Free radical induced degradation of high molecular weight partial hydrolysis polyacrylamide (HPAM) in a ferrous iron containing system

2021 ◽  
Author(s):  
Yifeng Cai ◽  
Zuohua Wang ◽  
Jian Zhang ◽  
Qingfang Li ◽  
Qiuhong Zhang
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
High Molecular Weight ◽  
Ferrous Iron ◽  
Partial Hydrolysis

scholarly journals The High-Molecular-Weight Cytochrome c Cyc2 of Acidithiobacillus ferrooxidans Is an Outer Membrane Protein

2002 ◽  
Vol 184 (1) ◽  
pp. 313-317 ◽  
Author(s):  
Andrés Yarzábal ◽  
Gaël Brasseur ◽  
Jeanine Ratouchniak ◽  
Karen Lund ◽  
Danielle Lemesle-Meunier ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Outer Membrane ◽  
High Molecular Weight ◽  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Membrane Fraction ◽  
Cytoplasmic Membrane ◽  
Respiratory Pathway ◽  
Membrane Components ◽  
Membrane Level

ABSTRACT A high-molecular-weight c-type cytochrome, Cyc2, and a putative 22-kDa c-type cytochrome were detected in the membrane fraction released during spheroplast formation from Acidithiobacillus ferrooxidans. This fraction was enriched in outer membrane components and devoid of cytoplasmic membrane markers. The genetics, as well as the subcellular localization of Cyc2 at the outer membrane level, therefore make it a prime candidate for the initial electron acceptor in the respiratory pathway between ferrous iron and oxygen.

The structures of the two lipopolysaccharide O-chains produced by Salmonella boecker

1988 ◽  
Vol 66 (10) ◽  
pp. 1066-1077 ◽  
Author(s):  
Jean-Robert Brisson ◽  
Malcolm B. Perry
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Molecular Weight ◽  
Nitrous Acid ◽  
Optical Rotation ◽  
Partial Hydrolysis ◽  
Magnetic Resonance Studies ◽  
High Molecular Weight Polymers ◽  
Nuclear Magnetic

Salmonella boecker, which belongs to group 0:6, 14(H) and shows the antigenic factors 6, 14, [1], and [25], defined by the Kauffmann–White system, produces two lipopolysaccharides differing from each other in the structures of their 0-polysaccharide moieties. By glycose composition, partial hydrolysis, nitrous acid deamination, methylation, optical rotation, and 1H and 13C nuclear magnetic resonance studies, the O-polysaccharides were demonstrated to be high-molecular-weight polymers (I and II) composed of either structurally related repeating tetrasaccharide or repeating pentasaccharide units having the structuresand[Formula: see text][Formula: see text]

High‐Molecular‐Weight Polyampholytes Synthesized via Daylight‐Induced, Initiator‐Free Radical Polymerization of Renewable Itaconic Acid

2020 ◽  
Vol 41 (4) ◽  
pp. 1900611 ◽  
Author(s):  
Kacper Mielczarek ◽  
Maria Łabanowska ◽  
Magdalena Kurdziel ◽  
Rafał Konefał ◽  
Hynek Beneš ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
High Molecular Weight ◽  
Radical Polymerization ◽  
Itaconic Acid ◽  
Free Radical Polymerization

scholarly journals Synthesis of new high molecular weight phosphorylated chitosans for improving corrosion protection

2019 ◽  
Vol 91 (3) ◽  
pp. 509-521 ◽  
Author(s):  
Clément Coquery ◽  
Claire Negrell ◽  
Nicolas Caussé ◽  
Nadine Pébère ◽  
Ghislain David
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Corrosion Protection ◽  
Phosphonic Acid ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Metallic Surface ◽  
Partial Hydrolysis ◽  
Solution Ph ◽  
Lower Efficiency

Abstract Two grades of chitosan [chitosan 30000 g mol−1 (N-chitosan 30) and 250000 g mol−1 (N-chitosan 250)] were functionalized by the Kabachnik–Fields reaction. To obtain the highest phosphonic ester grafting rate (55% and 40% for the N-chitosan 30 and N-chitosan 250, respectively), the pH must be kept constant during the reaction (pH=5). Then, a partial hydrolysis of the ester functions was carried out in HCl medium to generate phosphonic acid functions up to 25% and 20% for the N-chitosan 30 and N-chitosan 250, respectively. It was shown that the grafting of phosphonic acids on chitosan significantly reduced the dynamic viscosity. Afterwards, electrochemical impedance measurements were performed in an aqueous solution (pH=5) in the presence of either N-chitosans or P-chitosans (3 wt.%). The two native N-chitosans were little adsorbed onto the carbon steel surface and the corrosion protection was low. In contrast, the impedance results in the presence of the 30000 g mol−1 phosphorylated chitosan (P-chitosan 30) evidenced the beneficial effect of grafted phosphonic acid on its adsorption on the steel surface. The lower efficiency of the 250000 g mol−1 (P-chitosan 250) was attributed to its high molecular weight which made difficult the interactions between the phosphonic groups and the metallic surface.

Synthesis of Super-High Molecular Weight Polyacrylamides and their Flocculation Properties

2011 ◽  
Vol 396-398 ◽  
pp. 1667-1671 ◽  
Author(s):  
Yan Lin Sun ◽  
Hui Xiang Du ◽  
Hong Wang ◽  
Yun Hua Huang
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Dissolution Rate ◽  
High Molecular Weight ◽  
Monomer Concentration ◽  
Insoluble Fraction ◽  
Solution Polymerization ◽  
Clear Water ◽  
Sodium Hydrogen ◽  
Radical Solution

The super-high molecular weight polyacrylamide flocculants were synthesized using potassium persulfate/sodium hydrogen sulfite as initiators via free radical solution polymerization. The effects of monomer concentration and initiator dosage on the molecular weight, insoluble fraction and dissolution rate of PAM were investigated. The flocculation properties of PAMs prepared was examined by flocculating kaolin suspensions. The results show that the PAM products synthesized at the monomer concentration 30% and the initiator dosage 0.5‰ can meet the requirements. The molecular weight of this kind of PAM can reach 5.84×106, insoluble fraction can decrease to 0, and the dissolution can be completed in 10 minutes. Using this kind of PAM as flocculants (1.45mg PAM/100g kaolin suspension), the clear water transmittance can be up to 99% at pH 3.5~4.0.

Studies on flocculation of clay suspension by polyacrylamide

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
T. Niranjana Prabhu ◽  
Y. Jagannadha Rao ◽  
K. Prashantha
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
High Molecular Weight ◽  
Radical Polymerization ◽  
Settling Rate ◽  
Clay Suspension ◽  
Redox Pair ◽  
Key Factor ◽  
The Given ◽  
Different Molecular Weight

Abstract The flocculation of dilute pottery clay suspension using polyacrylamide (PAM) was investigated. Different molecular weight PAMs were synthesized by free-radical polymerization initiated with the persulfate-bisulfate redox pair. The synthesized polyelectrolytes (PAM1, PAM2 and PAM3, from low to high molecular weight) and a commercial one (C-492) were used for flocculation studies. The flocculating performance of polyelectrolytes was measured on 3% w/v pottery clay suspension using settling tests and turbidity measurements. PAM2 at pH 5.0 showed the maximum settling rate, which is nearly three times that of C-492, and it also showed a better turbidity reduction. Molecular weight is the key factor in influencing settling and turbidity reduction. In the present study, increasing molecular weight enhanced settling rate and turbidity reduction to a certain level beyond which there is a decrease, suggesting an optimum molecular weight for the given application. PAM2, a medium molecular weight polyelectrolyte (2.0·105 g/mol) has shown better performance than PAM1 (1.3·105 g/mol), PAM3 (6.0·105 g/mol) and the commercial polyelectrolyte C-492 (molecular weight of order 106).

Sign in / Sign up

Export Citation Format

Share Document