Co-reporter:Jinglong Zhang, Zhenping Qin, Libin Yang, Hongxia Guo, Siyuan Han
Journal of the Taiwan Institute of Chemical Engineers 2017 Volume 80(Volume 80) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.jtice.2017.07.027
•The activation promoted ionic liquid modification was used to modify RO membrane.•The method was carried out in a fast, facile and efficient way.•The modified membrane achieved 62% higher water flux than the pristine membrane.•This method can be potentially used to reduce energy consumption of RO process.The ionic liquid (1,3-dimethylimidazolium dimethyl phosphate ([MMIM][DMP])) synthesized by addition reaction was used to modify a commercial reverse osmosis (RO) membrane thorough activation method. The activation promoted modification process was completed within just 6−12 min under optimal condition of the immersion time of 4 min, activation temperature of 110°C and activation time of 4 min. The variation of surface morphologies and properties of the RO membrane were characterized by SEM, AFM, water contact angle, FTIR, and the RO performance was evaluated by desalination of 1000 mg⋅L−1 NaCl aqueous solution. The results showed that the active layer of the modified RO membrane became thinner, smoother, and more hydrophilic with increasing of activation temperature. The IL modified membrane achieved water flux of 33.7 L m−2 h−1 and rejection of 93.2%, showing 62% higher water flux comparing to the pristine membrane and 2.6% decrease in salt rejection. Moreover, the IL modified membrane showed an enhanced anti-fouling property with 95.5% of normalized water flux recovery. This work provides a facile and efficient way to modify and improve separation performance and anti-fouling property of commercial thin film composite (TFC) RO membranes.Download high-res image (191KB)Download full-size image
Co-reporter:Hongxia Guo, Yiwen Ma, Zhenping Qin, Zhaoxiang Gu, Suping Cui, and Guojun Zhang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 35) pp:23379
Publication Date(Web):August 18, 2016
DOI:10.1021/acsami.6b07106
The hierarchical-structured superhydrophilic poly(ethylenimine)/poly(acrylic acid) (PEI/PAA)calcium silicate hydrate (CSH) multilayered membranes (PEI/PAA-CSH)n were prepared as aqueous nanofiltration (NF) membrane, and then they were transformed into superhydrophobic organic solvent nanofiltration (OSN) membranes by one-step modification of trimethylperfluorinatedsilane (PFTS). Investigation on surface structures and properties of these multilayered membranes (PEI/PAA-CSH)n indicated that the hierarchical-structured (PEI/PAA-CSH)n multilayered membrane produced by in situ incorporation of CSH aggregates into PEI/PAA multilayers facilitated its one-step transformation from superhydrophilicity into superhydrophobicity. Both of the superwetting membranes showed better nanofiltration performances for retention of dyes of water and ethanol solution, respectively. Moreover, the long-term performance and antifouling behaviors, investigated by retention of methyl blue (MB), bovine serum albumin (BSA), and humic acid (HA) aqueous water solution and nonaqueous ethanol solution indicated that both of the superhydrophilic and superhydrophobic membrane showed higher stability and excellent antifouling property.Keywords: antifouling effect; nanocomposite membranes; nanofiltration; organic solvent nanofiltration; superhydrophilic membrane; superhydrophobic membrane
Co-reporter:Hongxia Guo;Pengzhi Sun;Zhenping Qin;Linglong Shan;Guojun Zhang;Suping Cui;Yucang Liang
European Journal of Inorganic Chemistry 2014 Volume 2014( Issue 6) pp:1001-1009
Publication Date(Web):
DOI:10.1002/ejic.201301228
Abstract
Sodium lignosulfonate (SL), a byproduct of the pulping industry, was used as a stabilizer for the mineralization of CaCO3. In a calcium acetate–urea–water system, the direct aging of the aqueous solution of calcium acetate and urea resulted in the formation of mixed aragonite and vaterite phases or a pure aragonite phase depending on the aging time. However, SL was introduced into the calcium acetate–urea–water system to markedly stabilize the formation of a thermodynamically unstable vaterite phase. Various morphologies of vaterite structures were observed by adjusting the concentration of urea and SL as well as the aging time. Based on these results, ion exchange, carbonate attacking the calcium(II) ions, aggregations of SL-stabilized primary CaCO3 particles through oriented attachment and Ostwald ripening, as well as mesoscale self-assembly were proposed as mechanisms to elucidate the formation of various morphologies.
Co-reporter:Wei Liu;Shu-Lan Ji;Hong-Xia Guo;Jing Gao;Zhen-Ping Qin
Journal of Applied Polymer Science 2014 Volume 131( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/app.40004
ABSTRACT
In this study, an in situ crosslinked polydimethylsiloxane/brominated polyphenylene oxide (c-PDMS/BPPO) membrane on ceramic tube has been prepared for the recovery of butanol by pervaporation. A series of BPPO with different bromide-substituted ratio were firstly synthesized through Wohl–Ziegler reaction. BPPO and PDMS were sequentially assembled and in situ crosslinked to form the final c-PDMS/BPPO membrane. The results of solid-state NMR and Differential Scanning Calorimeter demonstrated that the c-PDMS/BPPO copolymer has a crosslinking structure and the SEM result proved the coverage of ceramic tube by copolymer layer. The effects of preparation conditions including dipping time and bromide-substituted ratio of BPPO on the membrane performance were studied. The pervaporation experiments of butanol–water mixture indicated that the c-PDMS/BPPO membrane exhibited an acceptable flux of 220 g·m−2·h−1 and high separation factor of 35 towards butanol, when the bromide-substituted ratio was 34 wt % and the dipping time was 1.33 h. Moreover, the c-PDMS/BPPO membrane performed excellent stability in an about 200 h continuous butanol recovery, as compared to the PDMS membrane. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40004.
Co-reporter:Hongxia Guo, Zhenping Qin, Peng Qian, Peng Yu, Suping Cui, Wei Wang
Advanced Powder Technology 2011 Volume 22(Issue 6) pp:777-783
Publication Date(Web):November 2011
DOI:10.1016/j.apt.2010.11.004
Abstract
In this work, aragonite CaCO3 with complex morphologies was synthesized through homogeneous precipitation, in which calcium acetate and urea precipitated at 90 °C in the presence of PVP. The effect of the concentration of urea and PVP on the CaCO3 crystalline was investigated. The morphology and structure of the CaCO3 particles were characterized by SEM, XRD, and FT-IR. It was found that the concentrations of urea and PVP in the mixed aqueous solution were turned out to be important parameters for the morphology of CaCO3 particles. All CaCO3 particles were mainly aragonite with morphology from bundles of rods, bouquet-like and dumbbell-like. And there was no phase transition under the research conditions. Moreover, the possible process for the formation of the morphology of aragonite was discussed.
Co-reporter:Hongxia Guo, Mengmeng Chen, Qiang Liu, Ziming Wang, Suping Cui, Guojun Zhang
Desalination (1 June 2015) Volume 365() pp:108-116
Publication Date(Web):1 June 2015
DOI:10.1016/j.desal.2015.01.021
•The low cost SCF condensation polymer was used as anionic building blocks to fabricate nanofiltration membrane.•The multilayered membrane was formed by LbL self-assembly technique.•The membrane showed good separation performance for both cationic ions and dye molecules.The use of new polymeric building block is one of the important routes to extend the layer-by-layer (LbL) assembly technique to fabricate novel nanofiltration (NF) membrane. In this work, the low cost sulfonated cyclohexanone–formaldehyde (SCF) condensation polymer is used as anionic building blocks to prepare a novel positively charged nanofiltration membrane by LbL self-assembly technique. The LbL assembly process was investigated by XRD, FTIR, SEM and AFM measurements. The separation performance of cationic ions and dyes was evaluated by pressure-driven nanofiltration tests. It is found that the multilayer surfaces exhibited periodic variations in positive charges. And the prepared membrane showed an effective rejection of both cationic ions and dyes. The multilayer membrane of 4.5 bilayers exhibited rejections of 92.8% and 90.6% to Ni2 + and Ca2 +, along with flux of 40.8 and 44.9 L/(m2·h·MPa) and pure water flux of 49.3 L/(m2·h·MPa), respectively. Simultaneously, this membrane also showed rejection of 93.7% and 90.8% to RdB and EbT, along with flux of 24.3 and 20.5 L/(m2·h·MPa), respectively. Moreover, the long-term performance stability of the membrane was improved through cross-linking the multilayer membrane.Download high-res image (134KB)Download full-size image
