查看更多>>摘要：Soot particle exhausted from diesel engines are causing severe health and environmental problems. Alkali metals (Li, Na, K, Cs) doped CuFe2O4 catalysts were synthesized to eliminate soot residue. XRD, Raman, SEM, H-2-TPR and temperature-programmed oxidation (TPO) were employed to investigate the effect of alkali metals addition on CuFe2O4. Density functional theory (DFT) calculations were used to explore the inner reaction mechanism. The results revealed that the doping of all alkali metals facilitated the formation of oxygen vacancies which are the main active sites for soot oxidation. The CuFe2O4 doped by K showed smallest crystal size and the most oxygen vacancies. Therefore, Cu0.9K0.1Fe2O4 catalyst performed best catalytic activity in soot oxidation with the T-ig of 308 ? and T-max of 389 ?.
查看更多>>摘要：This study proposes an efficient Layered Double Hydroxide-based (LDH-based) Heterogenous Electro Fenton (Hetero-EF) strategy that ensures the stable operation for representative antidepressants Amitriptyline Hydrochloride removal in a wide pH tolerance. The extra brilliant mineralization ability was over ~ 90% after 5 cycles. Moreover, the detailed degradation pathways and intermediates of Amitriptyline Hydrochloride were firstly elucidated and probed using ultra performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS). According to the Density Functional Theory and D-Band Center Theory, the subsequent computational simulation shed new light on the ability of LDH catalyzing for hydroxyl radical formation, the relevant role of transition metal atoms in LDH catalysts, and the electrons transfer process in the Hetero-EF reaction, i.e., LDH's metal atoms are robust electron donor sites for the generation of hydroxyl radical and charges transformation for the redox reaction, which highlights the importance of the transition metal elements in catalysts and exerts feasibility for enhancing the performance of Heterogeneous Electro-Fenton (Hetero-EF). Thereby, this research proposes a reliable strategy for building efficient Hetero-EF systems and gives a global contribution to developing the high-performance LDH EF-catalysts through the optimization of the metal atom ratio modification, synthesis parameters, and computational modeling.
查看更多>>摘要：Nitrate or nitrite may be utilized as solitary electron acceptors for biological sulfide oxidation. In the presence of a limited sulfide concentration (360 mg S/L), the effect of multiple nitrogen (N) sources on the synchronized sulfur and nitrogen removal process was investigated based on the reactants biotransformation, product generation and bacterial genera analysis. Upon gradual transition from nitrate to nitrite, sulfide and nitrogen elimination percentages dropped from 99.46 +/- 1.11% and 96.41 +/- 1.30% to 71.57 +/- 1.33% and 12.31 +/- 6.80%, respectively. Synchronously, the elemental sulfur conversion percentage increased from 58.94 +/- 1.21% to 90.49 +/- 2.64%. A simulation model was established to investigate the contribution of reduced nitrate and nitrite towards sulfur-products separately. According to Pearson correlations, no significant relationship was observed amongst community richness/diversity and influent nitrogen source; while Principal component analysis (PCA) suggested that each phase formed a distinct group. Sulfurovum and Sulfurimonas were the dominant genera in all phases.
Ren, YuxuanHersch, Steven J.He, XiaoZhou, Rufan...
10页
查看更多>>摘要：Metal-organic frameworks (MOFs) suffer from low processability and recyclability due to their fragile powder form. Supporting MOFs on the lightweight and porous cellulose aerogels is an efficient way to dramatically extend their practical applications. Herein, a metal-organic framework (MOF) composite material, named as copper-benzenedicarboxylate/cellulose aerogel (CuBDC/CA), was designed and synthesized by one-pot precursor preparation of cellulose aerogels anchored with copper, followed by in-situ growth of CuBDC in the presence of terephthalic acid. The characterizations (scanning electron microscopy with energy-dispersive X-ray, powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, stability and mechanical tests) confirmed the successful synthesis of the lightweight (0.0625 & PLUSMN; 0.0010 g/cm3 for 20% CuBDC/CA), mechanically strong, stable, and porous aerogel composites with well dispersed CuBDC nanosheets. The aerogel composite showed great potential in wastewater treatment, including dye degradation and antibacterial assays. More than 90% methylene blue could be decomposed by CuBDC/CA in 240 min via the Fenton-like reaction, and the recycling test revealed its good reusability. Moreover, this composite exhibited great antibacterial performance (more than 99.99%) towards commonly used lab strains as well as multidrug-resistant pathogens, including Escherichia coli , Staphylococcus aureus, and Pseudomonas aeruginosa. The screening tests indicated that the mechanism of killing effect was associated with the damage of bacterial envelope integrity. This work has proven that the lightweight and robust MOF/cellulose aerogel is a promising candidate for environmental remediation in practice.
查看更多>>摘要：Organically bridged silica has been proven to be promising precursors for fabricating silica-based organic-inorganic hybrid membranes with excellent permselectivity. However, the large-area deposition of defect-free hybrid silica membranes onto the polymer substrate has always been an enormous challenge. Herein, we reported a fast and facile approach for the large-area production of flexible silica-based hybrid membranes, where a thin and uniform ethylene-bridged silica active layer was coated on a microporous polymer substrate via a spray coating process with a single-pass method. First, the optimal deposition conditions were investigated and established, including sol concentrations and different solvent systems that are used to prepare hybrid silica sol, as well as various spray coating conditions. Subsequently, thus-produced flexible hybrid silica composite membranes exhibited superior isopropanol (IPA) dehydration performance by vapor permeation for a 90 wt% isopropanol aqueous solution, with water permeation flux reaching 4.0 kg m(-2)h(-1) and with H2O/IPA separation factor exceeding 1000 (the selectivity of H2O/IPA is 770). This work has shown that the single-pass spray coating is a useful strategy for the large-scale fabrication of the flexible hybrid silica composite membrane.
查看更多>>摘要：Recently, hydrocyclone separator is introduced into the field of aerobic granular sludge (AGS), and applied in wastewater treatment plant to recover the dense sludge. However, the function of hydrocyclone separator for AGS cultivation is still unclear. Thus, the granulating and granular separation efficiencies of hydrocyclone separator were investigated from perspectives of experiment and hydrodynamic modelling. By comparing traditional sequencing batch reactor, the introduction of hydrocyclone separator greatly decreased the mixed liquid suspended sludge by maximum 61%, although it could improve the sludge settling performance and reduce SVI, no matter operational time of separator high or low. The reason might be attributed to strong shear force and centrifugal force provided by hydrocyclone separator. Therefore, the inlet water velocity, a factor of shear stress, was studied. The medium water velocity of 0.3 m/s contributed to appropriate tangential velocity and static pressure, reaching the optimal granular separation efficiency that was larger than 97% for the particle diameter over 400 mu m. Besides, carrier particles in previous studies were summarized and found to enhance AGS formation in short time (15 to 54 days). When they were combined with hydrocyclone separator for continuous AGS cultivation, the carrier particles with large particle size (GAC, ceramsite, etc) were proposed to be used, instead of biochar or graphite oxide nanoparticle. This study explored the feasibility of hydrocyclone separator to culture AGS, which is helpful to realize the continuous AGS cultivation.
查看更多>>摘要：Covalent organic frameworks (COFs) with uniform, tunable nanoporosities are promising alternatives to prepare nanofiltration membranes with homogeneous nanochannels for high-resolution molecular sieving. Due to the poor membrane-forming ability as well as the relatively inadequate strategies for pore engineering, thus far, the preparation of continuous and defect-free COF membranes with tunable pore sizes is still challenging. Herein, we demonstrate an ingenious strategy to prepare the heterostructured membranes featuring the loose polyamide networks masked COF nanofilms for precise sieving of small molecules. The loosely structured polyamides are created by the interfacial polymerization to mask the chemically stitched (chemically interlinked) ultrathin COF nanosheets. The masked polyamide with flexible, loose networks not only enhance the membrane-forming ability of the natively rigid ultrathin COF nanofilms, but also provide a masking effect that can effectively tune the pore size of the heterostructured COF membranes. Benefitting from the synergistic enhancement of the membraneforming ability and the pore size tunability, thus-prepared membranes exhibit excellent molecular sieving performances toward various small molecules. This work is expected to provide a guidance for the rational design and controllable preparation of COF membranes for precise nanofiltration.
查看更多>>摘要：Mechanical energy is a natural energy that can be considered as a form of rich, clean, and renewable energy and it can be harvested by using piezoelectric materials. Water pollution is one of the series of threats faced by our planet and jeopardizes the ecosystem. Piezocatalysis could be a promising solution for this issue. This research focused on the sonochemical synthesis of PbTiO3 (PTO) piezocatalyst and studied the effect of synthesis parameters, operation conditions during the piezocatalysis process, and the effect of DNA as a modifier on piezocatalytic activity of PTO. Results showed that the synthesis parameters show a significant effect on the piezocatalytic activity of PTO. The origin of this effect came from the morphology, purity, and orientation of final products. Results displayed that the degradation reaction was completed during the first hour. 97.1 % of Acid Red 141 (AR141) was degraded by controlling both synthesis and operation conditions. In this research, the ultrasonic probe with a power of 100-600 W and a frequency of 18 kHz was used.
查看更多>>摘要：Developing a highly effective material for CO storage and separation is a challenge. In this study, we first used microwave-assisted continuous-flow synthesis to create defective UiO-66(Zr) frameworks with improved surface area and pore structures, which is highly efficient for large-scale production. The defect concentration of UiO-66 (Zr) was rapidly and effectively controlled within a short reaction time of 10 min. Different amounts of Cu2+ were loaded onto defective UiO-66 samples, followed by reducing Cu2+ to Cu+ to obtain Cu(I)@UiO-66 adsorbents (Cu(I)@UiO). X-ray diffraction (XRD), N-2-adsorption, FT-IR, SEM, TEM, thermogravimetric analysis (TGA), and XPS analyses were used to characterize the physicochemical properties of the prepared adsorbent materials. Gas adsorption experiments revealed that Cu(I)-decorated defective UiO-66 exhibited high CO adsorption capacity due to the pi complexation between Cu+ and CO. The CO adsorbing amount and CO selectivity onto the Cu (I)@UiO-66 samples were improved by adjusting the defect concentration and Cu(I) load on the UiO-66 host. The breakthrough experiment confirms that this defective Cu(I)@UiO adsorbent can efficiently separate CO/N-2 mixture under dynamic mixture flow conditions. Furthermore, after several cyclic adsorption-desorption experiments, the defective Cu(I)@UiO-66 is highly regenerable and has a good oxygen-resistant ability. The study describes a simple and scalable method for producing pi-complexation adsorbent for CO adsorption.
NSTL
Elsevier