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Based on crystal engineering, three Zn/Cd-based metal--organic frameworks (MOFs) (FUM-153(Zn--H), FUM-167(Cd--H), and FUM-176(Cd--NH2)) were successfully prepared from rigid O-donor/flexible N-donor linkers (H2bdc (terephthalic acid) (L(O) H) or NH2-H2bdc (2-aminoterephthalic acid) (L(O) NH2) and bpfb (N,N'- 1,4-(phenylene) diisonicotinamide) (L(N))) with Zn/Cd ions. Structurally, the major difference among the FUMs is the various behaviors of the DMF solvent in the lattice or the coordination environment of the structures. This study investigated the effect of hydrogen bonding of NH2 substitution in 2-D layer linkers and its effect on the layer architecture. The results showed that hydrogen bonding indirectly affects the coordination of DMF solvent to the metal center and the porosity. To investigate the effect of the NH2 substitution in the presence or absence of the DMF solvent in the FUMs, the Cambridge Structural Database (CSD) was surveyed for similar structures with the L(O) H and L(O) NH2 linkers. Remarkably, the obtained data suggested that the existence of NH2 substitution may reduce the probability of the coordination of DMF to the metal centers. Theoretical studies were carried out to explore the gas adsorption performance of the title FUMs. A better CH4 adsorption compared to CO2 for all FUMs was observed. It is worth noting that CH4 and CO2 gas adsorption in FUM-176(Cd--NH2) is higher than that in FUM-153(Zn--H) and FUM-167(Cd--H). It can be deduced that the NH2 substitution in 2-D layer linkers prevented the entering of DMF molecules into the framework (lattice or coordinated solvent). Consequently, more accessible pores are provided for gas molecules. The work demonstrates the role of linker functionality in the crystal structure, pore size, and gas adsorption properties. [ABSTRACT FROM AUTHOR]

Spent lithium‐ion batteries (LIBs) are an essential secondary resource containing valuable metal elements. Transforming spent LIBs into efficient catalysts through a simple process presents a promising strategy to address both metal resource scarcity and clean energy challenges. Herein, a deep eutectic solvent‐assisted synthesis of Co3O4 material from spent LIBs is proposed. The obtained Co3O4 material possesses efficient and stable electrocatalytic activity for converting raw polyethylene terephthalate (PET) bottles into high‐purity formic acid and terephthalic acid products under ambient conditions. As expected, the Co3O4 catalyst exhibits a high FE of 92 % with a concentration of produced potassium formate of 23.6 mM under alkaline conditions. This study presents a waste‐treating‐waste strategy for the simultaneous recovery of spent LIBs and PET waste in a greener manner. [ABSTRACT FROM AUTHOR]

The new homochiral 1D metal–organic coordination polymer {Cu[bdc-(N-MePro)H2O]·0.25H2O}n was synthesized using 2-[(1-methyl- L -prolyl)amino]terephthalic acid, which was obtained for the first time. The unique crystal structure of the new compound was determined using powder X-ray diffraction. The catalytic performance of {Cu[bdc-(N-MePro)H2O]·0.25H2O}n in the asymmetric ring opening reactions of styrene oxide and cyclohexene oxide with aniline was evaluated. [ABSTRACT FROM AUTHOR]

ABSTRACT Methotrexate (MTX) is a chemotherapy agent and immune system suppressant that is widely used to treat a variety of malignant and nonmalignant diseases. Due to some drawbacks of the existing methods for the determination of MTX in aquatic and real samples, we prepared a new, simple, and selective dual‐mode fluorometric and electrochemical approach based on peroxidase‐mimic [Mo36] polyoxomolybdate nanoclusters (POMo) for sensing MTX. A turn‐on–off fluorometric approach for the detection of MTX was developed, which was based on the inhibition of the emission intensity of the terephthalic acid (TA)‐H2O2 system upon the addition of MTX to the reaction solution. The electrocatalytic performance of the obtained POMo was studied after making a carbon paste electrode (CPE) utilizing cyclic voltammetry and amperometry analysis. Under the optimum condition, good linearity was observed between the quenched emission intensity of the system and MTX dosage in the range of 0.5–250 μM with a limit of detection (LOD) of 0.91 μM. The electrochemical method illustrated a much better response with an extensive linear range of 0.01–475 μM and a lower LOD (1.61 nM). Analytical recoveries and RSD% values were, respectively, in the range of 87.72%–110% and 0.33%–1.32% for the fluorometric system and 96%–106% and 0.77%–1.02% for the electrochemical platform. Finally, the selectivity of the sensor was evaluated against various common interfering species, and the results indicated satisfactory selectivity of the POMo dual‐mode system towards MTX. [ABSTRACT FROM AUTHOR]

Ni phosphides and NiCo alloys are extensively explored for their remarkable efficiency in biomass alcohol oxidations, yet the underlying mechanisms remain inadequately understood. This study thoroughly elucidates the roles of Ni, Co, and P in improving the catalytic performance of Ni‐Co‐P catalysts for the electrochemical conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA), a promising biomass‐derived building block replacing terephthalic acid. Phosphorization of Ni results in the partial formation of Ni2P phase and significantly boosts the formation of the reactive NiOOH phase on the surface, which is the crucial catalytic phase for converting HMF into FDCA. The integration of Co into the heterojunction between Ni2P and NiOOH enhances the oxidation reactivity of 5‐formyl‐2‐furancarboxylic acid (FFCA), a pivotal intermediate influencing FDCA productivity, by selectively stabilizing aldehydes, thereby promoting further oxidation rather than surface desorption. in situ/operando spectroscopic analyses consistently highlight the equal significance of the rapid generation of NiOOH and the robust adsorption of reactant molecules at the surface in achieving high catalytic performance. These insights into elemental contributions set a new standard for designing multi‐component electrocatalysts for efficient biomass alcohol oxidation. [ABSTRACT FROM AUTHOR]

A reversible solid thermally responsive deep‐blue pure organic room temperature phosphorescent material is constructed by terephthalic acid (PPA), β‐cyclodextrin (β‐CD), and poly(vinylalcohol) (PVA). Attributed to the host‐guest interaction of β‐CD to isolate PPA chromophore and the rigid environment offered by hydrogen bonds to suppress the nonradiative decays, amorphous supramolecular assembly PPA‐CD/PVA not only induces a deep‐blue phosphorescence at 410 nm that differing from traditional PPA derivatives with green emission but also enhances the quantum yield up to 30.52%. Uncommonly, this film exhibits a unique reversible thermal stimulation response property with blue and cyan phosphorescence color transitions because heating can destroy the binding behavior between β‐CD and PPA, resulting in redshift phosphorescence emission from PPA stacking. Additionally, with the incorporation of Rhodamine B (RhB) or Sulforhodamine 101 (SR101) into the supramolecular film, color‐tunable phosphorescence from blue to white, yellow, and red relying on the thermal stimulation is realized through triplet‐to‐singlet Förster resonance energy transfer (TS‐FRET) platform. These thermochromic phosphorescence materials are successfully applied in multilevel anticounterfeiting and information encryption, which provides a new simple approach for temperature‐responsive TS‐FRET multicolor luminescence supramolecular materials. [ABSTRACT FROM AUTHOR]

Cobalt- and calcium-based metal–organic frameworks (Co-MOF and Ca-MOF) [Co (tpa) (Mi) and Ca (tpa)] (tpa = terephthalic acid and Mi = methyl imidazole) were synthesised through solvothermal method. Structural characterisation revealed that metal centres are equally occupied by Co2+ and Ca2+ ions. Supercapacitive behaviour of synthesised Co-MOF and Ca-MOF was evaluated using cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) measurements in 6 M KOH as electrolyte. The Co- and Ca-MOFs exhibited outstanding specific capacitance of 1726 and 185 Fg−1 at a discharge current density of 1 Ag−1, good rate capability, and 97.4% capacitance retention after 3000 cycles. To the best of our knowledge, Co-MOFs and Ca-MOFs are used in supercapacitor, and their encouraging properties indicate that Co-/Ca-MOF can be a promising candidate as an advanced electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

The solvothermal synthesis of LnCl3.nH2O with terephthalic acid (benzene-1,4-dicarboxylic acid, H2BDC) produced metal–organic frameworks (LnBDC), [Ln2(BDC)3(H2O)4]∞, where Ln = Sm, Eu, Tb, and Dy. The materials obtained were characterized by a number of physico-chemical techniques. The influence of the ionic radius of the lanthanides on the microstructural characteristics of the Ln-MOFs was evaluated by performing Rietveld refinement. The MOFs obtained were tested as fluorescent sensors for numerous cations and anions in water. The highly luminescent EuBDC and TbBDC demonstrated multi-responsive luminescence sensing functions to detect Ag(I), Fe(III), Cr(III), and Cr(VI), which are essential for their environmental applications. By applying the non-linear Stern–Volmer equation, the fluorescent quenching mechanism was determined. The stability of the obtained materials in water in a wide pH range (acidity pH = 4 and alkalinity pH = 9 solutions) was confirmed. [ABSTRACT FROM AUTHOR]

As an environmentally friendly technology, enzymatic degradation of waste polyethylene terephthalate (PET) has great application potential. Mono (hydroxyethyl) terephthalate (MHET), an intermediate product of PET degradation, accumulates during the degradation process. MHET reduces the activity of PETase and influences further enzymatic degradation. The combined catalysis of MHETase and PETase is an effective strategy to solve this problem. However, the difference in thermostability between MHETase and PETase limits their combination. In our previous study, a PETase of muEst1 exhibited acceptable PET-degradation ability, but the abundant MHET accumulation in its degradation products limited its further application. In this study, MHETases with good thermostability were screened for combination with muEst1 for the cascade reaction of PET degradation, and a two-stage variable-temperature program was developed. The results of this investigation show that this approach results in a PET-degradation rate of 92.71% with a terephthalic acid content above 85.9%. This investigation provides an alternative method for scaled-up enzymatic PET degradation. [ABSTRACT FROM AUTHOR]

Context: Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic. It was introduced to the plastics market in 1998 and since then has been widely used around the world. The main idea of this research is to perform quantum chemical calculations to study the potential toxicity of PBAT and its degradation products. We analyzed the electron transfer capacity to determine its potential toxicity. We found that biodegradable products formed with benzene rings are as good electron acceptors as PBAT and OOH•. Our results indicate that the biodegradation products are potentially as toxic as PBAT. This might explain why biodegradation products alter the photosynthetic system of plants and inhibit their growth. From this and other previous investigations, we can think that biodegradable plastics could represent a potential environmental risk. Methods: All DFT computations were performed using the Gaussian16 at M062x/6–311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as response functions. [ABSTRACT FROM AUTHOR]

Accumulation of polyethylene terephthalate (PET) polyester in ecosystems across the globe is a major pollution of concern. Microbial degradation recently generated novel insights into the biodegradation of varieties of plastics. In this study, a PET degrading bacterium Brucella intermedia IITR130 was isolated from a contaminated lake ecosystem at Pallikaranai, Chennai, India. Incubation of the bacterium along with the PET sheet (0.1 mm thickness) for 60 days resulted in 26.06% degradation, indicating a half-life of 137.8 days. Considerable changes in the surface morphology of the PET sheet were found as holes, pits, and cracks on incubation with strain IITR130, as revealed by scanning electron microscopy (SEM). After bacterial treatment of PET, the formation of new functional groups, most notably in the area of 3326 cm−1 suggestive of O–H stretch, leading to carboxylic acid and alcohol as products were suggested by fourier transform infrared (FTIR) analysis. Monomethyl terephthalate (MMT) and terephthalic acid (TPA) were identified by gas chromatography–mass spectrometry (GC–MS) analysis as PET degradation metabolites. Tributyrin clearance assay confirmed the presence of a lipase/esterase enzyme in the strain IITR130. In this study, a degradation pathway for PET by an isolated and identified bacterium Brucella intermedia IITR130 was characterized in detail. [ABSTRACT FROM AUTHOR]

We report the synthesis, structures and gas sorption studies of two three-dimensional (3D) metal–organic frameworks (MOFs) namely {[Zn2(OBZ)2L1]·4DMF}n (1) and {[Co3(TER)3(L2)(DMF)]·5DMF}n (2), where OBZ2− is deprotonated 4,4′-oxybis(benzoic acid), TER2− is deprotonated terephthalic acid, DMF is N,N-dimethylformamide, L1 is 2,2′-bis(pyridin-3-ylmethyl)-[5,5′-biisoindoline]-1,1′,3,3′-tetraone and L2 is 5,5′-carbonylbis(2-(pyridin-3-ylmethyl)isoindoline-1,3-dione). 1 and 2 are 3D MOFs containing 2D channels. The desolvated phases of 1 and 2 (1-d and 2-d) adsorb modest amounts of carbon dioxide (CO2) at 195 K and 273 K; however, 1-d displays stepwise adsorption of CO2 at 195 K and hysteretic desorption. Notably, a gate-opening effect is triggered after 1-d adsorbs 63 cm3 (STP) g−1, allowing the structure to open and adsorb an additional 54 cm3 (STP) g−1. In contrast, 1-d adsorbs relatively small amounts of hydrogen (H2) and nitrogen (N2) gases, 3 cm3 (STP) g−1 and 12 cm3 (STP) g−1, respectively, suggesting selectivity of CO2 over H2 and N2. [ABSTRACT FROM AUTHOR]

This study aimed to develop an eco-friendly, cost-efficient, and practically viable method for extracting terephthalic acid (H2BDC) from polyethylene terephthalic (PET) waste. Dimethyl sulfoxide (DMSO) was combined with either citric acid (C6H8O7) or H2SO4 to enhance the particle size of H2BDC, and the optimum conditions during the acidification step were determined. Additionally, response surface methodology was employed to examine the influence and interaction of extractant (NaOH) concentration, hydrolysis temperature, and time on the optimal H2BDC yield and recovery ratio. Experimental results demonstrated that NaOH concentration significantly impacted both H2BDC yield and recovery ratio, surpassing the effects of hydrolysis temperature and time. Under optimal conditions involving a temperature of 200 °C and a 12 h reaction time with 5% NaOH, the model predicted a 100% yield and recovery ratio, which closely matched the experimental results of 99% and 100% for yield and recovery ratio, respectively. To enhance particle size, a combination of DMSO and C6H8O7 was more effective than H2SO4. The maximum particle size achieved was 57.4 µm under the following optimum conditions: premixing 5 M C6H8O7 with DMSO at a 35:75 mL ratio and maintaining a reaction temperature of 75 °C for 40 min. The study demonstrated the stability and consistency of the method. The H2BDC yield remained between 96 and 98% with high purity over eight consecutive cycles of using the DMSO and C6H8O7 mixture. The findings highlight the importance of integrating C6H8O7 and DMSO to enhance H2BDC quality, meeting commercial product criteria with evidence of high purity and large particle size. This method presents a promising solution for extracting H2BDC from PET waste, with potential implications for the recycling industry and a positive environmental impact. [ABSTRACT FROM AUTHOR]

The replacement of polymers derived from petrochemical resources has been a prominent area of focus in recent decades. Polymers used in engineering materials must exhibit mechanical strength and stiffness while maintaining performance through a broad temperature range. Most of the polyesters used as engineering materials are based on terephthalic acid (TPA) and its derivatives, which provide necessary rigidity to molecular chains due to an aromatic ring. Bio-based alternatives for TPA-based polyesters that are gaining popularity are the polyesters derived from 2,5-furandicarboxylic acid (FDCA). To broaden applicational possibilities, one effective way to achieve specific properties in targeted applications is to adjust the composition and structure of polymers using advanced polymer chemistry techniques. The incorporation of rigid diols such as isosorbide, 1,4-cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) should result in a greater stiffness of the molecular chains. This review extensively explores the effect of incorporating rigid diols on material properties through a review of research articles as well as patents. Moreover, this review mainly focuses on the polyesters and copolyesters synthesized via two-step melt polycondensation and its alterations due to the industrial importance of this method. Innovative synthesis strategies and the resulting material properties are presented. [ABSTRACT FROM AUTHOR]

CO2 chemical fixation offers a feasible approach for carbon mitigation and high‐value utilization, but it is still challenging to develop an efficient catalyst for CO2 conversion into cyclic carbonate. Herein, the triethylenediamine‐derived dicationic ionic liquids (DIL‐X, X = Cl, Br, and I) were grafted into UiO‐66 linkers through self‐assembly of Zr4+ ions and the mixed ligands of terephthalic acid and DIL‐bearing dicarboxylic acid, resulting in UiO‐66‐DIL‐Xn, (n designated as molar amount of the feeding DIL‐X). Their catalytic performance was evaluated by the epoxide cycloaddition reaction in the absence of solvent and cocatalyst. Among them, the UiO‐66‐DIL‐Cl0.4 catalyst exhibited outstanding performance, with a chloropropene carbonate yield of 92% and a high selectivity of 99% under 0.1 MPa CO2 at 110 °C for 16 h. Its high activity could be ascribed to the cooperativity among Lewis acidity of MOF nodes, the enhanced CO2 absorption, and the strong nucleophilicity offered by halogen ions of ionic liquid‐modified MOF. Moreover, UiO‐66‐DIL‐Cl0.4 presented excellent recyclability and substrate extension. A potential catalytic mechanism for the epoxide‐CO2 cycloaddition into cyclic carbonate has been proposed. This work will shed light on the rational design of functionalized MOFs‐based catalysts for CO₂ utilization. [ABSTRACT FROM AUTHOR]

2,5-Furandicarboxylic acid (FDCA) is one of the most promising biodegradable substitutes for fossil-derived terephthalic acid (PTA) and adipic acid. The production of FDCA from biomass-derived 5-hydroxymethylfurfural (HMF) is significant and has attracted great attention. However, the major challenge lies in the development of a non-precious metal-based catalyst system without employing a homogeneous base. Herein, we successfully prepared an atomically dispersed Fe–N–C/γ-Al2O3 catalyst, which affords superior catalytic performance in terms of activity and stability with a FDCA yield of 99.8% and reusability of five recycle times in the catalytic oxidation of HMF to FDCA under base-free mild conditions. Based on controlled experiments and complementary characterization studies, we found that the atomically dispersed medium-spin Fe–N5 active sites together with the surface acidic/basic sites of alumina synergistically enhanced the catalytic activity and selectivity towards FDCA under base-free conditions. Our process eliminates the employment of expensive oxidants and corrosive bases, leading to economic and green biomass transformations. [ABSTRACT FROM AUTHOR]

A method of gas chromatography-mass spectrometry (GC-MS) was established to determine the migration of dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, decanedioic acid bis (2,2,6,6-tetramethyl-4-piperidinyl)ester in water-based, acidic and alcoholic food simulants, and olive oil and chemical alternative solvents. The 95% ethanol and isooctane chemical substitution solutions were directly analyzed by GC-MS. The olive oil samples were extracted with acetonitrile followed by QuEChERS purification, and then analyzed by GC-MS. Other simulants (water, 4% acetic acid, 10% ethanol, 20% ethanol, and 50% ethanol) were extracted with n-hexane and then determined by GC-MS. The results showed that the method is well performed under optimized conditions, with the correlation coefficient (r²) greater than 0.995. The limits of detection and the limits of quantitation of the four sebacic acid ester compounds in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, isooctane, and olive oil simulants are 0.1-0.2 mg/kg, 0.3- 0.5 mg/kg, respectively. Migration experiments on plastic samples were conducted, and spiking experiments at three concentration levels of 0.30, 2.0, 4.0 mg/kg in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, and isooctane food simulants, and three concentration levels of 0.50, 2.0, 4.0 mg/kg in olive oil food simulants were carried out. The spiking recoveries range from 92.5% to 108%, and the relative standard deviations (RSDs) are 2.4%-8.8%. The method solves the problem that decanedioic acid bis (2,2,6,6-tetramethyl-4-piperidinyl) ester cannot be extracted into n-hexane in 4% acetic acid by adjusting pH value using ammonium hydroxide, the optimal pH range was determined by comparing the responses of four targets at different pH values. QuEChERS was firstly used for migration experiments of sebacic acid esters in food contact materials to solve the turbidity and partial oil precipitation of olive oil simulants in the concentration process after extraction. By optimizing the QuEChERS filling material, the interference of organic acids, fatty acids, sugar and other impurities on the targets were reduced, producing greater separation effect of the targets. The separation efficiency of four chromatographic columns with different polarity was compared, and the DB-17HT column was selected to detect the four sebacic acid esters simultaneously. Plastics such as polypropylene, polyethylene terephthalic acid terephthalate, polyvinyl chloride, composite membranes, paper cups, recycled PET and recycled PVC were collected and migration experiments were carried out, the migration of sebacic acid esters in these plastics materials was investigated. This method is highly sensitive, precise, and accurate, fully meeting the requirement for determining the migration of the sebacic acid esters in food contact materials and their products. [ABSTRACT FROM AUTHOR]

The crystal structure of 2,3,5,6-tetraiodo-1,4-benzenedicarboxylic acid dihydrate is described and the following structural features are established by XRD: C8H6I4O6, M 705.73; monoclinic crystal system, P21/n space group; unit cell parameters: a = 5.78160(10) Å, b = 15.0976(2) Å, c = 17.3437(3) Å; α = 90°, β = 94.602(2)°, γ = 90°; V = 1509.02(4) Å3, Z = 4, ρcalc = 3.106 g/cm3. Some features of the thermolysis of terephthalic acid and its iodine derivatives are described. Diiodoterephthalic acid is the least thermally stable, tetraiodoterephthalic acid is the most stable. The iodinated terephthalic acids have similar heats of fusion. The largest amount of carbon residue is formed during the decomposition of 2,3,5,6-tetraiodo-1,4-benzenedicarboxylic acid. [ABSTRACT FROM AUTHOR]

Pt cocatalyst play bifunctions in the photoreforming of polyethylene terephthalate plastic waste by improving the charge transfer kinetics and regulating the adsorption-desorption of oxidation intermediates, thereby achieving efficient photocatalytic H 2 evolution rate and producing valuable commodities in the photoreforming reactions. [Display omitted] Upcycle polyethylene terephthalate (PET) waste by photoreforming (PR) is a sustainable and green approach to tackle environmental problems but with challenges to obtain valuable oxidation products and high purity hydrogen simultaneously. Noble metal cocatalysts are essential to enhance the overall PR reaction efficacy. In this work, TiO 2 nanotubes (TiO 2 NTs) decorated with single Pt atoms (Pt 1 /TiO 2) or Pt nanoparticles (Pt NPs /TiO 2) are used in the photoreforming reaction (in one batch), and the oxidation products from ethylene glycol (EG, hydrolysed product of PET) in liquid phase and hydrogen are detected. With Pt 1 /TiO 2 , EG is oxidized to glyoxal, glyoxylate or lactate, and hydrogen evolution rate (r H 2) reaches 51.8 μmol⋅h−1⋅g cat −1, that is 30 times higher than that of TiO 2. For Pt NPs /TiO 2 (size of Pt NPs: 1.97 nm), hydrogen evolution reaches 219.1 μmol⋅h−1⋅g cat −1, but with the oxidation product of acetate only. DFT calculation demonstrates that for Pt NPs, the reaction path for hydrogen evolution is preferred thermodynamically, due to the formation of Schottky junction. On the oxidation of EG, theoretical and spectroscopic analysis suggest that bidentate adsorption of EG at the interface is facile on Pt 1 /TiO 2 , compared to that on Pt NPs /TiO 2 (two Pt sites), but oxidation products, adsorb less strongly, compared to Pt NPs /TiO 2 , that eventually regulates the distribution of oxidation products. The results thus demonstrate the bifunctions of Pt in the PR reaction, i.e., electron transfer mediator for hydrogen evolution and reactive sites for molecules adsorption. The oxidation reaction is dominated by the adsorption-desorption behavior of molecules but the reduction reaction is controlled by the electron transfer. In addition, acidification of pretreated PET alkaline solution achieves separation of pure terephthalic acid (PTA), which further improves the reaction efficiency possibly by offering high density of active sites and acidic environment. Our work thus demonstrates that to upcycle PET plastics, an optimized process can be reached by atomic design of photocatalysts and proper treatment on the plastic wastes. [ABSTRACT FROM AUTHOR]

Enzymatic degradation of polyethylene terephthalic acid (PET) has been gaining increasing importance. This has resulted in a significant increase in the search for newer enzymes and the development of more efficient enzyme-based systems. Due to the lack of a standard screening process, screening new enzymes has relied on other assays to determine the presence of esterase activity. This, in turn, has led to various nomenclatures and methods used to describe them and measure their activity. Since all PET-hydrolyzing enzymes are α/β hydrolases, they catalyze a serine nucleophilic attack and cleave an ester bond. They are lipases, esterases, cutinases and hydrolases. This has been used interchangeably, leading to difficulties while comparing results and evaluating progress. This review discusses the varied enzyme nomenclature being adapted, the different assays and analysis methods reported, and the strategies used to increase PET-hydrolyzing enzyme efficiency. A section on the various ways to quantify PET hydrolysis is also covered. [ABSTRACT FROM AUTHOR]

The global increase in polyethylene terephthalate (PET)-based waste fiber poses a persistent environmental risk. While efforts have been made to repurpose waste fibers into bags, clothing, and building materials, the depolymerization process to extract pure raw materials for recycling remains underdeveloped. This study investigates the impact of normal hexane treatment on the purity of terephthalic acid (TPA) recovered from wastewater containing sodium terephthalate, ethylene glycol, and impurities generated during polyester fabric weight reduction or waste fiber recycling processes. Nuclear magnetic resonance analysis of the recovered TPA (rTPA) revealed a maximum purity of 99.81%, suggesting the effective removal of diverse contaminants such as adhesives and surfactants present in waste fibers through normal hexane and activated carbon treatments. This research contributes to the development of efficient and sustainable PET waste fiber recycling processes, highlighting the potential of normal hexane treatment in enhancing the purity of rTPA.

Abstract This study aimed to develop an eco-friendly, cost-efficient, and practically viable method for extracting terephthalic acid (H2BDC) from polyethylene terephthalic (PET) waste. Dimethyl sulfoxide (DMSO) was combined with either citric acid (C6H8O7) or H2SO4 to enhance the particle size of H2BDC, and the optimum conditions during the acidification step were determined. Additionally, response surface methodology was employed to examine the influence and interaction of extractant (NaOH) concentration, hydrolysis temperature, and time on the optimal H2BDC yield and recovery ratio. Experimental results demonstrated that NaOH concentration significantly impacted both H2BDC yield and recovery ratio, surpassing the effects of hydrolysis temperature and time. Under optimal conditions involving a temperature of 200 °C and a 12 h reaction time with 5% NaOH, the model predicted a 100% yield and recovery ratio, which closely matched the experimental results of 99% and 100% for yield and recovery ratio, respectively. To enhance particle size, a combination of DMSO and C6H8O7 was more effective than H2SO4. The maximum particle size achieved was 57.4 µm under the following optimum conditions: premixing 5 M C6H8O7 with DMSO at a 35:75 mL ratio and maintaining a reaction temperature of 75 °C for 40 min. The study demonstrated the stability and consistency of the method. The H2BDC yield remained between 96 and 98% with high purity over eight consecutive cycles of using the DMSO and C6H8O7 mixture. The findings highlight the importance of integrating C6H8O7 and DMSO to enhance H2BDC quality, meeting commercial product criteria with evidence of high purity and large particle size. This method presents a promising solution for extracting H2BDC from PET waste, with potential implications for the recycling industry and a positive environmental impact.

[Display omitted] • Four functionalized terephthalic acid-based HOFs were prepared. • Their ultrahigh proton conductivities were explored and compared. • The conducting mechanisms were highlighted. Recently, the utilization of hydrogen-bonded organic frameworks (HOFs) with high crystallinity and inherent well-defined H-bonding networks in the field of proton conduction has received increasing attention, but obtaining HOFs with excellent water stability and prominent proton conductivity (σ) remains challenging. Herein, by employing functionalized terephthalic acids, 2,5-dihydroxyterephthalic acid, 2-hydroxyterephthalic acid, 2-nitro terephthalic acid, and terephthalic acid, respectively, four highly water-stable ionic HOFs (iHOFs), [(C 8 H 5 O 6)(Me 2 NH 2)]∙2H 2 O (iHOF 1), [(C 8 H 5 O 5)(Me 2 NH 2)] (iHOF 2), [(C 8 H 4 NO 6)(Me 2 NH 2)] (iHOF 3) and [(C 8 H 5 O 4)(Me 2 NH 2)] (iHOF 4) were efficiently prepared by a straightforward synthesis approach in DMF and H 2 O solutions. The alternating-current (AC) impedance testing in humid conditions revealed that all four iHOFs were temperature- and humidity-dependent σ, with the greatest value reaching 10-2 S·cm−1. As expected, the high density of free carboxylic acid groups, crystallization water, and protonated [Me 2 NH 2 ]+ units offer adequate protons and hydrophilic environments for effective proton transport. Furthermore, the σ values of these iHOFs with different functional groups were compared. It was discovered that it dropped in the following order under 100 °C and 98 % relative humidity (RH): σ iHOF 1 (1.72 × 10−2 S·cm−1) > σ iHOF 2 (4.03 × 10−3 S·cm−1) > σ iHOF 3 (1.46 × 10−3 S·cm−1) > σ iHOF 4 (4.86 × 10−4 S·cm−1). Finally, we investigated the causes of the above differences and the proton transport mechanism inside the framework using crystal structure data, water contact angle tests, and activation energy values. This study provides new motivation to develop highly proton-conductive materials. [ABSTRACT FROM AUTHOR]

The pyrazine-based Fe-MOFs with modulated O-Fe-N coordination were developed by ligand substitution strategy, which exhibited enhanced catalytic hydroxyl radical (OH) generation in Fenton-like process via degreasing H 2 O 2 activation barrier and triggering OH involved Fe(III) reduction. [Display omitted] Rational design of coordination environment of Fe-based metal-organic frameworks (Fe-MOFs) is still a challenge in achieving enhanced catalytic activity for Fenten-like advanced oxidation process. Here in, novel porous Fe-MOFs with modulated O-Fe-N coordination was developed by configurating amino terephthalic acid (H 2 ATA) and pyrazine-dicarboxylic acid (PzDC) (Fe-ATA/PzDC-7:3). PzDC ligands introduce pyridine-N sites to form O-Fe-N coordination with lower binding energy, which affect the local electronic environment of Fe-clusters in Fe-ATA, thus decreased its interfacial H 2 O 2 activation barrier. O-Fe-N coordination also accelerate Fe(II)/Fe(III) cycling of Fe-clusters by triggering the reactive oxidant species mediated Fe(III) reduction. As such, Fe-ATA/PzDC-7:3/H 2 O 2 system exhibited excellent degradation performance for typical antibiotic sulfamethoxazole (SMX), in which the steady-state concentration of hydroxyl radical (OH) was 1.6 times higher than that of unregulated Fe-ATA. Overall, this study highlights the role of O-Fe-N coordination and the electronic environment of Fe-clusters on regulating Fenton-like catalytic performance, and provides a platform for precise engineering of Fe-MOFs. [ABSTRACT FROM AUTHOR]

The selective electrooxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is of great significance in replacing terephthalic acid for the production of high-performance polymeric materials. This necessitates the development of advanced electrocatalysts. Ni-based nanomaterials, known for their unique electronic structure and high intrinsic activity, show great promise for the selective electrooxidation of HMF to FDCA. To provide guidance for the further development of advanced HMF electrocatalysts, we present a comprehensive review of recent progress in this field, focusing on HMFOR mechanisms, effective engineering strategies (e.g., morphology design, defect engineering, interface engineering, and strain engineering) for improving electrocatalytic performance, and representative Ni-based catalysts used for HMFOR. Finally, we offer a conclusion and highlight the challenging issues that need to be addressed, providing researchers with direction for future endeavors. • A review on the oxidation of HMF into FDCA catalyzed by Ni-based materials is summarized. • The mechanisms of HMF electrooxidation are described thoroughly. • Strategies for optimizing the catalytic performance of Ni-based materials for HMFOR are mentioned. • Recent progresses, challenges, and perspectives are highlighted. [ABSTRACT FROM AUTHOR]

Development, rapid detection and quantification of anticancer drugs in biological samples are crucial for effective drug monitoring. The present work describes the design of a Hf(IV)‐based metal‐organic framework (MOF) (1) by the reaction between Hf(IV) ion and 2‐(thiophene‐2‐carboxamido)terephthalic acid linker with the surface area of 571 m2 g−1. Desolvated MOF (1′) displayed highly discriminative fluorescence sensing properties for the antineoplastic drug flutamide and biomolecule hemin in an aqueous medium in the presence of co‐existing biomolecules and ions. The MOF's response time for sensing flutamide and hemin was less than 5 s with low detection limits of 1.5 and 0.08 nM, respectively. Additionally, 1′ also demonstrated recyclability up to five cycles and maintained its sensing ability across different pH media, various water samples, and biological fluids. Experimental and theoretical analyses suggested photoinduced electron transfer and inner‐filter effect in the presence of flutamide and Förster resonance energy transfer in the presence of hemin are most likely reasons behind the fluorescence quenching of MOF. Furthermore, the MOF demonstrated catalytic activity in Friedel‐Crafts alkylation reactions, providing a 96 % yield with slight decay in its activity over four uses. The enhanced activity of 1′ compared to Hf‐BDC and Hf‐BDC‐NH2 (BDC: 1,4‐benzenedicarboxylic acid) is due to the functionalized thiophene moieties through hydrogen bond donating sites, confirmed by a series of control experiments. [ABSTRACT FROM AUTHOR]

Persistent environmental colored compounds, resistant to biodegradation, accumulate and harm eco-systems. Developing effective methods to break down these pollutants is crucial. This study introduces Ag-MIL-101 (Ag-MIL-101) as a composite and reusable catalyst that efficiently degrades specific colored organic pollutants (COPs) like Methylene blue (MB), 4-Nitrophenol (4-NP), and 4-Nitroaniline (4-NA) using sodium borohydride at room temperature. The MIL-101 was synthesized using Terephthalic acid (TPA) derived from the degradation of Polyethylene Terephthalate (PET) plastic waste, with the assistance of zinc chloride. To further investigation, the kinetics of degradation reaction was studied under optimized conditions in the presence of Ag-MIL-101 as catalyst. Our results demonstrated the remarkable efficiency of the degradation process, with over 93% degradation achieved within just 8 min. The catalyst was characterized using FTIR, XRD, FESEM, and TEM. In this study, the average particle size of Ag-MIL-101 was determined using SEM and XRD analysis. These methods allow us to accurately and precisely determine the particle size. We determined the reaction rate constants for the degradation of each COP using a pseudo first-order kinetic equation, with values of 0.585, 0.597 and 0.302 min−1 for MB, 4-NP, and 4-NA, respectively. We also evaluated the recyclability of the catalyst and found that it could be reused for up to three cycles with only a slight decrease in efficiency (10–15%). Overall, our findings highlight the promising application of Ag-MIL-101 as an effective catalyst for the degradation of COPs, emphasizing the importance of optimizing reaction conditions to achieve enhanced efficiency. [ABSTRACT FROM AUTHOR]

A new crystalline dinuclear Cu(I)/(II) complex (E.F: C32H28Cu2N6O14) (1) of terephthalic acid (TERE) and 1, 10‐Phenathroline (PHEN) was synthesized under one‐pot approach. Structure identification of the complex was carried out using the single crystal XRD technique, which revealed the penta coordination nature of Cu(I)/(II) in a square pyramidal environment. Further, the structural data was supported by employing other spectroscopic studies (UV, ESR, FT‐IR). In addition, the thermal stability and morphology of the complex were elucidated using TGA and SEM‐EDAX analysis. Photoluminescence experiments revealed the capability of 1 to act as a "turn‐off" sensor towards Zn2+ sensing. This luminescence quenching of 1 exhibited a threefold quenching in intensity by achieving a static quenching process corresponding to a limit of detection (LOD) of 3.7 μM. Further, considering the electroactive nature of Cu(I)/(II) complex, the cyclic voltammetric experiments were performed to study its competence to act as a modifier of GCE for the detection of glucose and its excellent potency to act as an effective electroactive material in the detection of glucose solutions. Also, molecular docking of 1 with human bovine serum (HSA) and bovine serum albumin (BSA) was investigated to prove their ability to act as pharmacological agents. [ABSTRACT FROM AUTHOR]

The hydrolytic depolymerization of poly(ethylene terephthalate) (PET) fibers with solid sodium hydroxide was investigated. The study presents an innovative recycling approach for the recovery of virgin‐quality terephthalic acid (TA) from textile blends consisting of PET and elastane fibers. PET fibers were depolymerized for 5 min at 140 °C. An internal mixer served as an investigation platform for the experiments. The quality of TA is quantified based on its color value. Both the hydrolytic depolymerization of polyester fibers and the quality of the recovered TA are not impaired by the presence of up to 15 % elastane fibers in textile blends. [ABSTRACT FROM AUTHOR]

MIL-101(Cr) stands as one of the extensively researched chromium-based metal-organic frameworks, comprised of chromium metal ions and terephthalic acid ligands. This study introduces an innovative approach to MIL-101(Cr) synthesis by employing ultrasound (UTS) irradiation. Our primary objective revolved around optimizing key operational parameters, namely time and temperature, using the central composite design method. Subsequently, we conducted an in-depth analysis using variance analysis to understand their respective impacts. To predict process behaviour, we developed quadratic equations under varying conditions, achieving a remarkable R2 value of 0.9998 to relate parameters and synthesis yield. Results revealed a more pronounced influence of time variation compared to temperature on the synthesis process. Moreover, we subjected the synthesized MIL-101(Cr) to rigorous characterization using FT-IR, XRD, SEM, TGA, and N2 physisorption techniques. Our findings showcased the synthesized MIL-101(Cr) possessing exceptional characteristics, including an ultra-high specific surface area (2143 m2. g-1), substantial pore size (0.8 cm3.g-1), and excellent thermal, chemical, and water stability. Further examination indicated the presence of microporous windows, mesoporous cages, and uniform octahedral particles ranging in size between 125-260 nm. Notably, our study emphasized the energy efficiency of UTS irradiation over conventional electric (CE) heating, highlighting its potential as a quicker, more efficient, and environmentally friendly alternative to conventional synthesis methods. [ABSTRACT FROM AUTHOR]

Bio-based PA56 has obtained much more attention thanks to its environmentally friendly raw material sources and comparable overall properties to commercial PA66. However, its usability in high-temperature scenarios is limited by the aliphatic nature of its monomeric structure. Therefore, the PA5T/56 incorporating terephthalic acid monomers was nvestigated to broaden its range of applications. This study focuses on the characterization of the bio-based semi-aromatic PA5T/56, which was synthesized by terephthalic acid monomer. A comparison was made between the structure and properties of PA5T/56 and bio-based aliphatic PA56. FTIR and NMR results confirm the structural differences of bio-based PA5T/56. In comparison to bio-based aliphatic PA56, bio-based semi-aromatic PA5T/56 exhibits a higher glass transition emperature (tg = 113 °C), exceptional thermal stability (td, 5% = 392 °C, tdmax 123 °C), as well as superior hermomechanical properties and melt viscosity suitable for processing (<10° Pa⋅s). Therefore, PA5T/56 is endowed with broaden application scenarios by virtue of its excellent performance. [ABSTRACT FROM AUTHOR]

In this study, a new and very quick method to depolymerize PET plastics is reported. The depolymerization experiments were conducted using a type-IV deep eutectic solvent containing ZnCl2 and urea, and a microwave oven as reactor. Different combinations of power and reaction times were employed while keeping the total energy constant. Successful conversions were obtained carrying out the process at 180 W for 2 min and 360 W for 1 min, whereas at higher powers and shorter times, an inclusion likely occurs of some solvent into the structure of the recovered PET flakes, as suggested by the porosity of the flakes, imaged by SEM microscopy. The flakes increase their crystalline character during the treatment, as indicated by the appearance of narrow diffraction peaks in the XRD patterns, at variance with the broad signals observed in the case of the pristine amorphous polymer. The NMR analysis of the supernatant liquid above the partially solubilized PET shows the presence of terephthalic acid peaks. The infrared spectra of the solid powder achieved upon the acidic treatment of the extract reveal the presence of C=O stretching peaks and the absence of typical CH2 wagging absorptions that satisfactorily comply with the presence of terephthalic acid. [ABSTRACT FROM AUTHOR]

In this paper, Cu-BTC derived mesoporous CuS nanomaterial (m-CuS) was synthesized via a two-step process involving carbonization and sulfidation of Cu-BTC for colorimetric glutathione detection. The Cu-BTC was constructed by 1,3,5-benzenetri-carboxylic acid (H3BTC) and Cu2+ ions. The obtained m-CuS showed a large specific surface area (55.751 m2/g), pore volume (0.153 cm3/g), and pore diameter (15.380 nm). In addition, the synthesized m-CuS exhibited high peroxidase-like activity and could catalyze oxidation of the colorless substrate 3,3′,5,5′-tetramethylbenzidine to a blue product. Peroxidase-like activity mechanism studies using terephthalic acid as a fluorescent probe proved that m-CuS assists H2O2 decomposition to reactive oxygen species, which are responsible for TMB oxidation. However, the catalytic activity of m-CuS for the oxidation of TMB by H2O2 could be potently inhibited in the presence of glutathione. Based on this phenomenon, the colorimetric detection of glutathione was demonstrated with good selectivity and high sensitivity. The linear range was 1–20 μM and 20–300 μM with a detection limit of 0.1 μM. The m-CuS showing good stability and robust peroxidase catalytic activity was applied for the detection of glutathione in human urine samples. [ABSTRACT FROM AUTHOR]

In this experiment, water soluble polyester (WSPET) was synthesized by two-step esterification with terephthalic acid (PTA), isophthalic acid (IPA), sodium phthalic acid-5-sulfonate (5-SSIPA), ethylene glycol (EG) and dihydroxymethyl propionic acid (DMPA) as raw materials, tetrabutyl titanate as catalyst. BOPET/WSPET composite membrane was prepared by emulsion crosslinking with hexa(methoxymethyl) melamine (HMMM) as crosslinking agent by the coating method. The effects of different amounts of 5-SSIPA and DMPA on the contact angle, thermal properties, boiling resistance, optical properties and physical properties of the samples were investigated. The result shows that with the increase of the amount of 5-SSIPA, the hydrophilicity of the water-soluble polyester increases, the glass transition temperature increases, and the boiling resistance decreases. With the increase of the amount of DMPA, the hydrophilicity of the water-soluble polyester is enhanced, the boiling resistance is enhanced, and the pencil hardness and adhesion of the composite membrane are significantly improved, but the flexibility is reduced. When the addition amount of 5-SSIPA is 50% (relative to IPA mole ratio) and the addition amount of DMPA is 250% (relative to IPA mole ratio), the comprehensive performance of the sample is the best. [ABSTRACT FROM AUTHOR]

A facile solvent-free solid-state method was adapted to synthesize the spherical-shaped Bi2WO6 engraved on phenyl-doped g-C3N4 nanosheet, i.e., Bi2WO6/Ph-gC3N4 (or BPCN) composites with varying weights of Bi2WO6. Several spectral analyses were used to characterize all the synthesized nanomaterials. The synthesized photocatalyst showed good absorption under visible light as confirmed by UV–visible DRS analysis. Morphological analyses like SEM and TEM determine the successful fabrication of binary heterocomposite. Further, the elements available in the fabricated binary nanocomposite were confirmed by XPS. The photocatalyst was used for the aerobic photocatalytic degradation of a few colorless pollutants like bisphenol A (BPA, 30 mg L−1), a microplastic constituent, and tetracycline (TC, 40 mg L−1), an antibiotic derivative to achieve the impressive results. The less intense PL signal obtained for the 20BPCN heterocomposite reveals the remarkable enhancement in e−-h+ pair separation and recombination rate. The quenching study, alkaline terephthalic acid photoluminescence test (TA-PL), and NBT phototransformation study explain the formation of reactive species involved in the decomposition process. An oral cancer cell line (A-254) was tested for the anticancer activity analysis of the 20BPCN photocatalyst. Based on the obtained results, a Z-scheme electron transfer mechanism has been proposed for the photodegradation of model compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recovery of c-Si PV module's backsheet was studied for the first time. • Green and non-toxic ethanol was used as a solvent. • TPA product with economic value can be obtained. • The reaction solution can be reused. The treatment and recycling of discarded crystalline silicon photovoltaic modules (c-Si PV modules) has become a research focus, but few research have paid attention to the standardized treatment of c-Si PV module's fluorinated backsheet. Improper management of fluorinated backsheet can pose ecological and human health risks. Therefore, this study presents a novel method for processing the backsheet. The proposed approach entailed the utilization of ethanol (CH 3 CH 2 OH) to separate the backsheet from the PV module. Subsequently, the separated backsheet underwent decomposition using an alkaline ethanol (NaOH-CH 3 CH 2 OH) solution. Finally, the backsheet was recovered in the form of terephthalic acid (TPA) with a purity of 97.47 %. This recovered TPA can then serve as a valuable raw material for producing new backsheets, fostering a closed-loop material circulation. Experimental results demonstrate that immersing the PV module in a 75 % CH 3 CH 2 OH-H 2 O solution at a temperature of 343 K for 30 min achieved 100 % separation of the backsheet. Furthermore, subjecting the separated backsheet to a 60 min reaction in an NaOH-CH 3 CH 2 OH solution with a temperature of 343 K and a NaOH concentration of 1.0 mol/L achieved complete decomposition. The reaction mechanism was analyzed through characterization methods such as SEM/EDS, NMR, FTIR and XRD. This method is efficient, non-toxic organic reagent-free and environmentally friendly, so it holds significant potential for further development in the field of c-Si PV module recycling. [ABSTRACT FROM AUTHOR]

Synthesizing stable MOF materials with good adsorption capability in a relatively green way is well worth investigating. In this work, a stable Ce-UiO-66-NH2 MOF was constructed from Ce(IV) salts and a bifunctional ligand, 2-amino terephthalic acid, in a mixture of water and ethanol at room temperature. The MOF solid was fully characterized and its adsorption properties for methylene blue were investigated in detail. Ce-UiO-66-NH2 showed excellent removal ability of MB over a wide pH range, the adsorption process followed a pseudo-second-order kinetic model, and the isothermal adsorption data fit well with a Langmuir model with a maximum capacity of 427 mg g-1. Moreover, a spontaneous heat adsorption process was concluded from thermodynamic study, and this MOF sorbent can be reused for several cycles with its structural stability maintained. A possible mechanism for MB adsorption was also proposed. [ABSTRACT FROM AUTHOR]

Copper telluride nanoparticles are classified as the family of metal chalcogenides and were synthesized using a simple solvothermal method using a new source of telluride, ditelluride diphenyl. The characterized techniques revealed that the atomic composition of copper tellurides is Cu2Te and particles are spherical. This study is greatly examined by different designed experiments for the proof of the intrinsic peroxidase‐like activity of copper telluride nanoparticles and its effectiveness in a variety of similar structures. Cu2Te nanoparticles can convert peroxidase substrates (TMB and OPD) to colored products in the presence of H2O2. In addition, the as‐prepared nanoparticles have the potential to oxidize DPPH and ABTS substrates. Michaelis–Menten constant KM value for TMB and H2O2 was found to be 12 mM and 0.60 mM for H2O2 and the Vmax value of the Cu2Te was found to be TMB and H2O2 was 2.50×10−7 and 0.82×10−8 MS−1. These data are found to be almost comparable with natural peroxidase HRP and other artificial enzymes reported in the literature. The natural peroxidase‐like activities of Cu2Te nanoparticles originated from the catalytic decomposition of H2O2 into ⋅OH radical, which was confirmed from the ESR spin‐trapping technique and using a fluorescence probe, terephthalic acid. [ABSTRACT FROM AUTHOR]

A series of seven novel amorphous amides and polyamides were synthesized from four biodegradable carboxylic acids by direct polycondensation with aliphatic diamines using Yamazaki-Higashi phosphorylation. Aliphatic carboxylic acids like acrylic acid, lactic acid, and adipic acid whereas aromatic carboxylic acid like terephthalic acid were reacted with ethylenediamine and diamino-propane respectively. The monocarboxylic acids yielded amides, whereas the dicarboxylic acids formed polyamides. The obtained products were characterized by FT-IR, 1H NMR, LCMS, SEM, TGA, and DSC along with microbial biodegradation. The TGA thermogram comparison studies show a decrease in thermal degradation with an increase in the aliphatic chain. Also, the introduction of an aromatic ring decreases degradability. Glass transition of aliphatic polyamide at 140 °C has negligible melting endotherm. Also, the samples were structurally degraded after 15 days of biological treatment which was confirmed via FT-IR. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of mixtures of 1,9‐nonanediamine (NMDA) and 2‐methyl‐1,8‐octanediamine (MODA) when used to produce polyamide food contact materials for contact with all food types for long‐term storage at room temperature and below, including heating up to 121°C for up to 2 h. The polyamide material is also intended to be used for repeated use up to 121°C with short contact (up to 30 min). The polymer typically contains ■■■■■ of a low molecular weight fraction (LMWF, < 1000 Da). The specific migration was measured with polyamide samples in a set of migration tests with 3% acetic acid and 10% ethanol. NMDA and MODA were not detected at ■■■■■, respectively. The specific migration of the LMWF consisting of NMDA/MODA‐related species was up to ■■■■■. The overall migration in olive oil was below the detection limit (3 mg/dm2). The most abundant migrating LMWF oligomers were identified. Toxicological studies were performed with NMDA, MODA and with polyamide formulations enriched in the LMWF. The results of genotoxicity assays did not raise a concern. From a repeated‐dose oral 90‐day toxicity study in rats, the Panel identified a no observed adverse effect level (NOAEL) of 1000 mg/kg body weight per day for the migrating LMWF. The CEP Panel concluded that NMDA/MODA mixtures do not raise a safety concern for the consumer when used as comonomer with terephthalic acid to manufacture polyamide articles intended for contact with all food types, except for infant formula and human milk, if the migration of NMDA and MODA does not exceed 0.05 mg/kg food (as a sum of the two substances) and if the migration of the LMWF consisting of NMDA/MODA‐related species does not exceed 5 mg/kg food. [ABSTRACT FROM AUTHOR]

Purified terephthalic acid (PTA) is widely used as a chemical raw material, with its production process resulting in significant compounds that generate a substantial amount of sludge waste annually. These compounds are known to possess active hydrogen. Utilizing this property, a novel approach for the treatment of PTA sludge waste was developed for its modification and re-use. This study focuses on the preparation of epoxy curing agents using PTA sludge-tank material. The modification of PTA sludge-tank material is achieved by using the one-pot method to investigate the toughening effect of home-made curing agents on epoxy resins and compare them with commercially available curing agents, and to analyze the mechanism of the structure of the curing agent on the material. The results showed that while the tensile strength of the experimental group was generally lower than that of the control group, the impact strength was significantly higher. Additionally, the hardness and tensile strength of the materials gradually decreased with an increase of the amount of hardener, while the elongation at break and impact strength increased. Notably, at a hardener amount of 35%, the elongation at break increased by 3.89%, and the tensile strength and impact strength reached 10.13 MPa and 42.86 kJ m−2, respectively, demonstrating excellent toughness and strength characteristics. These findings testified the feasibility of modifying PTA sludge waste to prepare an epoxy toughening curing agent is not only feasible, but also significantly enhances the material's toughness. [ABSTRACT FROM AUTHOR]

This paper describes initially the application of the Tyndall effect (TE) of metal–organic framework (MOF) materials as a colorimetric signaling strategy for the sensitive detection of pyrophosphate ion (PPi). The used MOF NH2-MIL-101(Fe) was prepared with Fe3+ ions and fluorescent ligands of 2-amino terephthalic acid (NH2-BDC). The fluorescence of NH2-BDC in MOF is quenched due to the ligand-to-metal charge transfer effect, while the NH2-MIL-101(Fe) suspension shows a strong TE. In the presence of PPi analyte, the MOFs will undergo decomposition because of the competitive binding of Fe3+ by PPi over NH2-BDC, resulting in a significant decrease in the TE signal and fluorescence restoration from the released ligands. The results demonstrate that the new method only requires a laser pointer pen (for TE creation) and a smartphone (for portable quantitative readout) to detect PPi in a linear concentration range of 1.25–800 μM, with a detection limit of ~210 nM (3σ) which is ~38 times lower than that obtained from traditional fluorescence with a spectrophotometer (linear concentration range, 50–800 µM; detection limit, 8.15 µM). Moreover, the acceptable recovery of PPi in several real samples (i.e., pond water, black tea, and human serum and urine) ranges from 97.66 to 119.15%. [ABSTRACT FROM AUTHOR]

Poly(ethylene terephthalate) (PET) is a very valuable and beneficial material for industrial purposes, with various different applications. Due to the high annual production volume of over 50 million tons worldwide and the indiscriminate disposal by consumers, the polymers accumulate in the environment, causing negative effects on various ecosystems. Biodegradation via suitable enzymes represents a promising approach to combat the plastic waste issue so validated methods are required to measure the efficiency and efficacy of these enzymes. PETase and MHETase from Ideonella sakaiensis are suitable enzymes needed in combination to completely degrade PET into its environmentally friendly monomers. In this project, we compare and combine a previously described bulk absorbance measurement method with a newly established 1H NMR analysis method of the PET degradation products mono(2-hydroxyethyl) terephthalic acid, bis(2-hydroxyethyl) terephthalic acid and terephthalic acid. Both were optimized regarding different solvents, pH values and drying processes. The accuracy of the measurements can be confirmed with sensitivity limits of 2.5–5 µM for the absorption method and 5–10 µM for the 1H NMR analysis. The combination of the described methods therefore allows a quantitative analysis by using bulk absorption coupled with a qualitative analysis through 1H NMR. The methods established in our work can potentially contribute to the development of suitable recycling strategies of PET using recombinant enzymes. [ABSTRACT FROM AUTHOR]

The stability constants of the complexes of europium(III) and terbium(III) ions with terephthalic acid anions were determined by potentiometric titration over a wide pH range. The luminescent properties of these complexes were studied. It was shown that the complexes are most stable in slightly acidic solutions. Analysis of the photoluminescence emission spectra confirmed the adequacy of the proposed model of complexation. [ABSTRACT FROM AUTHOR]

Curvularia verruculosa fungal causes leaf spot disease in rice plants. The bark extract of Michelia champaca could inhibit the growth of the fungi. The present research aimed to know the active compound responsible for antifungal activity. Extraction was done using the Maceration method, antifungal activity was measured using the Diffusion well method, and identification of active compounds was carried out using Gas chromatography-mass spectroscopy (GC-MS). The methanol extract obtained had a yield of 18.7%. It showed strong activity against C. verruculosa with an inhibition zone until 30.01 mm. The fractionation results showed that n-hexane extract (HE) was the strongest inhibiting the growth of C. verruculosa (32.45 mm), followed by chloroform extract (CE) (29.20 mm), while n-butanol extract (BE) was not active. Separating active compounds from HE extract was made using Column chromatography (CC) method with silica gel as the stationary phase and the mixture of n-hexane-acetone (3:1) as the mobile phase. This separation resulted in 5 combined fractions; HE3 and HE5 extracts showed very strong activity against C. verruculosa, with a diameter of the inhibition zone of 26.73 and 33.46 mm, respectively; HE2 extract showed strong activity with a diameter of the inhibition zone of 15.21 mm, while HE1 and HE4 extracts did not show activity. Identification using GC-MS, especially the HE3 extract, revealed that the extract contained two compounds: tributyl acetyl citrate and terephthalic acid, dodecyl-2-ethylhexyl ester. The result indicated that the bark extract of M. champaca had the potential to be a botanical fungicide. [ABSTRACT FROM AUTHOR]

Aldaric acids are becoming valuable platform chemicals in bioeconomy and circular economy approaches. Among them, mucic acid (meso‐galactaric acid) is gaining industrial attention as a bio‐based precursor of adipic acid found in polyamides, and of 2,5‐furan dicarboxylic acid, a valuable substitute for terephthalic acid in polyesters. A combination of detailed experimental protocols and conditions with DFT computational calculations for the synthesis of mucic acid from galactose are herein described. The product is obtained by reaction with diluted aqueous nitric acid as the oxidizing agent and the reaction medium. Optimized reaction conditions require 5 M nitric acid, 95 °C, galactose/HNO3 molar ratio 1 : 9, 100 g/L galactose concentration in the reaction medium. Computational calculations suggest that the oxidation mechanism may involve a contextual oxygen protonation and nitrate nucleophilic attack, leading to the oxidized product. The proposed mechanism requires a stoichiometry of 6 moles of nitric acid per galactose mole, albeit both experimental and computational data evidence that proton excess may be necessary to start the reaction. The reported study gives useful insights for the production of galactaric acid. [ABSTRACT FROM AUTHOR]