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Thesis FINAL - revised-Cong ZHANG.pdf (5.56 MB)

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Fibrous Microfilters by Multiplier Co-extrusion

Zhang, Cong
http://rave.ohiolink.edu/etdc/view?acc_num=case1554825751223345

Abstract Details

2019, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
A novel environmentally friendly co-extrusion and 2-dimentional multiplication technology in combination with a water jet procedure was utilized to produce dual-component nano/micro- fibrous filters for various applications including microfiltration water purification and water in fuel filtration. Polyvinylidene fluoride (PVDF)/ high density polyethylene (HDPE) dual-component fiber system were developed for microfiltration water purification. Due to the feature that the microfiltration mechanism is mainly size exclusion, a small filter pore size is vital important for achieving high filtration efficacy. A physical treatment method was utilized to decrease pore size. The filter pore size was successfully decreased to 0.2 μm from 7.7 μm. This PVDF/HDPE filters exhibit high water flux with low pressure requirement and high capacity of particle retention. Under the driving desire of removing micro water droplets from fuel, different fibrous filter systems were studied to probe the filtration mechanism. A hydrophobic PP/PVDF fibrous filter was firstly studied. The inversely correlation between filtration efficiency and pore size revealed that pore size plays an important role in promoting water-in-fuel filtration. Consequently, PP/PA6 fibrous filters were created with the ability to change the hydrophilicity by varying PP and PA6 composition from 10/90 to 90/10. The filtration mechanism varied with different PA6 composition. When the PA6 is only 10 ~ 20%, the filtration efficiency increases with increasing PA6 composition due to improved water capture. When the PA6 is 30% to 70%, the highest filtration efficiency was found at 50% PA6 as a result of competition of improved water droplet capture and good coalescence. When PA6 is higher than 70%, the water blockage starts to dominate making captured water hard to be released. Another approach to impart superhydrophobicity and electrical conductivity to PVDF/HDPE filters was developed for antibacterial purpose. Electrical conductivity was achieved by adding multiwall carbon nanotubes and superhydrophobicity was obtained by methyltrichlorosilane treatment. This electrically conductive and superhydrophobic HDPE/PVDF fibrous material is characterized by WCA of 164° and low surface resistivity of 87.4 Ω/sq. Electrochemical modification using cyclic voltammetry resulted in the formation of nanoparticles silver on the fibers surfaces which imparted antibacterial properties against Staphylococcus aureus and Escherichia coli.
Eric Baer (Advisor)
161 p.
Polymers
Microfiber, Microfilter, Water filtration, Fuel filtration

Recommended Citations

Citations

  • Zhang, C. (2019). Fibrous Microfilters by Multiplier Co-extrusion [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1554825751223345

    APA Style (7th edition)

  • Zhang, Cong. Fibrous Microfilters by Multiplier Co-extrusion. 2019. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1554825751223345.

    MLA Style (8th edition)

  • Zhang, Cong. "Fibrous Microfilters by Multiplier Co-extrusion." Doctoral dissertation, Case Western Reserve University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554825751223345

    Chicago Manual of Style (17th edition)

case1554825751223345
322
© 2019, some rights reserved.Creative Commons License Fibrous Microfilters by Multiplier Co-extrusion by Cong Zhang is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.