title: Polypiperazine-amide Nanofiltration Membrane Modified by Different Functionalized Multiwalled Carbon Nanotubes (MWCNTs).
abstract: In this work, three modified multiwalled carbon nanotubes (MWCNTs) with carboxyl (MWCNT-COOH), hydroxyl (MWCNT-OH) and amino groups (MWCNT-NH), respectively, were added into the aqueous phase containing piperazine (PIP) to fabricate the nanocomposite nanofiltration (NF) membranes via interfacial polymerization. The influences of functional groups of MWCNTs on the performance of modified NF membrane were investigated. The MWCNTs were characterized by TEM, FT-IR and TGA; meanwhile, the properties of the membranes were evaluated by XPS, TEM, AFM and contact angle. The XPS results proved the successful incorporation of MWCNT in the active layer of modified NF membrane. When the MWCNT concentration is 0.01% (w/v), all the nanocomposite membranes possessed the optimal separation properties, among which the membrane incorporated with MWCNT-OH demonstrated the highest water flux of 41.4 L·m(-2)·h(-1) and the Na2SO4 rejection of 97.6% whereas the one with MWCNT-COOH had the relative lowest rejection of 96.6%. Furthermore, the increased hydrophilicity of functional groups in modified MWCNTs resulted in different nodular surface morphologies, thicknesses and hydrophilicities of the nanocomposite membranes. All the membranes possessed a molecular weight cutoff (MWCO) within 300 Da and good operation stability.
authors.affiliation: State Key Laboratory of Chemical Engineering, Membrane Science and Engineering R&D Lab, Chemical Engineering Research Center, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China.
authors.forename: Shuang-Mei
authors.initials: SM
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Chemical Engineering, Membrane Science and Engineering R&D Lab, Chemical Engineering Research Center, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China.
authors.forename: Zhen-Liang
authors.initials: ZL
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Chemical Engineering, Membrane Science and Engineering R&D Lab, Chemical Engineering Research Center, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China.
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Chemical Engineering, Membrane Science and Engineering R&D Lab, Chemical Engineering Research Center, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, China.
authors.forename: Chen-Hao
authors.initials: CH
authors.lastname: Ji
keywords: functional group; interfacial polymerization; modification; multiwalled carbon nanotube (MWCNT); nanofiltration membrane