JOURNAL OF MEMBRANE SCIENCE
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2025
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IF 9
Bin Liu,Xinyue Cui,Xiaozhen Lu,Xuewu Zhu,Lin Wang,Junyong Zhu
Positively charged polyamide (PA) nanofiltration (NF) membranes with sub-nanopores show promise for lithium extraction from salt-lake brines with high Mg 2+ /Li + ratios. This study introduces the use of triamino guanidine (TG), a highly positively charged molecule, to regulate grafting on monolayer PA membranes, resulting in dual-layer (PEI-TMC-TG) NF membranes. The monolayer PA membranes were created via spin-coating assisted interfacial polymerization between polyethyleneimine (PEI) and tricarbonyl chloride (TMC). The PEI/TMC-TG NF membranes exhibited several advantages over unmodified PEI-TMC NF membranes, including higher positive charge density, narrower pore size distribution, excellent hydrophilicity, and a more porous separation layer microstructure. Experimental results indicated that enhanced Donnan effect, size sieving, and dielectric repulsion within the sub-nanopores contributed to exceptional Li + /Mg 2+ selectivity during filtration of East Taijiner brine (S Li + /Mg 2+ = 64.5). Furthermore, the TG hydrophilic layer significantly improved water permeability (15.4 LMH/bar) and long-term stability. To reduce membrane fouling in the charge-positive NF process by removing organic matter from complex salt lake brine, we explored electrocoagulation as a pre-treatment method and identified optimal conditions for the EC-NF process. This strategy maximizes sustainable lithium recovery from brine in an economically viable green manner while enhancing the efficiency of NF membranes for lithium extraction from salt lakes.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2023
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IF 9.5
Zhan Hao,Xinxia Tian,Vladimir Mankol,Qinghua Li,Jixiao Wang,Zhi Wang,Song Zhao
Tuning the reactivity and diffusion of amine monomers in interfacial polymerization (IP) process could efficiently regulate the formation and structure of the polyamide (PA) selective layer. Herein, novel thin-film composite NF membranes with dense and ultrathin PA selective layer were fabricated using 1,3,5-benzenetricarbonyl trichloride (TMC) and ultra-low concentration triaminoguanidine (Tg) as reactive monomers. Fabrication parameters, including Tg concentration, NaOH concentration and reaction time, were systematically explored to optimize the desalination performance of PA-Tg NF membrane. During the stability test over 48 h, PA-Tg-0.06 membrane displayed a water permeance of ∼12 L m −2 h −1 ·bar −1 and Na 2 SO 4 rejection of ∼99%. Meanwhile, detailed comparisons were made between PA-Tg NF membrane and a typical NF membrane fabricated with PIP as an aqueous monomer, including characteristics of the monomers as well as the structure, water permeance, salt rejection and antifouling property of the membranes. Molecular dynamics simulation and interfacial diffusion experiments indicated that the Tg monomer exhibited a higher reactivity but a lower diffusivity than the PIP monomer, making it feasible for the fabrication of PA-Tg NF membrane with ultra-low concentration of Tg monomer. In addition, compared with the PA-PIP membrane, the PA-Tg membrane exhibited a smoother, more hydrophilic and negatively charged surface, as well as a thinner and denser selective layer, thereby showing a higher water permeance, salt rejection and stronger fouling resistance.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2021
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IF 4.098
Kanagaraj Rajalakshmi,Tongtong Deng,Selvaraj Muthusamy,Meng Xie,Jimin Xie,Kang-Bong Lee,Yuanguo Xu
Citrate is a tricarboxylate, plays vital role in prostate cancer (PC) and the level of citrate is an indicator for PC identification. Herein, triaminoguanidine carbon dots (TAG-CDs) prepared by one step hydrothermal method and used as a citrate receptor. Notably the TAG-CDs without alkaline treatment were highly fluorescent at pH 7 with high quantum yield (11.3%). TAG-CDs were characterized through TEM, XRD, FT-IR, UV–vis and spectrofluorimetry. It is noted that the average size was of 2.8 nm, the presence of highly disordered carbon, retain the functionality of TAG. The absorbance maxima obtained at 294 nm and good emitting response observed at 396 nm. The Y-aromaticity of receptor guanidinium moiety acts as Lewis acid and have peculiar interaction with Lewis base citrate via electrostatic interaction and also protons in the TAG participate hydrogen bonds with citrate, which causes quenching of TAG-CDs. From the obtained linear quenching equation the LOD was found to be 4 nM. The probe expressed high selectivity, high interference tolerance (500 – fold), fast response in 15 mins and good biocompatible. Finally, TAG-CDs utilized for the intracellular imaging of citrate in live MCF-7 cells, it showed good cytotoxicity and delivered contrast images in presence, absence of citrate. TAG-CDs detected the citrate level in human urine samples, the obtained results are validated with HPLC method.
研究领域:
癌症研究
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分析化学
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生物材料
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生物成像
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Zhenxiang Pan,Yalong Lei,Fuxin Zheng,Jiang Zhan,Gang Han
Nanofiltration has gained extensive attention in various energetically efficient separations towards a sustainable water–energy nexus. However, state-of-the-art polyamide nanofiltration membranes are constrained by the inherent trade-off between water permeance and solute selectivity, and a remarkable improvement in membrane permselectivity remains a big challenge. Here we conceived a density functional theory (DFT) assisted surface modification approach using triaminoguanidine hydrochloride (TGH) as the functional modifier to fabricate polyamide membranes with extremely high surface electropositivity and well-defined nanopores to overcome this challenge. Experimental data and DFT simulation results show that TGH surface modification can significantly manipulate surface charges and polarity to facilitate water permeation and enhance Donnan exclusion selectivity. Compared with the pristine benchmark membrane, the TGH-modified membrane exhibited a 4-fold increase in water permeance and a 6-fold increase in salt rejection, which successfully breaks the trade-off, excellent monovalent/divalent cation selectivity, and superior operational stability over a wide range of testing pressure, feed pH, and operation time, outperforming state-of-the-art membranes with similar chemistry. Taken together, this study demonstrates a feasible and reliable method combining DFT and experiments to rationally tailor the membrane characteristics at the molecular level, enabling the successful fabrication of effective polyamide nanofiltration membranes with precisely regulated structural and surface properties for water purification and precision ion separations.
研究领域:
纳米技术
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膜科学
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水处理
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材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）