Characterization of broad molecular weight distribution polyethylene with multi-detection gel permeation chromatography

Cheng, Xi-Pei; Zhang, Huibo; Hu, Jijiang; Feng, Lianfang; Gu, Xue‐Ping; Corriou, Jean‐Pierre

doi:10.1016/j.polymertesting.2018.02.017

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…If the PDI value is close to 1, it indicates that the molecular weight distribution of the substance is narrow. If the PDI value is ≥ 2, it indicates that the molecular weight distribution of the substance is broad (Cheng et al, 2018). The PDI value of HA extracted from sludge in this paper was 2.0879, which indicated that the molecular weight distribution of HA was wide.…”

Section: Analysis Of Gpcmentioning

confidence: 70%

Hydrothermal-alkaline conversion of sewage sludge: Focus on optimization of process parameters and characterization of humic acid

Qiu

Xu²,

Wang³

et al. 2021

Preprint

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Sewage sludge (SS) dewatering is a key step in sludge disposal, which plays an important role in reducing sludge volume, facilitating transportation and subsequent treatment. In recent years, many studies have focused on sludge hydrothermal dewatering, while resource recovery during this process is less studied, especially humic substances. In this paper, a facile and low-cost hydrothermal-alkaline treatment for SS was proposed, which can be used for sludge dewatering and humic acid (HA) recycling at the same time. Response surface methodology (RSM) was used to determine the optimal conditions, and a mathematical model was established to accurately predict the change of sludge water content and the extraction rate of HA. Under the optimal conditions of 170 °C/42 min/0.05 (for hydrothermal temperature, hydrothermal time and mass ratio of KOH to wet sludge, respectively), the water content decreased to 46.7% and the extraction rate of HA (with a purity of 96.2%) was 89.1%. The improvement of the dewatering performance effectively facilitates the subsequent disposal of the sludge. The extraction of HA not only solves the problem that the sludge separation liquid needs further treatment, but also has potential economic value in agriculture, biological medicine, environment and other fields.

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Section: Analysis Of Gpcmentioning

confidence: 70%

Hydrothermal-alkaline conversion of sewage sludge: Focus on optimization of process parameters and characterization of humic acid

Qiu

Xu²,

Wang³

et al. 2021

Preprint

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“…20 Here, we demonstrate the importance of measuring the refractive index increment, dn/dc, to measure the amount of polymer exiting the columns and thereby identify whether any material is lost during the measurement. 21 Furthermore, we show that PS swells more than some conjugated polymers in the carrier solvent, chlorobenzene, 22 and leads to a fortuitous agreement between accurate molecular weights and PS-relative calibrations. As such, this work proposes an explanation of the intermittent success of molecular weight determination of conjugated polymers from GPC using PS standards while also establishing procedures for extracting absolute molecular weights using a universal calibration.…”

Section: ■ Introductionmentioning

confidence: 66%

“…Here, we demonstrate the importance of measuring the refractive index increment, d n /d c , to measure the amount of polymer exiting the columns and thereby identify whether any material is lost during the measurement . Furthermore, we show that PS swells more than some conjugated polymers in the carrier solvent, chlorobenzene, and leads to a fortuitous agreement between accurate molecular weights and PS-relative calibrations.…”

Section: Introductionmentioning

confidence: 72%

Molecular Weight Characterization of Conjugated Polymers Through Gel Permeation Chromatography and Static Light Scattering

Fair

Xie

Lee

et al. 2021

ACS Appl. Polym. Mater.

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Molecular weight is a key parameter of any polymer. Characterizing the molecular weight of conjugated polymers is often nontrivial due to their semiflexible backbones and poor solubilities. Perhaps the most used technique for measuring the molecular weight is gel permeation chromatography (GPC), and results are often calibrated relative to flexible polymer standards. This mismatch between chain flexibilities of samples and standards, combined with poor sample solubility in the mobile phase, leads to inaccuracies in many GPC measurements of conjugated polymers. In this work, we use a universal calibration combined with in-line concentration measurements to yield reliably accurate results for polymers of various stiffnesses. Accuracy of results is verified with absolute molecular weights obtained from static light scattering. We show that measuring the refractive index increment is key to confirm full recovery of the polymer and ensure accurate values of the absolute molecular weight from GPC.

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“…Molecular weight (MW) distribution in the leachate was determined by gel permeation chromatography (SHIMADZU, LC-10ADVP). MW is analyzed according to previous literature [17].…”

Section: Methodsmentioning

confidence: 99%

A Combined Catalytic Ozonation-MBR Approach to Remove Contaminants from the Mature Landfill Leachate in the Yellow River Basin

et al. 2022

Toxics

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The mature landfill leachate (MLL) is characterized by a large number of fulvic acids and humic acids, which is refractory organic matter and can be cleaned by ozone oxidation. However, the poor property of mass transfer prohibits the widespread use of ozone oxidation in actual leachate treatment. Meanwhile, some combined processes are adopted to treat the mature landfill leachate, which places catalytic ozonation before the membrane bioreactor (MBR) process to enhance the biodegradability of MLL. Thus, this research is conducted to investigate the practicability of applying nano-Fe3O4 loaded cow-dung ash (Fe3O4@CDA) and biological post-treatment with MBR for the effective removal of pollutants from MLL and puts forward the variation of organics in leachate between catalytic ozonation and MBR. The addition of catalytic ozonation not only improved the removal of hazardous organics but also enhanced the biodegradability of the leachate and favored the subsequent MBR process. Chemical oxygen demand (COD) removal in the catalytic ozonation step was optimized, and 53% removal was obtained at pH = 7, catalyst dosage = 1.0 g/L, and O3 dosage = 3.0 g/L. After the MBR process, COD in effluent stabilized in the range of 57.85–65.38 mg/L, and the variation range of the ammonia nitrogen (NH3-N) concentration was 5.98–10.24 mg/L. The catalytic ozonation-MBR integrated process showed strong feasibility in dealing with the biologically pre-treated leachate.

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Characterization of broad molecular weight distribution polyethylene with multi-detection gel permeation chromatography

Cited by 7 publications

References 15 publications

Hydrothermal-alkaline conversion of sewage sludge: Focus on optimization of process parameters and characterization of humic acid

Hydrothermal-alkaline conversion of sewage sludge: Focus on optimization of process parameters and characterization of humic acid

Molecular Weight Characterization of Conjugated Polymers Through Gel Permeation Chromatography and Static Light Scattering

A Combined Catalytic Ozonation-MBR Approach to Remove Contaminants from the Mature Landfill Leachate in the Yellow River Basin

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