Study on phosphorylated Zr-doped hybrid silicas/PSF composite membranes for treatment of wastewater containing oil
Introduction
Wastewater containing oil produced from industry pollutes the environment and is difficult to be treated. Many conventional methods including gravity settling, dewatering and incineration perform cannot efficiently treat emulsified and soluble oil in wastewater. Membrane technology is currently utilized in treating wastewater containing oil; this is because wastewater containing oil may be effectively treated using membrane technology [1]. However, membranes are easy to be contaminated by oil, which forms an oil-layer on membrane surface [2]. Hence, the enhancement of the hydrophilic and anti-fouling property of PSF membranes has become a focus of many researchers.
The method of doping inorganic oxide particles to polymer to prepare organic–inorganic composite membranes is attractive, owing to its simple operating process and preparation technology. Bottino et al. [3] improved membrane's thermodynamic property, mechanical strength, tenacity and so on by adding nanosilica to poly(vinyl alcohol) membrane. Nunes et al. [4] prepared composite membrane with SiO2 nano-dispersed in polyetherimides (PEI) and the resistance of the membrane to compactability has increased to some extent. Zhang and Ding [5] doped A12O3 to PSF membrane to enhance the hydrophilic property and anti-fouling ability of the membrane.
Though the capability of polymer membranes can be enhanced by adding inorganic oxide particles, further enhancement is limited because there are few Lewis acid sites and hydroxide radicals on the surface of stoichiometric monocomponent inorganic oxide particles [6]. Nonstoichiometric inorganic oxide nanoparticles have many point defects inside and lots of exposed hydroxide radicals on the surface, so these nanoparticles show stronger activity in the course of chemical bonding than stoichiometric monocomponent inorganic oxide particles [7], [8]; especially when nonstoichiometric inorganic oxide nanoparticles are filled in polymer membranes, the capability of membranes is evidently improved. Recently, Zhang et al. doped small-sized particles such as Ce-doped nonstoichiometric nanosilica, Y-doped nonstoichiometric zirconnia to PSF membrane to prepare composite membranes for enhancing its hydrophilic property and anti-fouling ability [9], [10].In this paper, a novel composite membrane (SZP/PSF) was prepared by adding SZP particles to the porous matrix of PSF to enhance the capability of PSF membrane, such as hydrophilic property, anti-fouling ability and tensile strength. The properties of membranes were evaluated by permeability, tensile strength, hydrophilic property and so on. Further more, these composite membranes could be used to treat wastewater containing oil.
Section snippets
Materials and reagents
PSF was purchased from Dalian Polysulfone Co., Ltd. and its MW and polydispersity were 84,400 Da and 1.37, respectively. SZP particles with the diameter from 1 to 3 μm were prepared in our laboratory. Bovine serum albumin (BSA), bought from Beijing Aobo Star Biotechnology GmbH. Polyethylene glycol with average MW 400 Da (PEG400) was supplied by Tianjin Jinyu Fine Chemical Factory. N,N-dimethylacetamide (DMAC) was obtained from Tianjin Damao Service of Chemical Instruments. The last two kinds of
Analysis of tensile strength
As indicated in Table 1, the tensile strength of the membrane increases as the addition amount of the SZP particles increases. It can be explained that the SZP particles with small size and large curvature can effectively decentralize the stress and impact from outside and make the composite membranes have the good capability of anti-impact and the tensile strength. The maximum tensile strength of SZP/PSF composite membrane prepared by the solution containing 10 wt.% SZP particles reaches 3.310
Conclusion
SZP/PSF composite membrane with high activity and hydrophilic property can be synthesized by adulterating SZP to PSF membrane. Tensile strength, hydrophilic property, porosity and pore diameter of the composite membrane are improved when SZP particles are adulterated to PSF membrane. SEM micrographs indicate that SZP/PSF composite membrane has the asymmetry structure with compact skin layer and porous substrate. SZP particles are uniformly dispersed in PSF membrane. The optimum operating
Acknowledgments
This project is supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (No. 2009-1341), by the Basic Research of Tianjin Municipal Science and Technology Commission (No. 07JCYBJC00700), by Petro China Innovation Fund (No. 060511-6-3), and by the Program of Introducing Talents of Discipline to Universities (No. B06006).
References (15)
- et al.
Preparation and characterization of novel porous PVDF-ZrO2 composite membranes
Desalination
(2002) - et al.
Membranes of poly(ether imide) and nanodispersed silica
J. Membr. Sci.
(1999) - et al.
Nonstoichiometry and P–T–x diagrams of binary systems
Intermetallics
(2003) - et al.
Characterization of point defects in nonstoichiometric compounds from thermodynamic considerations
J. Phys. Chem. Solids
(1967) - et al.
Preparation and characterization of novel Ce-doped nonstoichiometric nanosilica/polysulfone composite membranes
Sep. Purif. Technol.
(2008) - et al.
Development of a sulfated Y-doped nonstoichiometric zirconia/polysulfone composite membrane for treatment of wastewater containing oil
Sep. Purif. Technol.
(2009) - et al.
Study on the build of channels in accurate separation membrane and its selective mechanism
J. Membr. Sci.
(2009)
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2018, Progress in Natural Science: Materials InternationalCitation Excerpt :However, the application of these traditional metal oxides is restrained, which is ascribed to their limited hydrogen bonds on the surface. To overcome this drawback, Zhang et al. embedded nonstoichiometric oxides such as CexSi1-xO2 [12], sulfated YxZr1-xO2 [13] and phosphorylated ZrxSi1-xO2 [14] into polymer membrane and found that the integrated performance of the membrane is effectively improved. Unfortunately, embedding these nanomaterials into polymer membranes enhance the comprehensive properties only via physical interactions at the interface between aqueous solution and the polymer/nanomaterial, without any chemical reactions between them, restraining the further improvement of polymer membranes.