Application of Multistep Inversion Method for Online Monitoring Aerosol Particle Size Distribution and Aerosol Concentration

Aerosol concentration in the flow is usually time varying, and aerosol particle size distribution (PSD) is considered to be unchanged, which increases the difficulty of the measurement of aerosol PSD and concentration online. To solve these problems, a kind of multistep inversion method based on the angular light-scattering (ALS) signals is proposed. First, the aerosol PSD is estimated using shuffled frog-leaping algorithms (SFLAs) from relative ALS signals. Then, with aerosol PSD as priori information, the aerosol concentration is obtained by the Kalman filter (KF) algorithm, widely used in the real-time control system of industrial facilities for its ability of fast predictions. The result reveals that the performance of the improved SFLA is better than that of the original SFLA in solving the aerosol PSD. Moreover, in studying the aerosol concentration, more accurate results can be obtained with larger standard deviation of process noise or smaller standard deviation of measurement noise, while decreasing sampling time interval can improve the accuracy of retrieval results and reduce time delay to a certain degree. So, to improve retrieval accuracy, the noise should be controlled, and appropriate sampling time interval should be selected. All the numerical simulations confirm that the methodology provides effective and reliable results in real-time estimating

Electrochemical removal of NOx by La0.8Sr0.2Mn1−xNixO3 electrodes in solid electrolyte cells : Role of Ni substitution

Electrochemical removal of nitrogen oxides (NOx) by solid electrolyte cells (SECs) is a promising technology due to no required reductant. Herein, a series of La0.8Sr0.2Mn1−xNixO3 (0 ≤ x ≤ 0.5) perovskites were first synthesized and utilized as the electrode materials of SECs. The role of Ni substitution in electrode performance and NOx reduction mechanism were revealed by various experimental characterization and first-principle calculations. The results indicate that the moderate Ni substitution (x ≤ 0.3) increased the NOx conversion of electrodes while reduced the polarization resistance. The further investigation shows that this improvement was attributed to the more surface oxygen vacancies, better reducibility and higher Mn4+ proportion of the Ni-substituted perovskites. The electrochemical impedance spectroscopy (EIS) shows that these changes facilitated the NOx adsorption and dissociation processes on the electrode. According to first-principle calculations, the Ni-substituted perovskite had a lower formation energy of surface oxygen vacancy, while the NO molecule adsorbed on defect surface gained more electrons thus was easier to be reduced and dissociated. Finally, the electrode performance at different operating temperatures and the operational stability were verified

Study of the kinetics, mechanisms and catalysis activity of photo-electro degradation of organic pollutants via new neural network based methodology

A novel calculation methodology containing modeling and statistics was developed to assist the experimental process for the investigation of organics treatment process. A continuous-flow photo-electro treatment of Norfloxacin (NOR) was chosen as a target subject. The methodology is based on a new synergistic work of reaction energy calculation, full-scanned neural network (NN) simulation and new physical kinetics modeling. Degradation kinetics, mechanisms and activity of degradation catalyst, etc., were studied. As a result, the reaction energy calculation figured out eight potential degradation pathways of NOR with the corresponding intermediate. NN process with fully scanned parameters showed dominating advantage compared to non-linear regression and first-order law in simulation work. With the obtained database from NN, the new physical model successfully distributed degradation contribution into direct, indirect and water flow routes. The new methodology helped to gain more valuable information with less experimental work, which guided the efficient and greener investigation process in corresponding studies

Facile Synthesis of Polypyrrole-Functionalized CoFe2O4@SiO2 for Removal for Hg(II)

In order to avoid using toxic or harmful operational conditions, shorten synthesis time, enhance adsorption capacity, and reduce operational cost, a novel magnetic nano-adsorbent of CoFe2O4@SiO2 with core–shell structure was successfully functionalized with polypyrrole (Ppy). The physical and chemical properties of CoFe2O4@SiO2-Ppy are examined by various means. The as-prepared CoFe2O4@SiO2-Ppy nanomaterial was used to adsorb Hg2+ from water. During the process, some key effect factors were studied. The adsorption process of Hg2+ onto CoFe2O4@SiO2-Ppy was consistent with the pseudo-second-order kinetic and Langmuir models. The Langmuir capacity reached 680.2 mg/g, exceeding those of many adsorbents. The as-prepared material had excellent regeneration ability, dispersibility, and stability. The fitting of kinetics, isotherms, and thermodynamics indicated the removal was endothermic and spontaneous, and involved some chemical reactions. The application evaluation of electroplating wastewater also shows that CoFe2O4@SiO2-Ppy is an excellent adsorbent for Hg2+ ions from water

Unveiling the role of Ag-Sb bimetallic S-scheme heterojunction for vis-NIR-light driven selective photoreduction CO2 to CH4

The construction of interfacial engineered heterojunctions is an effective strategy to broaden the optical response and facilitate charge separation. Herein, a novel 0D/1D Ag2S/Sb2S3 heterojunction is prepared by in-situ growth of Ag2S quantum dots on Sb2S3 nanorods using a simple hydrothermal approach. The 10% Ag2S/Sb2S3 (10AS) heterojunction exhibited efficient CO2 photoreduction activity with a CH4 yield of 6.75 µmol g−1 h−1, which is six times higher than that of pure Sb2S3 NTs. The CH4 selectivity of the 10AS heterojunction reach 96.1%, owing to the construction of dual-metal sites. Intriguingly, the composite photocatalyst could be extended to infrared light, leading to the full utilization of the incident light. In the 10AS heterojunction, the formation of Ag-S-Sb type covalent bonds is demonstrated by Raman and XAFS tests. The pathways of CO2 conversion to CH4 are discussed in detail. Therefore, the work provides a promising strategy for highly selective and efficient CO2 photoreduction

Tungsten oxide quantum dots deposited onto ultrathin CdIn2S4 nanosheets for efficient S-scheme photocatalytic CO2 reduction via cascade charge transfer

A novel S-scheme photocatalytic heterojunction composite nanomaterial is developed by integrating zero-dimensional WO3 quantum dots (WQDs) on two-dimensional ultrathin CdIn2S4 (CIS) nanosheets with the aim of fostering carrier separation, enhancing the performance of carrier interface transport, minimizing carrier distance transport, and achieving effective photocatalytic CO2 reduction. The composite photocatalyst WQDs/CdIn2S4 (WCIS) allows for the efficient photocatalytic reduction of CO2 to CO and CH4, as shown by product analysis and isotopic measurement. The photogenerated electrons in WQDs recombine with the holes in CIS nanosheets, and the left electrons in CIS have stronger CO2 reduction abilities. The highest yields of CO and CH4 achieved with the WCIS photocatalyst are 8.2 and 1.6 μmol g-1h−1 ––2.6 and 8 times higher than those for CIS, respectively. Moreover, the S-scheme WCIS possesses a stable crystal structure and recycling ability. Finally, the S-scheme charge transfer path on the WCIS composite is proposed according to theoretical calculation, in-situ irradiated X-ray photoelectron spectroscopy, and electron paramagnetic resonance (ESR) analyses

Internal electric field engineering step-scheme–based heterojunction using lead-free Cs3Bi2Br9 perovskite–modified In4SnS8 for selective photocatalytic CO2 reduction to CO

This study focuses on improving photocatalytic CO2 reduction reaction (CRR) activity and modulating product selectivity. An In4SnS8/Cs3Bi2Br9-X (ISS/CBB-X) heterojunction is prepared using novel lead-free Cs3Bi2Br9 perovskite quantum dot–modified In4SnS8, which shows considerable potential as photocatalysts for CRRs under visible light. The optimised ISS/CBB photocatalyst exhibits high activity and CO selectivity with a CO yield and selectivity of 9.55 μmol g−1 h−1 and 92.9%, respectively, 3.8 and 1.5 times higher than those of pristine ISS, respectively. Moreover, the step-scheme (S-scheme) mechanism can be fully confirmed via in situ irradiated X-ray photoelectron spectroscopy, in situ electron spin resonance, femtosecond time-resolved absorption spectroscopy and density functional theory calculations. Based on in situ diffuse reflectance spectra and theoretical investigations, the ISS/CBB shows a decreased energy barrier towards CO2 reduction to CO through an adsorbed ⁕COOH intermediate. This study contributes to the further understanding of fabricating efficient S-scheme-based photocatalysts for selective CRR

Biodegradable glass fiber reinforced PVA hydrogel for cartilage repair: mechanical properties, ions release behavior and cell recruitment

Articular cartilage with limited ability of regeneration remains a grand challenge in the field of tissue engineering. Poly(vinyl alcohol) (PVA) hydrogel with low friction coefficient have been regarded as prior candidate for cartilage substitute, whereas lack of structure performance and bioactivity limited their application. Phosphate glass fiber (PGF) with outstanding mechanical performance and nature of biodegradability presents potential capability to improve mechanical stability of hydrogel and chondrocyte metabolism as well as cell recruitment. Herein, we describe a novel PGF-PVA composites hydrogel incorporated with continuous PGF. The presence of stiff PGF not only improves the mechanical properties of hydrogel with maximum tensile strength of 12.44 MPa and Young's modulus of 68.35 MPa, but also endows the hydrogel molecular structure with the increase of crystallinity and thermal stability via formation of crosslinking points. More importantly, the PVA hydrogel matrix exhibits efficient ions exchange behavior to control ions concentration during PGF degradation, resulting in more suitable metabolic environment for chondrocyte proliferation and induction with enhanced recruitment. Therefore, it is believed that this work provides a kind of fiber reinforced hydrogel material promising excellent properties for cartilage repair