Graphene aerogel is prepared for photocatalytic removal of uranium from water under visible light and air atmosphere. The photochemistry property of uranyl itself plays an essential role to generate ...H2O2 with O2 in air, thus to form (UO2)O2·2H2O. The neutral products can evacuate from the surface of GA-200 to regenerate the activity sites in-situ, resulting in a removal capacity of 1050 mg/g.
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•Graphene aerogel (GA) is synthesized with the controlled reduction degree.•GA photocatalyst can remove uranium under visible light and air atmosphere.•The photochemistry property of uranyl was essential during the photocatalytic process.•The (UO2)O2·2H2O products are obtained in air instead of UO2 in oxygen-free atmosphere.•The removal capacity is 1050 mg/g due to the in-situ regeneration of activity sites.
Photocatalysis-assist transition of uranium from soluble ions to insoluble nanoparticles is benefit for the extraction of uranium but has been rarely realized under air atmosphere. Here we developed a novel graphene aerogel (GA), GA-200, for the photocatalytic removal of uranium from water under visible light and air atmosphere for the first time. By controlling the reduction degree, GA-200 remained numbers of functional groups for anchoring uranium and possessed high photocurrent response and narrow band gap to generate and transfer electrons/holes readily. Under visible light irradiation, neutral (UO2)O2·2H2O nanoparticles were formed and could evacuate from the surface of GA-200 to regenerate the active sites in-situ, resulting in a high removal capacity of 1050 mg/g. The mechanism was further studied. It was found that at the presence of O2 in air, the photochemistry property of uranyl itself played an essential role to generate H2O2 and (UO2)O2·2H2O was formed instead of UO2, which was different from that in oxygen-free atmosphere.
Abstract Skeletal muscles have a robust capacity to regenerate, but under compromised conditions, such as severe trauma, the loss of muscle functionality is inevitable. Research carried out in the ...field of skeletal muscle tissue engineering has elucidated multiple intrinsic mechanisms of skeletal muscle repair, and has thus sought to identify various types of cells and bioactive factors which play an important role during regeneration. In order to maximize the potential therapeutic effects of cells and growth factors, several biomaterial based strategies have been developed and successfully implemented in animal muscle injury models. A suitable biomaterial can be utilized as a template to guide tissue reorganization, as a matrix that provides optimum micro-environmental conditions to cells, as a delivery vehicle to carry bioactive factors which can be released in a controlled manner, and as local niches to orchestrate in situ tissue regeneration. A myriad of biomaterials, varying in geometrical structure, physical form, chemical properties, and biofunctionality have been investigated for skeletal muscle tissue engineering applications. In the current review, we present a detailed summary of studies where the use of biomaterials favorably influenced muscle repair. Biomaterials in the form of porous three-dimensional scaffolds, hydrogels, fibrous meshes, and patterned substrates with defined topographies, have each displayed unique benefits, and are discussed herein. Additionally, several biomaterial based approaches aimed specifically at stimulating vascularization, innervation, and inducing contractility in regenerating muscle tissues are also discussed. Finally, we outline promising future trends in the field of muscle regeneration involving a deeper understanding of the endogenous healing cascades and utilization of this knowledge for the development of multifunctional, hybrid, biomaterials which support and enable muscle regeneration under compromised conditions.
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•Sintered Nd-Fe-B sludge was purified using a combination of physical and chemical methods to obtain purified sludge with a Nd2Fe14B phase.•Propose new strategies for ultra-short ...process recycling of a variety of sludges.•Break through the barrier of lower magnetic properties of regenerative magnets.•Low recycling cost and substantial reduction of recycling energy consumption.
The highly efficient and green recycling of sintered Nd-Fe-B sludge has emerged as a pressing concern in light of the escalating production of sludge. In this work, a novel ultra-short process strategy of purification-remixing incorporation is proposed for in-situ regeneration across several types of Nd-Fe-B sludges. The magnetic properties of the regenerated magnets are effectively restored by remixing the purified sludge at 30 wt% into customized high-remanence magnetic powder, followed by the adjustment of rare earth content to 30.5 % using rare earth-rich compounds. For magnets using 48SH sludge, the remanence and coercivity are recovered to 13.8 kG and 22.2 kOe, respectively, with recovery rates of 97 % and 108.3 %, which are almost as high as those of the original magnets. The temperature stability of the magnet is comparable to that of the original magnet as well. The comprehensive analysis attributes the attainment of high-performance to the repair and optimization of the microstructure, particularly focusing on the grain boundary phase.The ultra-short recovery process and the reuse of solvents in the purification phase minimize the total energy consumption and carbon emissions, and show great potential for green recycling for Nd-Fe-B sludge.
•Established the quaternary phase diagram FePO4-LiFePO4-NaFePO4-KFePO4 by DFT for the first time.•The competitive mechanism of alkali ions in FePO4 during extraction from a salt lake is ...revealed.•Na2/3FePO4 phase is the main reason for to decreased cyclability of FePO4 for lithium recovery in brines.•Proposed an innovative FePO4 regeneration process to enhance electrode performance and lifespan.
The rapid expansion of lithium battery applications has resulted in a shortage of lithium resources, prompting researchers to focus on the electrochemical extraction of lithium from water resources using FePO4 as the host material. However, a large amount of alkali metal impurity ions in brine leads to irreversible capacity loss, limiting the industrial application of FePO4 materials in lithium extraction. The mechanism of alkali metal ions’ influence on FePO4 materials remains unclear. To address this issue, the quaternary phase diagram of FePO4-LiFePO4-NaFePO4-KFePO4 and the diffusion barriers of lithium/sodium ions in FePO4 were obtained for the first time based on the theoretical calculation of density functional theory (DFT). DFT and X-ray diffraction (XRD) refinement revealed that the inability to remove Na2/3FePO4 from the FePO4 is a critical issue affecting electrode recyclability. An innovative electrode regeneration process was proposed to enhance the lifespan of FePO4 material. The Na2/3FePO4 impurity was converted to LiFePO4 using K2S2O8 abstersion and 0.1 mol/L LiCl lithiation regeneration process. After five rounds of regenerations, the total lithium extraction of the material could still reach 80.18 % of the extraction of the brand-new electrode, demonstrating the multiple reuses of the host material and cost savings. These innovative discoveries can advance the industrial application of electrochemical lithium extraction from FePO4 electrode materials.
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•A hollow, hydrophilicity surface molecularly imprinted materials were prepared.•Materials possess photocatalytic, reusability, and highly selectivity.•The removal contains of ...targeted adsorption, photocatalytic degradation.•Materials exhibited favorable adsorption capacity and selectivity towards SDZ.•The photodegradation of SDZ maintains 90.00 % after 6 cycles.
Novel hollow C, N-TiO2@C surface molecularly imprinted microspheres (HCNTC-SMIPs) with hydrophilicity, reusability, and selectivity were synthesized. The core–shell hollow structure yields large specific surface areas, high surface-to-volume ratios and effective diffusion rate on both inner and outer exposed surfaces. The C, N-TiO2 shell possesses high photo-catalytic decomposition capacity toward the specific pollutants. Moreover, TiO2 acts not only as a photocatalyst but also as a double cross-linker agent of molecularly imprinted to significantly reduce the molar ratio of formaldehyde. The hydrophilic surface imprinted layer provides the recognition sites and specific pore structures. The results showed that HCNTC-SMIPs possessed a high specific surface area of 305.10 m2 g−1 and a good visible light harvesting property with a bandgap of 1.67 eV. This could efficiently suppress the photoelectron-hole recombination, and thereby heightening the photocatalytic degradation of sulfadiazine (SDZ). The photodegradation efficiency of HCNTC-SMIPs can reach 99.25 % within 140 min and 90.00 % after 6 cycles. The HCNTC-SMIPs had a higher kinetic constant (0.01815 min−1) than those of HCNTC (0.00964 min−1) and TiO2 (0.00548 min−1). HCNTC-SMIPs can achieve targeted and efficient SDZ removal, as well as in-situ regeneration. The possible degradation pathways of SDZ primarily includes smiles-type rearrangement, SO2 extrusion, ring hydroxylation, direct oxidation and SN bond cleavage processes based on LC-MS analysis.
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•Flow synthesis of DAB-TFP COF was achieved at low temperature and in less time than the conventional batch process.•DAB-TFPFlow is highly efficient for the adsorption of methylene ...blue than DAB-TFPBatch.•In-situ flow adsorption was more effective for the removal of pollutants.•High recyclability and in-situ regeneration of DAB-TFPFlow COF in continuous flow.•The DAB-TFPFlow COF was also effective for the adsorption of simulated textile waste.
Covalent organic frameworks (COF) are increasingly gaining attention as adsorbents for industrial pollutants due to their high surface area and ordered porosity. However, often they have low removal efficiency due to the limited access to their pores. Approachability of foreign molecules to active sites within the framework can be maximized by pore engineering and introduction of defects. Here, we report the synthesis of an imine-based COF (DAB-TFP) at ambient conditions with the incorporation of disorder using continuous flow for the first time. A reusable microreactor that was fabricated using a cost-effective scaffolding technique was used for the flow reactions. The disorder in the COF increased accessibility of its surface for foreign molecules. Moreover, the disorder within the COF resulted in accelerated adsorption of methylene blue (MB) in continuous flow. The removal efficiency of the COF for MB was three folds higher during in-situ adsorption in continuous flow than the traditional batch mode of adsorption. The COF could be regenerated and recycled in continuous flow without any significant loss in the activity. Further, almost 100 % of MB could be reclaimed. The COF was also able to efficiently adsorb a mixture of pollutants as well as a simulated textile industrial waste. Hence, the reported method is a green and sustainable approach for industrial effluent treatment.
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•Bifunctional NHGBC-800 can adsorb TC and activate PDS with itself as the activator.•NHBC-800 could maintain above 77.18% adsorption capacity after the 6th cycles.•Non-radical ...electron-transfer and 1O2 pathways dominated the regeneration process.•PDS oxidation can regenerated carbon material saturated by organic pollutants well.
Carbonaceous material is not only the excellent adsorbent for organic contaminants removal, but also the effective activator for peroxydisulfate (PDS) activation. In this study, a nitrogen-doped hierarchical porous carbon material (NHGBC-800) presented the attractive bifunctional properties was developed for the removal of model organic contaminant antibiotic tetracycline (TC). On the one aspect, the NHGBC-800 had a large specific surface area (1178.0 m2/g) and achieved good TC removal with a maximal adsorption capacity (Qm) of 629.76 mg/g at 303 K. On the other aspect, TC-saturated NHGBC-800 could effectively activate PDS with itself as the activator, by which the mineralization of desorbed TC and in-situ regeneration of exhausted adsorbent were achieved simultaneously. The Qm of NHGBC-800 recovered 90.61% after first regeneration and still retained 77.18% even after the 6th adsorption-regeneration cycles. Moreover, the as-prepared material maintained good adsorption and regeneration performance under a wide range of pH conditions (3.02–9.83) and in the presence of inorganic anions such as Cl−, SO42−, NO3−, H2PO4−, HCO3−. The electro spin resonance (ESR), reactive oxygen species (ROS) quenching studies and electrochemical measurement revealed that the electron-transfer and single oxygen mediated the non-radical pathways dominated the TC degradation during the regeneration process. Compared with the conventional thermal and electrochemical regenerations, the in-situ regeneration of bifunctional carbon materials induced by PDS activation is more effective, sustainable and environmental-friendly.
Developing electrocatalytic reactions with high‐efficiency can make important contributions to carbon neutrality. However, poor long‐term stability of catalysts is a bottleneck for its practical ...application. Herein, an “in situ periodic regeneration of catalyst (PR‐C)” strategy is proposed to give long‐term high efficiency of CO2 electroreduction to generate C2+ products over Cu catalyst by applying a positive potential pulse for a short time periodically in the halide‐containing electrolyte. The high Faradaic efficiency (81.2 %) and current density (22.6 mA cm−2) could be maintained completely at least 36 h, while the activity and selectivity decreased continuously without using the PR‐C method. Control experiments and operando characterization demonstrated that the surface structure and oxidation state of Cu could be recovered periodically by the PR‐C method, which was beneficial for CO2 activation and C−C coupling.
An “in situ periodic regeneration of catalyst (PR‐C)” strategy is proposed to maintain the high efficiency of CO2 electroreduction towards C2+ products over a copper catalyst. A positive potential pulse is applied periodically for a short time in the halide‐containing electrolyte. As a result the surface structure and oxidation state of the Cu could be recovered periodically by the PR‐C method.
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•CO2 mineralization and vaterite CaCO3 selective preparation from coal fly ash.•Glycine as a multifunctional reagent.•Glycine promotes Ca leaching, CO2 mass transfer, and spherical ...vaterite formation.•Promising CaCO3 yield and stable vaterite properties in a wide range of conditions.
Leaching-mineralization cycle (LMC) technology using amino acid as a multifunctional reagent meets the need for CO2 removal and alkaline industrial residues treatment while avoiding the heavy consumption of exogenous chemical reagents (e.g., leaching reagent, CO2 absorbent, and crystal inducer) in traditional CO2 mineralization. However, the technical feasibility in diverse conditions and underlying mechanisms of this technology are not fully explored and still lack direct evidence. The influence of key operating factors, including leaching time, glycine concentration, and coal fly ash (CFA) dosage on Ca leaching efficiency, mineralization efficiency, Ca utilization efficiency, and CaCO3 yield, were systemically investigated to obtain an optimal process performance. Results showed that the optimal CaCO3 yield of 98.8 g/kg-CFA, leaching efficiency of 38.7%, and mineralization efficiency of 74.4% were obtained at conditions of 1 h leaching time, 200 g/L CFA dosage, and 2 M glycine solution. FT-IR results of the mineralized solution depicted a decline of deprotonated glycine and an increase of glycine overtime during the mineralization step, implying a continued regeneration of glycine. Mineralogy and morphology analysis of the carbonated product revealed that vaterite with a narrow particle size distribution and uniform spherical shapes were induced selectively by glycine as its preferential binding of acidic residues to metal ions in inhibition of vaterite dissolution, and the feasibility of the selective vaterite preparation from CFA was confirmed in a broad range of conditions. There was a quandary between high yield and low particle because of the particle agglomeration caused by the high dosage of the substrate.
In this study, the performance of catalytic ozonation in the treatment of bio-treated coking wastewater (BCW) using pilot- and full-scale systems was investigated. Additionally, the removal ...efficiency of organic pollutants from BCW, the deactivation mechanism of MnxCe1-xO2/γ-Al2O3, and backflushing optimization for in-situ catalyst regeneration, which have not been previously investigated, were analysed. Results of the 12-month pilot scale experiments showed that catalytic ozonation resulted in the effective removal of organic pollutants when backflushing was applied as an in-situ catalyst regeneration strategy. The effluent chemical oxygen demand (COD) content decreased from 150 to 78 mg L−1, and remained below a discharge limitation of 80 mg L−1, and the stable COD removal efficiencies (from 56.0% to 47.9%) indicated that catalyst deactivation, which primarily resulted from the deposition of inorganic salts on the surface of the catalyst that limited interaction between ozone and active sites and/or prevented electrons transfer, was primarily inhibited by backflushing. The catalyst regeneration via in-situ air- and water-backflushing was attributed to the scrubbing, collision, and/or the loosing effect. Additionally, in the full-scale experiment, the catalytic ozonation process with in-situ alternative backflushing exhibited a stable COD removal efficiency (above 45.6%) for 885 days when water- and air-flushing strengths of 10 L m−2 s−1 and 15 L m−2 s−1, respectively, were applied with a 7-day regeneration interval. Therefore, the results of this study provide new insights into catalytic ozonation and support its engineering application in BCW treatment.
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•Backflushing significantly improved COD removal stability in a one-year pilot study.•The mechanism of catalyst deactivation in the pilot study was analysed and discussed.•Catalyst deactivation mainly resulted from inorganic deposits occupying active sites.•Regular backflushing prevents tightly bound inorganic deposition on catalyst surface.•Four full-scale reactors with alternative backflushing operated stably for 885 days.
