A new type of chitosan-modified hyperbranched polymer (named HPDACS) was synthesized through the free-radical polymerization of surface-modified chitosan with acrylic acid (AA) and acrylamide (AM) to achieve an enhanced oil recovery. The optimal polymerization conditions of HPDACS were explored and its structure was characterized by Fourier-transform infrared spectroscopy, hydrogen nuclear magnetic resonance, and environmental scanning electron microscopy. The solution properties of HPDACS in ultrapure water and simulated brine were deeply studied and then compared with those of partially hydrolyzed polyacrylamide (HPAM) and a dendritic polymer named HPDA. The experimental results showed that HPDACS has a good thickening ability, temperature resistance, and salt resistance. Its viscosity retention rate exceeded 79.49% after 90 days of aging, thus meeting the performance requirements of polymer flooding. After mechanical shearing, the viscosity retention rates of HPDACS in ultrapure water and simulated brine were higher than those of HPAM and HPDA, indicating its excellent shear resistance and good viscoelasticity. Following a 95% water cut after preliminary water flooding, 0.3 pore volume (PV) and 1500 mg/L HPDACS solution flooding and extended water flooding could further increase the oil recovery by 19.20%, which was higher than that by HPAM at 10.65% and HPDA at 13.72%. This finding indicates that HPDACS has great potential for oil displacement.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570182 | PMC |
http://dx.doi.org/10.3390/polym12092130 | DOI Listing |
Anal Chim Acta
February 2025
Food Inspection and Quarantine Technology Center of Shenzhen Customs, Shenzhen Academy of Inspection and Quarantine, Shenzhen, 518045, PR China.
Background: Ochratoxin A (OTA) is toxic secondary metabolites produced by fungi and can pose a serious threat to food safety and human health. Due to the high stability and toxicity, OTA contamination in agricultural products is of great concern. Therefore, the development of a highly sensitive and reliable OTA detection method is crucial to ensure food safety.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Civil, Environmental and Architectural Engineering, University of Padova, Via Marzolo 9, 35131, Padova, Italy.
The materials removed in the oil separation units of wastewater treatment plants can be referred to as fat, oil and grease (FOG) waste. FOG waste accumulation in treatment plants can cause clogging of pipes, production of excessive scums and foams, and negatively affect air/liquid oxygen transfer. While conventional disposal routes of this material can be limited by its water and organic content, FOG can represent a source of bio-energy other than bio-diesel production.
View Article and Find Full Text PDFJ Chromatogr A
January 2025
College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, PR China. Electronic address:
α-Terpineol and 1,8-cineole are two important compounds in essential oils. This study developed an efficient method to recover α-terpineol from model oil (MO) based on association extraction by in situ formations of deep eutectic solvent (DES) between α-terpineol and some quaternary ammonium salts (QASs) by hydrogen-bond (HB) interaction. Such interaction could be broken almost completely by the introduction of water, due to the stronger HB interaction between water and QASs, which could release α-terpineol by liquid-liquid separation and save the organic solvents consumption.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Departamento de Química, Universidade Federal de Viçosa, Campus Universitário, Avenida Peter Henry Rolfs, s/n, Viçosa 36570-900, MG, Brazil.
Soxhlet extraction is a method recommended by the Association of Official Analytical Chemists (AOAC) to determine the lipid content in plant samples. Generally, n-hexane (toxicity grade 5) is used as the solvent (≈300 mL; ≈30 g sample) at boiling temperatures (69 °C) for long times (≤16 h) under a chilled water reflux (≈90 L/h), proportionally aggravated by the number of repetitions and samples determined. In this sense, the technique is neither safe nor sustainable for the analyst or the environment.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
State Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum (Beijing), Beijing 102249, China.
The Bohai oilfield is characterized by severe heterogeneity and high average permeability, leading to a low water flooding recovery efficiency. Polymer flooding only works for a certain heterogeneous reservoir. Therefore, supplementary technologies for further enlarging the swept volume are still necessary.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!