Facile and Efficient Synthesis of Silver Nanoparticles Based on Biorefinery Wood Lignin and Its Application as the Optical Sensor

Fabricating silver nanoparticles (AgNPs) based on renewable energy sources is wildly exploited because of the sustainable synthetic strategy and versatile applications of AgNPs. Alkali lignin (AL), as the byproduct from pulp mills, is a potential natural reducing agent. However, the synthetic methods of AL-based AgNPs (AL@Ag) still have drawbacks, such as unusual conditions and extra and high-cost purification processes. Here, a facile and efficient approach to synthesize and purify good-dispersing AL@Ag (17–27 nm) was presented, using Ag₂O as the silver precursor and AL as both reducing agents and stabilizers in dimethyl sulfoxide (DMSO) solvent. The maximum reduction capacity of AL to Ag⁺ was increased to 8 mM/g at room temperature because of the activation of both Ag₂O and DMSO. Most conveniently, the product was effectively purified by easy centrifugation. The reducing mechanism and reaction behavior were also systematically studied. Meanwhile, AL@Ag maintained versatile applications of AgNPs and exhibited great potential as the colorimetric sensor and plasmonic resonance energy acceptor for Hg²⁺ and rhodamine B, respectively. Our work displayed a general and efficient method to prepare AL@Ag, which might provide a realizable perspective to the high-value utilization of lignin

Liquid-Assisted Mechanochemical Synthesis of Copper Based MOF-505 for the Separation of CO₂ over CH₄ or N₂

Mechanochemical synthesis, driven the chemical transformation by mechanical force, has been a rapid and efficient strategy to prepare metal–organic frameworks (MOFs). In this work, a liquid-assisted mechanochemical method has been successfully applied to the synthesis of copper based MOF-505. The crystallinity and porosity of MOF-505 were investigated by adjusting the synthesis parameters, such as added solvent (type and amount) and grinding time. Results showed that the type and amount of added solvent were crucial parameters for the mechanochemical synthesis of MOF-505. Furthermore, the optimizations of MOF-505 synthesis were carried out: grinding Cu­(OAc)₂·H₂O and H₄bptc as starting materials for 80 min with 0.4 mL of DMF assisted, giving MOF-505-K with Brunauer–Emmett–Teller (BET) surface area of 977 m²/g. Meanwhile, MOF-505-K had moderate CO₂ adsorption capacity of 2.01 mmol/g at 298 K and 100 kPa. The adsorptive selectivity determined from ideal adsorbed solution theory (IAST) indicated that MOF-505-K had high CO₂/N₂ and CO₂/CH₄ selectivities (26.6 and 5.5) at 298 K. Highly efficient mechanochemical synthesis of MOF-505 provides the promise to facilitate the industrial application of CO₂ capture

Adsorptive Separation of Methanol–Acetone on Isostructural Series of Metal–Organic Frameworks M‑BTC (M = Ti, Fe, Cu, Co, Ru, Mo): A Computational Study of Adsorption Mechanisms and Metal-Substitution Impacts

The adsorptive separation properties of M-BTC isostructural series (M = Ti, Fe, Cu, Co, Ru, Mo) for methanol–acetone mixtures were investigated by using various computational procedures of grand canonical Monte Carlo simulations (GCMC), density functional theory (DFT), and ideal adsorbed solution theory (IAST), following with comprehensive understanding of adsorbate–metal interactions on the adsorptive separation behaviors. The obtained results showed that the single component adsorptions were driven by adsorbate–framework interactions at low pressures and by framework structures at high pressures, among which the mass effects, electrostatics, and geometric accessibility of the metal sites also played roles. In the case of methanol-acetone separation, the selectivity of methanol on M-BTCs decreased with rising pressures due to the pressure-dependent separation mechanisms: the cooperative effects between methanol and acetone hindered the separation at low pressures, whereas the competitive effects of acetone further resulted in the lower selectivity at high pressures. Among these M-BTCs, Ti and Fe analogues exhibited the highest thermodynamic methanol/acetone selectivity, making them promising for adsorptive methanol/acetone separation processes. The investigation provides mechanistic insights on how the nature of metal centers affects the adsorption properties of MOFs, and will further promote the rational design of new MOF materials for effective gas mixture separation

In Situ Assembly of Nanoparticles into Hierarchical Beta Zeolite with Tailored Simple Organic Molecule

A hierarchically structured beta zeolite with intercrystalline mesopores was successfully synthesized via in situ assembly of nanoparticles by employing a simple organic molecule N₂-<i>p</i>-N₂, tailored from polyquaternium surfactant, with no hydrophobic long chain. The generated samples were studied by using powder X-ray diffraction (XRD) and nitrogen adsorption/desorption isotherms. Computer simulation, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) technologies were also used. The characterized results show that the tailored template molecule N₂-<i>p</i>-N₂ without hydrophobic long-chain tail still can direct the zeolite crystallization, while the hydrophobic long-chain tail is not necessary during the mesoporous Beta zeolite formation. The catalytic performances of the sample were studied using alkylation of benzene with propene reaction to evaluate the relationship between the structure and property. The results apparently suggested an overall improved resistance against deactivation as compared to conventional beta zeolite in reactions. Furthermore, this tailored simple organic molecule strategy from dual-functional surfactant for making mesoporous zeolite would offer a new method of synthesizing other hierarchically structured zeolites

Construction of Novel <i>Saccharomyces cerevisiae</i> Strains for Bioethanol Active Dry Yeast (ADY) Production

<div><p>The application of active dry yeast (ADY) in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial <i>Saccharomyces cerevisiae</i> strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS) process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel <i>S. cerevisiae</i> mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes.</p> </div

Iron-Based Metal–Organic Framework with Hydrophobic Quadrilateral Channels for Highly Selective Separation of Hexane Isomers

A novel iron-based microporous metal–organic framework built of trinuclear iron clusters [Fe₃(μ₃-O)­(COO)₆] and 2,2-bis­(4-carboxyphenyl)-hexafluoropropane (6FDCA) has been prepared by solvothermal synthesis. It exhibits excellent chemical stability and strong hydrophobic character. More importantly, this material is capable of separating hexane isomers with good separation performance on the basis of a kinetically controlled process, making it a promising candidate for improving the research octane number of gasoline

Malondialdehyde (MDA) formation and tolerance to H₂O₂ of ZTW1 and Z3-86.

<p>MDA content determination of fresh and dried ZTW1 and Z3-86 cells (a). “*” indicates significant difference between samples at the P < 0.05 level, using <i>t</i> test. Growth of ZTW1 and Z3-86 on YPD plates containing H₂O₂ (b). Cells were pre-cultured in YPD liquid medium for 18 h, and 5 μL of 10-fold serial dilutions were spotted onto plates.</p

Viabilities of strains A1, ZTW1, and Z3-86 after drying and application of certain stressors.

<p>Ratios of viable cells of the three strains after dehydration described in the Material and methods section (a). The dired cells were then diluted serially and the appropriate dilutions were plated onto solid YPD medium to count the colony-forming. The sample without drying was used as the control. Comparison of the tolerance of A1, ZTW1, and Z3-86 to ethanol treatment [20% (v/v) for 2 h], osmotic pressure (4 M NaCl for 2 h), heat (55 °C for 5 min), and H₂O₂ (20 mM for 1 h) (b). Yeast cells were pre-cultured in YPD at 30 °C for 18 h with the initial OD(A600) of 0.05. The cells (~3×10⁷) were collected and transferred into 2 mL YPD (for heat tolerance test) or YPD with indicated stressors. The treated cells were diluted and plated onto solid YPD medium for viability calculation. “a” indicates significant difference between Z3-86 and ZTW1 at <i>P</i> < 0.01; “b” indicates significant difference between Z3-86 and A1 at the P < 0.05 level, using <i>t</i> test. The bars indicated the standard deviation here and other figures.</p

Differences in the trehalose metabolism of ZTW1 and Z3-86.

<p>Genes involved in trehalose metabolism were upregulated in Z3-86 (a). Osmotic pressure induced intracellular trehalose accumulation in ZTW1 and Z3-86 (b). Trehalose contents of ZTW1 and Z3-86 when cultured in YPD or YPD with 50 mM trehalose for 18 h (c). Exogenous trehalose enhanced the viability of ZTW1 and Z3-86 (d). “*” indicates significant difference between samples at the P < 0.05 level, using <i>t</i> test.</p

Growth curves of A1, ZTW1, and Z3-86.

<p>Cells were cultured in 25 mL of YPD at 30 °C with an initial OD (A600) of 0.05. 20 μL of yeast cells were aspirated at certain time points and the colony forming unites (CFU) were determined. The data was represented as the mean±SD of three independent experiments.</p