A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3...A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride （TMC） as organic monomer,thin film composite （TFC） nanofiltration membranes were prepared by interfacial polymerization technology.The salt rejection order of these TFC membranes is Na2SO4MgSO4MgCl2NaCl.This sequence indicates that the membranes are negatively charged.展开更多
A polypiperazine amide （PA）/polysulfone （PSF） thin film composite （TFC） was prepared by interracial polymerization （IP） using a trimesoyl chloride hexane solution as the oil phase and a piperazine aqueous solu...A polypiperazine amide （PA）/polysulfone （PSF） thin film composite （TFC） was prepared by interracial polymerization （IP） using a trimesoyl chloride hexane solution as the oil phase and a piperazine aqueous solution as the water phase on a porous polysulfone hollow fiber substrate. Its separating behaviors were investigated systematically to various salts such as NaCl KCl, Na2SO4, MgCl2, CaCl2 and MgSO4, showing the highest rejection rate to Na2SO4, the second to MgSO4 the third to MgCl2 and CaCl2, and the lowest to KCI, NaCl, being 99%, 98%, 70%, 60%, 15% and 10% respectively. Under an increasing pressure or with time, the rejection rate of the TFC rises to a plateau. To various concentration of the feed, the rejection rate reduced gradually with the higher concentration.展开更多
Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized polyethyleneimine （PEI） and trimesoy...Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized polyethyleneimine （PEI） and trimesoyl chloride （TMC） to perform interfacial polymerization reaction on a polydopamine coated hydrolyzed polyacry-lonitrile substrate to obtain a positively charged nanofiltration membrane. Effects ofpolydopamine coating time, PEI concentration, TMC reaction time and concentration on the membrane physicochemical properties and separation performance were systematically investigated using scanning electron microscopy, streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions （93.6±2.6% for MgSO4, 92.4±1.3% for MgCl2, and 90.4±2.1% for Na2SO4）, accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L.m-2.h-1 at an applied pressure of 8 bar （salt concentrations were all 1000 mg.L-1）. The synthesized membranes showed promising potentials for the applications of water soft-ening.展开更多
基金Supported by the National Natural Science Foundation of China（21076176） the Research and Development Project of Tangshan（10140201C-3）+1 种基金 the Research and Development Project of Hebei Province（07275113） the Research Fund of Tangshan Normal College
文摘A new aromatic diamine,3,5-diaminobenzoylpiperazine （3,5-DABP）,was synthesized from 3,5-diaminobenzoic acid and 1-formyl piperazine.The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride （TMC） as organic monomer,thin film composite （TFC） nanofiltration membranes were prepared by interfacial polymerization technology.The salt rejection order of these TFC membranes is Na2SO4MgSO4MgCl2NaCl.This sequence indicates that the membranes are negatively charged.
基金China High-Tech R&D Program (863 Program) #2002AA302619 and Tianjin Science and Technology Develop Program #05YFGDGX10000-2
文摘A polypiperazine amide （PA）/polysulfone （PSF） thin film composite （TFC） was prepared by interracial polymerization （IP） using a trimesoyl chloride hexane solution as the oil phase and a piperazine aqueous solution as the water phase on a porous polysulfone hollow fiber substrate. Its separating behaviors were investigated systematically to various salts such as NaCl KCl, Na2SO4, MgCl2, CaCl2 and MgSO4, showing the highest rejection rate to Na2SO4, the second to MgSO4 the third to MgCl2 and CaCl2, and the lowest to KCI, NaCl, being 99%, 98%, 70%, 60%, 15% and 10% respectively. Under an increasing pressure or with time, the rejection rate of the TFC rises to a plateau. To various concentration of the feed, the rejection rate reduced gradually with the higher concentration.
文摘Most commercial NF membranes are negatively charged at the pH range of a typical feed solution. In order to enhance the removal of cations （such as Mg2＋ or Ca2＋）, we utilized polyethyleneimine （PEI） and trimesoyl chloride （TMC） to perform interfacial polymerization reaction on a polydopamine coated hydrolyzed polyacry-lonitrile substrate to obtain a positively charged nanofiltration membrane. Effects ofpolydopamine coating time, PEI concentration, TMC reaction time and concentration on the membrane physicochemical properties and separation performance were systematically investigated using scanning electron microscopy, streaming potential and water contact angle measurements. The optimal NF membrane showed high rejection for divalent ions （93.6±2.6% for MgSO4, 92.4±1.3% for MgCl2, and 90.4±2.1% for Na2SO4）, accompanied with NaCl rejection of 27.8±2.5% with a permeation flux of 17.2±2.8 L.m-2.h-1 at an applied pressure of 8 bar （salt concentrations were all 1000 mg.L-1）. The synthesized membranes showed promising potentials for the applications of water soft-ening.
