查看更多>>摘要：Particulate matter (PM) is one of the major air pollutants that is harmful to both environment and human health. Herein, Ti-based metal-organic frameworks (MOFs) of MIL-125 and MIL-125-NH2 were integrated into bacteria cellulose/chitosan foam (BCH) and used as air filters. A directional freeze-drying approach was used to construct foam matrix, in which the meso-/macropores of polymer skeleton contribute to the required accessibility toward MOFs and minimize gas diffusion barriers. Benefiting from the hierarchically porous structure, the composites foam presented superior filtration properties with high removal efficiencies and low pressure drops. The filtration efficiency of MIL-125-NH2@BCH filter for PM_(2.5) could exceed 99.5% with a good long-time (30 days) stability. The pressure drop is determined to be 39.4 Pa. The filtration mechanisms are attributed to the electrostatic interaction between MOFs and PM particles, the presence of amine groups, as well as the inhibition effect of fibrous polymer network. This work will shed light on the development of MOF-polysaccharide composites for air purification applications.
查看更多>>摘要：To recover the rare earth element yttrium (Y) from spent fuel by molten salt electrolysis technology, the electrochemical redox mechanism of Y(III) and Ga(III) ions on tungsten electrode and the electrode reaction of Y(III) ions on the liquid Ga electrode were systematically detected by a series of electrochemical test methods, including cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry, etc. The thermodynamic and kinetic parameters of the electrode process on Ga(III) and Y(III) ions were obtained in this work. The measured diffusion activation energies (Ea) of electrode process for Y(III) and Ga(III) ions were calculated as 30.40 kJ · mol~(-1) and 33.33 kJ - mol~(-1). The electrodeposition process of Y and Ga was studied by CV and OCP, and thermodynamic parameters of Ga-Y alloys formed were also calculated. Thermodynamic parameters of Ga2Y intermetallic compounds were calculated based on open circuit chronopotentiometry at different temperatures ( △Hf~0 (GaaY) = -279.205 kJ mol~(-1) and △Sf~0 (Ga2Y) = -123.9 J mol~(-1) K ~(-1)). Yttrium was extracted by potentiostatic electrolysis and galvanostatic electrolysis on liquid Ga electrode in molten salts. In order to save the amount of liquid metal gallium, the best initial (2.5 g) was used. The cathodic deposition Products were characterized by X-ray diffraction analysis and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. According to ICP-AES analysis, the extraction rate of Y on Ga electrode can reach a maximum of 99.39%.
查看更多>>摘要：The magnetic Fe-MOFs derivatives obtained by high-temperature calcination under inert atmosphere have been studied and acted as high-efficiency catalysts in wastewater remediation. However, due to the shortcoming that the unstable structure of Fe-MOFs derivatives tends to collapse and agglomerate easily, it is necessary to find a support to improve its dispersibility and stability. In this work, an effective method was provided to fabricate biochar-loaded MIL-53(Fe) derivatives (BC@FexC) to activate peroxydisulfate (PDS) for norfloxacin (NOR) degradation. The efficiency of the BC@FexC/PDS system for NOR removal can reach to 91.2% within 15 min, and the reaction constant (k) was 52.15 times of BC/PDS and 22.19 times of FexC/PDS. Characterization results illustrated that the superior spatial pore structure and exposed active sites of BC@FexC allowed NOR to diffuse and interact with the catalyst efficiently. ·OH, SO4~(·-) and ~10O2 were the main reactive oxygen species involved in NOR degradation. Moreover, the BC@FexC/PDS system exhibited excellent stability that almost unaffected by various environmental conditions (such as tap water, river water, and medical wastewater), which would provide a reference path for application in actual water treatment.
查看更多>>摘要：Embedding metal particles into carbonaceous materials has promising prospects in antibiotic removal because of its good peroxymonosulfate (PMS) activation efficiency and low metal leaching risk. However, previous studies focused on metal particles embedding nanotubes, which is limited by high cost and complex preparation processes. Hence, in this study, low-cost and easily obtained biochar (BC) was chosen to prepare Co nanoparticles (Co NPs) embedded into carbonaceous materials through a one-step facile pyrolysis method. The optimized Co@RBC800 exhibited excellent PMS activation efficiency toward levofloxacin (LVF) degradation. Compared to the structure of conventional Co particles loaded on the surface of BC (Co-BC), this special structure of Co NPs embedded into BC exhibited more stability in cycle experiments and negligible Co ion leaching. Based on the quenching experiment, electron paramagnetic resonance (EPR), in situ Raman testing, electrochemical analysis, and density functional theory (DFT) calculations, it was found that the ~1O2 and electron transfer mechanisms played a dominant role in LVF degradation in the Co@RBC800/PMS system. In addition, Co@RBC800 displayed excellent anti-interference ability, easy recovery performance and universal applicability. This work supplies a new means for the rational modification of BC materials for high-efficiency PMS activation performance with little metal ion leaching risk in antibiotic removal, which is proven by an in-depth exploration of the reaction mechanism.
查看更多>>摘要：Nanofibers fabricated by electrospinning are attractive in the field of air filtration, but limited by insufficient filtration performance. Furthermore, it still remains a great challenge to regenerate secondary structure in the surface of nanofiber to realize advanced and sustainable filtration. Herein, high-performance, ecofriendly and biosafety polyvinyl alcohol/sodium alginate/hydroxyapatite (T-PVA/SA/HAP) nanofiber with hierarchical structure are fabricated by green electrospinning and thermal treatment. Based on the morphology-modification strategy, a unique wrinkled helical structure (UWHS) is created after thermal treatment and promotes the physical interception for particulate pollutants. Moreover, owing to the electrostatic adsorption effect of HAP nanoparticle, the ability of nanofibrous membranes for capturing PM is further improved (Removal more than 99% for PM_(0.3-2.5)). This work provides novel strategy and insight into development of high-efficiency particulate filtration materials by morphology engineering.
查看更多>>摘要：Herein, a novel all-solid-state Z-scheme NH2-MIL-125(Ti)/Ti3C2 MXene quantum dots/ZnIn2S4 (Ti-MOF/QDs/ZIS) photocatalyst was prepared, then applied for photocatalytic antibiotic (tetracycline and sulfamethazine) degradation and hydrogen evolution under visible light. The Z-scheme Ti-MOF/QDs/ZIS photocatalyst afforded very efficient degradation of tetracycline (TC, 96% in 50 min) and sulfamethazine (SMZ, 98% in 40 min), as well as a high rate of hydrogen generation (2931.9 μmol g~(-1) h~(-1)) under visible light irradiation. Trapping studies showed superoxide radicals (·O2~) to be the main active species for antibiotic degradation, with the intermediates formed during antibiotic photo-oxidation identified by liquid chromatography-mass spectrometry. Photocatalyst recycling studies showed the Z-scheme composite photocatalyst to be stable during both antibiotic photo degradation and hydrogen generation experiments. The Ti3C2 MXene quantum dots facilitated electron transfer between the semiconducting components of Z-scheme composite photocatalyst. This work identifies a promising new Z-scheme photocatalyst system for water purification and solar hydrogen production.
查看更多>>摘要：The associated carbonaceous material in ore will deteriorate the flotation process. However, only a few studies have been conducted on the properties of carbonaceous materials in lead-zinc ore flotation. The properties and adsorption performance of carbonaceous materials remain unclear. In this study, the closed-circuit flotation of bench-scale experiments shows that carbon pre-flotation can improve the grade and recovery of lead. The properties of the enriched carbonaceous materials were analysed. Amorphous carbon accounts for 99.70% of the total carbon in the concentrate. The structure of amorphous carbon is similar to the properties of coal, which has rich aromatic rings, carbonyl, and hydrocarbyl. Moreover, amorphous carbon has abundant pore structures with a specific surface area of 16.18 m~2/g and an average pore diameter of 12.94 nm. The adsorption isotherm of diethyl dithiocarbamate (DDTC) onto amorphous carbon fits the Freundlich model well. The pseudo-second-order (PSO) model can better interpret the adsorption process. The adsorption capacity of amorphous carbon for DDTC is superior to that of galena, leading to the depletion of DDTC in the flotation pulp.
查看更多>>摘要：Natural deep eutectic solvents have a high solvation and food-grade characteristics, which make them a preffered choice for extracting bioactives to develop nutraceutical and cosmetic formulations. This research aimed to investigate the systematic effects of several NADESs on the ultrasonic-assisted extraction of steroidal saponins from the rhizomes of Trillium govanianum Wall, ex D.Don, which is utilized in traditional Ayurvedic medicine. After screening of fifteen different NADESs, choline chloride: lactic acid (1:1) (NADES 1) was found most effective eutectic solvent for the extraction of steroidal saponins performed by the three-round micro-extraction (1 mL). Compared with hydro-ethanolic solvent-based extraction, lactic acid-derived NADESs showed higher extractability of steroidal saponins. The extraction efficiency of bioactive steroidal saponins e.g. borassoside E and protodioscin was also enhanced with NADES 1. The effects of extraction variables such as S:L ratio, working duration, and temperature on the extraction of steroidal saponins by NADES 1 was also studied and optimized. Furthermore, optimized parameters were validated by performing 100 mL NADES 1-based extraction to recover phytomolecules and NADES 1 by using Diaion HP20 resin column chromatography. As a proof of concept, this study suggested that lactic acid-derived NADESs are effective media for the extraction of steroidal saponins from biomass. The cytocompatibility assay of NADESs with NRK-52E and IEC-6 cells revealed the safe nature of NADESs to normal animal cells. The steroidal saponins-enriched extract obtained with NADES 1 has shown promising antagonistic effects on acetylcholinesterase activity.
查看更多>>摘要：Zero-valent aluminum (ZVAl) as a cost-effective additive with excellent reducibility is a promising material for application in heavy metal elimination. However, dense surface oxide films suppress the reactivity of ZVAl. Herein, we prepared mZVAl/MFe2O4 (M = Mn, Zn, Ni) composites via an accessible ball milling process and confirmed their satisfactory adsorption-reduction performance for Cr(VI) removal. The removal efficiency was not significantly affected by the changes in pH and presence of ions and humic acid. Direct spectroscopic analyses and density functional theory calculations revealed that ball milling with MFe2O4 destroyed the oxide film and increased the lattice spacing of mZVAL The enhanced adsorption and reduction performances of ZVAl after ball milling was the primary reason for the improvement in Cr(VI) removal. This study presents a new pathway for the development of reductive materials for heavy metal removal in wastewater treatment.
查看更多>>摘要：Herein, the Sn-doped perovskite oxide Sr_(1.95)Fe_(1.4)Sn_(0.1)Mo_(0.5)O_(6-δ) (SFSnM), which exhibited in situ exsolved Fe-Sn alloy nanoparticles and controllable phase transformation, was synthesized to catalyze the reduction of CO2 through A-site deficiency regulation. The in situ exsolved Fe-Sn alloy nanoparticles were uniformly distributed on the surface of the SFSnM substrate after reduction, which significantly enhanced the catalytic activity and CO2 adsorption capacity of the SFSnM cathode. Moreover, a single cell with an FeSn@SFSnM cathode exhibited excellent CO2 electrolysis performance, achieving a current density of 3.269 A cm~(-2) and an Rp value of 0.145 Ω cm~2 at 800 °C and 1.8 V. Additionally, no significant performance attenuation was observed during a long-term stability test (200 h), indicating the good stability of FeSn@ SFSnM cathode. Overall, these results demonstrated that the designed FeSn@SFSnM cathode shows great potential for high-performance solid oxide electrolysis cells (SOECs).
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