Hydrophilic porous PVDF membrane embedded with BaTiO3 featuring controlled oxygen vacancies for piezocatalytic water cleaning

Surface modification of poly(vinylidene fluoride) (PVDF) membrane was accomplished by the adsorption of ferric hydroxide sol to impove its hydrophilicity. The adsorption curves of the membranes were analyzed by weight measurements, and the typical results showed a two-platform character in low concentration. The effects of the adsorption time, the ferric hydroxide sol concentration, the test temperature, as well as the water cleaning time on the adsorption amount were observed. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/ FTIR) analysis showed that the adsorption of ferric hydroxide sol on poly(vinylidene fluoride) microporous membranes (PVDFMM) is effective. The membranes hydrophilic performance was represented by water contact angle measurements. The water contact angles changes from the virgin 128°to the lowest value 81.90° in the range of 0~0.10 mol/L ferric hydroxide aqueous solution. The results indicated that ferric hydroxide sol can be immobilized on the PVDF films by adsorption, and the membrane hydrophilic performence increases with the increase of the adsorption amount of the ferric hydroxide sol onto the PVDF membrane surface.

Download Full-text

Highly Effective Anti-Organic Fouling Performance of a Modified PVDF Membrane Using a Triple-Component Copolymer of P(Stx-co-MAAy)-g-fPEGz as the Additive

Membranes ◽

10.3390/membranes11120951 ◽

2021 ◽

Vol 11 (12) ◽

pp. 951

Author(s):

Xiaoji Zhou ◽

Yizhuo Sun ◽

Shusu Shen ◽

Yan Li ◽

Renbi Bai

Keyword(s):

Contact Angle ◽

Polymeric Membranes ◽

Water And Wastewater Treatment ◽

Water Contact ◽

Water Emulsion ◽

Pvdf Membrane ◽

Water Cleaning ◽

Good Potential ◽

And Performance ◽

Lower Ratio

In this study, a triple-component copolymer of P(Stx-co-MAAy)-g-fPEGz containing hydrophobic (styrene, St), hydrophilic (methacrylic acid, MAA), and oleophobic (perfluoroalkyl polyethylene glycol, fPEG) segments was synthesized and used as an additive polymer to prepare modified PVDF membrane for enhanced anti-fouling performance. Two compositions of St:MAA at 4:1 and 1:1 for the additive and two blending ratios of the additive:PVDF at 1:9 and 3:7 for the modified membranes were specifically examined. The results showed that the presence of the copolymer additive greatly affected the morphology and performance of the modified PVDF membranes. Especially, in a lower ratio of St to MAA (e.g., St:MAA at 1:1 versus 4:1), the additive polymer and therefore the modified PVDF membrane exhibited both better hydrophilic as well as oleophobic surface property. The prepared membrane can achieve a water contact angle at as low as 48.80° and display an underwater oil contact angle at as high as 160°. Adsorption experiments showed that BSA adsorption (in the concentration range of 0.8 to 2 g/L) on the modified PVDF membrane can be reduced by as much as 93%. From the filtration of BSA solution, HA solution, and oil/water emulsion, it was confirmed that the obtained membrane showed excellent resistance to these organic foulants that are often considered challenging in membrane water treatment. The performance displayed slow flux decay during filtration and high flux recovery after simple water cleaning. The developed membrane can therefore have a good potential to be used in such applications as water and wastewater treatment where protein and other organic pollutants (including oils) may cause severe fouling problems to conventional polymeric membranes.

Download Full-text

Conditions for atomic imaging of mullite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154068 ◽

1989 ◽

Vol 47 ◽

pp. 418-419

Author(s):

T. A. Epicier ◽

G. Thomas

Keyword(s):

Oxygen Vacancies ◽

High Resolution Electron Microscopy ◽

Ceramic Materials ◽

Work Conditions ◽

Real Space ◽

Potential Candidate ◽

Silicate Mineral ◽

Resolution Electron ◽

The Subject ◽

Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

Download Full-text

Investigation of Some Characterizations of Black TiO\(_2\) Nanotubes Via Spectroscopic Methods

Communications in Physics ◽

10.15625/0868-3166/29/2/13762 ◽

2019 ◽

Vol 29 (2) ◽

pp. 189 ◽

Cited By ~ 1

Author(s):

Tho Truong Nguyen ◽

Thi Minh Cao ◽

Hieu Van Le ◽

Viet Van Pham

Keyword(s):

Water Splitting ◽

Oxygen Vacancies ◽

Light Response ◽

Nanotube Arrays ◽

Spectroscopic Methods ◽

Visible Light Response ◽

Uv Visible ◽

Visible Reflectance ◽

Splitting Effect ◽

Anodization Method

The black TiO\(_2\) with substantial Ti\(^3+\) and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport the extended visible light response. In this study, black TiO\(_2\) nanotube arrays synthesized by the anodization method, and then, they have been investigated some characterizations by spectroscopic methods such as UV-visible reflectance (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectrum. The results showed that some highlighted properties of the black TiO2 nanotube arrays and they could apply for water-splitting effect.

Download Full-text