User-Friendly and Responsive Electrochemical Detection Approach for Triclosan by Nano-Metal-Organic Framework.

Antimicrobial resistance poses a significant challenge to public health, and is worsened by the widespread misuse of antimicrobial agents such as triclosan (TCS) in personal care and household products. Leveraging the electrochemical reactivity of TCS's phenolic hydroxyl group, this study investigates the electrochemical behavior of TCS on a Cu-based nano-metal-organic framework (Cu-BTC) surface. The synthesis of Cu-BTC via a room temperature solvent method, with triethylamine as a regulator, ensures uniform nanoparticle formation. The electrochemical properties of Cu-BTC and the signal enhancement mechanism are comprehensively examined. Utilizing the signal amplification effect of Cu-BTC, an electrochemical sensor for TCS detection is developed and optimized using response surface methodology. The resulting method offers a simple, rapid, and highly sensitive detection of TCS, with a linear range of 25-10,000 nM and a detection limit of 25 nM. This research highlights the potential of Cu-BTC as a promising material for electrochemical sensing applications, contributing to advancements in environmental monitoring and public health protection.

Soot Erased: Catalysts and Their Mechanistic Chemistry.

Soot formation is an inevitable consequence of the combustion of carbonaceous fuels in environments rich in reducing agents. Efficient management of pollution in various contexts, such as industrial fires, vehicle engines, and similar applications, relies heavily on the subsequent oxidation of soot particles. Among the oxidizing agents employed for this purpose, oxygen, carbon dioxide, water vapor, and nitrogen dioxide have all demonstrated effectiveness. The scientific framework of this research can be elucidated through the following key aspects: (i) This review situates itself within the broader context of pollution management, emphasizing the importance of effective soot oxidation in reducing emissions and mitigating environmental impacts. (ii) The central research question of this study pertains to the identification and evaluation of catalysts for soot oxidation, with a specific emphasis on ceria-based catalysts. The formulation of this research question arises from the need to enhance our understanding of catalytic mechanisms and their application in environmental remediation. This question serves as the guiding principle that directs the research methodology. (iii) This review seeks to investigate the catalytic mechanisms involved in soot oxidation. (iv) This review highlights the efficacy of ceria-based catalysts as well as other types of catalysts in soot oxidation and elucidate the underlying mechanistic strategies. The significance of these findings is discussed in the context of pollution management and environmental sustainability. This study contributes to the advancement of knowledge in the field of catalysis and provides valuable insights for the development of effective strategies to combat air pollution, ultimately promoting a cleaner and healthier environment.

Cobalt Encapsulated in Nitrogen-Doped Graphite-like Shells as Efficient Catalyst for Selective Oxidation of Arylalkanes.

Selective oxidation of ethylbenzene to acetophenne is an important process in both organic synthesis and fine chemicals diligence. The cobalt-based catalysts combined with nitrogen-doped carbon have received great attention in ethylbenzene (EB) oxidation. Here, a series of cobalt catalysts with metallic cobalt nanoparticles (NPs) encapsulated in nitrogen-doped graphite-like carbon shells (Co@NC) have been constructed through the one-pot pyrolysis method in the presence of different nitrogen-containing compounds (urea, dicyandiamide and melamine), and their catalytic performance in solvent-free oxidation of EB with tert-butyl hydrogen peroxide (TBHP) as an oxidant was investigated. Under optimized conditions, the UCo@NC (urea as nitrogen source) could afford 95.2% conversion of EB and 96.0% selectivity to acetophenone, and the substrate scalability was remarkable. Kinetics show that UCo@NC contributes to EB oxidation with an apparent activation energy of 32.3 kJ/mol. The synergistic effect between metallic cobalt NPs and nitrogen-doped graphite-like carbon layers was obviously observed and, especially, the graphitic N species plays a key role during the oxidation reaction. The structure-performance relationship illustrated that EB oxidation was a free radical reaction through 1-phenylethanol as an intermediate, and the possible reaction mechanistic has been proposed.

Tailoring Defect Density in UiO-66 Frameworks for Enhanced Pb(II) Adsorption.

Defect engineering of metal organic frameworks offers potential prospects for tuning their features toward particular applications. Herein, two series of defective UiO-66 frameworks were synthesized via changing the concentration of the linker and synthetic temperature of the reaction. These defective materials showed a significant improvement in the capability of Pb(II) removal from wastewater. This strategy for defect engineering not only created additional active sites, more open framework, and enhanced porosity but also exposed more oxygen groups, which served as the adsorption sites to improve Pb(II) adsorption. A relationship among degree of defects, texture features, and performances for Pb(II) removal was successfully developed as a proof-of-concept, highlighting the importance of defect engineering in heavy metal remediation. To investigate the kinetic and adsorption isotherms, we performed adsorption experiments influenced by the time and concentration of the adsorbate, respectively. For the practicality of the materials, the most significant parameters such as pH, temperature, adsorbent concentration, selectivity, and recyclability as well as simulated natural surface water were also examined. This study provides a clue for the researchers to design other advanced defective materials for the enhancement of adsorption performance by tuning the defect engineering.

Synthesis, Structure, and Photoluminescence of Color-Tunable and White-Light-Emitting Lanthanide Metal-Organic Open Frameworks Composed of AlMo6(OH)6O183- Polyanion and Nicotinate.

A series of isostructural compounds Na(HL)(CH3COO)Ln(Al(OH)6Mo6O18)(H2O)6·10H2O [L = nicotinate; Ln = Eu (1), Tb (2)] and Na(HL)(CH3COO)EumTbnLa1-m-n(AlMo6(OH)6O18)(H2O)6·10H2O (3-8, L = nicotinate), wherein Anderson-type polyanions AlMo6(OH)6O183- as basic inorganic building blocks are connected by Eu(CH3COO)(HL)(H2O)3]24+ and [Na2(H2O)8]2+ cations, resulting in formation of three-dimensional lanthanide metal-organic open frameworks, were synthesized successfully with AlCl3·6H2O, Na2MoO4·2H2O, nicotinic acid, and lanthanide nitrates as starting materials. The compounds were characterized by UV-vis, IR, elemental analysis, powder XRD, and TG-DTA measurements. The single-crystal structures of compounds 1 and 2 show that the two compounds display three-dimensional open frameworks with 1D channels along the b and c axes. Investigation of the energy transfer mechanism indicated that the organic nicotinate ligand can transfer energy efficiently to Tb3+ rather than Eu3+. The influence of the POM moiety on the fluorescence of the compounds is also studied. Compounds 1-8 exhibit tunable luminescence color, and emitting of white light was realized through adjusting the molar ratio of Eu:Tb:La within the compounds.

Turning precious metal-loaded e-waste to useful catalysts: Investigation into supercilious recovery and catalyst viability for peroxymonosulfate activation.

Here, the key tasks to be accomplished are selective precious metal recovery from e-wastewater and their conversion into valuable catalysts for peroxymonosulfate (PMS) activation. In this regard, we developed a hybrid material using 3D functional graphene foam and copper para-phenylenedithol (Cu-pPDT) MOF. The prepared hybrid showed a supercilious recovery of 92-95% even up to five cycles for Au(III) and Pd(II), which can be viewed as a reference for both the 2D graphene and the MOFs family. The outstanding performance has been attributed principally to the impact of diverse functionality as well as the unique morphology of 3D graphene foam, which provided a wide range of surface area and additional active sites in the hybrid frameworks. To prepare the surface-loaded metal nanoparticle catalysts, the sorbed samples recovered after precious metal extraction were calcined at 800 °C. The viability of the developed catalysts for the breakdown of 4-nitrophenol (4-NP) via PMS activation was investigated. Electron paramagnetic resonance spectroscopy (EPR) and experiments with radical scavengers suggest that sulfate and hydroxyl radicals are the main reactive species involved in the breakdown of 4-NP. This is because the active graphitic carbon matrix and the exposed precious metal and copper active sites work together in a way that is more effective.

Singlet oxygen dominance for phenolic degradation mediated by mixed-valence FeOx nanospheres.

In this investigation, we successfully synthesized magnetic FeOx nanosphere catalysts with mixed-valence and high operational stability through the pyrolysis of a hybrid material containing polyferrocenlyphosphazene with coordinating heteroatoms (N, P, O). We evaluated the degradation performance of these catalysts using the peroxymonosulfate (PMS) activation process against four different phenolic compounds, namely phenol, 4-nitrophenol, 2,4-dinitrophenol, and 2,4,5-trinitrophenol. Our results demonstrate the significant role of FeOx in the degradation process. The presence of mixed iron species, such as ferric iron, zero-valent iron, and iron oxides, activated PMS to generate radicals. Additionally, the heteroatoms facilitated the anchoring and dispersion of FeOx nanospheres while also breaking the inertness of the carbon structure. Notably, the FeOx-800 catalyst exhibited a maximum degradation activity of 98% for phenol, surpassing its counterparts. Electron paramagnetic resonance and free radical scavenging experiments confirmed that singlet oxygen (1O2) is the principal reactive oxygen species (ROS) that leads to the oxidative breakdown of phenolic compounds. This study introduces new concepts for designing Fenton-like catalysts incorporating heteroatoms into the carbon matrix. Due to their low cost and non-toxicity, these catalysts have recently received a great deal of attention for peroxymonosulfate (PMS) activation and environmental remediation.

Ultra-deep removal of Pb by functionality tuned UiO-66 framework: A combined experimental, theoretical and HSAB approach.

A specific functionality in the adsorbent materials plays a significant role for the selective capture of heavy metals based on Pearson's Hard-Soft-Acid-Base (HSAB) concept. Herein, we introduced single and double amino- and thiol-functionalities into the UiO-66 framework, which acted as hard and soft base sites for heavy metal adsorption, respectively. The synthesized adsorbents (labelled as NH2-UiO-66, (NH2)2-UiO-66, SH-UiO-66 and (SH)2-UiO-66) were applied for the selective removal of lead (Pb) ions from contaminated water. The removal efficiency of Pb was about 64, 85, 75 and 99% (pH = 6, T = 30 °C, sample dosage = 10 mg, Pb concentration = 100 mg L-1), respectively, based on available number of interacting sites in the respective adsorbent. To elaborate HSAB concept, the interacting sites of these functional groups towards Pb were explored by identifying their possible types of interactions in terms of soft acid-base affinity, coordinate and covalent bonding, chelation, π-π interactions and synergetic effect of bonding. Density functional theory (DFT) simulation was used to confirm these interactions and to help the better understanding of adsorption mechanism. Model fitting and characterization of Pb-sorbed adsorbents were also performed to reveal kinetics, order of adsorptive reaction, thermodynamics and adsorption mechanism. Moreover, the optimization of adsorptive removal was performed by controlled parameters including time, initial concentration, pH and temperature. The reusability and selectivity of these adsorbents along with recovery of Pb(II) were also assessed. This study presents the conceptual framework for the design of functional adsorbents in the removal of heavy metals using the HSAB principle as an intended guideline.

Synthesis of γ-alumina (Al2O3) nanoparticles and their potential for use as an adsorbent in the removal of methylene blue dye from industrial wastewater.

Non-toxic nanomaterials have gained significant importance recently in the treatment of industrial wastewater that sometimes contains organic dyes such as methylene blue. We report here an easy approach for the synthesis of γ-alumina (Al2O3) nanoparticles via a method that incorporates the use of formamide and the non-ionic surfactant Tween-80. Together, formamide and Tween-80 serve as an effective precipitating agent and a convenient synthetic template, respectively, in directing the growth of the alumina nanoparticles. The morphology and structure of the nanoparticles were investigated by FT-IR, XRD, TGA, SEM, EDX, elemental mapping and TEM methods. The sizes of the nanoparticles are in the 30-50 nm range. The maximum pore size is 4.13 nm and the surface area is 112.9 m2 g-1 as determined by the Brunauer-Emmett-Teller (BET) method. The nanomaterials are excellent adsorbents for the cationic methylene blue dye from aqueous solution. The effects of pH, time, temperature and concentration on the adsorption have been examined and the adsorption capacity increased from 490 to 2210 mg g-1 as the initial concentration was increased from 50 to 400 mg L-1 under the following conditions: pH 9, 10 min reaction time, and 60 °C. The adsorption mechanism is considered to encompass electrostatic interactions in water between the Al2O3 nanoparticles and the cationic methylene blue dye. These readily made nanoparticles may well prove useful in both wastewater treatment and industrial catalysis.

Correction: Synthesis of γ-alumina (Al2O3) nanoparticles and their potential for use as an adsorbent in the removal of methylene blue dye from industrial wastewater.

[This corrects the article DOI: 10.1039/C8NA00014J.].

Morphology Control of Novel Cross-Linked Ferrocenedimethanol Derivative Cyclophosphazenes: From Microspheres to Nanotubes and Their Enhanced Physicochemical Performances.

Polyphosphazenes have grabbed focal attention in materials research due to their structural diversity, intrinsic backbone stability, and capability to form hybrid molecules. Herein, for the first time, we report morphology-controlled cross-linked hybrid nanotubes and microspheres composed of a novel iron-containing poly(ferrocenedimethano)cyclotriphosphazene synthesized via a facile polycondensation between 1,1'-ferrocenedimethanol and hexachlorocyclotriphosphazene. The morphology was tuned by introducing two sets of mixed solvent systems that are tetrahydrofuran:acetonitrile and acetone:toluene mixtures, for the growth of nanotubes and microspheres, respectively. A growth mechanism for nanotubes and microspheres has been proposed. The nanotubes exhibited intrinsic paramagnetic properties (saturation magnetization of 53 emu/g and coercivity of 19.6) and fluorescence emission (2450 au) as compared to microspheres owing to their remarkable cross-linked structure. Both nanotubes and microspheres demonstrated significant potential to absorb negatively charged hazardous methyl orange dye, and their adsorption capacities came out under the range of 880-2235 and 737-2125 mg g-1, respectively. This facile fabrication route is anticipated to open a new window for structural manipulation of other metal-containing polymers for improved physicochemical properties.

Enhanced adsorptive desulfurization by iso-structural amino bearing IRMOF-3 and IRMOF-3@Al2O3versus MOF-5 and MOF-5@Al2O3 revealing the predominant role of hydrogen bonding.

Desulfurization of oragnosulfur-containing fuels signify a great importance in improving the quality of fuel and is also beneficial to the environment. In this work, we report two new composites, namely, MOF-5@γ-Al2O3 and IRMOF-3@γ-Al2O3, synthesized by loading iso-structural MOF-5 and amino bearing IRMOR-3 onto the γ-Al2O3 beads (the loading amount of MOF-5 and IRMOF-3 are 13.4 wt% and 16.3 wt%, respectively). The composites are fully characterized by IR spectroscopy, XRD, SEM, BET and XRF. These iso-structural MOFs and their composites exhibit substantially high adsorptive desulfurization capacities for benzothiophene (BT), 3-methylthiophene (3-MT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The adsorption capacities of amino bearing IR-MOF-3 and IRMOF-3@γ-Al2O3 are significantly greater than those of MOF-5 and MOF-5@γ-Al2O3, e.g., the adsorption capacities for DBT of IRMOF-3@γ-Al2O3, IRMOF-3, MOF-5@γ-Al2O3 and MOF-5 are 54.9, 45.1, 31.4 and 24.1 mg S g-1 MOFs, respectively, under optimal conditions (time 60 min, temperature 30 °C, MOFs@γ-Al2O3/Moil = 1/40). The adsorption results revealed the predominant role of hydrogen bonding between the Lewis basic S atoms of the organo sulfurs and -NH2 groups in IR-MOF-3 and also the π-π interactions that works well in MOF-5. The enhancement in the desulfurization capability of MOFs@γ-Al2O3versus the corresponding pristine MOFs shall be attributed to the advantage of the confinement effect of the γ-Al2O3 pores that results in larger specific surface area, much more exposed active sites, and shorter diffusion channels of the MOFs. The kinetics and thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic, and the increase in entropy is the primary driving force for the desulfurization. In addition, it is found that the composites possess good reusability and can be regenerated by simple washing due to enhanced mechanical strength.

Layer-by-layer assembly of Cu3(BTC)2 on chitosan non-woven fabrics: a promising haemostatic decontaminant composite material against sulfur mustard.

Cu3(BTC)2 (H3BTC = 1,3,5-benzenetricarboxylic acid) was anchored onto the surface of carboxymethylated chitosan non-woven fabrics by a controllable layer-by-layer technique in alternating solution baths of Cu(OAc)2·H2O and H3BTC solutions, and the resulting [Cu3(BTC)2]n@chitosan non-woven fabric composite materials (n = number of alternate deposition cycles) were thoroughly characterized. The results showed that the composite materials not only exhibited excellent decontamination ability against sulfur mustard (HD), with an enhanced degradation rate of HD with increasing n, but also possessed remarkable haemostasis performance. The degradation efficiency of sulfur mustard by [Cu3(BTC)2]4@chitosan was found to be much higher than that of pristine [Cu3(BTC)2]4. The inherent haemostatic capabilities of the chitosan non-woven fabrics were not affected by the growth of Cu3(BTC)2 on the surface of chitosan. Oral and histological toxicity examinations of the pristine Cu3(BTC)2 sample showed that damage and toxicity in the viscera of mice was very low, even if the intra-gastric administration dose of Cu3(BTC)2 reached a very high level (50 mg of Cu3(BTC)2 per kg of mouse). The results have shown that the as-prepared composite can be used safely as a promising haemostatic decontaminant with good recyclability against sulfur mustard.

Two series of reactant's ratio-dependent lanthanide organic frameworks derived from nicotinic acid N-oxide and oxalate: synthesis, crystal structures and luminescence properties.

Two series of lanthanide(III)­organic frameworks with the molecular formula [Ln2(NNO)2(OX)2(H2O)4]n (Ln = Eu 1, Tb 2, Sm 3, Dy 4, Gd 5) and [Ln2(NNO)4(OX)(H2O)2]n (Ln = Eu 6, Tb 7, Sm 8, Dy 9, Gd 10) were synthesized successfully under the same hydrothermal conditions with nicotinic N-oxide (HNNO) and oxalic acid (H2OX) as the mixed ligands merely through varying the molar ratio of the reactants. The compounds were characterized by IR, elemental analysis, UV, TG-DTA and powder X-ray diffraction (XRD). X-ray single-crystal diffraction analyses of compounds 1 and 7 selected as representatives and powder XRD analysis of the compounds revealed that both the series of compounds feature three-dimensional (3-D) open frameworks, and crystallize in the triclinic P1 space group while with different unit cell parameters. In compound 1, pairs of Eu(3+) ions and pairs of NNO(−) ligands connect with each other alternately to form a 1-D infinite Eu-NNO double chain, the adjacent 1-D double-chains are then joined together through OX(2−) ligands leading to a 2D layer, the 2-D layers are further 'pillared' by OX(2−) ligands resulting in a 3-D framework. In compound 7, the 1-D Tb-NNO infinite chain and its 2-D layer are formed in an almost similar fashion to that in compound 1. The difference between the structures of the two compounds 1 and 7 is that the adjacent 2-D layers in compound 7 are further connected by NNO(−) ligands resulting in a 3-D framework. The photoluminescence properties and energy transfer mechanism of the compounds were studied systematically. The energy level of the lowest triplet states of the HNNO ligand (23148 cm(−1)) was determined based on the phosphorescence spectrum of compound 5 at 77 K. The (5)D0 (Eu(3+)) and (5)D4 (Tb(3+)) emission lifetimes are 0.46 ms, 0.83 ms, 0.69 ms and 0.89 ms and overall quantum yields are 1.03%, 3.29%, 2.58% and 3.78% for the compounds 1, 2, 6 and 7, respectively.

Ferrocene-Based Bioactive Bimetallic Thiourea Complexes: Synthesis and Spectroscopic Studies.

Bioactive 1,1'-(4,4'-di-ferrocenyl)di-phenyl thiourea and various metal complexes of this ligand have been successfully synthesized and characterized by using physicoanalytical techniques such as FT-IR and multinuclear ((1)H and (13)C) NMR spectroscopy along with melting point and elemental analyses. The interaction of the synthesized compounds with DNA has been investigated by using cyclic voltammetric and viscometric measurements. The intercalation of the complexes into the double helix structure of DNA is presumably occurring. Viscosity measurements of the complexes have shown that there is a change in length and this is regarded as the least ambiguous and the most critical test of the binding model in solution. The relative potential of the complexes as anti-bacterial, antifungal, and inhibition agents against the enzyme, alkaline phosphatase EC 3.1.3.1, has also been assessed and the complexes were found to be active inhibitors.