Molar Ratio Research Articles

Development of an Efficient Process for the Separation of Co(ii), Mn(ii), and Ni(ii) from Chloride Solution by Precipitation

ABSTRACT The demand for nickel, cobalt, and manganese is increasing owing to their critical role in the performance of lithium-ion batteries. Precipitation is simpler to operate than solvent extraction in the separation of metal ions. In this work, precipitation-based procedures were developed to separate Co(II), Mn(II) and Ni(II) from synthetic chloride solutions. Dimethylglyoxime (DMG) was effective in selectively precipitating Ni(II) from the chloride solutions containing Co(II) and Mn(II). Solution pH greatly affected the precipitation of Ni(II) by DMG. In the first procedure, Ni(II) was first precipitated using DMG from solution with initial pH 6 at a DMG/Ni(II) molar ratio of 3, a reaction time of 30 min and then Co(II) was separated from the filtrate by precipitation with Na2S, with optimal conditions being an initial pH of 6, a Na2S/Co(II) molar ratio of 2 and a reaction time of 15 min. In the second procedure, both Ni(II) and Co(II) was simultaneously precipitated with Na2S, leaving Mn(II) in the filtrate. Then the mixed sulfides of Co(II) and Ni(II) were dissolved by using HCl solution containing NaClO as an oxidizing agent. From the leaching solution, Ni(II) was separated by precipitation with DMG. Optimum conditions for the separation conditions were obtained. In both procedures, the separation degree among the three metal ions was higher than 99%. The developed procedures were simple and effective for the separation of the three metal ions compared to solvent extraction.

Exploring the performance of Co/Al2O3–ZrO2 nanocatalysts developed through the thermal evaporation method in dry reforming of methane

Abstract This study aimed to investigate the performance of the thin layer nanostructures of Co/Al2O3–ZrO2 in the dry reforming of methane (DRM) in a microchannel reactor. The nanostructures were prepared via utilizing the thermal evaporation method. Reactor tests were carried out at various coating times of 2, 3, and 4 min and temperatures of 700, 750, and 800 °C with a feed flow rate of 10 ml/min and a 1:1:8 ratio of helium, carbon dioxide, and methane. Also, grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) were used to identify catalyst features. According to the obtained results, the highest percentage of conversion in all samples was observed at 800 °C. The results of the reactor tests also revealed that the activity of catalyst layers highly depends on coating time. The findings demonstrated that raising deposition time improves the distribution of particle size and catalyst loading. Considering the nanostructure of Co/Al2O3–ZrO2, the sample undergoing 4 min coating time yielded the highest amount of primary methane conversion (89.3 %), primary carbon dioxide conversion (92.4 %), and H2/CO molar ratio (0.91). The stability test of the catalyst layers for 28 h at the optimum condition (P = 1 atm, T = 800 °C, t = 4 min deposition time, CH4/CO2 = 1, and GHSV = 48,000 mL g−1 h−1) showed that the catalysts prepared by this method had a good stability.

Highly Adsorptive Organic Xerogels for Efficient Removal of Metformin from Aqueous Solutions: Experimental and Theoretical Approach

Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl2, NaCl, MgCl2, and synthetic urines. Reuse cycles demonstrated that xerogels could be reused for up to three cycles without any loss in adsorptive efficiency. The adsorption mechanisms of metformin in the adsorption process highlight the strong electrostatic interactions and hydrogen bonds between the adsorbate and the adsorbent material. Xerogels synthesized show promise as efficient adsorbents to remove metformin from aqueous solutions, helping to mitigate its environmental impact.

Effect of magnetron sputtering power on the properties of the AlO X monolayer and AlO X /MgF2 bilayer anti-reflection films

The AlO X monolayer anti-reflection (MLAR) films and the AlO X /MgF2 bilayer anti-reflection (BLAR) films were deposited on high-purity glasses with magnetron sputtering. We investigated the influences of sputtering power on the O/Al molar ratio, microstructure, and optical properties of the AlO X MLAR films and AlO X /MgF2 BLAR films. The results showed that a too high or a too low sputtering power was detrimental to the preparation of the high-quality films, which could only be obtained when the sputtering power was 115 W. However, the sputtering power did not affect the crystallinity of the films, all of which were amorphous. When the sputtering power was 115 W, the high-purity AlO X MLAR film exhibited an O/Al molar ratio of 2.27:1, a refractive index of 1.426, and an average transmittance (T avg: average transmittance of the quartz glass deposited the film, hereinafter the same) of 94.03% within 300–1100 nm wavelength range. The T avg of AlO X /MgF2 BLAR film with a power of 115 W was 94.99%, which was 1.92% higher than that of the glass substrate. And it improved the cell’s photoelectric conversion efficiency (PCE) by 3.19%.

Enhancing photocatalytic hydrogen production in conjugated porous polymers through donor-π-donor fragment insertion

Recent progress in conjugated polymer photocatalysts has opened avenues for enhancing photocatalytic hydrogen production (PHP) activity through structural design. This study highlights the impact of the acceptor-to-donor feed ratio on PHP activity in copolymers, influencing their energy level structures. Five conjugated porous polymers (CPPs) were synthesized by adjusting the acceptor-to-donor molar ratio. Notably, at a 2:1 acceptor-to-donor ratio, the polymer demonstrated a high hydrogen evolution rate (HER) of 61.9 mmol g−1 h−1 under full arc irradiation without co-catalysts and an apparent quantum yield (AQY) of 7.77% at 475 nm. However, further increasing the proportion of the donor unit in the copolymers decreases their HER. Experiments and theoretical simulation characterized that the feed ratios effectively tune the polymer's molecular structure, hydrophilicity, band gap, and the generation and transport efficiency of photo-induced charge carriers, ultimately affecting the hydrogen production kinetics and efficiency. This research demonstrates that tuning the band structure and chemical compositions of CPPs through statistical copolymerization significantly impacts their PHP activity.

Fingerprint profiling for quality evaluation and the related biological activity analysis of polysaccharides from Liuweizhiji Gegen-Sangshen beverage

IntroductionLiuweizhiji Gegen-Sangshen beverage (LGS) is popular in China, which has been used for alleviating alcohol-mediated discomfort and preventing alcoholic liver disease (ALD). This beverage is consisted of six herbal components that are known as functional foods and fruits. LGS is rich in polysaccharides, however, the activity and quality evaluation of LGS-derived polysaccharides remain unexplored. The purpose of this study is thus to establish a comprehensive quality control methodology for the assessment of LGS polysaccharides (LGSP) and to further explore the anti-oxidant, anti-inflammatory as well as prebiotic effect of LGSP.MethodsLGSP was extracted, followed by analysis of molecular weight distribution, monosaccharide content and structural characterization via integrating the application of high-performance size exclusion chromatography (HPSEC), 1-phenyl-3-methyl-5-pyrazolone-HPLC (PMP-HPLC), fourier transform infrared spectroscopy (FT-IR) as well as nuclear magnetic resonance spectroscopy (NMR) techniques. The anti-oxidation activity of LGSP was determined by DPPH, ABTS, hydroxyl radical scavenging capacity and total antioxidant capacity. The anti-inflammation of LGSP were assessed on the RAW 264.7 cells. The effect of LGSP on growth of Lactobacillus, Bifidobacterium bifidum and Bifidobacterium adolescentis was evaluated.ResultsThe results demonstrated that LGSP had two molecular weight distribution peaks, with the average molecular weights of (6.569 ± 0.12) × 104 Da and (4.641 ± 0.30) × 104 Da. LGSP was composed of 8 monosaccharides, with galacturonic acid, glucose rhamnose and galactose representing the highest molar ratios. Homogalacturonic acid (HG) type and rhamnosegalacturonic acid glycans I (RG-I) type and α-1,4-glucan were present in LGSP. LGSP concentration in LGS was 17.94 ± 0.28 mg/mL. Furthermore, fingerprint analysis combined with composition quantification of 10 batches of LGSP demonstrated that there was a high similarity among batches. Notably, LGSP exhibited anti-oxidant effect and inhibited expressions of pro-inflammatory factors (TNF-α and IL-6) in LPS-stimulated RAW 264.7 cells. In addition, LGSP remarkably promoted the proliferation of probiotics Lactobacillus, Bifidobacterium bifidum and Bifidobacterium adolescentis, showing good prebiotic activity.DiscussionThe results of present study would be of help to gain the understanding of structure–activity relationship of LGSP, provide a reference for quality evaluation of bioactive LGSP, and facilitate development of unique health and functional products in the future.

Development of biobased, sustainable and environmentally friendly glycerol ester rosins for the production of thermoplastic road marking paint

AbstractIn recent years, natural rosin derivatives have gained significant importance in the production of sustainable bio‐based materials, including thermoplastic road marking paint (TRMP). This study evaluates the use of sustainable natural glycerol ester rosins as bio‐based binders in TRMP formulations, specifically focusing on pine, wood, and tall oil rosins. Various analytical techniques, such as FT‐IR, TGA, MALDI‐TOF‐MS and GPC‐HPLC, were utilized to analyze both unmodified and glycerol ester rosins. Standard tests, including acid number (mg KOH/g) ASTM D 465‐05 and softening point (°C) ASTM E 28‐99, were also conducted on the samples. The optimum synthesis conditions for glycerol ester rosins (GER) were determined as follows: a rosin/glycerol molar ratio of 2.54, catalyst/rosin weight ratio of 0.5%, and antioxidant/rosin weight ratio of 1.0%. GPC‐HPLC analysis revealed average esterification reaction yields of over 90.85%. Furthermore, TRMPs underwent various tests, including gloss factor (β), chromaticity coordinates (x, y), UVB aging, and softening point (°C). The results demonstrated that GERs exhibited superior performance, especially in the UVB aging test, with all TRMPs classified as UV1 type. These findings highlight the promising potential of GERs derived from different types of rosins in producing sustainable, environmentally friendly, and bio‐based next‐generation TRMPs.

Advancing hydrogen generation: Kinetic insights and process refinement for sorption-enhanced steam gasification of biomass utilizing waste carbide slag

Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (∼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.

PET Imaging of Differentiated Thyroid Cancer with TSHR-Targeted [89Zr]Zr-TR1402.

Thyroid cancer is the most common endocrine cancer, with differentiated thyroid cancers (DTCs) accounting for 95% of diagnoses. While most DTC patients are diagnosed and treated with radioiodine (RAI), up to 20% of DTC patients become RAI refractory (RAI-R). RAI-R patients have significantly reduced survival rates compared to patients who remain RAI-avid. This study explores [89Zr]Zr-TR1402 as a thyroid-stimulating hormone receptor (TSHR)-targeted PET radiopharmaceutical for DTC. [89Zr]Zr-TR1402 was synthesized with a molar activity of 25.9 MBq/nmol by conjugating recombinant human TSH (rhTSH) analogue TR1402 to chelator p-SCN-Bn-deferoxamine (DFO) in a molar ratio of 3:1 (DFO/TR1402) and radiolabeling with 89Zr (t1/2 = 78.4 h, β+ = 22.7%). As TSHR is absent in commonly available DTC-derived cell lines, TSHR was reintroduced via stable transduction by delivering a lentivirus containing the full-length coding region of the human TSHR gene. Receptor-mediated uptake of [89Zr]Zr-TR1402 was evaluated in vitro in stably transduced TSHR+ and wild-type TSHR- DTC cell lines. In vivo PET imaging was performed on Days 1-3 postinjection in male and female athymic nude mice bearing TSHR+ and TSHR- xenografts, along with ex vivo biodistribution on Day 3 postinjection. In vitro uptake of 1 nM [89Zr]Zr-TR1402 was significantly higher in TSHR+ THJ529T (P < 0.0001) and FTC133 (P < 0.01) cells than in TSHR- THJ529T and FTC133 cells. This uptake was shown to be specific in both TSHR+ THJ529T (P < 0.0001) and TSHR+ FTC133 (P < 0.0001) cells by blocking uptake with 250 nm DFO-TR1402. In vivo PET imaging showed accumulation of [89Zr]Zr-TR1402 in TSHR+ tumors, which was the highest on Day 1. In the male FTC133 xenograft model, ex vivo biodistribution confirmed a significant difference (P < 0.001) in uptake between FTC133+ (1.3 ± 0.1%ID/g) and FTC133- (0.8 ± 0.1%ID/g) tumors. A significant difference (P < 0.05) in uptake was also seen in the male THJ529T xenograft model between THJ529T+ (1.8 ± 0.6%ID/g) and THJ529T- (0.8 ± 0.4%ID/g) tumors. The in vitro and in vivo accumulation of [89Zr]Zr-TR1402 in TSHR-expressing DTC cell lines support the continued preclinical optimization of this approach.

Copper sulfide precipitation from alkaline monosodium glutamate solutions

Recent studies of metal leaching using monosodium glutamate have shown promising results of this being an alternative to conventional leaching reagents. However, limited information is available covering the treatment of leaching solutions and the final recovery of metals. In this regard, this article presents an experimental study on the precipitation of copper from glutamate solutions using sodium hydrosulfide (NaHS), as a simple and efficient route for the processing of leaching solutions from this new system. Synthetic pregnant leach solutions (PLS) with varying copper total concentrations [CuT] and glutamate concentrations were used. The effects of [CuT], [CuT]:[NaHS] molar ratio and glutamate concentration on the particle size distribution and copper recovery were investigated. The results revealed that higher [CuT] led to smaller particle sizes, with the P90 decreasing from 106 µm to 60.7 µm and 73.2 µm for Cu concentrations of 1 g/L, 2.5 g/L, and 5 g/L, respectively. The [CuT]:[NaHS] molar ratio reduced the P90 particle size, from 60.7 µm to 56.4 µm and 7.44 µm as the molar ratio increased from 1:0.8 to 1:1 and 1:1.2, respectively. Copper recovery from glutamate solutions increased with higher molar ratios, achieving values of 70.95 %, 88.24 %, and 99.55 % for molar ratios of 1:0.8, 1:1, and 1:1.2, respectively, agreeing with copper recovery values of other chemical systems. The glutamate concentration had minimal impact on particle size but affected copper recovery, with a decrease from 88.24 % to 85.83 % when increasing the glutamate concentration from 0.5 M to 1 M. X-ray diffraction (XRD) analysis confirmed the presence of pure covellite with hexagonal phase in the precipitates. These findings contribute to understanding copper precipitation dynamics from glutamate solutions using NaHS and have implications for optimizing copper recovery processes in the perspectives of the advent of alkaline leaching of copper ores.

Base-Free Oxidation of HMF to FDCA over Ru/Cu-Co-O·MgO under Aqueous Conditions

The copper–cobalt metal oxide composite magnesium oxide catalyst loaded with Ru has achieved the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to the bio-based polyester monomer 2,5-furandicarboxylic acid (FDCA) under base-free conditions. Several Ru/Cu-Co-O·MgO catalysts were prepared, with Cu-Co-O being a combination of CuO and Co3O4. The catalyst’s activity was boosted by the synergistic interaction between copper and cobalt, as well as an optimal copper-to-cobalt molar ratio. Optimal catalytic activity was observed in the Ru4/Cu1-Co1-O·MgO catalyst, loaded with 4 wt% Ru when copper-to-cobalt molar ratio of 1:1 and magnesium oxide compounding amount of 6 mmol were employed. The inclusion of MgO and the load of Ru not only expanded the specific surface area of the catalyst but also heightened its basicity. Additionally, the presence of loaded Ru improved the catalyst’s reducibility at low temperatures. In aqueous solution under oxygen pressure, the conversion rate of HMF achieved 100%, and the yield of FDCA was 86.1%. After five reaction cycles, examining the catalyst and solution revealed that Ru nanoparticles resisted leaching or oxidation, and MgO exhibited only slight dissolution. The green separation of the product was achieved using semi-preparative liquid chromatography, selectively collecting the FDCA-containing solution by exploiting variations in interactions between solutes and the stationary/mobile phases. The subsequent steps involved rotary evaporation and drying, resulting in FDCA powder with a purity exceeding 99%. Notably, this approach eliminated the need to introduce concentrated hydrochloric acid into the system for FDCA separation, providing a novel method for synthesising powdered FDCA.

(La1−xCax)MnO3−δ (x = 0, 0.2, 0.3, 0.4) Perovskites as Redox Catalysts in Chemical Looping Hydrogen Production Process: The Relation between Defect Chemistry and Redox Performance

The interaction between point defects in (La1−xCax)MnO3−δ (x = 0, 0.2, 0.3, 0.4) perovskites and their redox catalytic properties in a three-reactor chemical looping hydrogen production process is investigated. During the reduction step with CH4, the behavior of the materials is extrinsically determined and strongly depends on the Ca content. At small oxygen deficiencies, CH4 becomes oxidized to CO2. As the deficiency increases, partial oxidation to CO and H2 at a molar ratio of approximately 2 is favored. During the water-splitting step, the dependency on the Ca content is much weaker since it is intrinsically determined by the Mn2+→Mn3+ oxidation with simultaneous annihilation of oxygen vacancies that are not required to compensate for the extra negative charge of the Ca dopant. Hydrogen productivities in the order of 13 cm3 (STP) H2/g solid could be achieved during the water-splitting step at 1000 °C. The materials exhibited reproducible catalytic behavior during 10 cycles of the complete three-step process and were found to retain their perovskite structure.

Layered carbon encapsulated CuOx nanopaticles for selective hydrogenation of furfural to furfuryl alcohol

Furfuryl alcohol (FOL) is commercially available by selective hydrogenation of furfural (FAL). A variety of catalysts have been developed for such purpose, among which Cu-based catalysts show superior catalytic performance. However, copper nanoparticles with complex valence states are easy to agglomerate during hydrogenation reaction, which might have a negative influence on the catalytic performance. The carbon coating is an efficient strategy to prevent the sintering of Cu-based catalysts. Herein, a strategy based on the thermal decomposition of Cu-EDTA complex was designed to prepare carbon encapsulated Cu-based catalysts. The prepared catalysts were applied in the selective hydrogenation of FAL to FOL in the batch reactor. The results showed that a nearly quantitative conversion of FAL with a selectivity of 98.7 % towards FOL was achieved using CuOx@NC-150 (molar ratio of Cu: Na4EDTA·4H2O=2:1; obtained by oxidative activation at 150 °C) under 140 °C, 3 MPa in 4 h. The performance was comparable to that of the commercial CuCr2O4 catalyst under the identical conditions. In addition, the developed carbon encapsulated Cu-based catalysts exhibited a slightly better stability than CuCr2O4 catalyst in terms of FOL yield in five consecutive cycles. XPS and XAES characterizations implied that the presence of a suitable surface ratio of Cu+/(Cu++Cu0) of the prepared catalyst may contribute to the selective hydrogenation of FAL to FOL.

Sb-loaded MnOx/TiO2/CNTs catalysts for selective catalytic reduction of NOx: insight to the SO2 and H2O tolerance

PurposeThis paper aims to synthesize and test Mn-Sb/TiO2-CNT catalysts with different Sb/Mn molar ratios to be used in NH3-SCR reaction.Design/methodology/approachA series of Sb-loaded carbon nanotubes (CNTs)-based Mn/TiO2 catalysts were prepared by the incipient wetness co-impregnation method and tested for the selective catalytic reduction (SCR) of NOx with NH3.FindingsThe Sb-loaded Mn/TiO2-CNTs catalyst outperformed other catalysts and presented the highest activity in the temperature regime of 100–400°C. The catalyst loaded with Sb also showed good SO2 and H2O resistance and exhibited better thermal stability. A stepwise study of SO2 addition evidenced that Mn-Sb/TiO2-CNTs catalyst exhibited better SO2 resistance than the base catalyst Mn/TiO2, where the Sb doping greatly inhibited the sulphating of active phase of the catalyst.Originality/valueIn Sb-loaded catalysts, the formed SOx species fused with SbOx instead of MnOx. This favoured interaction of SO2 with SbOx successfully prevents the MnOx from being sulphated by SO2 which substantially improves the SO2 tolerance of Sb-loaded catalysts.

Structural characterization of extracellular polysaccharides from Phellinus igniarius SH-1 and their therapeutic effects on DSS induced colitis in mice

Phellinus igniarius is a valuable medicinal and edible mushroom, and its polysaccharides exhibit excellent anti-inflammatory activity. During liquid fermentation to produce P. igniarius mycelia, the fermentation liquid is often discarded, but it contains extracellular polysaccharides. To better utilize these resources, P. igniarius SH-1 was fermented in a 100 L fermenter, and PIPS-2 was isolated and purified from the fermentation broth. The structural characteristics and anti-inflammatory activity of PIPS-2 were determined. PIPS-2 had a molecular weight of 22.855 kDa and was composed of galactose and mannose in a molar ratio of 0.38:0.62. Structural analysis revealed that the main chain of PIPS-2 involved →2)-α-D-Manp-(1 → 3)-β-D-Galf-(1→, and the side chains involved α-D-Manp-(1 → 6)-α-D-Manp-(1→, α-D-Manp-(1 → 3)-α-D-Manp-(1→, and α-D-Manp-(1. PIPS-2 alleviated the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice, improved the imbalance of inflammatory factors and antioxidant enzymes, and increased short-chain fatty acid contents. Combining the intestinal flora and metabolite results, PIPS-2 was found to regulate the abundance of Firmicutes, Lachnospiraceae_NK4A136_group, Proteobacteria, Bacteroides, and many serum metabolites including hexadecenal, copalic acid, 8-hydroxyeicosatetraenoic acid, artepillin C, and uric acid, thereby ameliorating metabolite related disorders in mice with colitis. In summary, PIPS-2 may improve colitis in mice by regulating the gut microbiota and metabolites.

Chemical insights into plasma-assisted dry reforming of methane in a nanosecond discharge

The present study explores the chemical kinetics of plasma-assisted dry reforming of methane (340 K, 30 Torr) in a flow reactor activated by a nanosecond pulsed dielectric barrier discharge (DBD). Experiments are conducted with the inlet CO2/CH4 mol ratios varying from 0.4 to 2.8 in CH4/CO2/Ar mixture. Synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) is employed for detailed species measurement of the ions, radicals, and molecules in this system. Eight ions are observed, including CH3+, O+, CH4+, Ar2+, CO+, C2H4+, Ar+, and CO2+. The identification of several intermediate species and products are achieved based on the photoionization efficiency (PIE) spectra, such as methyl radical (CH3), water (H2O), acetylene (C2H2), carbon monoxide (CO), ethylene (C2H4), formaldehyde (CH2O), methanol (CH3OH), ketene (CH2CO), and acetone (CH3COCH3). Species mole fraction profiles as a function of inlet CO2 concentrations are obtained. The present work provides a unique dataset and enriches our understanding of the kinetics of plasma-assisted dry reforming of methane. A kinetic mechanism incorporating plasma reactions and combustion reactions is developed for this system, and its prediction performance of the product selectivity is validated against the experimental data. The main reaction pathways for the consumption of CH4 and CO2 and the formation of products and intermediates are indicated based on the rate of production (ROP) analysis. The ionic reactions are predominant for CH4 consumption, leading to CH4+ and CH5+, while CH4 reactions with electrons and Ar* contribute to CH2 and CH3 formation. CO2 mainly reacts with electrons and Ar*, producing CO, and can also undergo reactions with CH4+ and CH5+, forming HCO2+. The principal formation pathways for H2, CO, CH2O, and CH3OH are discussed. A competition between the discharge pathways and oxygen-containing pathways in CH4/CO2/Ar plasma is proposed.

Strong and tough semi-crystalline poly(aryl ether nitrile) with low coefficient of thermal expansion

The crystallization of poly(aryl ether nitrile) (PEN) has an essential impact on improving heat resistance, mechanical properties, chemical resistance, and dielectric properties. However, during the synthesis process, high crystallinity PEN is prone to precipitate out, which makes it difficult to carry out the synthesis reaction, which poses a significant challenge to synthesizing high crystallinity and high molecular weight PEN. In this work, hydroquinone (HQ) as the main phenolic monomer and 4,4’-biphenol (BP) as the second phenolic monomer were used to solve the technical difficulties in synthesis by copolymerization. The crystalline PEN with high molecular weight and significant crystallinity was obtained by regulating the molar ratio of BP to HQ. The effects of isothermal heat treatment on its crystalline, mechanical, and thermal properties were investigated. The influence laws of molecular chain structure and heat treatment process on the properties of PEN films were revealed. Among them, when the isothermal treatment temperature was 270 °C and the HQ: BP was 85:15, the mechanical strength reached 130 MPa, and the elongation at break could be up to an astonishing 50%. Besides, the CTE value from 50 °C ∼ 150 °C is 40.84 ppm/ °C, which is lower than most thermoplastics. Therefore, PEN with the HQ to BP molar ratio of 85:15 is suitable for large-scale production, providing new crystalline plastic specifications for high-performance special engineering plastics. A crystal bridge-tie chain model is summarized by the properties of HQ/BP-PEN films under different crystallization conditions, which provides an idea for preparing stiff and tough films.

Phosphorus recovery via struvite crystallization in batch and fluidized-bed reactors: Roles of microplastics and dissolved organic matter

Struvite crystallization, a promising technology for nutrient recovery from wastewater, is facing considerable challenges due to the presence of emerging contaminants such as microplastics (MPs) ubiquitously found in wastewater. Here, we investigate the roles of MPs and humic acid (HA) in struvite crystallization in batch and fluidized-bed reactors (FBRs) using synthetic and real wastewater with a Mg:N:P molar ratio of 1:3:(1–1.3) at an initial pH of 11. Batch reactor (BR) experiment results show that MPs expedited the nucleation and growth rates of struvite (e.g., the rate of crystal growth in the presence of 30 mg L−1 of polyethylene terephthalate (PET) was 1.43 times higher than that in the blank system), while HA hindered the formation of struvite. X-ray diffraction and the Rietveld refinement analysis revealed that the presence of MPs and HA can result in significant changes in phase compositions of the reclaimed precipitates, with over 80 % purity of struvite found in the precipitates from suspensions in the presence of 30 mg L−1 of MPs. Further characterizations demonstrated that MPs act as seeds of struvite nucleation, spurring the formation of well-defined struvite, while HA favors the formation of newberyite rather than struvite in both reactors. These findings highlight the need for a more comprehensive understanding of the interactions between emerging contaminants and struvite crystallization processes to optimize nutrient recovery strategies for mitigating their adverse impact on the quality and yield of struvite-based fertilizers. Environmental ImplicationThe presence of microplastics in wastewater poses a significant challenge to struvite crystallization for nutrient recovery, as it accelerates nucleation and growth rates of struvite crystals. This can lead to changes in the phase compositions of the reclaimed precipitates, with implications for the quality and yield of struvite-based fertilizers. Additionally, the presence of humic acid hinders the formation of struvite, favoring the formation of other minerals like newberyite. Understanding the interactions between emerging contaminants and struvite crystallization processes is crucial for optimizing nutrient recovery strategies and mitigating the environmental impact of these contaminants on water quality and struvite-based fertilizers.

Optimizing Biocompatibility and Gene Delivery with DMAEA and DMAEAm: A Niacin-Derived Copolymer Approach.

Gene therapy is pivotal in nanomedicine, offering a versatile approach to disease treatment. This study aims to achieve an optimal balance between biocompatibility and efficacy, which is a common challenge in the field. A copolymer library is synthesized, incorporating niacin-derived monomers 2-acrylamidoethyl nicotinate (AAEN) or 2-(acryloyloxy)ethyl nicotinate (AEN) with N,N-(dimethylamino)ethyl acrylamide (DMAEAm) or hydrolysis-labile N,N-(dimethylamino)ethyl acrylate (DMAEA). Evaluation of the polymers' cytotoxicity profiles reveals that an increase in AAEN or DMAEA molar ratios correlates with improved biocompatibility. Remarkably, an increase in AAEN in both DMAEA and DMAEAm copolymers demonstrated enhanced transfection efficiencies of plasmid DNA in HEK293T cells. Additionally, the top-performing polymers demonstrate promising gene expression in challenging-to-transfect cells (THP-1 and Jurkat cells) and show no significant effect on modulating immune response induction in ex vivo treated murine monocytes. Overall, the best performing candidates exhibit an optimal balance between biocompatibility and efficacy, showcasing potential advancements in gene therapy.

Trans-catena-Poly[[(bis-(µ-N,N′-bis[(pyridin-3-yl)methyl]ethanediamide))-diaqua-cadmium(II)] bis(nitrate) tetrahydrate)

The reaction between cadmium nitrate tetrahydrate and N,N′-bis(pyridin-3-ylmethyl)oxalamide (L) in a 1:3 molar ratio in a water/acetonitrile (1:6 v/v) mixture afforded single crystals of compound 1 suitable for X-ray diffraction analysis. Compound 1 consists of the coordination polymer (CP) [[Cd(L)2(OH2)2](NO3)2·4H2O]∞, in which CdII ions are bridged by neutral L antiperiplanar N-ligands in a wavy ribbon fashion developed along the c-axis. Two trans-disposed water molecules complete the pseudo-octahedral coordination geometry of the metal ion. The crystal packing of 1 revealed the interplay between π–π stacking interactions and an intricate hydrogen-bonded network involving oxalamides, nitrates, and water molecules. The donor properties of L and the intermolecular interactions in compound 1 are interpreted based on hybrid-DFT calculations.