dechlorination of waste PVC and produces clean solid and liquid fuels

Dechlorination of waste PVC (WPVC) by hydrothermal treatment (HTT) is a potential technology for upcycling WPVC in order to create non-toxic products. Literature suggests that acids can improve the HTT process, however, acid is expensive and also results in wastewater. Instead, the acidic process fluid (PF) of hydrothermal carbonization (HTC) of orange peel was utilized in this study to enhance the dechlorination of WPVC during HTT. Acidic HTT (AHTT) experiments were carried out utilizing a batch reactor at 300–350 °C, and 0.25–4 h. The finding demonstrated that the dechlorination efficiency (DE) is high, which indicates AHTT can considerably eliminate chlorine from WPVC and relocate to the aqueous phase. The maximum DE of 97.57 wt% was obtained at 350 °C and 1 h. The AHTT temperature had a considerable impact on the WPVC conversion since the solid yield decreases from 56.88 % at 300 °C to 49.85 % at 350 °C. Moreover, AHTT char and crude oil contain low chloride and considerably more C and H, leading to a considerably higher heating value (HHV). The HHV increased from 23.48 to 33.07 MJ/kg when the AHTT time was raised from 0.25 to 4 h at 350 °C, indicating that the AHTT time has a beneficial effect on the HHV. The majority fraction of crude oil evaporated in the boiling range of lighter fuels include gasoline, kerosene, and diesel (57.58–83.09 wt%). Furthermore, when the AHTT temperature was raised from 300 to 350 °C at 1 h, the HHV of crude oils increased from 26.11 to 33.84 MJ/kg. Crude oils derived from AHTT primarily consisted of phenolic (50.47–75.39 wt%), ketone (20.1–36.34 wt%), and hydrocarbon (1.08–7.93 wt%) constituents. In summary, the results indicated that AHTT is a method for upcycling WPVC to clean fuel.

N-Doped Ti3C2Tx Interfacial Layer Enabling Uniform Zn Deposition along (002) Plane for Stable Aqueous Zinc-Ion Battery.

Aqueous zinc-ion batteries hold great potentials for large-scale grid energy storage. However, the electrode corrosion, hydrogen evolution, and dendrite growth of Zn anode often lead to cell failure. Herein, N groups in Ti3C2Tx (NMXH) are introduced as interfacial layer through hydrothermal treatment of Ti3C2Tx with urea. The experimental analysis and density functional theory calculation indicate that N groups in Ti3C2Tx can homogenize electric field distribution, promote adsorption of Zn2+ on N groups, and strength interactions between N groups and Zn atoms on (002) plane. Thereby, the use of NMXH interfacial layer can effectively suppress the side reactions and realize uniform Zn deposition along the (002) plane. As a consequence, the NMXH─Zn//Zn cell exhibits an ultralow nucleation overpotential (1mA cm-2, 18.9mV) and can stably operate for 1400h at 1mA cm-2 (1 mAh cm-2) and 110h at 40mA cm-2 (1 mAh cm-2). A full battery with V2O5 nanowires as cathode displays a discharge capacity of 219 mAh g-1 (1.0 A g-1), along with a decent rate capability and cyclability. The significant role of N groups reported in this work offers a promising avenue to improve the cycling stability of Zn anodes of aqueous zinc batteries.

Determination of Tetracaine and Oxymetazoline in Drugs and Saliva via Potentiometric Sensor Arrays Based on Fluoropolymer/Polyaniline Composites

AbstractA growing interest in dental practice in intranasal anesthesia using tetracaine and oxymetazoline dictates the need for their simultaneous determination in combination drugs and human saliva. Potentiometric multisensory systems based on perfluorosulfonic acid membranes, including polyaniline‐modified ones, were developed for these purposes. A change in the distribution of the sensor sensitivity to the related analytes was achieved by variation of the conditions for concentration polarization at the membrane interface with a studied solution due to a change in the intrapore volume, nature, and availability of the sorption centers, as well as the hydrophilicity of the membrane surface that were specified by the conditions for their synthesis and subsequent hydrothermal treatment. Reversibility of the analyte sorption using the chosen conditions for regeneration provided long‐term stable work of both the sensors and the calibration equations established by multivariate linear regression. The membrane modification promoted their resistance to fouling. The relative errors of the simultaneous tetracaine and oxymetazoline determination in the combination drug solutions were no greater than 7% and 11%, while in the artificial saliva solutions, they were 15% and 17%, respectively, when an array of the cross‐sensitive sensors based on the composite membranes prepared by different methods was used. The analysis errors were reduced to 3%–6% when analyzing the drug and to 0.2%–6% when analyzing the artificial saliva if an array was organized with the sensors based on the membrane with the dopant and the membrane without it, due to the decreasing correlation between their responses.

Enhancing Bioactivity and Mechanical Properties of Nano-Hydroxyapatite Derived from Oyster Shells through Hydrothermal Synthesis.

Nano-hydroxyapatite (nHA) demonstrates favorable biological activity, cell adhesion, cell proliferation, and osteoconductivity, making it highly valuable in biomedicine. It is extensively used as a bone substitute and in bone transplantation within the dental and orthopedic fields. This study employed oyster shells as a calcium source to synthesize nHA at 150 °C with various hydrothermal reaction durations (10 min, 1 h, 6 h, and 12 h). As a control, HA synthesized via a wet precipitation method for 1 h at room temperature was utilized. Subsequent material analyses, including XRD, FE-SEM, FTIR, and ICP-MS, were conducted, followed by comprehensive evaluations of the bioactivity, cell attachment, cell proliferation, and sintering properties of the synthesized nHA. The results indicated that nHA synthesized through the hydrothermal reaction produced nanoscale crystals, with the aspect ratio of nHA particles increasing with the duration of hydrothermal treatment. Notably, rod-like nHA particles became prominent with hydrothermal durations exceeding 6 h. nHA particles derived from oyster shells contained carbonate and trace elements (Na, Mg, K, and Sr), similar to constituents found in human hard tissue such as bone and teeth. The immersion of nHA synthesized at 150 °C for 1 h (HT2) in simulated body fluid (SBF) for 28 d led to the formation of a bone-like apatite layer on the surface, indicating the excellent bioactivity of the synthesized nHA. The cell culture results revealed superior cell attachment and proliferation for nHA (HT2). Following the sequential formation and sintering at 1200 °C for 4 h, HT2 ceramics exhibited enhanced microhardness (5.65 GPa) and fracture toughness (1.23 MPa·m0.5), surpassing those of human tooth enamel.

Highly active carbon dots based nanozyme for enhanced cholesterol detection and antibacterial activity

Recently, nanozyme have emerged as promising direction for chemical sensing, biomedicine, environmental monitoring. However, the novel nanozyme with better catalytic activity and specificity is urgently required realized great application performance. Herein, Fe doped carbon dots (Cit-Fe-CDs) with peroxidase (POD) like activity are synthesized by hydrothermal treatment of ferric ammonium citrate. Due to the strong coordination capacity between Fe(Ⅲ) and citric acid, the Cit-Fe-CDs exhibited excellent POD activity. Namely the catalytic constant (Kcat) and catalytic efficiency (Kcat /Km) are determined, which are much higher than previous work. Highly effective colorimetric detection of cholesterol in human serum have been realized by the POD activity of Cit-Fe-CDs. Under optimal conditions, the linear range is determined to be 10 and 100 μM with a detection limit (LOD) of 0.061 μM. The LOD is two orders of magnitude lower than most of the existing analysis method. Since substantial amounts of free radicals are involved in the catalytic cycle of POD activity, excellent antibacterial activity against Methicillin-Resistant Staphylococcus aureus (MRSA) should be realized by Cit-Fe-CDs. Notably, about 99.999 % inactivation rate towards MRSA can be realized by 125 μg/mL Cit-Fe-CDs, which showcases promising prospects in addressing bacterial resistance concerns. And we have confirmed that the antibacterials mechanism is related to the generation of hydroxyl radicals by the excellent POD activity of Cit-Fe-CDs.

Towards a sustainable rice husk ash-derived solid-phase extraction: Perfluoroalkyl substances as probe contaminants of waters

Rice husk ash is an important waste of agricultural industry that, within the framework of the circular economy, has been easily converted into a sustainable sorbent material. This was tested in this work for the pre-concentration of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), representative perfluoroalkyl substances as probe environmental pollutants of waters, with HPLC-MS/MS quantification. The preparation involves a rapid microwave-assisted oxidation followed by a hydrothermal treatment, which was studied using a 22 design of experiments. The final material was thoroughly characterized and tested for its affinity to the target analytes by solid-phase extraction in environmental waters and wastewaters. Recoveries in the range 67–113 % (RSD < 11 %, n=3) were achieved at environmentally relevant concentrations (10, 50, and 100 ng L-1) and the sorbent was reusable for at least ten consecutive extractions. Good linearity (R2 = 0.9997) was observed, with a method quantification limit in the water sample of 10 ng L-1 that allows the analysis of PFOA and PFOS below the established limits. The method was evaluated for greenness using AGREEprep and SPMS metrics, and it was then applied to the analysis of actual water samples from Northern Italy.

A novel high-entropy rare-earth hydroxycarbonate synthesized via facile hydrothermal synthesis with superior decomposition temperature

This study presents for the first time the synthesis of a novel high-entropy rare-earth hydroxycarbonate, specifically (Sm₀.₂La₀.₂Y₀.₂Nd₀.₂Gd₀.₂)(CO3)OH, by using a simple hydrothermal treatment. The resulting rare-earth hydroxycarbonate exhibits superior thermal stability compared to the related single-component rare-earth hydroxycarbonates, and a distinctive rod-like morphology, maintained even after prolonged calcination (i.e. 800 °C for 12 h), suggesting its potential as a “sacrificial template” for high-entropy bixbyite-structured oxides. Thus, our pioneering work opens new possibilities for the application of a novel class of high-entropy hydroxycarbonates in the field of catalysis, luminescence, and sensing technologies.