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Chen P.-P.,Ocean University of China | Xu J.,Ocean University of China | Jiang Y.-Y.,Ocean University of China | Feng C.-C.,Ocean University of China | And 2 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2013

Polyethylenimine(PEI) polyelectrolyte layer was firstly formed on a polyacrylonitrile(PAN) substrate. Copper(II) ions were immobilized onto the PEI layer via two different approaches for the anti-biofouling membrane preparation, including static immersion and dynamic electro-deposition. Finally, a novel ultrafiltration membrane with Cu2+ immobilization was obtained. The results indicated that both the PEI layer and Cu2+ on the resulting membrane had relatively high stability. The rejection rate to humic acid of this membrane up to 99.0%, and this membrane also had an excellent bacteriostatic property, the bacteriostasis rate was 85.7%. In addition, compared to the static immersion method, dynamic electro-deposition method was a much more effective method for immobilizing Cu2+, which could reduce the Cu2+ immobilization time and significantly improve the immobilization efficiency. Source

Dong H.,Zhejiang University | Zhang L.,Zhejiang University | Chen H.,Zhejiang University | Gao C.,Zhejiang University | Gao C.,Hangzhou Water Treatment Technology Development Center
Progress in Chemistry | Year: 2014

1Reverse osmosis (RO) and nanofiltration (NF) are widely used in many water treatment processes, such as seawater and brackish water desalination. Membranes with improved separation performance and anti-fouling properties can be prepared by incorporating nanoparticles into membrane matrix. A number of nanomaterials can serve as potential water transport channels and modify the structure and surface properties of the membrane thin film layers. Mixed-matrix membranes (MMMs) can benefit from the high performance of both the organic matrix and inorganic fillers, which are believed to be the next generation of novel membrane materials. Recent advances of the nanoparticle-filled RO, NF and forward osmosis (FO) MMMs are reviewed in this paper. The effects of nanomaterials with various properties on membrane structure and separation performance are discussed, including zeolites, nanotubes, mesoporous materials, pure metal, metallic oxides, graphene oxide and aquaporin. The dispersibility of nanofillers in MMMs and their compatibility with polymer matrix can be improved by surface modification. Different methods of nanoparticle addition and membrane preparation are also illustrated in detail. Based on the analysis of the recent works, the membrane formation and separation mechanisms are explored and the main problems of membrane synthesis and application are summarized. Finally, the future development of RO, NF and FO MMMs for water treatment process is suggested. ©, 2014, Chinese Academy of Sciences. All right reserved. Source

Tao J.,Hefei University of Technology | Huang N.,Hefei University of Technology | Li J.,Hefei University of Technology | Li J.,Hangzhou Water Treatment Technology Development Center | And 4 more authors.
Journal of Physical Chemistry Letters | Year: 2014

Despite the important role and potential application of charged cylindrical polyelectrolytes, biomacromolecules, and self-assembles, salt-modulated organization of those 1D charged nanostructures remains a topic relatively unexplored with an obscure underlying mechanism. In this Letter, the aggregation of oriented nanotubes self-assembled by ionic aromatic oligoamide in aqueous solution of NaCl over a wide concentration range is probed via small-angle X-ray scattering and a transmission electron microscope. The arrangement of nanotubes undergoes order-disorder transition sequences from an ordered rectangular phase to hexagonal packing and then to a lamellar gel. The observed transitions are understood by ionic effects on the electrostatic interaction between charged nanotubes and osmotic pressure due to ion partitioning. Above the physiological condition, electrostatic interactions are largely screened by the salts, while osmotic effects start to regulate the aggregation behavior and concomitantly deform the nanotubes. The study demonstrates rich phase behaviors of ordered, charged 1D nanostructures by tuning the ionic strength and underlying key physical principles. © 2014 American Chemical Society. Source

Wei X.,Zhejiang University of Technology | Shi Y.,Zhejiang University of Technology | Fei Y.,Zhejiang University of Technology | Chen J.,Zhejiang University of Technology | And 5 more authors.
Chemical Engineering Journal | Year: 2016

Rejection behavior of five kinds of phthalate acid ester (PAEs) including dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-n-octyl phthalate (DnOP) and diethylhexyl phthalate (DEHP) from water sources using lab-fabricated hollow fiber nanofiltration (NF) membranes were investigated. Adsorption kinetic behaviors of PAEs were studied as well as the different operation parameters on the rejection of PAEs. The results showed that the times in which PAEs reach saturation adsorption on membrane surface are different. The equilibrium time increased with the molecular weight of the PAE increase. After the PAE reached adsorption equilibrium, the rejection rates of DMP, DEP, DBP, DnOP and DEHP by NF membranes were 82.3%, 86.7%, 91.5%, 95.1% and 95.4%, respectively. The influence of operation parameters including the operation pressure, pH, ionic strength, and temperature on PAE rejection behaviors were also studied. © 2016 Elsevier B.V. Source

Xu L.,Hefei University of Technology | Huang Y.,Nanyang Technological University | Li J.,Hefei University of Technology | Li J.,Hangzhou Water Treatment Technology Development Center | And 7 more authors.
Langmuir | Year: 2013

A novel fully rigid, rod-shaped oligo(p-benzamide) (OPBA-6) molecule was designed and synthesized, which can be recrystallized into a three-dimensional (3D) multilayer material via an antiparallel molecular packing model. Intermolecular hydrogen bonding and π-π interaction are brought to ensure a strong intralayer interaction, while decoration of layer surface with sulfonic groups promotes water to enter interlayer space and facilitates the swelling and exfoliation of sample. With a simple dispersion in water, the obtained multilayer material can be easily swollen by water without destruction of in-plane morphology and subsequently delaminated into 2D nanosheets with thickness of about 5.38 nm. This achievement may be the first attempt to exfoliate layered organic materials and thus provide a new strategy to prepare 2D organic nanosheets without using any substrates or templates as required by conventional and widely used self-assembly routes. Based on exfoliated nanosheets, poly(vinyl alcohol) nanocomposites were prepared using a simple water solution processing method. A 64% increase in tensile stress and a 63% improvement in Young's modulus were achieved by addition of 7 wt % OPBA-6 loading. © 2013 American Chemical Society. Source

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