Topics in Catalysis最新文献

Enzymes have revolutionized conventional industrial catalysts as more efficient, eco-friendly, and sustainable substitutes that can be used in different biotechnological processes, food, and pharmaceutical industries. Yet, the enzymes from nature are engineered to make them adapt and enhance their durability in the industrial environment. One promising approach involves the combined use of multiple enzymes that catalyze highly selective and sequential reactions in a single reaction vessel. The multi-enzymatic biocatalytic systems, achieved through gene fusion, fusion proteins, DNA manipulation and bioconjugation, protein engineering, or attachment to solid support materials for immobilization, such as protein-polymer, silica, metal organic framework, Carbon nanotubes or graphene based hybrids, have found widespread utility across various sectors, including the food industry, wastewater treatment, drug delivery, biosensors and methanol production. Enzyme conjugation enables the creation of novel enzymes with improved kinetics and synergistic effects. Researchers can evolve fusion proteins by fusion enzymes which can evolve novel catalytic activities in Biotechnological processes. These engineered enzymes can contribute in synthetic Biology in construction of synthetic system for various applications. Enzyme conjugation helps in metabolic engineering by optimization of pathways. Researchers can develop pathways for production of Bio-sensors, pharmaceuticals, biofuels and other valuable industrial products. This review comprehensively explores the techniques and applications of enzyme conjugation, highlighting its pivotal role in advancing the field of bio-catalysis.

Graphical Abstract

Several sepiolite-based catalysts have been prepared and investigated for pyrolytic H₂ production from a post-consumer mixture of residual plastics. The experimental installation involved a two-stage reaction system: first, the plastic mixture was thermally pyrolyzed at 500 ºC; then, the generated volatiles were reformed by increasing the temperature to 700 ºC and 800 ºC in the presence of the sepiolite-based catalysts. The real mixture came from non-separate waste collection streams and contained post-consumer polypropylene (rigid and film), expanded polystyrene, high-impact polystyrene, and polyethylene. The results demonstrated that the two-stage pyrolysis technique using sepiolite-based catalysts successfully generated hydrogen. The effects of the type of polymer, temperature, and catalyst were analyzed. The higher production of hydrogen (27.2 mmol H₂/g) was obtained when the mixture of plastic waste was pyrolyzed and then the volatiles were reformed at 800 °C with the SN5-800 12 nickel-modified sepiolite. Additionally, the generation of hydrogen also increased after acidifying natural sepiolite (from 18.2 mmol H₂/g plastic for natural sepiolite to 26.4 mmol H₂/g for acidified sepiolite at 800 ºC with a plastic/catalyst ratio of 1:2). Finally, the carbon deposited in the catalysts was examined. Approximately, only 20% of the carbon that was deposited in the sepiolite-based catalysts was filamentous carbon; the majority was amorphous carbon.

The results have therefore shown that it is possible to obtain a hydrogen-rich gas from the reforming of the pyrolysis vapors of a mixture of plastic waste using a low-cost catalyst based on nickel-modified sepiolite.

A new ZnO/MXene material was made using a simple hydrothermal method and heat treatment for measuring glucose without enzymes in sports drinks and human blood samples. The best ZnO/MXene-300 material, made at 150 °C and heated at 300 °C, had a large surface area of 152 m2/g, high current density of 1.12 mA/cm2, and low activation energy of 32.6 kJ/mol for glucose oxidation. The sensor could measure a wide range of glucose levels (0.01-12 mM) with a low detection limit (0.005 µM), worked well in the presence of other substances, remained stable (93.6% after 7 days), and gave consistent results (RSD of 3.2%). The material was tested by measuring glucose in sports drinks and blood samples, with measured values close to the actual values (96.4–104.5%) and high precision (RSDs of 2.8% and 3.8%). These results show that ZnO/MXene materials are promising for making sensitive and stable glucose sensors that don’t need enzymes.

Catalysts are essential for accelerating chemical reactions without altering the reaction itself. They can be homogeneous or heterogeneous, with heterogeneous catalysts being more recognized due to their lower energy consumption and cost-effectiveness. Biocatalysts, such as enzymes, are highly selective and efficient. The performance of catalysts is influenced by factors such as ideal porosity, pore width, surface area, and promoters like rare earth metals, alkaline, and alkaline earth metals. The effectiveness of multivalent metals as homogeneous or heterogeneous catalysts depends on a variety of variables, including coexistence, pH, formulation, and others. Currently, Fe-based catalysts, such as magnetite, olivine, and ilmenite, have gained interest due to their lower cost, higher reactivity, and stability. Metal-organic frameworks have gained interest as catalyst supports due to their high porosity, higher surface area, and ability to alter the size and shape of pores. The growing global population has led to environmental pollution and energy crises, necessitating the need for clean, renewable energy sources. This review focuses on the potential and utility of sustainable green catalysts like nanocatalysts and biochar-based catalysts for the efficient and sustainable production of biofuels. In addition, the usage of metal oxides, heteropoly acids, and aluminuminosilicate catalysts for wastewater remediation is also discussed in this review.

The use of renewable resources to generate energy is growing, but regrettably, the large amount of CO₂ emissions it releases harms the environment. The main greenhouse gas, CO₂, is a major factor in global climate change, which eventually disrupts the delicate balance of ecosystems within the globe. Therefore, the development of effective and sustainable technology for CO₂ capture and storage is both urgent and compelling. Among many different approaches for CO₂ capture, membrane separation has shown to be one of the most promising, yielding excellent results in terms of effectiveness as well as affordability. Nonetheless, to enhance membrane performance more significantly in CO₂ separation, researchers have focused on ionic liquids, a family of organic salts recognized for their high thermal stability, low volatility, and tuneable characteristics. Because of this, ionic liquids have attracted a lot of attention from the academic and industrial sectors as possible additions to enhance membranes’ capacity for CO₂ separation. This study explores the potential of Tetrahexyl tetradecyl phosphonium chloride incorporated into Pebax-1657 to enhance CO₂/CH₄ separation performance. Ion gel membranes were synthesized with varying ionic liquid concentrations (5, 10, 20 wt%) and characterized for structural and morphological evaluations. Gas separation performance was assessed through permeation experiments, showing increased CO₂/CH₄ selectivity from 19.23 to 21.81 with higher IL concentrations, especially under high pressure. CO₂ permeability increased from 70.01 to 273.61 barrer with the addition of 20% [THTDP][Cl]. Density functional theory calculations provided theoretical insights into the interaction energies between ionic liquid and gas molecules, corroborating experimental findings. The study demonstrates the novelty of integrating phosphonium-based ionic liquid with Pebax-1657, significantly enhancing CO₂/CH₄ selectivity due to strong CO₂ interactions. This research offers a promising approach to developing advanced membranes for efficient and selective CO₂ capture, contributing to sustainable gas separation technologies.

Graphical Abstract

Rapid electrochemical strategy-based sensor fabricated for measuring vanillin as an important additive compound in the food industry by combining iron oxide/graphene (Fe₃O₄/Gr) nanocomposite as a catalyst and 1-butyl-3-ethyl imidazolium chloride (1B3EICl) as an ionic liquid binder to make a modified carbon paste electrode (Fe₃O₄/Gr/1B3EICl/CPE). For optimization of the proposed sensor, some electrochemical parameters such as pH, scan rate, the ratio of Fe₃O₄/Gr, and 1B3EICl in the sensor matrix were investigated by differential pulse voltammetric method. The obtained results showed a wide dynamic range between 1.0 nM and 220 µM and detection limit of 0.5 nM to monitor vanillin using electrochemical signals. Finally, Fe₃O₄/Gr/1B3EICl/CPE was employed for analysis of real food samples and statistical analyses confirmed the efficiency of Fe₃O₄/Gr/1B3EICl/CPE for the determination of vanillin in real situations.