Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Ultrahigh Capacity and Rapid Selective Recycling of Gold Ions by Organic Intercalated and Exfoliated Few-Layer Ti3C2TX Nanosheets
No full textFor the sustainable development of the ecological environment in gold recycling, it is urgently desired to develop a more efficient and highly selective process for gold ions from e waste or mineral lixivium. As a kind of emerging two-dimensional nanomaterials, Ti3C2Tx has emerged as a rapidly developing novel water treatment material. Herein, the preparation of few-layer Ti3C2Tx nanosheets and their performance for recycling of gold ions were studied. Notably, it exhibits an impressive capacity of 2973.57 mg/g at room temperature, almost 124 times that of commercially available activated carbon (24 mg/g), and an exciting selectivity for Au(III) in the presence of competing ions due to perfectly weak reduction caused by the removal of the Al layer. The Langmuir isotherm and pseudo-second-order kinetic model can accurately depict the rapid adsorption process. Additionally, it can be regenerated effectively by thiourea and exhibits excellent reutilization. A critical mechanism involves an adsorptive-reduction pathway between Au(III) and active Ti sites. Excellent performance in real lixiviums from e-waste and gold-bearing sludge is also exhibited, demonstrating great potential for Au(III) recycling. It may be a sustainable direction for the capture and separation of Au(III) and also lays the foundation for the interface control of Ti3C2Tx and Au NPs as a catalyst and other functional materials
Recent Research and Application Prospect of Functional Oligosaccharides on Intestinal Disease Treatment
No full textThe intestinal tract is an essential digestive organ of the human body, and damage to the intestinal barrier will lead to various diseases. Functional oligosaccharides are carbohydrates with a low degree of polymerization and exhibit beneficial effects on human intestinal health. Laboratory experiments and clinical studies indicate that functional oligosaccharides repair the damaged intestinal tract and maintain intestinal homeostasis by regulating intestinal barrier function, immune response, and intestinal microbial composition. Functional oligosaccharides treat intestinal disease such as inflammatory bowel disease (IBD) and colorectal cancer (CRC) and have excellent prospects for therapeutic application. Here, we present an overview of the recent research into the effects of functional oligosaccharides on intestinal health
Integrated microsphere-packed bed enzymatic membrane reactor for enhanced bioconversion efficiency and stability: A proof-of-concept study
No full textFabricating high-performance enzyme reactors is requested for achieving efficient and stable bioconversions, but remains challenging, because few of them can possess high enzyme loading, sufficient mixing, and efficient mass transfer at the same time. Herein, we propose to develop a novel enzymatic packed bed membrane reactor (EPBMR) by integrating the advantages of both packed bed reactor (PBR) and enzymatic membrane reactor (EMR). A prototype study is conducted with the simplified enzyme-loaded microsphere-ultrafiltration EMR model (Mic-UF EMR). Invertase and dextranase are used in this work to produce glucose and oligodextran by hydrolysis of sucrose and dextran, respectively. Specifically, the use of microspheres can enlarge the contact area between enzymes and substrates and mitigate membrane fouling induced by free enzymes. Thus, Free&Mic-UF EMR (with both free and immobilized enzymes) exhibits a higher sucrose conversion rate (84%) than the EMR with free invertase (34%) and a negligible decline in sucrose conversion for 36 h continuous operation. Membrane fouling is ameliorated by alkaline cleaning and implementation of covalent bonding strategy. In addition, commercial resins with larger sizes are employed to replace konjac glucomannan microspheres (KGM) which reduce the pressure drop of EMR. Finally, by selecting the UF membrane with proper molecular weight cut-off (MWCO), the dextranase-based Mic-UF EMR system successfully produces oligodextran with desired molecular weight (Mw) and narrow Mw distribution. The outcome of this work not only offers a novel enzyme reactor construction strategy but also provides guidance for regulating the performance of EMR
Integrated microsphere-packed bed enzymatic membrane reactor for enhanced bioconversion efficiency and stability: A proof-of-concept study
No full textFabricating high-performance enzyme reactors is requested for achieving efficient and stable bioconversions, but remains challenging, because few of them can possess high enzyme loading, sufficient mixing, and efficient mass transfer at the same time. Herein, we propose to develop a novel enzymatic packed bed membrane reactor (EPBMR) by integrating the advantages of both packed bed reactor (PBR) and enzymatic membrane reactor (EMR). A prototype study is conducted with the simplified enzyme-loaded microsphere-ultrafiltration EMR model (Mic-UF EMR). Invertase and dextranase are used in this work to produce glucose and oligodextran by hydrolysis of sucrose and dextran, respectively. Specifically, the use of microspheres can enlarge the contact area between enzymes and substrates and mitigate membrane fouling induced by free enzymes. Thus, Free&Mic-UF EMR (with both free and immobilized enzymes) exhibits a higher sucrose conversion rate (84%) than the EMR with free invertase (34%) and a negligible decline in sucrose conversion for 36 h continuous operation. Membrane fouling is ameliorated by alkaline cleaning and implementation of covalent bonding strategy. In addition, commercial resins with larger sizes are employed to replace konjac glucomannan microspheres (KGM) which reduce the pressure drop of EMR. Finally, by selecting the OF membrane with proper molecular weight cut-off (MWCO), the dextranase-based Mic-UF EMR system successfully produces oligodextran with desired molecular weight (Mw) and narrow Mw distribution. The outcome of this work not only offers a novel enzyme reactor construction strategy but also provides guidance for regulating the performance of EMR
A one-component phosphonium borane Lewis pair serves as a dual initiator and catalyst in the ring-opening alternating copolymerization of anhydrides and epoxides
No full textLewis pairs as synergistic catalysts have demonstrated versatile adaptabilities towards different monomers. Herein, we converted a bi-component Lewis pair into a one-component Lewis pair by integrating a Lewis acid and ionic Lewis base within one molecule to enhance the synergistic effect on the polymerization reaction. To exemplify the design strategy, one-component phosphonium borane Lewis pairs 1-6 were rationally designed, readily synthesized, and employed as metal-free catalysts for the ring-opening alternating copolymerization (ROAC) of anhydrides and epoxides. Detailed MALDI-ToF MS analysis illustrated the microstructure of the obtained copolymers and verified the presence of two types of initiating species derived from Br- and cyclohexane-1,2-diol (CHD) in the polymerization set-up. Kinetic studies and in situ B-11{H-1} NMR experiments further clarified the mechanism of polymerization. Strikingly, Lewis pair 3 featuring pentamethyl-ene -(CH2)(5)- linked triphenylphosphonium bromide (Lewis base) and a borabicyclo[3.3.1]nonane moiety (Lewis acid) showed high activity (TOF = 1920 h(-1)), thermal robustness (120 degrees C) and good alternating selectivity (>92%) in the ROAC of phthalic anhydride (PA) and cyclohexene oxide (CHO). Lewis pair 3 achieved a feed ratio of CHO/PA/catalyst = 15 000 :10 000 :1 in 96% conversion within 5 h at 150 degrees C. The higher molecular weight fraction of the produced P(PA-alt-CHO) had an M-n value of 51.8 kg mol(-1) with a polydispersity D = 1.10. The lower molecular weight fraction was ascribed to Br- initiation. In particular, P(PA-alt-CHO) with unimodal distribution can be generated by deliberate addition of water. The relatively larger radius parameter of the phosphonium countercation led to a weak electrostatic interaction, thus yielding a loose Lewis pair to allow for much easier dissociation of carboxylate active species, accounting for the high catalytic and synergistic behavior of the designed phosphonium borane Lewis pair in the ROAC of PA and CHO. One-component Lewis pairs will not only diversify organocatalyst structures, but also deepen our understanding of the polymerization mechanism and provide a possibility to realize controlled copolymerization of anhydrides and epoxides
