scholarly journals Chitosan Modified Cationic Polyacrylamide Initiated by UV-H2O2 for Sludge Flocculation and New Insight on the Floc Characteristics Study

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2738
Author(s):  
Jie Chen ◽  
Xiaojun Xu ◽  
Rui Nie ◽  
Li Feng ◽  
Xuhao Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Regeneration Ability ◽  
Electron Microscopic ◽  
Sludge Dewatering ◽  
X Ray ◽  
Practical Applications ◽  
Floc Size ◽  
Sludge Flocs ◽  
Cake Moisture ◽  
Floc Characteristics

In the present study, a novel graft modified flocculant CTS-g-PAMD was synthesized and applied to conduct sludge conditioning and dewatering. CTS-g-PAMD was copolymerized with AM, DMC and chitosan (CTS) under UV-H2O2 initiation. In addition, the effects of single factor experiments on the molecular weight (MW) CTS grafting efficiency (GE) of CTS-g-PAMD were determined and the optimal copolymerization conditions were achieved. The GE of CTS-g-PAMD reached 91.1% and the MW was 4.82 × 106 Da. As revealed from the characterized results of Fourier-transform infrared spectra (FT-IR), 1H/ NMR, X-ray diffraction (XRD), scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS), the successful synthesis of CTS-g-PAMD was confirmed, which is considered to be conducive to explaining sludge dewatering performance. Under the optimal conditions (pH = 7.0, flocculant dosage = 35 mg/L), the best flocculating performance (FCMC: 73.7%; SRF: 4.7 × 1012 m·kg−1, turbidity: 9.4 NTU) and large and dense sludge flocs (floc size d50 = 379.142 µm, floc fractal dimension Df = 1.58) were formed. The DMC and CTS chain segments exhibiting cationic properties significantly improved the positive charge density and enhanced the electrical patching effect of CTS-g-PAMD. The long molecular chain of CTS-g-PAMD exhibited superior extensibility, which enhanced bridging effect on adsorption. Moreover, the sludge floc after undergoing CTS-g-PAMD conditioning exhibited robust shear resistance and regeneration ability. After the sludge floc was crushed and broken, a large and dense sludge floc was formed, helping significantly reduce the sludge specific resistance (SRF), turbidity and cake moisture content (FCMC) and enhance the sludge dewatering effect. The novel CTS-g-PAMD flocculant shows promising practical applications and high market value.

scholarly journals Superior Adsorption and Photocatalytic Degradation Capability of Mesoporous LaFeO3/g-C3N4 for Removal of Oxytetracycline

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 301 ◽  
Author(s):  
Ke Xu ◽  
Xiaosheng Yang ◽  
Luda Ruan ◽  
Shaolv Qi ◽  
Jianling Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Degradation ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Thermal Polymerization ◽  
X Ray ◽  
Practical Applications ◽  
Ultrathin Nanosheets ◽  
Lafeo3 Nanoparticles ◽  
Reheating Process

Mesoporous LaFeO3/g-C3N4 Z-scheme heterojunctions (LFC) were synthesized via the incorporation of LaFeO3 nanoparticles and porous g-C3N4 ultrathin nanosheets. The as prepared LFC were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, powder X-ray diffraction, Raman spectra and N2 adsorption analysis. The structural analysis indicated that the reheating process and the addition of NH4Cl in the thermal polymerization were the key factors to get porous g-C3N4 ultrathin nanosheets and to obtain high specific surface areas of LFC. It remarkably enhanced the adsorption capacity and photocatalytic degradation of LFC for removal of oxytetracycline (OTC). The effect of the mass percentage of LaFeO3 in LFC, pH and temperature on the OTC adsorption was investigated. The LaFeO3/g-C3N4 heterojunction with 2 wt % LaFeO3 (2-LFC) exhibited highest saturated adsorption capacity (101.67 mg g−1) and largest photocatalytic degradation rate constant (1.35 L g−1 min−1), which was about 9 and 5 times higher than that of bulk g-C3N4 (CN), respectively. This work provided a facile method to prepare mesoporous LaFeO3/g-C3N4 heterojunctions with especially well adsorption and photocatalytic activities for OTC, which can facilitate its practical applications in pollution control.

scholarly journals О структуре тонких пленок монооксида германия

2020 ◽  
Vol 54 (12) ◽  
pp. 1296
Author(s):  
К.Н. Астанкова ◽  
В.А. Володин ◽  
И.А. Азаров
Keyword(s):  
Raman Spectroscopy ◽  
Ir Spectroscopy ◽  
Mixture Model ◽  
Atomic Structure ◽  
Photoelectron Spectroscopy ◽  
Mechanical Stresses ◽  
Electron Microscopic ◽  
X Ray ◽  
Random Mixture ◽  
Germanium Monoxide

By means of optical (Raman spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy) and electron microscopic methods, it was found that the atomic structure of stoichiometric germanium monoxide films corresponds to the random bonding model, without the formation of germanium nanoclusters. This structure is metastable and transforms into a structure which is close to random mixture model at a temperature 260 oC and higher. The metastability of solid GeO may be related to the presence of internal mechanical stresses in the atomic network.

scholarly journals Selective Mineralization and Recovery of Au(III) from Multi-Ionic Aqueous Systems by Bacillus licheniformis FZUL-63

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 392
Author(s):  
Yangjian Cheng ◽  
Zhibin Ke ◽  
Xiaojing Bian ◽  
Jianhua Zhang ◽  
Zhen Huang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Bacillus Licheniformis ◽  
Photoelectron Spectroscopy ◽  
Precious Metals ◽  
Aqueous Systems ◽  
Tem Analysis ◽  
X Ray ◽  
Practical Applications ◽  
Bacterial Surface ◽  
20 Nm

The recovery of precious metals is a project with both economic and environmental significance. In this paper, how to use bacterial mineralization to selectively recover gold from multi-ionic aqueous systems is presented. The Bacillus licheniformis FZUL-63, isolated from a landscape lake in Fuzhou University, was shown to selectively mineralize and precipitate gold from coexisting ions in aqueous solution. The removal of Au(III) almost happened in the first hour. Scanning electron microscope with X-ray energy dispersive spectroscopy (SEM/EDS-mapping) results and fourier transform infrared spectroscopy (FTIR) data show that the amino, carboxyl, and phosphate groups on the surface of the bacteria are related to the adsorption of gold ions. X-ray photoelectron spectroscopy (XPS) results implied that Au(III) ions were reduced to those that were monovalent, and the Au(I) was then adsorbed on the bacterial surface at the beginning stage (in the first hour). X-ray diffraction (XRD) results showed that the gold biomineralization began about 10 h after the interaction between Au(III) ions and bacteria. Au(III) mineralization has rarely been influenced by other co-existing metal ions. Transmission electron microscope (TEM) analysis shows that the gold nanoparticles have a polyhedral structure with a particle size of ~20 nm. The Bacillus licheniformis FZUL-63 could selectively mineralize and recover 478 mg/g (dry biomass) gold from aqua regia-based metal wastewater through four cycles. This could be of great potential in practical applications.

Automation in sludge dewatering by novel on-line characterisation of flocculation

2003 ◽  
Vol 47 (2) ◽  
pp. 157-164 ◽  
Author(s):  
M. Sievers ◽  
C. Schroeder ◽  
H. Bormann ◽  
T.I. Onyeche ◽  
O. Schlaefer ◽  
...  
Keyword(s):  
Image Processing ◽  
Size Distribution ◽  
Experimental Period ◽  
Filter Press ◽  
Sludge Dewatering ◽  
Floc Size ◽  
Sludge Flocs ◽  
Extended Range ◽  
On Line ◽  
Flocculation Process

A novel on-line method and system for characterisation of sludge flocs in view of improving sludge dewatering has been developed. The characterisation of sludge flocs was carried out after the conditioning or the flocculation process. The system uses a conventional CCD-line scan camera providing an on-line monitoring of the relative floc size distribution by image processing procedures. The image processing procedure has been re-evaluated and adapted to the practical dewatering results, obtained from a chamber filter press of 250 × 250 mm size. A good correlation between the calculated sensor signal and the sludge dewaterability of digested sludge in terms of the up-concentration factor was found. Although different sludge compositions and flocculation systems have been tested within the whole experimental period of six months, a good reproducibility of this correlation was also found. A well balanced floc size distribution is necessary showing that not too many but still some fine flocs and also not too large but compact flocs lead to improved dewaterability. This has been illustrated by an extended range of floc size measurements ranging between 50 mm and 29 mm. The conditioning monitoring system would be suitable for the control of production of good size-balanced flocs to compensate fluctuations in sludge characteristics of the sludge to be conditioned.

Solvent-Free Environmentally Benign Approach for the Selective Olefin Epoxidation Catalyzed by Mn(III)-Immobilized Mesoporous Nanoarchitectonics

2020 ◽  
Vol 20 (5) ◽  
pp. 2858-2866 ◽  
Author(s):  
Luna Paul ◽  
Biplab Banerjee ◽  
Asim Bhaumik ◽  
Mahammad Ali
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solvent Free ◽  
Olefin Epoxidation ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Epoxidation Reaction ◽  
Selective Catalytic Oxidation ◽  
Hexagonally Ordered

Immobilization of transition metal complexes at the surface of 2D-hexagonal functionalized SBA-15 material is one of the promising strategies in designing an efficient catalytic system for the olefin epoxidation reaction. Here we have immobilized Mn(III) on the Schiff-base anchore 2D-hexagonally ordered functionalised mesoporous SBA-15 material. Powder X-ray diffraction (PXRD), N2-sorption and high resolution transmission electron microscopic (HRTEM) studies of the resulting SBA-15-SB-Mn material suggested 2D-hexagonally ordered porous nanostructure and X-ray photoelectron spectroscopy (XPS) analysis suggested the presence of surface bound Mn(III) species in this nanomaterial. This mesoporous material showed excellent performance in the selective catalytic oxidation of various alkenes to the corresponding epoxides in the presence of tert-butyl hydroperoxide (TBHP, 70% aqueous solution) as oxidant under solvent-free mild reaction conditions together with high recycling efficiency.

scholarly journals Fabrication of Si3N4@Si@Cu Thin Films by RF Sputtering as High Energy Anode Material for Li-Ion Batteries

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2824
Author(s):  
Hocine Merabet ◽  
Yannis De Luna ◽  
Khadiga Mohamed ◽  
Nasr Bensalah
Keyword(s):  
Electron Microscopy ◽  
Silicon Nitride ◽  
Magnetron Sputtering ◽  
Electrochemical Performance ◽  
Anode Material ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray ◽  
Practical Applications ◽  
Li Ion

Silicon and silicon nitride (Si3N4) are some of the most appealing candidates as anode materials for LIBs (Li-ion battery) due to their favorable characteristics: low cost, abundance of Si, and high theoretical capacity. However, these materials have their own set of challenges that need to be addressed for practical applications. A thin film consisting of silicon nitride-coated silicon on a copper current collector (Si3N4@Si@Cu) has been prepared in this work via RF magnetron sputtering (Radio Frequency magnetron sputtering). The anode material was characterized before and after cycling to assess the difference in appearance and composition using XRD (X-ray Powder Diffraction), XPS (X-ray Photoelectron Spectroscopy), SEM/EDX (Scanning Electron Microscopy/ Energy Dispersive X-Ray Analysis), and TEM (Transmission Electron Microscopy). The effect of the silicon nitride coating on the electrochemical performance of the anode material for LIBs was evaluated against Si@Cu film. It has been found that the Si3N4@Si@Cu anode achieved a higher capacity retention (90%) compared to Si@Cu (20%) after 50 cycles in a half-cell versus Li+/Li, indicating a significant improvement in electrochemical performance. In a full cell, the Si3N4@Si@Cu anode achieved excellent efficiency and acceptable specific capacities, which can be enhanced with further research.

Microstructure and Reaction Mechanism during Fluorination of Isotropic Pitch

2012 ◽  
Vol 174-177 ◽  
pp. 44-49
Author(s):  
Jin Cai Zhang ◽  
Jing Li Shi ◽  
Xue Min Guo ◽  
Quan Gui Guo ◽  
Lang Liu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fine Particles ◽  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Surface Molecules ◽  
Isotropic Pitch ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Isotropic pitch fluorides were prepared via the reaction of isotropic pitch with gas mixture containing F2 and N2 in a rotation nickel reactor. Isotropic pitch fluorides were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and elemental analysis. The results showed that the interlayer spacing of the resultant materials dramatically increase from 0.345 nm of the isotropic pitch to the range 0.643 nm to 0.798 nm. Further studies on the diversity of the functional groups indicated that the whole reaction process was composed of two steps, namely, diffusion of F2 inside the voids among isotropic pitch molecules on the surface of the particles and fluorination. The two processes interacted with each other and jointly determined the apparent speed of the reaction. The scanning electron microscopic micrographs showed that the larger bulk of isotropic pitch was gradually desquamated and became small particles, which can be attributed to the crack resulting from the volume expansion of the surface molecules of the isotropic pitch fluorides during the reaction. The final isotropic pitch fluorides were fine particles with diameters of less than 1 µm.

scholarly journals Nano-SiO2 used with cationic polymer to improve the strength of sack paper

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3348-3359
Author(s):  
Jiawei Yang ◽  
Liulian Huang ◽  
Yonghao Ni ◽  
Lihui Chen ◽  
Qingxian Miao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sio2 Nanoparticles ◽  
Strength Properties ◽  
Packaging Material ◽  
Cationic Polymer ◽  
Attenuated Total Reflection ◽  
X Ray ◽  
Physical Strength ◽  
Practical Applications ◽  
Diallyldimethylammonium Chloride

As a green and sustainable packaging material, industrial sack paper has gained increased attention in recent years due to the public’s heightened environmental awareness. Practical applications for industrial packaging sack paper demands that the paper possess high physical strength properties. In this study, silicon dioxide (SiO2) nanoparticles in conjunction with poly(diallyldimethylammonium chloride) (PDADMAC) were applied to improve the physical strength of sack paper. The results showed that the physical strength properties of the sack paper increased with the addition of the SiO2 nanoparticles and PDADMAC, while the air permeability of the paper also remained high. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to characterize the sack paper with the SiO2 nanoparticle filler.

Electron Microscopy and X-Ray Photoelectron Spectroscopy of Oxygen Plasmaetched Bacterial Spores and Cells

1976 ◽  
Vol 34 ◽  
pp. 134-135
Author(s):  
Richard S. Thomas ◽  
Merle M. Millard ◽  
René Scherrer
Keyword(s):  
Photoelectron Spectroscopy ◽  
Organic Matrix ◽  
Structural Features ◽  
Mineral Elements ◽  
Bacterial Spores ◽  
Electron Microscopic ◽  
X Ray ◽  
Culture Cells ◽  
Combined Application ◽  
Morphological Studies

Low-temperature, oxygen plasma etching (OPE) is a useful technique in electron-microscopic (EM) morphological studies of mineral-containing organic polymers and biological structures. OPE gently and cleanly etches away the organic matrix at the surface of the specimen, leaving behind oxides and salts of exposed mineral elements. X-ray photoelectron spectroscopy (XPS) is widely used for macroscopic chemical analysis of the surfaces of polymers and inorganic specimens. The XPS signal originates from a surface depth of less than 100 Å. Combined application of the three techniques, OPE, EM and XPS to dispersible, macroscopic specimens which are microscopically homogeneous should allow correlation of fine structural features with surface and subsurface chemical composition. The present, preliminary study explores this possibility on bacterial spores and cells. Further details, and similar studies on tissue culture cells will be reported elsewhere.

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