Cycles Of Reuse Research Articles

Preparation and characterization of Ru-TiO2/PC/Fe3O4 composite catalyst with enhanced photocatalytic performance and magnetic recoverability under simulated solar light.

This research focuses on the development of a novel Ru-doped TiO2/grapefruit peel biochar/Fe3O4 (Ru-TiO2/PC/Fe3O4) composite catalyst, which exhibits exceptional photocatalytic efficacy under simulated solar light irradiation. The catalyst is highly effective in the degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), as well as actual industrial dye wastewater (IDW), and can be recovered magnetically for multiple reuse cycles. Significantly, the PCTRF-100 sample exhibited degradation efficiencies of 99.4% for RhB and 99.8% for MB within 60 min, and 98.04% for MO within 120 min. In the case of actual dye wastewater, a reduction in chemical oxygen demand from 1540 mg L-1 to 784 mg L-1 was achieved within 300 min, corresponding to a degradation rate of 46.81%. The remarkable photocatalytic activity observed is primarily attributed to the synergistic interactions among Ru-TiO2, biochar, and Fe3O4, which effectively facilitate the separation and migration of electron-hole pairs in TiO2.

Magnetic nanoparticle modified moss Biochar: A novel solution for effective removal of enrofloxacin from aquaculture water.

The presence of residual antibiotics in water constitutes a potential threat to aquatic environments. Therefore, designing environmentally friendly and efficient biochar adsorbents is crucial. Aquaculture by-product moss (bryophyte) was transformed into biochar, which can eliminate antibiotics from wastewater through adsorption. This study successfully fabricated moss biochar (BC) and magnetically modified moss biochar (MBC), and explored their adsorption performance for enrofloxacin (ENR). Characterization analyses revealed that the specific surface area, total pore volume, and the quantity of functional groups of the MBC were significantly larger than those of the BC. The Langmuir isotherm model suggests that the maximum adsorption capacities of BC and MBC for ENR are 7.24mgg⁻1 and 11.62mgg⁻1. The adsorption process conforms to a pseudo-second-order kinetic model. Studies carried out at different temperatures disclose the spontaneous and endothermic thermodynamic characteristics of the system. Under neutral conditions, the adsorption efficiency attains its peak. The existence of various coexisting ions in water exerts a negligible influence on the adsorption process; furthermore, when the concentration of humic acid (HA) ranges from 0 to 20mg/L, the removal rate remains above 90%. In actual water samples, the antibiotic removal rate can be as high as 96.84%. After three cycles of reuse, the structure of MBC remains unchanged while maintaining a high removal efficiency. The primary mechanisms for antibiotic adsorption by MBC involve electrostatic interactions, hydrophobic interactions, pore-filling effects, hydrogen bonding, and π-π interactions. This reusable magnetic moss biochar provides a promising research direction for effectively eliminating antibiotics from water sources.

“Green” Synthesis of Substituted Tetraketones with Prominent Bactericide Effect

: Effective and “green” synthesis of tetraketone derivatives was elaborated. The last compounds developed prominent bactericide activity against both MIC and MBC S. aureus (ATCC-6538P) bacteria. The novelty of this approach is concluded in the application of Al(OH)3 catalyst for the Knoevenagel-Michael cascade reaction of aromatic aldehydes and 1,3- cyclic diketones in water. The process is chemoselective and affords high yield of tetraketones under benign conditions. The catalyst maintained 80% of initial activity within four cycles. The proposed method can be regarded as an alternative to the existing syntheses of biologically active tetraketones that utilize homogeneous and expensive heterogeneous catalysts.

NiFe2O4/g- C3N4 modified chitosan Schiff base composite for efficient removal of Cu(II) and Hg(II) ions from the aquatic environment and its antibacterial properties

Modification of chitosan has been achieved by the reaction of chitosan with 4- nitro-benzaldehyde via the sol-gel method, resulting in a Schiff base. A novel magnetic Graphitic Carbon Nitride/chitosan-Schiff base/NiFe2O3 (SBIV@NiFe/g-C3N4) adsorbent was synthesized by hydrothermal route for the adsorption of Cu(II) and Hg(II) ions from the aquatic environment. The synthesized SBIV@NiFe/g-C3N4 was characterized using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET), with a surface area of approximately 13.657 m2/g. It was anticipated by the results that magnetic SBIV@NiFe/g-C3N4 would be effectively synthesized. On Cu(II) and Hg(II) adsorption, the impacts of significant variables, including pH solution, contact duration, metal ion concentration, adsorbent dosage, and co-existing ions, were examined. Under ideal circumstances, the optimum adsorption capacities of Cu(II) and Hg(II) ions were 889.76 mg/g and 703.21 mg/g, respectively. Furthermore, the SBIV@NiFe/g-C3N4 material exhibited the beneficial property of simple separation, permitting the continuation of high removal effectiveness for heavy metals like Cu (II) and Hg(II) despite experiencing many reuse cycles. In summary, there are a lot of opportunities for the effective elimination of Cu (II) and Hg (II) from different water sources shortly with the use of SBIV@NiFe/g-C3N4, a new adsorbent. The as-synthesized SBIV@NiFe/g-C3N4 displayed better antibacterial activity against highly lethal bacteria like S. aureus and P. vulgaris.

Sustainable Recycling of Spent Li-Ion Batteries and Iron Ore Tailings for Cobalt Ferrite Synthesis and Its Dual Applications as a Photocatalyst in Solar Photo-Fenton Process and an Electrochemical Sensor

This study presents a solution to solid waste problems, focusing on spent lithium-ion batteries (LiBs) and iron ore tailings (IOT) from the Mariana environmental accident in Brazil. The approach involves the production CoFe2O4 from LiBs and IOT, which serves as a catalyst for solar photo-Fenton reactions for methylene blue (MB) decolorization and as an electrochemical sensor for ascorbic acid (AA) detection. Chemical analysis showed recycling potential, with 45.22 ± 0.22% m m−1 Co from LiBs and 14.9 ± 1.5% m m−1 Fe from IOT, determined by inductively coupled plasma atomic emission spectroscopy (ICP OES) and flame atomic absorption spectrometry (FAAS). The sol-gel synthesized CoFe2O4 exhibited a crystallite size of 51.9 ± 1.3 nm and agglomerated crystal clusters. Recycled-CoFe2O4 exhibited a 98.1% MB decolorization efficiency in 60 min under solar irradiation and remained above 92.3% in all 7 reuse cycles. The electrochemical sensor exhibited a coefficient of determination of 0.9987, a sensitivity of 3.352 ± 0.0428 μA mol L−1, and a limit of detection of 0.5511 µM in the concentration range of 1.96 to 23.08 mmol L−1 for AA detection. This study demonstrates the potential of recycled-CoFe2O4 in an environmentally friendly dye removal and as an electrochemical sensor, offering sustainable waste management and resource utilization with solar energy.

A temperature-sensitive and fluorescent Tr-CD/AuNP-based catalyst for efficient, monitorable, and recyclable catalytic reactions.

Gold nanoparticles (AuNPs) have been widely used as efficient and environmentally friendly catalysts due to their high specific surface area and abundant active sites. However, AuNP-based catalytic systems face several challenges, including the instability of AuNPs during the reaction, the difficulty in monitoring the process, which can easily result in insufficient reaction due to short reaction time or waste of resources due to long reaction time, as well as issues of catalyst recovery. This study proposes a novel catalyst integrating various functions, such as high stability, the capacity for real-time monitoring of the catalytic process, and rapid recycling. Temperature-sensitive polymers (HPEI-IBAm) terminated with isobutyramide (IBAm) groups were prepared by reacting isobutyric anhydride with hyperbranched polyethyleneimine (HPEI). Subsequently, temperature-sensitive and reducing fluorescent carbon dots (Tr-CDs) were synthesized using HPEI-IBAm as a carbon source. Tr-CDs can reduce the HAuCl4 precursor in situ, yielding high-performance catalysts, Tr-CDs/AuNPs, with both temperature-sensitive and fluorescence properties. With the help of changes in fluorescence intensity and the real-time synchronous change in the reaction conversion rate, monitoring of the catalytic reaction process is achieved. Moreover, their temperature sensitivity enables the rapid recovery of the catalysts. Using the reduction of p-nitrophenol as a model, we thoroughly investigated the catalytic performance of Tr-CDs/AuNPs. Importantly, the catalytic process exhibited a good linear relationship between the change in fluorescence intensity and the reaction time (R2 = 0.9993) and maintained a synchronous change with the conversion rate, enabling the monitoring of the reaction process. Meanwhile, the catalytic efficiency of this catalyst remained above 90% after five recycling and reuse cycles, indicating no obvious decline in catalytic activity. This catalyst demonstrates good performance, reusability, and real-time reaction monitoring, promising bright application prospects.

Tetracycline removal from aqueous media and hospital wastewater using a magnetic composite of mango lignocellulosic kernel biochar/MnFe2O4/Cu@Zn-BDC MOF.

This study explored the use of mango lignocellulosic kernel biochar (MKB) modified with MnFe2O4 magnetic nanoparticles and a Cu@Zn-BDC metal-organic framework (MOF) (MKB/MnFe2O4/Cu@Zn-BDC MOF) for tetracycline (TC) removal from aqueous solutions and hospital wastewater. The modified biochar exhibited strong magnetic properties (19.803 emu/g) and a specific surface area of 30.456 m2/g, facilitating easy separation after adsorption. Using Response Surface Methodology-Central Composite Design (RSM-CCD), the adsorption model demonstrated high accuracy (F-value: 315.510, p < 0.0001, R2 = 0.9959). Thermodynamic analysis indicated that the process was endothermic and spontaneous, driven by physical interactions, with positive enthalpy and negative Gibbs free energy values. The pseudo-second-order kinetic model best described the adsorption, highlighting significant chemical interactions, while the Freundlich isotherm suggested adsorption on heterogeneous surfaces. The maximum TC adsorption capacities for MKB and its magnetic composite were 27.050 mg/g and 42.670 mg/g, respectively. The RL, n, and E parameters confirmed the desirability and physical nature of the interactions (0-1,〉1, and < 8 kJ/mol, respectively). The intraparticle diffusion model indicated multiple mechanisms were involved, and the biochar maintained excellent performance across reuse cycles, making it a highly effective and reusable adsorbent for water and wastewater treatment.

Azithromycin removal from water via adsorption on drinking water sludge-derived materials: Kinetics and isotherms studies.

In this study, we utilized drinking water treatment sludge (WTS) to produce adsorbents through the drying and calcination process. These adsorbents were then evaluated for their ability to remove azithromycin (AZT) from aqueous solutions. The L-500 adsorbent, derived from the calcination (at 500°C) of WTS generated under conditions of low turbidity in the drinking water treatment plant, presented an increase in the specific surface area from 70.745 to 95.471 m2 g-1 and in the total pore volume from 0.154 to 0.211 cm3 g-1, which resulted in a significant AZT removal efficiency of 65% in distilled water after 60 min of treatment. In synthetic wastewater, the rate of AZT removal increased to 80%, in comparison, in a real effluent of a municipal wastewater treatment plant, an AZT removal of 56% was obtained. Kinetic studies revealed that the experimental data followed the pseudo-second-order model (R2: 0.993-0.999, APE: 0.07-1.30%, and Δq: 0.10-2.14%) suggesting that chemisorption is the limiting step in the adsorption using L-500. This finding aligns with FTIR analysis, which indicates that adsorption mechanisms involve π-π stacking, hydrogen bonding, and electrostatic interactions. The equilibrium data were analyzed using the nonlinear Langmuir, Freundlich, and Langmuir-Freundlich isotherms. The Langmuir-Freundlich model presented the best fitting (R2: 0.93, APE: 2.22%, and Δq: 0.06%) revealing numerous interactions and adsorption energies between AZT and L-500. This adsorbent showed a reduction of 19% in its AZT removal after four consecutive reuse cycles. In line with the circular economy principles, our study presents an interesting prospect for the reuse and valorization of WTS. This approach not only offers an effective adsorbent for AZT removal from water but also represents a significant step forward in advancing sustainable water treatment solutions within the framework of the circular economy.

A potential eco-friendly degradation of methyl orange by water-ball (sodium polyacrylate) stabilized zero valent iron nanoparticles.

This study presents the synthesis and application of water-ball (sodium polyacrylate) stabilized zero-valent iron nanoparticles (wb@Fe0) for the eco-friendly degradation of Methyl Orange (MO). The nanoparticles were prepared using a chemical reduction method using NaBH4. Characterization techniques including Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD) were employed to analyze the morphology, elemental composition, valent state and crystallinity of the nanoparticles. The catalytic performance was evaluated under standard conditions, with a maximum degradation efficiency of 94% achieved for a 0.05mM MO solution using 10mg of the catalyst, 0.1mM NaBH4, at neutral pH and room temperature within 10min. Optimal degradation occurred at 40°C and pH 6. The catalyst demonstrated excellent recyclability, maintaining activity over ten reuse cycles. Kinetic studies revealed that the degradation followed first-order kinetics with an R2 value of 0.8907 and a rate constant of 0.3708. Though with a lower R2 value (0.6884), the second-order kinetics model indicated the highest rate constant of 2.6522. Regression and ANOVA analysis confirmed the accuracy of the reaction protocol. This study highlights the potential of water-ball stabilized zero-valent iron nanoparticles for effective dye pollutant removal and degradation, offering a promising approach for environmental remediation.

Immobilization of lipase on mesoporous silica nanocarriers for efficient preparation of phytosterol esters

Phytosterol esters (PEs) are favored for their good solubility, high bioavailability, and various health benefits. Mesoporous silica (MS) nanocarriers were synthesized and utilized to immobilize free lipase AYS “Amano” (from Candida rugosa) for further preparing PEs. The optimal immobilization conditions were an initial enzyme content of 160 mg/mL, pH of 7.0, temperature of 30 °C, and adsorption time of 6 h, resulting in a protein loading of 42.3 mg/g and an immobilization efficiency of 73.4 %. Compared to commercial carriers, MS carriers demonstrated superior immobilization efficiency and phytosterol conversion rates when soybean oil was used as the PEs source for the transesterification. The phytosterol conversion rate reached 97.7 % in a solvent system with optimal reaction conditions. After 30 days of storage, the immobilized lipase retained 55.7 % of its activity, and it had 63.0 % retention activity after 10 reuse cycles. This study significantly enhanced the lipase's phytosterols conversion and reusability, supporting sustainable and efficient industrial production of PEs.

Polyamide Microparticles with Immobilized Enological Pectinase as Efficient Biocatalysts for Wine Clarification: The Role of the Polymer Support.

Free pectinase is commonly employed as a biocatalyst in wine clarification; however, its removal, recovery, and reuse are not feasible. To address these limitations, this study focuses on the immobilization of a commercial pectinolytic preparation (Pec) onto highly porous polymer microparticles (MPs). Seven microparticulate polyamide (PA) supports, namely PA4, PA6, PA12 (with and without magnetic properties), and the copolymeric PA612 MP, were synthesized through activated anionic ring-opening polymerization of various lactams. Pectinase was non-covalently immobilized on these supports by adsorption, forming Pec@PA conjugates. Comparative activity and kinetic studies revealed that the Pec@PA12 conjugate exhibited more than twice the catalytic efficiency of the free enzyme, followed by Pec@PA6-Fe and Pec@PA4-Fe. All Pec@PA complexes were tested in the clarification of industrial rosé must, demonstrating similar or better performance compared to the free enzyme. Some immobilized biocatalysts supported up to seven consecutive reuse cycles, maintaining up to 50% of their initial activity and achieving complete clarification within 3-30 h across three consecutive cycles of application. These findings highlight the potential for industrial applications of noncovalently immobilized pectinase on various polyamide microparticles, with possibilities for customization of the conjugates' properties.

Optimizing Melamine Sponges Modified With Titanium Dioxide Nanoparticles for Environmental and Industrial Applications

ABSTRACTThis study explored the development and characterizations of a lightweight, cost‐effective, and easily accessible titanium dioxide (TiO2)/melamine sponge with outstanding hydrophobicity, oil absorption/separation, flame retardancy, durability, and electromagnetic wave absorption capacities. Commercial melamine sponges were modified using the silane coupling agent and TiO2 nanoparticles via a solution‐immersion method. Scanning Electron Microscopy revealed the structural integrity and surface morphology with increased surface roughness and uniform distribution of TiO2 particles. The hydrophobicity of the TiO2/sponge was confirmed by contact angle measurements, showing a high value of 145°. The oil absorption capacity and separation efficiency were also quantified, with the modified sponges able to absorb oils at 70 to 120 times their weight while maintaining a separation efficiency above 95% even after 10 reuse cycles. Additionally, the TiO2/sponge exhibited excellent flame resistance, strong mechanical abrasion resistance, and stability in saline environments. Electromagnetic absorption tests over the 2–18 GHz range showed efficient absorption, with reflection loss values below −10 dB at higher frequencies for thicker sponges. These results suggest that TiO2/sponge composites provide multifaceted enhancements, making them suitable for various environmental and industrial applications, including oil spill management and electromagnetic radiation mitigation.

Utilizing urban and agricultural waste for sustainable production of mesoporous hybrid nanocomposites in synthetic dye removal and antimicrobial activity.

The discharge of untreated dye waste from various industrial sectors into wastewater poses significant environmental and health risks. This study presents an innovative approach by developing a cost-effective and eco-friendly hybrid mesoporous nanocomposite, silver nanoparticles@mesoporous mango peel-derived carbon (AgNPs@MMC), synthesized from agricultural waste (mango peels) and urban waste (X-ray film waste). The core objectives of this work are: (i) recycling agricultural and urban waste to produce valuable materials; (ii) achieving effective removal of methyl violet 10B (MV10B) through simultaneous adsorption and photocatalytic degradation; and (iii) evaluating the antimicrobial properties of the developed material. The findings for identifying the optimal parameters for the adsorption and photodegradation process showed that 25mg of AgNPs@MMC can remove >98% of the MV10B dye in 30min at pH of 7. Furthermore, the nanocomposite maintained its high efficiency for five reuse cycles without significant loss in performance. This work highlights the dual functionality of AgNPs@MMC, combining adsorption and catalytic degradation, while also showcasing its potential for practical wastewater treatment applications. The nanocomposite's structural stability in water and its superior antibacterial activity against Gram-negative bacteria, such as Escherichia coli, Pseudomonas vulgaris, and Vibrio parahaemolyticus, further confirm its environmental suitability.

In situ formed Se-TiO2 as a highly reusable photocatalyst for selenium reduction and removal from industrial wastewater.

Selenium (Se) release from anthropogenic activities such as mining, power generation, and agriculture poses considerable environmental and ecological risks. Increasing prevalence and awareness of Se-related issues have driven the development of many innovative Se treatment technologies. Photocatalysis has shown promise towards Se removal from industrial wastewaters with minimal residuals, and is generally considered a low-cost, robust, non-toxic, and potentially solar-powered method. Despite this, its real-world application towards environmental remediation remains extremely limited. This is because research into practical considerations, such as photocatalyst stability and reusability, is often overlooked or understudied in favor of developing academically interesting but impractical materials. In this work, commercial anatase TiO2 is stress tested through fifteen cycles of reuse towards the photocatalytic reduction and removal of selenate in synthetic mine-influenced brine (SMIB) without washing or regeneration. Remarkably, selenate removal exceeds 99.3% throughout all cycles. In situ Se-TiO2 heterojunction formation, and changes to its properties including Se loading, particle size, and crystal phase, are characterized through X-ray absorption spectroscopy, scanning transmission electron microscopy, and diffuse reflectance UV/vis, while their effects on catalyst performance are elucidated. This work underscores the importance of catalyst recyclability for practical photocatalytic environmental remediation and discusses the effects of extensive use on photocatalyst performance.

Synthesis and antioxidant activity of 14-Aryl-14H-dibenzo[a,j] xanthene’s and bis(3-hydroxy-5,5′-dimethyl-2-cyclohexene-1-ones) derivatives using silica-tungstosulfonic acid catalyst

The synthesis of biologically active benzoxanthene, and bis(3-hydroxy-5,5’-dimethyl-2-cyclohexene-1-ones) derivatives has been conducted under an environmentally benign method by using an efficient catalyst, silica-tungstosulphonic acid. The benefits of this catalyst include being safe for the environment, low-cost, and simple to construct. It produces good yields and high purity in a short time and facilitates easy cleansing, products are obtained by straightforward recrystallization without the need for column chromatography. The reagent retained its catalytic activity for at least five consecutive cycles of reuse. The catalyst is described by IR, XRD, and SEM-EDX, which clearly shows that sulfonation happens in silica tungstic acid. In addition, the targeted derivatives were studied for anti-oxidant properties such as DPPH, reducing power assay, and H2O2 scavenging activity. The synthesized products such as 3e, 5k, 5 m, 5o, and 5p showed good anti-oxidant properties. Among all of these compounds, 5p showed good activity due to the nitro substitution on the benzene ring.

Characterization of Nanofibrous Acrylonitrile Membranes Functionalized with Immobilized Laccases via Ugi Technique

ABSTRACT The Ugi reaction offers notable advantages for enzyme immobilization by forming stable covalent bonds between the enzymes and polymers, thus ensuring enhanced stability and activity. In this study, Trametes versicolor laccase was immobilized on poly(acrylonitrile-co-methacrylic acid) (PANCMAA) nanofibers via the Ugi reaction. PANCMAA was electrospun using a 12.5% w/v solution in DMF at 1.0 mL.h−1, with an applied voltage of 10–13 kV, humidity between 50 and 60%, and temperature at 20°C. The Ugi reaction was conducted in 0.1 mol.L−1, phosphate buffer with 2 mg.mL−1 laccase, 59 µL acetone, 24 µL cyclohexyl isocyanide, and PANCMAA (5 cm × 8 cm) for 48 h under agitation. Control samples without enzymes were prepared for comparison. Morphological analysis via SEM revealed a decrease in porosity from 63% to 44% post-reaction. DSC revealed that the exothermic cyclization enthalpy decreased from −521 mJ.mg−1 to −194 mJ.mg−1 after the Ugi reaction. TGA showed increased mass loss at lower temperatures, indicating structural changes. FTIR-ATR confirmed enzyme immobilization, with new peaks at 1625 cm−1 and 1560 cm−1 corresponding to covalent bonding between fibers and laccase. The immobilization yield was 86 mg.g−1, with Km and Vmax values of 0.72 mm and 0.054 mm.min−1, respectively. The enzymes retained activity across a pH range of 3–6 and at temperatures ranging from 30°C to 60°C. After seven reuse cycles, the immobilized laccase retained more than 60% of its initial activity, demonstrating its potential for continuous use.

Clay minerals-mediated removal of Norfloxacin and Norfloxin-resistant bacteria from water environments and associated mechanisms.

Norfloxacin (NOR) is frequently detected in various water bodies and has the potential to promote the proliferation of NOR-resistant bacteria/genes in the environment. Efficiently removing residual NOR and NOR-resistant bacteria from contaminated water is critical to mitigating their environmental risks. This study investigated the ability of two common clay minerals, kaolinite and montmorillonite, to remove NOR and NOR-resistant bacteria from five different water environments (ultrapure water, simulated and real freshwater, and simulated and real seawater) and explored the underlying removal mechanisms. The results showed that both clays adsorbed NOR according to a pseudo-first-order kinetic model. In simulated and actual freshwater and seawater, the adsorption of NOR by kaolinite was 0.199, 0.120, 0.094, and 0.010mgg-1, while montmorillonite adsorbed NOR at significantly higher levels, with values of 2.880, 2.208, 0.433, and 0.067mgg-1, respectively. The primary mechanisms of adsorption included electrostatic interactions, cation exchange, and cation bonding and bridging. In addition to NOR sorption, culture tests revealed that montmorillonite exhibited significant antibacterial activity against NOR-resistant bacteria, achieving an inhibition ratio of 83.84 ± 4.01% when the initial concentrations of bacteria and montmorillonite were 1.68 ± 1.00 × 105CFU·mL-1 and 40mgmL-1, respectively. Remarkably, montmorillonite maintained its high sorption capacity and antibacterial activity even after multiple reuse cycles. These findings highlight the promising application potential of montmorillonite, particularly in terms of its storage and long-distance distribution capabilities, making it an effective material for removing both NOR and NOR-resistant bacteria from the environment. However, it is important to note that under estuarine conditions, clay-bound NOR could be released if water quality changes. Therefore, we conclude that strategies to degrade and remove antibiotics adsorbed onto clay minerals should be developed to prevent the release of antibiotics when clay particles enter the ocean, thus avoiding further environmental contamination.

Comparing the Photocatalytic Activity of Suspended and Floating Ag-decorated TiO2 for Dye Removal

We proposed a two-step synthesis process to fabricate floating TiO2 and Ag-decorated TiO2 (Ag/TiO2) photocatalysts. In the first step, an ultrasound-assisted sol-gel method followed by spray drying was adopted to synthesize powder photocatalysts. Next, the powder samples were immobilized onto a floating polyurethane foam (PUF) support with an ultrasound-assisted impregnation method. The photocatalytic activity of TiO2 and Ag/TiO2 was evaluated to remove methyl orange (MO) as a dye pollutant in two suspended and floating photocatalytic systems. Ag decoration on TiO2 improved the optical and textural properties by narrowing the bandgap energy to 2.9 eV and increasing the surface area from 10 m2/g to 30 m2/g. Ag/TiO2 exhibited higher photocatalytic activity compared to TiO2 for MO removal, which was 98% for suspended and 95% for floating catalysts under simulated sunlight irradiation. In addition, floating photocatalysts exhibited higher photocatalytic activity over five cycles of reuse. Floating Ag/TiO2@PUF maintained 89% of its initial photoactivity, while suspended Ag/TiO2 lost 50% after the five cycles. Moreover, we investigated the effect of operating conditions on the photocatalytic performance of floating Ag/TiO2@PUF. Optimal conditions for the complete removal of MO below detection limits were obtained as follows: Ag/TiO2@PUF loading = 0.4:200 g/mL, initial MO concentration = 5 mg/L, time = 90 min, and pH = 4 under simulated sunlight irradiation. This study highlights the potential of floating photocatalyst systems as a sustainable, reusable, and scalable approach for wastewater treatment, addressing challenges in catalyst recovery and efficiency under real-world conditions.

Bisphenol A in Water Systems: Risks to Polycystic Ovary Syndrome and Biochar-Based Adsorption Remediation: A Review.

Access to clean and safe water sadly remains an issue in the 21st century. Water reservoirs, whether groundwater or surface water, are routinely contaminated by various harmful Emerging Contaminants (ECs). One of most prevalent pollutants among these pollutants is Bisphenol A, which is classified as an Endocrine Disrupting Compound (EDC). This substance adversely interferes with the endocrine system, primarily by mimicking estrogen, and has been considered a potential contributor to Polycystic Ovary Syndrome (PCOS) with 82.70 % of 1,391 women studied showing a positive correlation between BPA exposure and PCOS. PCOS is currently the most prevalent endocrine disorder affecting women of reproductive age; however, its pathogenesis remains unclear, complicating diagnosis and subsequently patient care. In this review, these topics are thoroughly examined, with particular emphasis on biochar, a new promising method for large-scale water purification. Biochar, derived from various organic waste materials, has emerged as a cost-effective substance with remarkable adsorption properties achieving up to 88 % efficiency over four cycles of reuse, similar to that of activated carbon. This review interrogates the suitability of biochar for counteracting the issue of EDC pollutants.

Micromolar-level glucose detection using a colorimetric sensor based on imprinted polymer-coated Fe3O4 nanoparticles

The glucose concentration in the blood, commonly referred to as blood sugar level, typically ranges from 3.9 to 5.6 mmol/L. It is one of the most critical physiological parameters in the human body, requiring strict regulation to maintain proper bodily function. There is a strong demand for glucose sensors that are highly sensitive, user-friendly, and exhibit high selectivity towards glucose molecules, even in challenging environments. In this study, a colorimetric sensor based on imprinted polymer and Fe3O4 nanoparticles (NPs) was developed, enabling the detection of glucose at micromolar levels, observable by the naked eye. Fe3O4 NPs were prepared using a sol–gel method and served as cores for the deposition of polydopamine (PDA) via in situ polymerization. An imprinting process created glucose-imprinted PDA, resulting in molecular cavities on the PDA surface, with the polymeric layer approximately 25 nm thick. The surface of the Fe3O4 NPs facilitated the degradation reaction of H2O2 to produce hydroxyl radicals (•OH), which subsequently oxidized 3,3′,5,5′-Tetramethylbenzidine (TMB) to its oxidized form (TMB+), causing a color change from colorless to blue. The cavities played a crucial role in the sensing mechanism, connecting the catalytic surface of the Fe3O4 NPs to the surrounding environment. When glucose molecules occupied the cavities, the catalytic activity decreased, leading to a corresponding variation in color change depending on glucose concentration. Leveraging these advantages, the imprinted PDA was applied to detect glucose in aqueous solutions and human plasma with a limit of detection as low as 10 µM. The sensor exhibited high selectivity towards glucose over other common analytes in human blood, such as lysine, Ca2+, and K+, along with reproducibility, maintaining approximately 73 % of its sensing signal after six cycles of reuse. This study demonstrates the detection of glucose by the naked eye at micromolar levels. The detection procedure can be conducted outside of laboratory settings, presenting a highly promising approach for glucose detection in real-world applications, particularly in remote areas.