EDTA-functionalized KCC-1 and KIT-6 mesoporous silicas for Nd3+ ion recovery from aqueous solutions

2D Amino-Functionalized Black Phosphorus: A New Approach to Improve Hydrogen Gas Detection Performance

In recent years, hydrogen has gained attention as a potential solution to replace fossil fuels, thus reducing greenhouse gas emissions. The development of ever improving hydrogen sensors is a topic that is constantly under study due to concerns about the inherent risk of leaks of this gas and potential explosions. In this work, a new, long-term, stable phosphorene-based sensor was developed for hydrogen detection. A simple functionalization of phosphorene using urea was employed to synthesize an air-stable material, subsequently used to prepare films for gas sensing applications, via the drop casting method. The material was deeply characterized by different techniques (scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and Raman spectroscopy), and the stability of the material in a noninert atmosphere was evaluated. The phosphorene-based sensor exhibited high sensitivity (up to 700 ppm) and selectivity toward hydrogen at room temperature, as well as long-term stability over five months under ambient conditions. To gain further insight into the gas sensing mechanism over the surface, we employed a dedicated apparatus, namely operando diffuse reflectance infrared Fourier transform, by exposing the chemoresistive sensor to hydrogen gas under dry air conditions.

Benzene Oxidation in Air by an Amine-Functionalized Metal-Organic Framework-Derived Carbon- and Nitrogen-Loaded Zirconium Dioxide-Supported Platinum Catalyst

To learn more about the behavior of amine (NH2)-functionalized metal-organic framework (MOF)-derived noble metal catalysts in the removal of aromatic volatile organic compounds in air, benzene oxidation at low temperatures has been investigated using 0.2-, 0.8-, and 1.5%-platinum (Pt)/Universitetet i Oslo (UiO)-66-NH2. The benzene conversion (XB) of x%-Pt/UiO-66-NH2-R under dry conditions (175 °C) was 23% (x = 0.2%) < 52% (x = 0.8%) < 100% (x = 1.5%): 'R' suffix denotes reduction pretreatment using a hydrogen (10 vol %) and nitrogen mixture at 300 °C for the generation of metallic Pt (Pt0) sites and simultaneous partial MOF decomposition into carbon- and nitrogen-loaded zirconium dioxide. The prominent role of reduction pretreatment was apparent in benzene oxidation as 1.5%-Pt/UiO-66-NH2 did not exhibit catalytic activity below 175 °C (dry condition). The promotional role of moisture in benzene oxidation by 1.5%-Pt/UiO-66-NH2-R was evident with a rise in the steady-state reaction rate (r) at 110 °C (21 kPa molecular oxygen (O2)) from 1.3 × 10-3 to 5.0 × 10-3 μmol g-1 s-1 as the water (H2O) partial pressure increased from 0 to 1.88 kPa. In contrast, the activity was lowered with increasing RH due to catalyst poisoning by excess moisture (r (110 °C) of 6.6 × 10-04 μmol g-1 s-1 at 2.83 kPa H2O (21 kPa O2)). Kinetic modeling suggests that XB proceeds through the Langmuir-Hinshelwood mechanism on the Pt/UiO-66-NH2-R surface (dissociative O2 chemisorption and the involvement of two oxygen species in benzene oxidation). According to the density functional theory simulation, the carbon and nitrogen impurities are to make the first XB step (i.e., hydrogen migration from the benzene molecule to the substrate) energetically favorable. The second hydrogen atom from the benzene molecule is also extracted effectively, while the oxygen derived from O2 facilitates further XB. The Pt0 sites dissociate the O2 and H2O molecules, while the product of the latter, i.e., free hydrogen and hydroxyl, makes the subsequent XB steps energetically favorable.

Fabrication of an all-in-one self-enhanced solid-state electrochemiluminescence sensing platform for the selective detection of spermine

The fabrication of an all-in-one solid-state ECL sensing platform is beneficial not only for expediting the miniaturization of sensing devices, but also, more importantly, for enabling point-of-care applications. In the present work, a self-enhanced solid-state ECL sensing platform is fabricated using newly synthesised silica polyethylene nanoparticles (SiO2-PEI NPs) which generate a co-reactant in situ and easily self-assemble with Ru(bpy)32+ and shows selective and sensitive detection of spermine at physiological pH (7.4). Spermine induces the maximum ECL emission intensity compared to other biogenic amines due to the presence of two secondary amines. A possible ECL reaction mechanism has been proposed based on CV and ECL experiments, DFT calculations, and in situ ECL spectrum analysis. The developed solid-state sensor showed a linear increase in ECL intensity with increasing spermine concentration in the range of 10 nM to 100 nM with an LOD of 12.2 nM. Compared to other biogenic amines in previous works, chemically synthesised SiO2-PEI NPs used in the present study act as an effective label- and enzyme-free sensor, and the new method is observed to be simple and cost-effective, to overcome various limitations of solution-phase ECL and to avoid the usage of any noble metals.

Overview of Functionalized Porous Materials for Rare-Earth Element Separation and Recovery

The exceptional photoelectromagnetic characteristics of rare-earth elements contribute significantly to their indispensable position in the high-tech industry. The exponential expansion of the demand for high-purity rare earth and related compounds can be attributed to the swift advancement of contemporary technology. Nevertheless, rare-earth elements are finite and limited resources, and their excessive mining unavoidably results in resource depletion and environmental degradation. Hence, it is crucial to establish a highly effective approach for the extraction and reclamation of rare-earth elements. Adsorption is regarded as a promising technique for the recovery of rare-earth elements owing to its simplicity, environmentally friendly nature, and cost-effectiveness. The efficacy of adsorption is contingent upon the performance characteristics of the adsorbent material. Presently, there is a prevalent utilization of porous adsorbent materials with substantial specific surface areas and plentiful surface functional groups in the realm of selectively separating and recovering rare-earth elements. This paper presents a thorough examination of porous inorganic carbon materials, porous inorganic silicon materials, porous organic polymers, and metal-organic framework materials. The adsorption performance and processes for rare-earth elements are the focal points of discussion about these materials. Furthermore, this work investigates the potential applications of porous materials in the domain of the adsorption of rare-earth elements.

A Highly Electrostrictive Salt Cocrystal and the Piezoelectric Nanogenerator Application of Its 3D-Printed Polymer Composite

Ionic cocrystals with hydrogen bonding can form exciting materials with enhanced optical and electronic properties. We present a highly moisture-stable ammonium salt cocrystal [CH3C6H4CH(CH3)NH2][CH3C6H4CH(CH3)NH3][PF6] ((p-TEA)(p-TEAH)·PF6) crystallizing in the polar monoclinic C2 space group. The asymmetry in (p-TEA)(p-TEAH)·PF6 was induced by its chiral substituents, while the polar order and structural stability were achieved by using the octahedral PF6- anion and the consequent formation of salt cocrystal. The ferroelectric properties of (p-TEA)(p-TEAH)·PF6 were confirmed through P-E loop measurements. Piezoresponse force microscopy (PFM) enabled the visualization of its domain structure with characteristic "butterfly" and hysteresis loops associated with ferro- and piezoelectric properties. Notably, (p-TEA)(p-TEAH)·PF6 exhibits a large electrostrictive coefficient (Q33) value of 2.02 m4 C-2, higher than those found for ceramic-based materials and comparable to that of polyvinylidene difluoride. Furthermore, the composite films of (p-TEA)(p-TEAH)·PF6 with polycaprolactone (PCL) polymer and its gyroid-shaped 3D-printed composite scaled-up device, 3DP-Gy, were prepared and evaluated for piezoelectric energy-harvesting functionality. A high output voltage of 22.8 V and a power density of 118.5 μW cm-3 have been recorded for the 3DP-Gy device. Remarkably, no loss in voltage outputs was observed for the (p-TEA)(p-TEAH)·PF6 devices even after exposure to 99% relative humidity, showcasing their utility under extremely humid conditions.

Intermetallic Pd-Y nanoparticles/N-doped carbon nanotubes as multi-active catalysts for oxygen reduction reaction, ethanol oxidation reaction, and zinc-air batteries

Intermetallic nanomaterials are unique in terms of their band gap, atomic-level arrangement, and well-defined stoichiometry, which allows them to exhibit significantly enhanced catalytic performance in electrochemical applications. However, the preparation of durable intermetallic catalysts with a lower content of platinum group metals is challenging, while the lack of control over the loss of active components limits their long-term application due to weak interaction between the support and the nanostructure. Here, we have designed the intermetallic alloyed nanoparticles (NPs) of PdY on N-doped carbon nanotubes (PdY/NCNTs) as a multifunctional catalyst for the oxygen reduction reaction (ORR), the ethanol oxidation reaction (EOR), and zinc-air batteries (ZABs). The strong adhesion through nitrogen ensures the anchoring of alloyed PdY NPs on the NCNTs, which restrains atomic migration and sintering during their conversion to intermetallic phases. This study confirms that there is negligible active site leaching owing to the strong and multiple dative bonds between the NCNTs and PdY NPs. Therefore, this catalyst exhibits remarkable catalytic activity, resulting in a mass activity of 1317 and 2902 mA mgPd-1 at jk and jf for the ORR and the EOR, respectively, and remains stable for a longer period. In addition, the PdY/NCNT-containing air cathode-fabricated ZAB achieved a higher power density (0.236 W cm-2) compared to the benchmark Pt/C.

Sensing of hyperprolinemia biomarker and its recognition in biological sample through "turn-on" event by Zn-based metal-organic framework

A hydrogen bonded ability metal organic framework (MOF, 1Zn) is used for the ultra-sensitive "turn-on" detection of hyperprolinemia biomarker with ultrafast (within 5 s) colorimetric response making the first MOF based hyperprolinemia biomarker sensor. The detection limit (4.46 ppb) is outperformed compared to all contemporary hyperprolinemia biomarker based sensors. Further, the sensor showed the recognition of biomarker in biological sample (human saliva). The detection of biomarker is also realized through colorimetric response (solution based and paper strip method). The mechanism of sensing is established through the electron transfer and the absorption caused emission (ACE). Moreover, the theoretical study is performed to support the sensing mechanism. The control titration of 1Zn suggest that the free -NH2 group of linker in 1Zn is involved in supramolecular interaction (hydrogen bonding) with the carboxylic group present on biomarker results the facile occurrence of electron transfer and ACE. Consequently, the luminescence "turn-on" effect of 1Zn for hyperprolinemia biomarker is observed.

Selective recovery of copper from copper tailings and wastewater using chelating resins with bis-picolylamine functional groups

Industrial and mining wastewater, along with copper tailings, are typically highly acidic and contain copper and other heavy metals, which may contaminate and damage the environment. Copper (Cu) is, however, a valuable metal, making its removal and recovery from such wastewater and tailings environmentally and economically advantageous. Chelating ion exchange resins featuring bis-picolylamine functional groups are especially suitable for application requiring selective recovery of Cu(II) from highly acidic media. In this study, and for the first time, the kinetics, binding capacity and selectivity of Lewatit MDS TP 220 chelating resin towards Cu(II) are reported. The resin was characterized by Zeta potential, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Factors including pH, initial concentration, contact time, temperature, and selectivity were investigated to assess the adsorption performance of the chelating resin. The adsorption kinetics tests revealed fast adsorption within the first 5-30 min and fitted the pseudo-second-order model, signifying chemisorption process. The adsorption isotherm followed the Langmuir model, implying monolayer adsorption process. The maximum adsorption capacity (qm) for Cu(II) determined by the Langmuir model was 103.9 mg/g. The adsorption thermodynamics showed an endothermic and spontaneous adsorption. FTIR and XPS studies suggested coordination or chelation as the possible adsorption mechanism. Lewatit MDS TP 220 exhibited excellent Cu(II) adsorption, desorption with 2 M ammonium hydroxide (NH4OH), and selectivity in multi-metal ions solution. Additionally, the resin demonstrated excellent reusability after five regeneration steps. This chelating resin is a potential adsorbent for effective and recurrent recovery of Cu(II) from copper tailings and wastewater, thereby contributing to environmental remediation.

Pyrene and Eu3+ modified mesoporous silica used as a fluorescent probe for ratiometric detection of tetracycline antibiotics

The detection of residual tetracycline antibiotics (TCs) in the aquatic environment is important because of the irreversible damage of TCs to the ecosystem and human health. Considering the photostability, sensitivity, and accuracy of the detection systems, mesoporous SBA-15 silica material was an ideal support matrix for improving photostability because it can protect the optical properties of fluorescent signals. To achieve ratiometric detection (with sensitivity and accuracy), pyrene and Eu3+ as two fluorescent signals were implemented into SBA-15, and an organic-inorganic hybrid fluorescent nanoprobe Py/EDTA-SBA-15@Eu3+ was constructed. In the presence of TCs, the red emission of Eu3+ in the nanoprobe was sensitized, and the fluorescence resonance energy transfer occurred from pyrene to Eu3+, resulting in the increased emission of Eu3+ at 617 nm and the decreased emission of pyrene at 384 nm. By monitoring the fluorescent intensity changes at 617 and 384 nm (F617/F384), the nanoprobe achieved the ratiometric detection of oxytetracycline (OTC) and tetracycline (TC) in the range of 0.20-80 and 0.40-80 μM, respectively, with detection limits of 0.18 nM for OTC and 5.83 nM for TC. In addition, the practical application of the nanoprobe was validated in tap water and honey samples.

Enhancing cationic dye removal via biocomposite formation between chitosan and food grade algae: Optimization of algae loading and adsorption parameters

Herein, a natural material including chitosan (CTS) and algae (food-grade algae, FGA) was exploited to attain a bio-adsorbent (CTS/FGA) for enhanced methyl violet 2B dye removal. A study of the FGA loading into CTS matrix showed that the best mixing ratio between CTS and FGA to be used for the MV 2B removal was 50 %:50 % (CTS/FGA; 50:50 w/w). The present study employed the Box-Behnken design (RSM-BBD) to investigate the impact of three processing factors, namely CTS/FGA-(50:50) dose (0.02-0.1 g/100 mL), pH of solution (4-10), and contact time (5-15 min) on the decolorization rate of MV 2B dye. The results obtained from the equilibrium and kinetic experiments indicate that the adsorption of MV 2B dye on CTS/FGA-(50:50) follows the Langmuir and pseudo-second-order models, respectively. The CTS/FGA exhibits an adsorption capacity of 179.8 mg/g. The characterization of CTS/FGA-(50:50) involves the proposed mechanism of MV 2B adsorption, which primarily encompasses various interactions such as electrostatic forces, n-π stacking, and H-bonding. The present study demonstrates that CTS/FGA-(50:50) synthesized material exhibits a distinctive structure and excellent adsorption properties, thereby providing a viable option for the elimination of toxic cationic dyes from polluted water.

High adsorptive performance of chitosan-microalgae-carbon-doped TiO2 (kronos)/ salicylaldehyde for brilliant green dye adsorption: Optimization and mechanistic approach

A composite of chitosan biopolymer with microalgae and commercial carbon-doped titanium dioxide (kronos) was modified by grafting an aromatic aldehyde (salicylaldehyde) in a hydrothermal process for the removal of brilliant green (BG) dye. The resulting Schiff's base Chitosan-Microalgae-TiO2 kronos/Salicylaldehyde (CsMaTk/S) material was characterised using various analytical methods (conclusive of physical properties using BET surface analysis method, elemental analysis, FTIR, SEM-EDX, XRD, XPS and point of zero charge). Box Behnken Design was utilised for the optimisation of the three input variables, i.e., adsorbent dose, pH of the media and contact time. The optimum conditions appointed by the optimisation process were further affirmed by the desirability test and employed in the equilibrium studies in batch mode and the results exhibited a better fit towards the pseudo-second-order kinetic model as well as Freundlich and Langmuir isotherm models, with a maximum adsorption capacity of 957.0 mg/g. Furthermore, the reusability study displayed the adsorptive performance of CsMaTk/S remains effective throughout five adsorption cycles. The possible interactions between the dye molecules and the surface of the adsorbent were derived based on the analyses performed and the electrostatic attractions, H-bonding, Yoshida-H bonding, π-π and n-π interactions are concluded to be the responsible forces in this adsorption process.

Polarizable Additive with Intermediate Chelation Strength for Stable Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries are promising due to inherent safety, low cost, low toxicity, and high volumetric capacity. However, issues of dendrites and side reactions between zinc metal anode and the electrolyte need to be solved for extended storage and cycle life. Here, we proposed that an electrolyte additive with an intermediate chelation strength of zinc ion-strong enough to exclude water molecules from the zinc metal-electrolyte interface and not too strong to cause a significant energy barrier for zinc ion dissociation-can benefit the electrochemical stability by suppressing hydrogen evolution reaction, overpotential growth, and dendrite formation. Penta-sodium diethylene-triaminepentaacetic acid salt was selected for such a purpose. It has a suitable chelating ability in aqueous solutions to adjust solvation sheath and can be readily polarized under electrical loading conditions to further improve the passivation. Zn||Zn symmetric cells can be stably operated over 3500 h at 1 mA cm-2. Zn||NH4V4O10 full cells with the additive show great cycling stability with 84.6% capacity retention after 500 cycles at 1 A g-1. Since the additive not only reduces H2 evolution and corrosion but also modifies Zn2+ diffusion and deposition, highlyreversible Zn electrodes can be achieved as verified by the experimental results. Our work offers a practical approach to the logical design of reliable electrolytes for high-performance aqueous batteries.

Cell adhesion molecule immobilized gold surfaces for enhanced neuron-electrode interfaces

To provide a long-term solution for increasing the biocompatibility of neuroprosthetics, approaches to reduce the side effects of invasive neuro-implantable devices are still in need of improvement. Physical, chemical, and bioactive design aspects of the biomaterials are proven to be important for providing proper cell-to-cell, cell-to-material interactions. Particularly, modification of implant surfaces with bioactive cues, especially cell adhesion molecules (CAMs) that capitalize on native neural adhesion mechanisms, are promising candidates in favor of providing efficient interfaces. Within this concept, this study utilized specific CAMs, namely N-Cadherin (Neural cadherin, N-Cad) and neural cell adhesion molecule (NCAM), to enhance neuron-electrode contact by mimicking the cell-to-ECM interactions for improving the survival of cells and promoting neurite outgrowth. For this purpose, representative gold electrode surfaces were modified with N-Cadherin, NCAM, and the mixture (1:1) of these molecules. Modifications were characterized, and the effect of surface modification on both differentiated and undifferentiated neuroblastoma SH-SY5Y cell lines were compared. The findings demonstrated the successful modification of these molecules which subsequently exhibited biocompatible properties as evidenced by the cell viability results. In cell culture experiments, the CAMs displayed promising results in promoting neurite outgrowth compared to conventional poly-l-lysine coated surfaces, especially NCAM and N-Cad/NCAM modified surfaces clearly showed significant improvement. Overall, this optimized approach is expected to provide an insight into the action mechanisms of cells against the local environment and advance processes for the fabrication of alternative neural interfaces.

Diaminopropane-appended activated carbons for the adsorptive removal of gaseous formaldehyde using a portable indoor air purification unit

It is of significant practical interest to develop high-performance air purifier (AP) for removing carcinogenic volatile organic compounds present ubiquitously in indoor air (e.g., formaldehyde (FA)). In this regard, a portable AP system was designed by loading honeycomb ceramic filters with diaminopropane (DAP)-appended activated carbon (AC). The maximum removal efficiencies (REs) of AP loaded with 10, 20, 30, and 50 %-DAP/AC were 26.2, 28, 88.3, and 89.4 %, respectively, against 5 ppm FA (at 160 L min-1). Hence, the 30 % DAP unit was used mainly in this work. The removal efficiency of 30 %-DAP/AC (160 L min-1), when tested against 2 ppm FA, decreased from 90.3 to 73.2 % with an increase in relative humidity from 0 to 60 %. The performance of the AP unit, when assessed kinetically in terms of the clean air delivery rate (CADR), reached as high as 10.2 L min-1 at the flow rate of 160 L min-1. Isotherm analysis further demonstrated the complex multilayered adsorption behavior of FA. Based on the density functional theory (DFT) simulation, the superiority of DAP/AC for FA adsorption can be attributed to the synergy of covalent (chemisorption) and non-covalent (pore filling and film diffusion) interactions.

Green synthesis of N,S-doped carbon dots for tartrazine detection and their antibacterial activities

A simple, green and low-cost method was developed for the synthesis of highly fluorescent N,S-doped carbon dots (N,S-CDs) via the hydrothermal treatment of Gandha Prasarini (GP) leaves as a natural source of carbon, nitrogen and sulfur. The as-prepared N,S-CDs exhibited excitation-dependent green fluorescence emission (λex = 450 nm, λem = 525 nm) with excellent stability, and were used as a fluorescent probe for the selective detection of tartrazine with a limit of detection of 0.18 μM. The fluorescence quenching of N,S-CDs was due to the inner filter effect. The developed method has been employed for the determination of tartrazine in honey and soft drinks with satisfactory recovery ranging from 92 to 110.2%. In addition, the antibacterial activity of the N,S-CDs was explored against both Gram-negative bacteria, Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), and Gram-positive bacteria, Staphylococcus aureus (S. aureus). The antibacterial mechanism of the N,S-CDs was investigated. The results indicated that the antibacterial activity was due to the membrane damage of the bacteria by the N,S-CDs. Besides, the N,S-CDs showed negligible lytic effects on human erythrocytes. These findings will inspire further exploitation of CD-based nano-bactericides in biomedical applications.

Dendritic mesoporous nanoparticles for the detection, adsorption, and degradation of hazardous substances in the environment: State-of-the-art and future prospects

Equipped with hierarchical pores and three-dimensional (3D) center-radial channels, dendritic mesoporous nanoparticles (DMNs) make their pore volumes extremely large, specific surface areas super-high, internal spaces especially accessible, and so on. Other entities (like organic moieties or nanoparticles) can be modified onto the interfaces or skeletons of DMNs, accomplishing their functionalization for desirable applications. This comprehensive review emphasizes on the design and construction of DMNs-based systems which serve as sensors, adsorbents and catalysts for the detection, adsorption, and degradation of hazardous substances, mainly including the construction procedures of brand-new DMNs-based materials and the involved hazardous substances (like industrial chemicals, chemical dyes, heavy metal ions, medicines, pesticides, and harmful gases). The sensitive, adsorptive, or catalytic performances of various DMNs have been compared; correspondingly, the reaction mechanisms have been revealed strictly. It is honestly anticipated that the profound discussion could offer scientists certain enlightenment to design novel DMNs-based systems towards the detection, adsorption, and degradation of hazardous substances, respectively or comprehensively.

Multilayered LDH/Microcapsule Smart Epoxy Coating for Corrosion Protection

A multilayered smart epoxy coating for corrosion prevention of carbon steel was developed and characterized. Toward this direction, as a first step, zinc-aluminum nitrate-layered double hydroxide (Zn/Al LDH) was synthesized using the hydrothermal crystallization technique and then loaded with dodecylamine (DOD), which was used as an inhibitor (pH-sensitive). Similarly, the synthesis of the urea-formaldehyde microcapsules (UFMCs) has been carried out using the in-situ polymerization method, and then the microcapsules (LAUFCs) were encapsulated with linalyl acetate (LA) as a self-healing agent. Finally, the loaded Zn/Al LDH (3 wt %) and modified LAUFCs (5 wt %) were reinforced into an epoxy matrix to develop a double-layer coating (DL-EP). For an exact comparison, pre-layer epoxy coatings comprising 3 wt % of the loaded Zn/Al LDH (referred to as LDH-EP), top-layer epoxy coatings comprising 5 wt % linalyl acetate urea-formaldehyde microcapsules (referred to as UFMLA COAT), and a blank epoxy coating (reference coating) were also developed. The developed epoxy coatings were characterized using various techniques such as XRD, XPS, BET, TGA, FTIR, EIS, etc. Electrochemical tests performed on the synthesized coatings indicate that the DL-EP demonstrates improved self-healing properties compared to LDH-EP and UFMLA COAT.

Natural Rubber/Hexagonal Mesoporous Silica Nanocomposites as Efficient Adsorbents for the Selective Adsorption of (-)-Epigallocatechin Gallate and Caffeine from Green Tea

(-)-Epigallocatechin gallate (EGCG) is a bioactive component of green tea that provides many health benefits. However, excessive intake of green tea may cause adverse effects of caffeine (CAF) since green tea (30-50 mg) has half the CAF content of coffee (80-100 mg). In this work, for enhancing the health benefits of green tea, natural rubber/hexagonal mesoporous silica (NR/HMS) nanocomposites with tunable textural properties were synthesized using different amine template sizes and applied as selective adsorbents to separate EGCG and CAF from green tea. The resulting adsorbents exhibited a wormhole-like silica framework, high specific surface area (528-578 m2 g-1), large pore volume (0.76-1.45 cm3 g-1), and hydrophobicity. The NR/HMS materials adsorbed EGCG more than CAF; the selectivity coefficient of EGCG adsorption was 3.6 times that of CAF adsorption. The EGCG adsorption capacity of the NR/HMS series was correlated with their pore size and surface hydrophobicity. Adsorption behavior was well described by a pseudo-second-order kinetic model, indicating that adsorption involved H-bonding interactions between the silanol groups of the mesoporous silica surfaces and the hydroxyl groups of EGCG and the carbonyl group of CAF. As for desorption, EGCG was more easily removed than CAF from the NR/HMS surface using an aqueous solution of ethanol. Moreover, the NR/HMS materials could be reused for EGCG adsorption at least three times. The results suggest the potential use of NR/HMS nanocomposites as selective adsorbents for the enrichment of EGCG in green tea. In addition, it could be applied as an adsorbent in the filter to reduce the CAF content in green tea by up to 81.92%.

Neutral - Eradication of As (III) and Congo red (CR) with green iron oxide (GIO) loaded chitosan(C) - (C - GIO) beads by a non - Thermal plasma jet via potential study

In this potential - study, the non - thermal atmospheric pressure plasma is utilized for the neutral - eradication of water contaminants. In the air ambient region, plasma induced reactive species, like as OH^•, O (O₂^-), H₂O₂ (OH^•+OH^•) & NO_x are performed for the oxidative and reductive transformation of As^III (H₃AsO₃) to As^V (H₂As O₄^-) & Fe₃O₄ (Fe³⁺) (C-GIO) to Fe₂O₃ (Fe²⁺). Whereas, the H₂O₂ & NO_x are quantified maximum (max.) in water, which is 144.24 & 111.82 μM, respectively. In the absence of plasma and plasma with C-GIO, the As^III was more eradicated, which is 64.01 and 100.00%. While, the C - GIO (catalyst) synergistic enhancement was performed and proved by the neutral - degradation of CR. Also, the As^V adsorbed on C-GIO adsorption capacity q_max and redox-adsorption yield were evaluated, which are 1.36 mg/g and 20.80 g/kWh, respectively. In this research, the waste material (GIO) was recycled, modified, and utilized for the neutral - eradication of water contaminates, which are organic (CR) and inorganic (As^III) toxicants by the controlling of H and OH^• under the interaction of plasma with catalyst (C-GIO). However, in this research, plasma can't adopt the acidic, which is controlled by the C-GIO via RONS. Moreover, in this eradicative study, various water pH alignments were performed, from neutral to acidic & neutral & base for toxicants removal. Furthermore, according to WHO norms, the arsenic level was reduced to 0.01 mg/l for environmental safety. The kinetic and isotherm studies were followed by the mono and multi-layer adsorption was performed on the surface of C - GIO beads, which is estimated by the fitting of rate limiting constant R² ≈ 1. Furthermore, the C-GIO was examined several characterizations alignments, such as crystal, surface, functional, elemental composition, retention time, mass spectrum, and elemental oriented properties. Overall, the suggested hybrid system is an eco-friendly pathway for the natural - eradication of contaminants, such as organic and inorganic compounds via waste material (GIO) recycling, modification, oxidation, reduction, adsorption, degradation, and neutralization phenomenon.

Palladium nanoparticles supported on ionic liquid and glucosamine-modified magnetic iron oxide as a catalyst in reduction reactions

A magnetic nanocomposite comprising imidazolium ionic liquid and glucosamine is successfully synthesized and used for stabilization of Pd nanoparticles. This new material, Fe₃O₄@SiO₂@IL/GA-Pd, is fully characterized and applied as a catalyst in the reduction of nitroaromatic compounds to desired amines at room temperature. Also, the reductive degradation of organic dyes such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB) is studied and compared with another previous publications. The survey of the stabilization of the palladium catalytic entities is described demonstrating the separation ability and recycling of them. In addition, TEM, XRD, and VSM analyses of the recycled catalyst confirmed its stability.

Speciation of Hexavalent Chromium in Aqueous Solutions Using a Magnetic Silica-Coated Amino-Modified Glycidyl Methacrylate Polymer Nanocomposite

A new magnetic amino-functionalized polymeric sorbent based on glycidyl methacrylate was synthesized and used in the separation of chromium Cr(VI) oxyanions sorption from aqueous solutions in a static batch system. The kinetic and isothermal parameters of the sorption process were determined. The experimental data were best fitted by a pseudo-second-order model with R² = 0.994 and χ² = 0.004. The sorption process of Cr(VI) removal by amino-functionalized sorbent was controlled by both intraparticle diffusion and liquid film diffusion. The equilibrium results showed that the sorption process is best described by the Freundlich model, followed closely by the Sips isotherm model, with a maximum sorption capacity of 64 mg/g. Quantum chemical modeling revealed that the sorption sites on the sorbent surface are fragments with diethylenetriamine and aminopropyl silane groups that coated the magnetic nanoparticles. The calculations showed that Cr(VI) oxyanions (Cr₂O₇^2-, CrO₄^2- and HCrO₄^-) bind to both sorption sites, with diethylenetriamine centers slightly favored. The X-ray photoelectron spectroscopy (XPS) spectra demonstrate that the chromium bound to the sorbent in the form of Cr(III), indicating that the Cr(VI) can be converted on the surface of the sorbent to a less harmful form Cr(III) due to the sorbent's chemical composition.

Probing the Interfacial Properties of Oil-Water Interfaces Decorated with Ionizable, pH Responsive Silica Nanoparticles

Particle-stabilized emulsions (Pickering emulsions) have recently attracted significant attention in scientific studies and for technological applications. The interest stems from the ease of directly assembling the particles at interfaces and modulating the interfacial properties. In this paper, we demonstrate the formation of stable, practical emulsions leveraging the assembly of ionizable, pH responsive silica nanoparticles, surface-functionalized by a mixture of silanes containing amine/ammonium groups, which renders them positively charged. Using pH as the trigger, the assembly and the behavior of the emulsion are controlled by modulating the charges of the functional groups of the nanoparticle and the oil (crude oil). In addition to their tunable charge, the particular combination of silane coupling agents leads to stable particle dispersions, which is critical for practical applications. Atomic force microscopy and interfacial tension (IFT) measurements are used to monitor the assembly, which is controlled by both the electrostatic interactions between the particles and oil and the interparticle interactions, both of which are modulated by pH. Under acidic conditions, when the surfaces of the oil and the nanoparticles (NPs) are positively charged, the NPs are not attracted at the interface and there is no significant reduction in the IFT. In contrast, under basic conditions in which the oil carries a high negative charge and the amine groups on the silica are deprotonated while still positively charged because of the ammonium groups, the NPs assemble at the interface in a closely packed configuration yielding a jammed state with a high dilatational modulus. As a result, two oil droplets do not coalesce even when pushed against each other and the emulsion stability improves significantly. The study provides new insights into the directed assembly of nanoparticles at fluid interfaces relevant to several applications, including environmental remediation, catalysis, drug delivery, food technology, and oil recovery.

Carbon Nanotube-Incorporated Nanofibers for Immunosensor Preparation against CD36

The increased serum concentration of CD36 is significantly associated with atherosclerosis, insulin resistance, and diabetes mellitus. Currently, there is no sensor system used for the detection of CD36 in the clinical field. Therefore, there is a need to develop a sensor system for the detection of CD36. The large surface area/volume ratio and controllable surface conformation of electrospun nanofibers (ENs) make them highly attractive for immunosensor applications. In the present study, PS/MWCNT-PAMAM ENs were produced and used as an immobilization matrix of Anti-CD36. Thus, the electrochemical behavior of the developed nanocomposite-based ENs and their usage potential were investigated for immunosensor applications. First, an oxidized multiwall carbon nanotube (MWCNT-OH) was synthesized and modified with a polyamidoamine generation 3 (PAMAM G3) dendrimer. The synthesized MWCNT-PAMAM nanocomposite was mixed with polystyrene (PS) solutions at different ratios to produce bead-free, smooth, and uniform PS/MWCNT-PAMAM ENs. PS/MWCNT-PAMAM ENs were accumulated on a screen-printed carbon electrode (SPCE) using the electrospinning technique. A biofunctional surface on the PS/MWCNT-PAMAM EN-coated SPCE was created using carbodiimide chemistry by covalent immobilization of Anti-CD36. The analytic performance characteristics of the developed PS/MWCNT-PAMAM/Anti-CD36 immunosensor were determined by performing electrochemical measurements in the presence of the CD36 protein. The linear detection range was found to be from 5 to 40 ng/mL, and the limit of detection was calculated as 3.94 ng/mL for CD36. The developed PS/MWCNT-PAMAM/Anti-CD36 immunosensor also displayed high tolerance to interference substances, good repeatability, and high recovery percent (recovery%) for artificial blood serum analysis.

Highly gallol-substituted, rapidly self-crosslinkable, and robust chitosan hydrogel for 3D bioprinting

Although three-dimensional (3D) bioprinting is a promising technology for reconstructing artificial tissues and organs using bioink, there is a lack of a bioink that satisfies all requirements, including printability, gelation, mechanical properties, and cytocompatibility, Herein, a novel self-crosslinkable bioink derived from chitosan (CS) and gallic acid (GA) is presented. 3D printed scaffolds with excellent shape fidelity are realized by systematically analyzing the self-crosslinking mechanism of hydrogel formation from CS-GA conjugates and by optimizing various parameters of the printing process. The CS-GA hydrogel forms rapidly in a physiological pH without any chemical crosslinking agent. In addition, the CS-GA hydrogel exhibited various physical and chemical intermolecular interactions, fast gelation rates, and excellent mechanical properties (>337 kPa). Moreover, the CS-GA hydrogel singificantly improves the cell viability (>92 %) and proliferation of the bioink. Therefore, the self-crosslinkable CS-GA bioink has great potential to overcome the limitations of conventional bioinks.

Mussel-Inspired Two-Dimensional Halide Perovskite Facilitated Dopamine Polymerization and Self-Adhesive Photoelectric Coating

Polydopamine (PDA) is a good adhesion agent for lots of gels inspired by the mussel, whereas hybrid organic-inorganic perovskites (HOIPs) usually exhibit extraordinary optoelectronic performance. Herein, mussel-inspired chemistry has been integrated with two-dimensional HOIPs first, leading to the preparation of new crystal (HDA)₂PbBr₄ (1) (DA = dopamine). The organic cation dopamine can be introduced into PDA resulting in a thin film of (HPDA)₂PbBr₄ (PDA-1). The dissolved inorganic components of layered perovskite in DMF solution together with H₂O₂ addition can facilitate DA polymerization greatly. More importantly, PDA-1 can inherit an excellent semiconductor property of HOIPs and robust adhesion of the PDA hydrogel resulting in a self-adhesive photoelectric coating on various interfaces.

Dual (pH- and ROS-) Responsive Antibacterial MXene-Based Nanocarrier for Drug Delivery

In this study, a novel MXene (Ti₃C₂T_x)-based nanocarrier was developed for drug delivery. MXene nanosheets were functionalized with 3, 3'-diselanediyldipropionic acid (DSeDPA), followed by grafting doxorubicin (DOX) as a model drug to the surface of functionalized MXene nanosheets (MXene-Se-DOX). The nanosheets were characterized using scanning electron microscopy, atomic force microscopy (AFM), transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and zeta potential techniques. The drug-loading capacity (17.95%) and encapsulation efficiency (41.66%) were determined using ultraviolet-visible spectroscopy. The lateral size and thickness of the MXene nanosheets measured using AFM were 200 nm and 1.5 nm, respectively. The drug release behavior of the MXene-Se-DOX nanosheets was evaluated under different medium conditions, and the nanosheets demonstrated outstanding dual (reactive oxygen species (ROS)- and pH-) responsive properties. Furthermore, the MXene-Se-DOX nanosheets exhibited excellent antibacterial activity against both Gram-negative E. coli and Gram-positive B. subtilis.

Sensitive Electrochemical Detection of 4-Nitrophenol with PEDOT:PSS Modified Pt NPs-Embedded PPy-CB@ZnO Nanocomposites

In this study, a selective 4-nitrophenol (4-NP) sensor was developed onto a glassy carbon electrode (GCE) as an electron-sensing substrate, which decorated with sol-gel, prepared Pt nanoparticles- (NPs) embedded polypyrole-carbon black (PPy-CB)/ZnO nanocomposites (NCs) using differential pulse voltammetry. Characterizations of the NCs were performed using Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Ultraviolet-visible Spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction Analysis (XRD). The GCE modified by conducting coating binders [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate; PEDOT:PSS] based on Pt NPs/PPy-CB/ZnO NCs functioned as the working electrode and showed selectivity toward 4-NP in a phosphate buffer medium at pH 7.0. Our analysis of 4-NP showed the linearity from 1.5 to 40.5 µM, which was identified as the linear detection range (LDR). A current versus concentration plot was formed and showed a regression co-efficient R² of 0.9917, which can be expressed by i_p(µA) = 0.2493C(µM) + 15.694. The 4-NP sensor sensitivity was calculated using the slope of the LDR, considering the surface area of the GCE (0.0316 cm²). The sensitivity was calculated as 7.8892 µAµM^-1cm^-2. The LOD (limit of detection) of the 4-NP was calculated as 1.25 ± 0.06 µM, which was calculated from 3xSD/σ (SD: Standard deviation of blank response; σ: Slope of the calibration curve). Limit of quantification (LOQ) is also calculated as 3.79 µM from LOQ = 10xLOD/3.3. Sensor parameters such as reproducibility, response time, and analyzing stability were outstanding. Therefore, this novel approach can be broadly used to safely fabricate selective 4-NP sensors based on nanoparticle-decorated nanocomposite materials in environmental measurement.

Highly Luminescent MOF and Its In Situ Fabricated Sustainable Corn Starch Gel Composite as a Fluoro-Switchable Reversible Sensor Triggered by Antibiotics and Oxo-Anions

Frequent use of antibiotics and the growth of industry lead to the pollution of several natural resources which is one of the major consequences for fatality to human health. Exploration of smart sensing materials is highly anticipated for ultrasensitive detection of those hazardous organics. The robust porous hydrogen bonded network encompassing a free-NH₂ moiety, Zn(II)-based metal-organic framework (MOF) (1), is used for the selective detection of antibiotics and toxic oxo-anions at the ppb level. The framework is able to detect the electronically dissimilar antibiotic sulfadiazine and nitrofurazone via fluorescence "turn-on" and "turn-off" processes, respectively. The antibiotic-triggered reversible fluoro-switching phenomena (fluorescence "on-off-on") are also observed by using the fluorimetric method. An extensive theoretical investigation was performed to establish the fluoro-switching response of 1, triggered by a class of antibiotics and also the sensing of oxo-anions. This investigation reveals that the interchange of the HOMO-LUMO energy levels of fluorophore and analytes is responsible for such a fluoro-switchable sensing activity. Sensor 1 showed the versatile detection ability which is reflected by the detection of a carcinogenic nitro-group-containing drug "roxarsone". In view of the sustainable environment along with quick-responsive merit of 1, an in situ MOF gel composite (1@CS; CS = corn starch) is prepared using 1 and CS due to its useful potential features such as biocompatibility, toxicologically innocuous, good flexibility, and low commercial price. The MOF composite exhibited visual detection of the above analytes as well as antibiotic-triggered reversible fluoro-switchable colorimetric "on-off-on" response. Therefore, 1@CS represents a promising smart sensing material for monitoring of the antibiotics and oxo-anions, particularly appropriate for the real-field analysis of carcinogenic drug molecule "roxarsone" in food specimens.

Synthesis of Surface-Functionalized Molybdenum Disulfide Nanomaterials for Efficient Adsorption and Deep Profiling of the Human Plasma Proteome by Data-Independent Acquisition

Blood is one of the most important clinical samples for protein biomarker discovery, as it provides rich physiological and pathological information and is easy to obtain with low invasiveness. However, the discovery of protein biomarkers in the blood by mass spectrometry (MS)-based proteomic strategies has been shown to be highly challenging due to the particularly large concentration range of proteins and the strong interference by the high-abundant proteins in the blood. Therefore, developing sensitive methods for low-abundant biomarker protein identification is a key issue that has received great attention. Here, we report the synthesis and characterization of surface-functionalized magnetic molybdenum disulfide (MoS₂) for the large-scale adsorption of low-abundant plasma proteins and deep profiling by MS. MoS₂ nanomaterials resulted in the coverage of more than 3400 proteins (including a single-peptide hit) in a single LC-MS analysis without peptide prefractionation using pooled plasma samples, which were five times more than those obtained by the direct analysis of the plasma proteome. A detection limit in the low ng L^-1 range was obtained, which is rare compared with previous reports.

Integrated ratiometric fluorescence probe-based acoustofluidic platform for visual detection of anthrax biomarker

The sensitive detection of dipicolinic acid (DPA) as an excellent biomarker of Bacillus anthracis, especially through visual point-of-care testing, is significant for accurate and rapid diagnosis of anthrax to timely prevent anthrax disease or biological terrorist attack. Herein, an acoustofluidics-based colorimetric platform with the integrated ratiometric fluorescence probe (INT-probe) was fabricated, which improved the sensitivity of visual detection for DPA and overcame the poor reproducibility of the existing acoustofluidics-assisted colorimetric analysis. For the design of INT-probe, Eu³⁺-EDTA complex as sensing moiety was grafted onto the surface of blue organosilane-functionalized carbon dots (SiCDs)-doped SiO₂ nanoparticles (NPs). Upon exposure to DPA, Eu³⁺ was sensitized by DPA to emit red luminescence, while the SiCDs as reference inside the SiO₂ NPs still kept the blue fluorescence unchanged. Attributed to the acoustic radiation force-driven enrichment of the INT-probe, slight color changes caused by low concentration of DPA could be amplified and distinguished by naked-eyes/smartphone. With the increase of DPA concentration, obvious color variations of INT-probe/DPA aggregates from blue to pink could be observed, and the color information of the fluorescent aggregates was converted to red, green and blue values for quantitative analysis, whose lowest detectable concentration reached 100 nM that is about 2-3 orders of magnitude lower than the infectious dosage of Bacillus anthracis spores (60 μM). Importantly, benefiting from the great color signal enhancement by acoustofluidic sensing platform, the usage of Eu³⁺ reduced to as low as 0.273 μmol per gram of SiO₂ NPs, providing a meaningful way to utilize lanthanide resource efficiently.

Water-compatible Janus molecularly imprinted particles with mouth-like opening: Rapid removal of pharmaceuticals from hospital effluents

Pharmaceuticals in hospital effluents, often discharged into the public sewage network without sufficient treatment, have shown negative impacts to the human health and aquatic environment. However, the conventional adsorbents used to remove these micropollutants had several deficiencies, including slow uptake kinetics and poor selectivity. To overcome these challenges, water-compatible Janus MIP particles (J-MIPs) with mouth-like openings were synthesized using seeded interfacial polymerization in this work. Among the series of J-MIPs, the selected J-MIP₃ showed fast binding kinetics (∼40 s) towards the target pollutant. The theoretical and instrumental analysis suggested that the electrostatic interaction, hydrogen bond and hydrophobic reaction constituted the dominant mechanism for J-MIP₃'s recognition of target pharmaceutical. Selectivity and robustness tests indicated that the synthetic method was promising in practical application. Finally, the feasibility of the J-MIP₃ fixed-bed column in the rapid removal of propranolol (PRO) from hospital effluents was successfully demonstrated. Compared to the activated carbon fixed-bed column, the J-MIP₃ fixed-bed column showed at least 7-fold enhancement in its treatment efficiency. To the best of our knowledge, this is the first time that the accelerated mass transfer and fast removal of the pharmaceutical from wastewater have been achieved by the synthetic receptor with asymmetric structure. We believe the present study will open new avenues for the development of multi-functional molecularly imprinted polymers as well as Janus materials in environmental science.

Liquid Foam Stabilized by a CO2-Responsive Surfactant and Similarly Charged Cellulose Nanofibers for Reversibly Plugging in Porous Media

CO₂ foams are of great importance in oil recovery but challenging in some aspects like long-term stabilization and time-separated conflict. In this work, a stability-enhanced switchable foam was fabricated using bis-(2-hydroxyethoxy) olefine amine (BOA) and trace amounts (0.05 wt %) of cationic-modified cellulose nanofibers (CCNFs). The CCNF was developed using sequentially functionalized CNF with diamine groups, which were essential to promote the aqueous dispersibility and a key for strengthening the stabilization of foam. The combination of similarly charged CCNFs and BOA in the presence of CO₂ contributed to both surface activity and viscoelasticity. It was demonstrated that CCNFs were entangled and stacked to form the compact films and possessed the ability to costabilize the lamellae, as observed by microscopic studies. In addition, the intermolecular H-bonds were promoted in the binary system after being protonated by CO₂ and thus balancing the electrostatic forces, as explored by spectroscopy characterizations. The soft fibrous structure of the CCNF was also capable of wrapping gas bubbles in the form of a functional membrane with both low gas permeability and high surface potential, which slowed down the coarsening and coalescence. Of particular interest is that the reversible protonation state of CCNF-BOA complexes upon the alternate treatment with CO₂/N₂ led to reversible fast foaming/defoaming, which would be beneficial to construct the steerable plugging in the sand pack. This work is expected to provide a new direction and application of the CO₂ responsive foam stabilized by similarly charged nanocellulose fibers in oilfield development.

Humic acid complex formation with urea alters its structure and enhances biomass production in hydroponic maize

BACKGROUND

Humic acid (HA)-enhanced urea (HAU) is the top-selling efficiency-enhanced urea in China. Comprehensive investigation into the structure and efficacy of HA complex formation with urea (HACU) - the main reaction product during HAU's production - is required to clarify the reaction mechanism between HA and urea, and to provide guidance for the development of high-efficiency HAU.

RESULTS

HACU showed discrepant structural and compositional features from raw HA. Nitrogen (N) content in HACU was 7.3 times greater than that of HA. Several high-resolution analytical methods showed a sharp increase of ammonia in the gaseous product during HACU pyrolysis, suggesting that urea contributed N to HACU. HACU was characterized with significantly fewer carboxyl groups than in raw HA, implying that the carboxyl group was the main group in HA to participate in the reaction between HA and urea. The presence of amide-N in HACU verified the structure of the reaction product. Furthermore, both HACU and HA could enhance the biomass in hydroponically grown maize seedlings, but the highest stimulation for HACU came about when its carbon concentrations were 50-100 mg L^-1 , higher than the optimal carbon concentration for HA (25 mg L^-1 ), attributed to the lower carboxyl group content for HACU to some extent.

CONCLUSION

During HAU's production, reaction with N derived from urea to form amide-N decreased the carboxyl groups in HA, leading to higher concentrations for HACU required to achieve the similar bioefficacy of HA. © 2021 Society of Chemical Industry.

Functionalization of Diamine-Appended MOF-Based Adsorbents by Ring Opening of Epoxide: Long-Term Stability and CO2 Recyclability under Humid Conditions

Although diamine-appended metal-organic framework (MOF) adsorbents exhibit excellent CO₂ adsorption performance, a continuous decrease in long-term capacity during repeated wet cycles remains a formidable challenge for practical applications. Herein, we present the fabrication of diamine-appended Mg₂(dobpdc)-alumina beads (een-MOF/Al-Si-Cx; een = N-ethylethylenediamine; x = number of carbon atoms attached to epoxide) coated with hydrophobic silanes and alkyl epoxides. The reaction of epoxides with diamines in the portal of the pore afforded sufficient hydrophobicity, hindered the penetration of water vapor into the pores, and rendered the modified diamines less volatile. een-MOF/Al-Si-C17-200 (een-MOF/Al-Si-C17-y; y = 50, 100, and 200, denoting wt % of C17 with respect to the bead, respectively), with substantial hydrophobicity, showed a significant uptake of 2.82 mmol g^-1 at 40 °C and 15% CO₂, relevant to flue gas concentration, and a reduced water adsorption. The modified beads maintained a high CO₂ capacity for over 100 temperature-swing adsorption cycles in the presence of 5% H₂O and retained CO₂ separation performance in breakthrough tests under humid conditions. This result demonstrates that the epoxide coating provides a facile and effective method for developing promising adsorbents with high CO₂ adsorption capacity and long-term durability, which is a required property for postcombustion applications.

Controlled, partially exfoliated, self-supported functionalized flexible graphitic carbon foil for ultrasensitive detection of SARS-CoV-2 spike protein

This paper reports on an ultrasensitive and label-free electrochemical immunosensor for monitoring the SARS-CoV-2 spike protein (SARS-CoV-2 SP). A self-supported electrode, which can simultaneously serve as an antibody immobilization matrix and electron transport channel, was initially fabricated by a controlled partial exfoliation of a flexible graphitic carbon foil (GCF). Mild acidic treatment enabled the partial oxidation and exfoliation (down to a few layers) of the flexible GCF; this also provided a high percentage of oxygen functionality and an enhanced surface roughness. The substrate electrode was further functionalized with ethylenediamine (EDA) to provide a suitable platform with even a higher surface roughness, for the covalent immobilization of an anti-SARS-CoV-2 antibody. The change in the current response for the [Fe(CN)₆]^3-/4- redox couple, induced by the binding of SARS-CoV-2 SP to the antibody immobilized on the electrode surface, was used to determine the SARS-CoV-2 SP concentration. The immunosensor thus prepared could detect SARS-CoV-2 SP within 30 min with high reproducibility and specificity over a wide concentration range (0.2-100 ng/mL). Detection limits of 25 pg/mL and 27 pg/mL were found in a phosphate buffer solution (pH 7.4), and diluted blood plasma, respectively. The immunosensor was also employed to detect SARS-CoV-2 SP in artificial human saliva.

Metal-bio functionalized bismuthmagnetite [Fe3-x Bi x O4/SiO2@l-ArgEt3 +I-/Zn(ii)]: a novel bionanocomposite for the synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine malononitriles and malonamides at room temperature and under sonication

In this work, a new magnetized composite of bismuth (Fe_3−xBi_xO₄) was prepared and functionalized stepwise with silica, triethylargininium iodide ionic liquid, and Zn(ii) to prepare a multi-layered core–shell bio-nanostructure, [Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii)]. The modified bismuth magnetic amino acid-containing nanocomposite was characterized using several techniques including Fourier-transform infrared (FT-IR), X-ray fluorescence (XRF), vibrating sample magnetometer (VSM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), thermogravimetric/differential scanning calorimetric (TGA/DSC) analysis, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and inductively coupled plasma-optical emission spectrometry (ICP-OES). The magnetized bionanocomposite exhibited high catalytic activity for the synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine malononitriles via five-component reactions between 1,2-phenylenediamines, Meldrum's acid, malononitrile, aldehydes, and isocyanides at room temperature in ethanol. The efficacy of this protocol was also examined to obtain malonamide derivatives via pseudo six-component reactions of 1,4-phenylenediamine, Meldrum's acid, malononitrile, aldehydes, and isocyanides. When the above-mentioned MCRs were repeated under the same conditions with the application of sonication, a notable decrease in the reaction time was observed. The recovery and reusability of the metal-bio functionalized bismuthmagnetite were examined successfully in 3 runs. Furthermore, the characteristics of the recovered Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii) were investigated though FESEM and EDAX analysis.

In this work, a new magnetized composite of bismuth (Fe_3−xBi_xO₄) was prepared and functionalized stepwise with silica, triethylargininium iodide ionic liquid, and Zn(ii) to prepare a multi-layered core–shell bio-nanostructure, [Fe_3−xBi_xO₄/SiO₂@l-ArgEt₃⁺I⁻/Zn(ii)].

Critical review of functionalized silica sorbent strategies for selective extraction of rare earth elements from acid mine drainage

The ubiquitous and growing global reliance on rare earth elements (REEs) for modern technology and the need for reliable domestic sources underscore the rising trend in REE-related research. Adsorption-based methods for REE recovery from liquid waste sources are well-positioned to compete with those of solvent extraction, both because of their expected lower negative environmental impact and simpler process operations. Functionalized silica represents a rising category of low cost and stable sorbents for heavy metal and REE recovery. These materials have collectively achieved high capacity and/or high selective removal of REEs from ideal solutions and synthetic or real coal wastewater and other leachate sources. These sorbents are competitive with conventional materials, such as ion exchange resins, activated carbon; and novel polymeric materials like ion-imprinted particles and metal organic frameworks (MOFs). This critical review first presents a data mining analysis for rare earth element recovery publications indexed in Web of science, highlighting changes in REE recovery research foci and confirming the sharply growing interest in functionalized silica sorbents. A detailed examination of sorbent formulation and operation strategies to selectively separate heavy (HREE), middle (MREE), and light (LREE) REEs from the aqueous sources is presented. Selectivity values for sorbents were largely calculated from available figure data and gauged the success of the associated strategies, primarily: (1) silane-grafted ligands, (2) impregnated ligands, and (3) bottom-up ligand/silica hybrids. These were often accompanied by successful co-strategies, especially bite angle control, site saturation, and selective REE elution. Recognizing the need to remove competing fouling metals to achieve purified REE "baskets," we highlight techniques for eliminating these species from acid mine drainage (AMD) and suggest a novel adsorption-based process for purified REE extraction that could be adapted to different water systems.

An Earth-abundant cobalt based photocatalyst: visible light induced direct (het)arene C-H arylation and CO2 capture

In this work, we have reported a noble metal free heterogeneous photocatalyst to carry out direct (het)arene C-H arylation and solvent-free CO₂ capture via single-electron transfer processes at room temperature and under pressure. The catalytic system comprises a cobalt(III) complex grafted over the silica coated magnetic support for the efficient recovery of the photocatalytic moiety without hampering its light-harvesting capability. The novel Earth-abundant cobalt(III) based photocatalyst possesses various fascinating properties such as high surface area to volume ratios, large pore volume, crystalline behaviour, high metal loading, excellent stability and reusability. The general efficacy of the highly abundant and low-cost cobalt based heterogeneous nanocatalyst was checked for the selective conversion of aryldiazonium salts into synthetically and pharmaceutically significant biaryl motifs under ambient conditions upon irradiation with visible light. The highly efficient photocatalytic conversion of carbon dioxide (CO₂) to a value-added chemical was accomplished under mild reaction conditions with high selectivity, showing the added benefit of operational simplicity.

Adsorption of cationic dyes onto carrageenan and itaconic acid-based superabsorbent hydrogel: Synthesis, characterization and isotherm analysis

Polysaccharide-based hydrogels offer a great overlook for environmental applications and help in the elimination of various noxious pollutants from the water system. Novel carrageenan and itaconic acid-based superadsorbent hydrogel having appreciable swelling properties and adsorption capacity towards Methylene blue (MB), Crystal violet (CV), and Methyl Red (MR) was synthesized by suspension polymerization technique. The swelling study showed the dependency upon the temperature in which the swelling rate increased with increasing temperature with a maximum swelling rate of 417% at 318 K. For ascertaining the maximum adsorption capacity, various influential parameters such as contact time, adsorbent dose, dye concentration, and temperature were systematically studied. Maximum adsorption capacity as calculated from the Langmuir isotherm was 2439.02, 1111.11, and 666.68 mg/g for MB, CV, and MR, respectively. Thermodynamic studies revealed the spontaneous nature of the undertaken dye adsorption experiment. Overall, the present study reveals that the synthesized superadsorbent hydrogel can be used as an efficient adsorbent for the removal of dyes from an aqueous solution.

Supported copper on a diamide-diacid-bridged PMO: an efficient hybrid catalyst for the cascade oxidation of benzyl alcohols/Knoevenagel condensation

In this study, a novel periodic mesoporous organosilica (PMO) containing diamide-diacid bridges was conveniently prepared using ethylenediaminetetraacetic dianhydride to support Cu(ii) species and affording supramolecular Cu@EDTAD-PMO nanoparticles efficiently. Fourier transform infrared (FT-IR) and energy dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) analysis, and high-resolution transmission electron microscopy (HRTEM) results confirmed the successful synthesis of Cu@EDTAD-PMO. The stabilized Cu(ii) nanoparticles inside the mesochannels of the new PMO provided appropriate sites for selective oxidation of different benzyl alcohol derivatives to their corresponding benzaldehydes and subsequent Knoevenagel condensation with malononitrile. Therefore, Cu@EDTAD-PMO can be considered as a multifunctional heterogeneous catalyst, which is prepared easily through a green procedure and demonstrates appropriate stability with almost no leaching of the Cu(ii) nanoparticles into the reaction medium, and easy recovery through simple filtration. The recycled Cu@EDTAD-PMO was reused up to five times without significant loss of its catalytic activity. The stability, recoverability, and reusability of the designed heterogeneous catalyst were also studied under various reaction conditions.