Synthesis of moderate-sized uniform spherical covalent organic frameworks (COFs) within 10-50 & micro;m is crucial for their applications in separation fields, while the spherical 2D COFs with such particle sizes has not been reported till now. Herein, a type of moderate-sized spherical 2D COF (TFB-BD COF) with uniform size within 10-50 & micro;m was size-controllably synthesized via an 'emulsion polymerization-crystallization' strategy. The obtained TFB-BD COF showed monodisperse full-spherical morphology, good crystal structure and uniform controllable particle sizes. Moreover, another spherical 2D COF (TAPT-PDA COF) with particle size of 15 & micro;m was also synthesized through a similar method for investigating the application potential of the spherical 2D COFs. As an application case, the spherical TAPT-PDA COF was used as the adsorbent for the disperse solid-phase extraction (d-SPE) of bisphenol F (BPF). The adsorbent showed good adsorption selectivity, high adsorption capacity, fast binding kinetics, good reusability (at least four cycles) and high enrichment factor (60 folds). By combining this d-SPE technique with high-performance liquid chromatography, a new analytical method was established for determination of trace BPF in water samples and an orange juice with recoveries of 94.8-101.6% and LOD of 0.56 ng/mL. The synthesis strategy proposed in this work opens a way for size-controllably synthesizing moderate-sized spherical 2D COFs, and the developed analytical method provides a viable path for detecting trace BPF in water samples and beverages.

Converting waste biomass resources into electrochemical energy storage materials has been regarded as a valuable contribution to implementing sustainable energy. Herein, waste cotton fiber-based graphitized carbon/Fe7S8 (CFGC/Fe7S8) composites were successfully synthesized from sulfurization of Fe-Fe3C inter-mediates, produced by simple pyrolysis of waste cotton fabric and low-cost iron compound. The as -pre-pared CFGC/Fe7S8 composites were composed of partly graphitized carbon fiber embedded with well -dispersed Fe7S8 nanoparticles. This structure offers excellent performance for electrochemical sodium storage. Acting as an anode in sodium-ion battery, CFGC/Fe7S8 composites deliver a high discharge specific capacity of 661 mAh g-1 after 100 cycles at 0.1 A g-1 and an initial Coulombic efficiency of 85.8% and achieve a discharge specific capacity of 328 mAh g-1 after 800 cycles even at a high current density of 2 A g-1. These results demonstrate that Fe-Fe3C intermediate derived-Fe7S8 nanoparticles combined with cotton fiber -based graphitic carbon plays a significant role in the electrochemical performance of sodium ion storage. These findings present a novel strategy for transferring waste textile into high-performance sodium storage materials.(c) 2022 Published by Elsevier B.V.

Chitosan-based carbon materials have attracted great attention in electrochemical energy storage. Introducing iron metal or iron compounds into carbon materials favors to boost their electrochemical performance. Herein, chitosan-based graphitic carbon@Fe3C composites (CSGC@Fe3C) have been prepared as anode materials for lithium ion battery by a simple pyrolysis method. By manipulating the temperature higher than 700 °C, pure Fe3C encapsulated in chitosan-based graphitic carbon with different mass ratio from 30 to 53.8 wt% can be achieved. The resulting CSGC@Fe3C composites retain porous carbon sheet structure embedded with a large amount of Fe3C nanoparticles in size from 20 to 300 nm. The electrochemical measurements demonstrate CSGC@Fe3C with 53.8 wt% Fe3C as anode material for lithium ion battery can provide a highest reversible capacity of 423 mAh g−1 at 0.1 A g−1 over 100 charge/discharge cycles and stable cycling capacity of 195 mAh g−1 at a high current density of 2 A g−1 during 200 cycles. The catalysis of Fe3C on the reversible formation and decomposition of solid electrolyte interphase (SEI) has been corroborated and results in the improvement of surface capacitive contribution. This work provides a basic insight into metal carbides constructing biomass-based carbon anode materials to realize high-performance electrochemical energy storage device.

采用催化石墨化法将废旧棉纤维直接制备成棉纤维基石墨化碳/Fe3 C复合材料,并将该材料组装成锂离子电池,进行电化学性能表征.结果表明:在煅烧温度为700℃ 、保温时间2 h、硝酸铁浓度为1 mol/L的条件下,可以制备出棉纤维基石墨化碳/Fe3 C复合材料.通过SEM、XRD、Raman对样品进行表征,该材料由微米级的棉短纤维基石墨化碳负载纳米Fe3 C构成.在电流密度为0.1 A·g-1条件下,循环100次后,比容量保持在279 mAh·g-1,循环寿命稳定.在2 A·g-1条件下进行充放电测试,容量可达134 mAh·g-1.与直接碳化的棉纤维基碳材料相比,棉纤维基石墨化碳/Fe3 C复合材料表现出更优越的电池比容量和倍率性能.该工作将废旧棉织物通过铁离子直接催化石墨化作用,成功地构造棉纤维基石墨化碳/Fe3 C复合材料.制备过程无水洗和酸洗后处理步骤,大大简化工艺流程,为纺织废弃资源转化为锂离子电池材料提供新思路.

Nowadays, freshwater shortage, energy crisis and environmental pollution are the three major threats to human beings. Bio-waste is an important source of environmental pollutant emissions and a renewable resource with great potential. Herein, we develop a photothermal material based on bagasse for solar steam generation to relieve the freshwater crisis and mitigate environmental pollution caused by bio-waste. The mainly functional part of the solar-driven steam generator here is bagasse-based photothermal aerogel (B-PTA), which composes of carbonized bagasse (CB) and bagasse-derived cellulose fiber (BDCF). The B-PTA relying on CB can effectively absorb sunlight (~ 95%), resulting in a prominent light-to-heat ability. The B-PTA with DBCF has super-hydrophilicity, water transport and retention ability. Depending on the excellent light absorption and 3D water passageway, the B-PTA gives a water evaporation rate of 1.36 kg m–2 h–1, and achieves a photothermal conversion efficiency of 77.34% under 1-sun illumination (1 kW m–2). The B-PTA shows remarkable stability that the efficiency without significant change after 20 cycles. In addition, the B-PTA can effectively desalt seawater and purify dye wastewater with natural sunlight. Therefore, turning bio-waste into valuable photothermal material for solar steam generation is possible. Due to the merits of low cost, scalability, environmental friendliness, B-PTA has the potential for real-world water purification.

Solar vapor generation is a renewable and hopeful technology for obtaining freshwater from underground water, dyeing wastewater, and seawater. Herein, hierarchical MnO2 nanosheets grown on cotton fabric (Mn-CF) have been developed for solar-driven water evaporation. Black MnO2 nanosheets and nanoflowers are in situ chemically deposited on cotton fabric (CF), which leads to a solar absorption ability as high as 95% from 300 to 2500 nm. Due to the synergistic effect of the super-hydrophilic CF and hierarchical MnO2 nanosheets, Mn-CF results in a water evaporation rate of 1.40 kg m(-2) h(-1) with the photothermal conversion efficiency of 87.48% under 1 sun illumination (1 kW m(-2)). During the desalination test, Mn-CF can be renewed by washing off the steamed salts through a simple ultrasonication or hand-washing. Moreover, Mn-CF remains stable after 40 cycles, each lasting 1 h under 1 sun irradiation. A Mn-CF-based solar steam generator (Mn-CF-SSG) enables to effectively purifying simulated dyeing wastewater and seawater using natural sunlight. The cost of preparing 1 m(2) Mn-CF is about $1.5. This work provides a simple method to prepare flexible and washable Mn-CF-SSG with low-cost and high efficiency that has huge potential for practical application of seawater desalination.