Enhanced performance and mechanism of KMnO4 pre-oxidation to coagulation on the removal of the DON and proteins

2016 ◽  
Vol 16 (5) ◽  
pp. 1432-1440 ◽  
Author(s):  
Cheng Liu ◽  
Siyuan He ◽  
Bin Wang ◽  
Jie Wang ◽  
Wei Chen
Keyword(s):  
Molecular Weight ◽  
Organic Nitrogen ◽  
Adsorption Ability ◽  
Turbidity Removal ◽  
Main Category ◽  
Common Operation ◽  
Kmno4 Oxidation ◽  
Water Plants ◽  
Dimensional Electrophoresis

Proteins were the main category of the dissolved organic nitrogen (DON) in eutrophicate water sources and posed a threat to the water quality safety and common operation of water plants, while the KMnO4 pre-oxidation and coagulation were the two important ways to control the organics. Intracellular organic matter (IOM) and phycocyanin were chosen as the target DON to study the performance of KMnO4 pre-oxidation to the enhanced removal effects for coagulation process, and molecular weight distribution, hydrophobicity, two-dimensional electrophoresis and MnO2 adsorption experiment were used to study the mechanism. The results showed that KMnO4 pre-oxidation enhanced the IOM and phycocyanin removal performance of coagulation significantly, although poor removal was found for KMnO4 oxidation alone. KMnO4 pre-oxidation altered the molecular weight, hydrophobicity and proteins' categories insignificantly. However, the in-situ formed MnO2 showed better adsorption ability for the IOM and phycocyanin. The main enhanced removal mechanism was the adsorption of MnO2 formed from the reduction of KMnO4 and little difference existed between the IOM and phycocyanin. In addition, the KMnO4 pre-oxidation could enhance the turbidity removal of the coagulation due to a similar mechanism.

scholarly journals Ecological Function of Myroilysin, a Novel Bacterial M12 Metalloprotease with Elastinolytic Activity and a Synergistic Role in Collagen Hydrolysis, in Biodegradation of Deep-Sea High-Molecular-Weight Organic Nitrogen

2009 ◽  
Vol 75 (7) ◽  
pp. 1838-1844 ◽  
Author(s):  
Xiu-Lan Chen ◽  
Bin-Bin Xie ◽  
Fei Bian ◽  
Guo-Yan Zhao ◽  
Hui-Lin Zhao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Deep Sea ◽  
Organic Nitrogen ◽  
The Novel ◽  
Amino Acid Residues ◽  
Human Pathogenic Bacterium ◽  
Low Levels ◽  
Low Activity

ABSTRACT Nearly all high-molecular-weight (HMW) dissolved organic nitrogen and part of the particulate organic nitrogen in the deep sea are present in hydrolysis-resistant amides, and so far the mechanisms of biodegradation of these types of nitrogen have not been resolved. The M12 family is the second largest family in subclan MA(M) of Zn-containing metalloproteases and includes most enzymes from animals and only one enzyme (flavastacin) from a human-pathogenic bacterium (Flavobacterium meningosepticum). Here, we characterized the novel M12 protease myroilysin with elastinolytic activity and collagen-swelling ability from the newly described deep-sea bacterium Myroides profundi D25. Myroilysin is a monomer enzyme with 205 amino acid residues and a molecular mass of 22,936 Da. It has the same conserved residues at the four zinc ligands as astacin and very low levels of identity (≤40%) to other metalloproteases, indicating that it is a novel metalloprotease belonging to subfamily M12A. Myroilysin had broad specificity and much higher elastinolytic activity than the bacterial elastinase pseudolysin. To our knowledge, it is the first reported elastase in the M12 family. Although it displayed very low activity with collagen, myroilysin had strong collagen-swelling ability and played a synergistic role with collagenase in collagen hydrolysis. It can be speculated that myroilysin synergistically interacts with other enzymes in its in situ biotic assemblage and that it may play an important role in the degradation of deep-sea HMW organic nitrogen.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

scholarly journals Achieving Good Protection on Ultra-High Molecular Weight Polythene by In Situ Growth of Amorphous Carbon Film

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 584
Author(s):  
Rui Dang ◽  
Liqiu Ma ◽  
Shengguo Zhou ◽  
Deng Pan ◽  
Bin Xia
Keyword(s):  
Molecular Weight ◽  
Epitaxial Growth ◽  
High Molecular Weight ◽  
Amorphous Carbon ◽  
Transition Layer ◽  
In Situ Growth ◽  
Good Protection ◽  
Ultra High Molecular Weight ◽  
Carbon Plasma

Ultra-high molecular weight polythene (UHMWPE), with outstanding characteristics, is widely applied in modern industry, while it is also severely limited by its inherent shortcomings, which include low hardness, poor wear resistance, and easy wear. Implementation of feasible protection on ultra-high molecular weight polythene to overcome its shortcomings would be of significance. In the present study, amorphous carbon (a-C) film was fabricated on ultra-high molecular weight polythene (UHMWPE) to provide good protection, and the relevant growth mechanism of a-C film was revealed by controlling carbon plasma currents. The results showed the in situ transition layer, in the form of chemical bonds, was formed between the UHMWPE substrate and the a-C film with the introduction of carbon plasma, which provided strong adhesion, and then the a-C film continued epitaxial growth on the in situ transition layer with the treatment of carbon plasma. This in situ growth of a-C film, including the in situ transition layer and the epitaxial growth layer, significantly improved the wetting properties, mechanical properties, and tribological properties of UHMWPE. In particular, good protection by in situ growth a-C film on UHMWPE was achieved during sliding wear.

Wear behavior of in situ polymerized carbon nanotube/ultra high molecular weight polyethylene composites

2013 ◽  
Vol 21 (9) ◽  
pp. 965-970 ◽  
Author(s):  
Hong-Jo Park ◽  
Jihun Kim ◽  
Yongsok Seo ◽  
Junho Shim ◽  
Moon-Yong Sung ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Nanotube ◽  
High Molecular Weight ◽  
Wear Behavior ◽  
Ultra High Molecular Weight ◽  
Polyethylene Composites

scholarly journals Preparation of Porous Polymers by ”in Situ Precipitation” Using Low Molecular Weight Gelators

2002 ◽  
Vol 34 (6) ◽  
pp. 474-477 ◽  
Author(s):  
Masahiro Suzuki ◽  
Yasuhiko Sakakibara ◽  
Satoshi Kobayashi ◽  
Mutsumi Kimura ◽  
Hirofusa Shirai ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Porous Polymers ◽  
Low Molecular Weight ◽  
Low Molecular Weight Gelators

Preparation and Properties of the Polystyrene/Alumina Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 519-522
Author(s):  
Xu Man Wang ◽  
Cai Ning Zhang
Keyword(s):  
Molecular Weight ◽  
Thermal Resistance ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Experimental Results ◽  
Solvent Resistance ◽  
Silane Coupling

Silane coupling agent KH-570 was applied to modify the surface capability of the alumina (Al2O3). The modified Al2O3were dispersed in styrene. The in-situ polymerization was used to prepare the polystyrene/alumina (PS/Al2O3) composites, in which azodiisobutyronitrile (AIBN) was used as initiator. FTIR, DSC and TG were applied to characterize the prepared composites. The solvent resistance, thermal resistance of the composites and the average molecular weight of PS in PS/Al2O3nanocomposites were studied. The experimental results demonstrated that the solvent resistance of PS/Al2O3nanocomposites was improved by the adding of Al2O3nanoparticles. The thermal resistance of the composites increased with the increasing of the Al2O3content. Meanwhile, the molecular weight of PS in the composites increased with the increasing of the Al2O3content.

Research on In Situ Anionic Polymerization of PA6/PI Alloy

2011 ◽  
Vol 295-297 ◽  
pp. 21-25
Author(s):  
Hong Kai Zhao ◽  
Li Guang Xiao ◽  
Hong Jie Wang
Keyword(s):  
Molecular Weight ◽  
Bisphenol A ◽  
High Performance ◽  
Hot Spot ◽  
Microscopic Analysis ◽  
Infrared Analysis ◽  
Elongation At Break ◽  
System Temperature ◽  
Lamellar Crystals

High performance trend of plastics has become a hot spot of current research. Select bisphenol A dianhydride and bisphenol A diamine with excellent water resistance as the reactant monomers to obtain anhydride-terminated polyimide with very high molecular weight by two-step polymerization, graft the active radicals of acyl caprolactam using the activity of anhydride and obtain PI modified nylon resin by polymerization.When the system temperature is above 160 °C and the added modifiers are greater than 10%, the system viscosity increases very fast; when the system temperature reaches 140 °C and the added modifiers are at 5%, the system viscosity increases very slowly. It is proved that the reaction in each above step is successful through infrared analysis. The mechanical properties of modified PI nylon increases with the increase of consumption and molecular weight of polyimide, when the molecular weight is selected to be about 8000~10000 and the adding amount is 10wt%~15 wt%, the tensile strength reaches over 85MPa, the notch impact strength is increased to 19.6kJ.m-2 and the elongation at break reaches 18%, which are remarkably better than general engineering plastics.Through microscopic analysis, the molecules of polyimide does not enter crystallization phase of nylon resin, but forms compact lamellar crystals existing in nylon matrix.

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

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