Study on Removal of Organics of Different Molecular Weight by Coagulation-Membrane Filtration Process

The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (Mw) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA30-b-POEGA70 and PnBA27-b-POEGA73 (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA27-b-POEGA73 micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA30-b-POEGA70 + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA30-b-POEGA70 and PnBA27-b-POEGA73 micelles.

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Study of Solid Polyurethane Electrolytes Synthesized from HDI and PEO of Different Molecular Weight

Journal of Electroanalytical Chemistry ◽

10.1016/j.jelechem.2021.115305 ◽

2021 ◽

pp. 115305

Author(s):

Qian Zhang ◽

Yuhao Wen ◽

Kang Liu ◽

Nailiang Liu ◽

Yaping Du ◽

...

Keyword(s):

Molecular Weight ◽

Different Molecular Weight

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Effect of PDADMAC with different molecular weight regulating Hβ Properties on hydrogenation performance of NiMoC/Hβ catalysts

Fuel Processing Technology ◽

10.1016/j.fuproc.2020.106704 ◽

2021 ◽

Vol 213 ◽

pp. 106704

Author(s):

Chenguang Jiang ◽

Yonggang Wang ◽

Haiyong Zhang ◽

Xiongchao Lin ◽

KeChang Xie

Keyword(s):

Molecular Weight ◽

Different Molecular Weight

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Investigating Lignin-Derived Monomers and Oligomers in Low-Molecular-Weight Fractions Separated from Depolymerized Black Liquor Retentate by Membrane Filtration

Molecules ◽

10.3390/molecules26102887 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2887

Author(s):

Kena Li ◽

Jens Prothmann ◽

Margareta Sandahl ◽

Sara Blomberg ◽

Charlotta Turner ◽

...

Keyword(s):

Molecular Weight ◽

High Performance ◽

Membrane Filtration ◽

Black Liquor ◽

Complex Mixture ◽

Value Added ◽

Kraft Pulping ◽

Classification Model ◽

Low Molecular Weight ◽

Chemical Complexity

Base-catalyzed depolymerization of black liquor retentate (BLR) from the kraft pulping process, followed by ultrafiltration, has been suggested as a means of obtaining low-molecular-weight (LMW) compounds. The chemical complexity of BLR, which consists of a mixture of softwood and hardwood lignin that has undergone several kinds of treatment, leads to a complex mixture of LMW compounds, making the separation of components for the formation of value-added chemicals more difficult. Identifying the phenolic compounds in the LMW fractions obtained under different depolymerization conditions is essential for the upgrading process. In this study, a state-of-the-art nontargeted analysis method using ultra-high-performance supercritical fluid chromatography coupled to high-resolution multiple-stage tandem mass spectrometry (UHPSFC/HRMSn) combined with a Kendrick mass defect-based classification model was applied to analyze the monomers and oligomers in the LMW fractions separated from BLR samples depolymerized at 170–210 °C. The most common phenolic compound types were dimers, followed by monomers. A second round of depolymerization yielded low amounts of monomers and dimers, while a high number of trimers were formed, thought to be the result of repolymerization.

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Investigation on the tunable effect of oxidized konjac glucomannan with different molecular weight on gelatin-based composite hydrogels

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2020.12.056 ◽

2021 ◽

Vol 168 ◽

pp. 233-241

Author(s):

Gaiying Li ◽

Yongchao Jiang ◽

Mengya Li ◽

Wenjie Zhang ◽

Qian Li ◽

...

Keyword(s):

Molecular Weight ◽

Konjac Glucomannan ◽

Composite Hydrogels ◽

Oxidized Konjac Glucomannan ◽

Different Molecular Weight

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Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18136807 ◽

2021 ◽

Vol 18 (13) ◽

pp. 6807

Author(s):

Jingtao Duan ◽

Zhiyuan Xu ◽

Zhen Yang ◽

Jie Jiang

Keyword(s):

Molecular Weight ◽

Electron Transfer ◽

Humic Acids ◽

Weight Fraction ◽

Electrochemical Analysis ◽

Microbial Reduction ◽

Redox Potentials ◽

Groundwater Environment ◽

Redox Active ◽

Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

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