With the advancement of social process, the resource problem is becoming more prominent, biomass materials come into being, and it is becoming more and more important to explore and prepare efficient and multifunctional biomass materials to alleviate the problems of energy storage and water pollution. In this paper, nitrogen-doped hierarchical porous carbon materials (NRRC) were produced by one-step carbonization of withered rose as raw material and melamine as nitrogen source with KOH-activated porosification. The resulting nitrogen-doped porous carbon material had the most abundant pores and the best microspherical graded pore structure, with a specific surface area of up to 1393 m2·g–1, a pore volume of 0.68 cm3·g–1, and a nitrogen-doped content of 5.52%. Electrochemical tests showed that the maximum specific capacitance of NRRC in the three-electrode system was 346.4 F·g–1 (0.5 A·g–1), which was combined with favorable capacitance retention performance and cycling stability. The NRRC//NRRC symmetric supercapacitors were further assembled, and the maximum energy density of a single device was 23.88 Wh·kg–1, which still maintains excellent capacitance retention and cyclic charging/discharging stability. For example, the capacitance retention rate was always close to 96.27% with almost negligible capacitance loss after 10000 consecutive charge/discharge cycles (current density: 10 A·g–1). Regardless of the three-electrode or two-electrode system, the super capacitive performance of NRRC porous carbon materials was comparable to the electrochemical performance of many reported biomass porous carbon materials, which showed better energy storage advantages and practical application potential. In addition, NRRC porous carbon materials had excellent water purification ability. The dye adsorption test confirmed that NRRC had a high adsorption capacity (491.47 mg·g–1) for methylene blue. This undoubtedly also showed a potential and promising avenue for high value-added utilization of this material.
Increasing global water shortages are accelerating the pace of membrane manufacturing, which generates many environmentally harmful solvents. Such challenges need a radical rethink of developing innovative membranes that can address freshwater production without generating environmentally harmful solvents. This work utilized the synthesized ultra-long hydroxyapatite (UHA) by the solvothermal method using the green solvent oleic acid in preparing UHA-based forward osmosis membranes. The membranes were developed using different loading ratios of graphene oxide (GO) by vacuum-assisted filtration technique. The prepared GO/UHA membranes were identified using X-ray diffraction, scanning electron microscope, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Water contact angle and pore size distribution were determined for the obtained GO/UHA membranes. The obtained hierarchical porous structure in the prepared membranes with interconnected channels results in a stable water flux with reverse salt flux. The best water flux rate of 42 ± 2 L·m–2·h–1 was achieved using the 50 mg GO/UHA membrane, which is 3.3 times higher than the pristine membrane, and a reverse salt flux of 67 g·m–2·h–1. The obtained results showed a promising capability of a new generation of sustainable inorganic-based membranes that can be utilized in freshwater generation by energy-efficient techniques such as forward osmosis.
Photothermal catalytic oxidation emerges as a promising method for the removal of volatile organic compounds (VOCs). Herein, via sol-gel impregnation method, spinel CuMn2O4 was coated on attapulgite honeycombs with integrating biochar (BC) film as the second carrier, using chestnut shell as complexation agent. Various mass ratios of CuMn2O4 to chestnut shell was modulated to investigate the catalytic toluene degradation performance. Results indicated that the monolithic CuMn2O4/BC/honeycomb catalyst demonstrated superior photothermal catalytic toluene degradation with a low T90 (temperature at 90% degradation) of 263 °C when the mass ratio of CuMn2O4 to biomass was 1:4. The addition of BC film substantially increased the honeycomb's specific surface area and improved the photothermal conversion of spinel, leading to enhanced photothermal catalytic activity. This study presents a cost-effective strategy for eliminating industrial VOCs using clay-biomass based monolithic catalyst.
The engineering of microbial cell factories for the production of high-value chemicals from renewable resources presents several challenges, including the optimization of key enzymes, pathway fluxes and metabolic networks. Addressing these challenges involves the development of synthetic auxotrophs, a strategy that links cell growth with enzyme properties or biosynthetic pathways. This linkage allows for the improvement of enzyme properties by in vivo directed enzyme evolution, the enhancement of metabolic pathway fluxes under growth pressure, and remodeling of metabolic networks through directed strain evolution. The advantage of employing synthetic auxotrophs lies in the power of growth-coupled selection, which is not only high-throughput but also labor-saving, greatly simplifying the development of both strains and enzymes. Synthetic auxotrophs play a pivotal role in advancing microbial cell factories, offering benefits from enzyme optimization to the manipulation of metabolic networks within single microbes. Furthermore, this strategy extends to coculture systems, enabling collaboration within microbial communities. This review highlights the recently developed applications of synthetic auxotrophs as microbial cell factories, and discusses future perspectives, aiming to provide a practical guide for growth-coupled models to produce value-added chemicals as part of a sustainable biorefinery.
A significant reaction in the synthesis of biomass-based chemicals is the catalyst-based and targeted oxidation of monosaccharides into valuable sugar acids. In this study, an activated carbon supported gold catalyst was used to oxidize glucose and xylose to gluconic acid and xylonic acid under neutral condition. Optimization of reaction conditions for the catalysts was performed using both a batch reactor and a flow-through reactor. In a batch reactor, the yields of gluconic and xylonic acid reached 93% and 92%, respectively, at 90 °C within 180 min. In a flow reactor, both reactions reached a similar yield at 80 °C with the weight hourly space velocity of 47.1 h–1. The reaction kinetics were explored in the flow reactor. The oxidation of glucose and xylose to gluconic and xylonic acid followed a first-order kinetics and the turnover frequency was 0.195 and 0.161 s–1, respectively. The activation energy was evaluated to be 60.58 and 59.30 kJ·mol–1, respectively. This study presents an environmentally friendly and feasible method for the selective oxidation of monosaccharides using an activated carbon supported gold catalyst, benefiting the high-value application of carbohydrates.
Genomic rearrangements play a crucial role in shaping biological phenotypic diversity and driving species evolution. Synthetic chromosome rearrangement and modification by LoxP-mediated evolution (SCRaMbLE) has been applied to explore large-scale genomic rearrangements, yet it has been observed that these rearrangements occur exclusively in genomic regions containing loxPsym sites. Here, we found that SCRaMbLE of synthetic yeast harboring synthetic chromosome V and X can generate a variety of synthetic segment insertions into wild-type chromosomes, ranging from 1 to 300 kb. Furthermore, it was revealed that the novel insertions impacted the transcriptional level of neighboring regions and affected the production of exemplar pathway of zeaxanthin. Collectively, our results improve the understanding of the ability of SCRaMbLE to generate complex structural variations in nonsynthetic regions and provide a potential model to explore genomic transposable events.
The cost-effective separation of ethylene (C2H4), ethyne (C2H2), and ethane (C2H6) poses a significant challenge in the contemporary chemical industry. In contrast to the energy-intensive high-pressure cryogenic distillation process, zeolite-based adsorptive separation offers a low-energy alternative. This review provides a concise overview of recent advancements in the adsorptive separation of C2H4, C2H2, and C2H6 using zeolites or zeolite-based adsorbents. It commences with an examination of the industrial significance of these compounds and the associated separation challenges. Subsequently, it systematically examines the utilization of various types of zeolites with diverse cationic species in such separation processes. And then it explores how different zeolitic structures impact adsorption and separation capabilities, considering principles such as cation-π interaction, π-complexation, and steric separation concerning C2H4, C2H2, and C2H6 molecules. Furthermore, it discusses methods to enhance the separation performance of zeolites and zeolite-based adsorbents, encompassing structural design, modifications, and ion exchange processes. Finally, it summarizes current research trends and future directions, highlighting the potential application value of zeolitic materials in the field of C2H4, C2H2, and C2H6 separation and offering recommendations for further investigation.