The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Jiangnan Shen - One of the best experts on this subject based on the ideXlab platform.
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Monovalent Anion selective Anion exchange membranes with imidazolium salt terminated side chains investigating the effect of hydrophobic alkyl spacer length
Journal of Membrane Science, 2020Co-Authors: Junbin Liao, Huimin Ruan, Jiangnan Shen, Xing Gao, Quan Chen, Congjie GaoAbstract:Abstract Ion-conductive polymers having highly ordered and well-defined phase-separated structures are potential materials for use as Monovalent Anion-selective membranes (MASMs). In this work, to investigate the effect of hydrophobic spacers, four side-chain-type imidazolium salt-tethered poly(arylene ether sulfone) Anion-exchange membranes (AEMs) with different alkyl spacer lengths (–CH2– number: 3, 6, 9, and 12) were fabricated for use in electrodialysis (ED). Our investigations using atomic force microscopy, small angle X-ray scattering and X-ray diffraction demonstrate that the extended alkyl spacers change the nano-phase-separated structures, with an increased ion cluster space ranging from 3.29 nm to 7.76 nm, resulting from increased immiscibility between the additional hydrophobic alkyl spacers and (i) the hydrophobic aromatic backbones and (ii) the hydrophilic ion-conductive groups. In addition, with the extension of the alkyl spacer, chloride (Cl−) ion conductivity at 25 °C decreases from 16.4 mS cm−1 to 11.4 mS cm−1 and water uptake is reduced to 12.8% (20 °C). It is found that the as-prepared AEM with a hexyl alkyl spacer shows the superior perm-selectivity (Cl−/SO42−) of 7.10 (separation efficiency: 70.3%), as compared with three others (3.48, 6.81, and 4.26). This work thus presents an efficient strategy to guide the architectural design of novel MASMs.
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Separation of mixed salts (Cl-/SO42-) by ED based on Monovalent Anion selective membranes
Chinese Journal of Chemical Engineering, 2019Co-Authors: Wei Zhang, Huimin Ruan, Jiangnan ShenAbstract:Abstract The industrial products or wastewater rich in the mixed salts (Cl−/SO42−) not only causes the environmental damage, but also induces waste of resource. In this study, an ED stack with Monovalent selective AEMs and conventional CEMs was employed to separate the Cl− and SO42− from simulated wastewater. The effect of current density and mass fraction percentage was investigated in order to optimize the experimental conditions during ED process. It was found that at a concentration ratio between NaCl and Na2SO4 of 95/5 (wt%/wt%) and a current density of 40 mA·cm−2, a current efficiency of 72%, an energy consumption of 1.6 kW·h·kg−1 NaCl and a Cl−/SO42− concentration (67.5/3.5 g·L−1) were obtained. Hence, it is appropriate and effective to separate Cl− and SO42− by ED using the Monovalent selective AEMs.
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mussel inspired surface functionalization of aem for simultaneously improved Monovalent Anion selectivity and antibacterial property
Membranes, 2019Co-Authors: Zhihao Zheng, Huimin Ruan, Congjie Gao, Bart Van Der Bruggen, Junbin Liao, Pang Xiao, Jiangnan ShenAbstract:A facile membrane surface modification process for improving permselectivity and antimicrobial property was proposed. A polydopamine (PDA) coating was firstly fabricated on pristine Anion exchange membrane (AEM), followed by in situ reduction of Ag without adding any extra reductant. Finally, 2,5-diaminobenzene sulfonic acid (DSA) was grafted onto PDA layer via Michael addition reaction. The as-prepared AEM exhibited improved permselectivity (from 0.60 to 1.43) and effective inhibition of bacterial growth. In addition, the result of the long-term (90-h continuous electrodialysis) test expressed the excellent durability of the modified layer on membrane surface, because the concentration of Cl− and SO42− in diluted chamber fluctuated ~0.024 and 0.030 mol·L−1 with no distinct decline. The method described in this work makes the full use of multifunctional PDA layer (polymer-like coating, in situ reduction and post-organic reaction), and a rational design of functional AEM was established for better practical application.
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a durable and antifouling Monovalent selective Anion exchange membrane modified by polydopamine and sulfonated reduced graphene oxide
Separation and Purification Technology, 2018Co-Authors: Yali Jin, Congjie Gao, Yan Zhao, Huimin Liu, Arcadio Sotto, Jiangnan ShenAbstract:Abstract Developing a durable and antifouling Monovalent selective Anion exchange membrane is critical in practical electrodialysis (ED) process. Herein, a commercial Anion exchange membrane was modified by sulfonated reduced graphene oxide (S-rGO) and polydopamine (PDA). Inspired by biological adhesion from mussels, the PDA coating on the surface of S-rGO-PDA membrane enhanced the stability of S-rGO nanosheets due to strong adhesion. The Monovalent Anion selectivity was evaluated by means of the Cl - / SO 4 2 - permeselectivity, and stability property was measured by the ion concentration changes of Cl - and SO 4 2 - for a long time application of ED. Moreover, antifouling property was measured by recording the time course of the potential difference in the presence of sodium dodecyl benzene sulfonate (SDBS). The results show that permselectivity of S-rGO-PDA membrane is 2.50, which is higher than pristine membrane (1.08). In addition, S-rGO-PDA membrane is stable, the permselectivity did not change significantly during 70 h ED process. Besides antifouling property of S-rGO-PDA membranes is improved compared with S-rGO membranes.
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sandwich like structure modified Anion exchange membrane with enhanced Monovalent selectivity and fouling resistant
Journal of Membrane Science, 2018Co-Authors: Liang Hao, Yuliang Jiang, Bart Van Der Bruggen, Yan Zhao, Junbin Liao, Arcadio Sotto, Jiajie Zhu, Jiangnan ShenAbstract:Abstract Surface modification is a critical method for fabricating novel Anion exchange membranes (AEMs) with high Monovalent Anion selectivity and desired antifouling property. In this work, we have modified a commercial AEM with “sandwich”-like structure, composed of upper/bottom bilayers of polydopamine (PDA) and sandwich alternating bilayers of poly (sodium 4-styrene sulfonate) (PSS)/hydroxypropyltrimethyl ammonium chloride chitosan-nano silver particles (HACC-Ag Np), aiming to enhance the Monovalent selectivity and fouling resistant for electrodialysis (ED) application. Our investigations suggest that the permselectivity ( P S O 4 2 − C l − ) of the modified AEM with 4.5 bilayers of PSS can reach 5.1, significantly outperforming that of commercial standard AEM (0.98). Due to the electrostatic repulsion resulted from the negatively charged top layer in sandwich structure and hydrophilia of PDA, the time elapsed until the occurrence of fouling (transition time) of the modified AEM (125 min) is much longer than that of the original one (60 min). In addition, anchored silver nanoparticles in sandwich alternating bilayers endow the modified AEMs with effective antibacterial activities of Escherichia coli. These results are indicative of the desired fouling resistant for ED process. The facile fabrication process and superior performances of modified AEM suggest that the as-prepared “sandwich”-like structure modified AEM is potentially applicable in ED for separation of Monovalent and multivalent Anions.
Congjie Gao - One of the best experts on this subject based on the ideXlab platform.
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Monovalent Anion selective Anion exchange membranes with imidazolium salt terminated side chains investigating the effect of hydrophobic alkyl spacer length
Journal of Membrane Science, 2020Co-Authors: Junbin Liao, Huimin Ruan, Jiangnan Shen, Xing Gao, Quan Chen, Congjie GaoAbstract:Abstract Ion-conductive polymers having highly ordered and well-defined phase-separated structures are potential materials for use as Monovalent Anion-selective membranes (MASMs). In this work, to investigate the effect of hydrophobic spacers, four side-chain-type imidazolium salt-tethered poly(arylene ether sulfone) Anion-exchange membranes (AEMs) with different alkyl spacer lengths (–CH2– number: 3, 6, 9, and 12) were fabricated for use in electrodialysis (ED). Our investigations using atomic force microscopy, small angle X-ray scattering and X-ray diffraction demonstrate that the extended alkyl spacers change the nano-phase-separated structures, with an increased ion cluster space ranging from 3.29 nm to 7.76 nm, resulting from increased immiscibility between the additional hydrophobic alkyl spacers and (i) the hydrophobic aromatic backbones and (ii) the hydrophilic ion-conductive groups. In addition, with the extension of the alkyl spacer, chloride (Cl−) ion conductivity at 25 °C decreases from 16.4 mS cm−1 to 11.4 mS cm−1 and water uptake is reduced to 12.8% (20 °C). It is found that the as-prepared AEM with a hexyl alkyl spacer shows the superior perm-selectivity (Cl−/SO42−) of 7.10 (separation efficiency: 70.3%), as compared with three others (3.48, 6.81, and 4.26). This work thus presents an efficient strategy to guide the architectural design of novel MASMs.
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A chemically assembled Anion exchange membrane surface for Monovalent Anion selectivity and fouling reduction
Journal of Materials Chemistry A, 2019Co-Authors: Yan Zhao, Congjie Gao, Shushan Yuan, Junyong Zhu, Sofie Houtmeyers, Raf Dewil, Bart Van Der BruggenAbstract:Separation and extraction of Monovalent Anions from salt lakes or oceans is very important in view of a sustainable supply of industrial chemical compounds. In this work, a novel Anion exchange membrane (AEM) with simultaneously enhanced Monovalent Anion selectivity and reduced organic fouling properties was synthesized through oxidative self-polymerization and an amide condensation reaction. Using a rapid deposition and polymerization procedure, L-dopa was coated on a commercial AEM surface to form an L-dopa polymer layer (L-PDA) by using CuSO4 and H2O2 as a trigger. This layer was chemically assembled with a 4-amino-benzenesulfonic acid monosodium salt (ABS) via an amide condensation reaction. The resulting Anion exchange membrane L-PDA#ABS, with a unique hydrophilic characteristic and negatively charged thin layer, was found to have a high Monovalent Anion permselectivity of 5.29 (SO42−/Br−) and 4.66 (SO42−/Cl−) in electrodialysis (ED) (10 min, initial concentration of 50 mM Br−, Cl− and SO42−, and current density of 10.00 mA cm−2), while the original AEM had corresponding permselectivities of 1.22 and 1.00. Furthermore, the selective separation efficiency parameter of the L-PDA#ABS AEM in SO42−/Br− and SO42−/Cl− was 66% and 63%, which is higher than those of the original AEM (8% and 2%). Sodium dodecyl benzene sulfonate, bovine serum albumin and humic acid were used as model organic fouling materials; the L-PDA#ABS AEM has a much higher antifouling potential than a commercial reference AEM. The work also demonstrated that the chemically assembled functional layer with high stability was suitable for long term application.
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mussel inspired surface functionalization of aem for simultaneously improved Monovalent Anion selectivity and antibacterial property
Membranes, 2019Co-Authors: Zhihao Zheng, Huimin Ruan, Congjie Gao, Bart Van Der Bruggen, Junbin Liao, Pang Xiao, Jiangnan ShenAbstract:A facile membrane surface modification process for improving permselectivity and antimicrobial property was proposed. A polydopamine (PDA) coating was firstly fabricated on pristine Anion exchange membrane (AEM), followed by in situ reduction of Ag without adding any extra reductant. Finally, 2,5-diaminobenzene sulfonic acid (DSA) was grafted onto PDA layer via Michael addition reaction. The as-prepared AEM exhibited improved permselectivity (from 0.60 to 1.43) and effective inhibition of bacterial growth. In addition, the result of the long-term (90-h continuous electrodialysis) test expressed the excellent durability of the modified layer on membrane surface, because the concentration of Cl− and SO42− in diluted chamber fluctuated ~0.024 and 0.030 mol·L−1 with no distinct decline. The method described in this work makes the full use of multifunctional PDA layer (polymer-like coating, in situ reduction and post-organic reaction), and a rational design of functional AEM was established for better practical application.
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Developments on Monovalent Anion-Selective Membranes (MASMs): A Mini-review of Our Recent Contributions
2019Co-Authors: Junbin Liao, Huimin Ruan, Shen Jiangnan, Xing Gao, Congjie GaoAbstract:Ion Exchange Membrane (IEM)-based Electrodialysis (ED), as one of the most promising separation techniques, plays a vital role in industrial separation. In particular, for special mono-/multivalent Anion separation process in practical industries or academic explorations, highly ion-selective membranes for ED applications is critical but challengeable. To further understand the advances of this specific technique, herein, we have summarized our recent contributions on Monovalent Anion-Selective Membranes (MASMs) fabricated in our research group through: (1) Surface modification on commercial Anion Exchange Membrane (AEM) (2) Micro-phase structure regulation of homogeneous AEM. We have also discussed the advantages and disadvantages with respect to some specific cases in detail and the future perspectives of MASMs
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a durable and antifouling Monovalent selective Anion exchange membrane modified by polydopamine and sulfonated reduced graphene oxide
Separation and Purification Technology, 2018Co-Authors: Yali Jin, Congjie Gao, Yan Zhao, Huimin Liu, Arcadio Sotto, Jiangnan ShenAbstract:Abstract Developing a durable and antifouling Monovalent selective Anion exchange membrane is critical in practical electrodialysis (ED) process. Herein, a commercial Anion exchange membrane was modified by sulfonated reduced graphene oxide (S-rGO) and polydopamine (PDA). Inspired by biological adhesion from mussels, the PDA coating on the surface of S-rGO-PDA membrane enhanced the stability of S-rGO nanosheets due to strong adhesion. The Monovalent Anion selectivity was evaluated by means of the Cl - / SO 4 2 - permeselectivity, and stability property was measured by the ion concentration changes of Cl - and SO 4 2 - for a long time application of ED. Moreover, antifouling property was measured by recording the time course of the potential difference in the presence of sodium dodecyl benzene sulfonate (SDBS). The results show that permselectivity of S-rGO-PDA membrane is 2.50, which is higher than pristine membrane (1.08). In addition, S-rGO-PDA membrane is stable, the permselectivity did not change significantly during 70 h ED process. Besides antifouling property of S-rGO-PDA membranes is improved compared with S-rGO membranes.
Bart Van Der Bruggen - One of the best experts on this subject based on the ideXlab platform.
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A chemically assembled Anion exchange membrane surface for Monovalent Anion selectivity and fouling reduction
Journal of Materials Chemistry A, 2019Co-Authors: Yan Zhao, Congjie Gao, Shushan Yuan, Junyong Zhu, Sofie Houtmeyers, Raf Dewil, Bart Van Der BruggenAbstract:Separation and extraction of Monovalent Anions from salt lakes or oceans is very important in view of a sustainable supply of industrial chemical compounds. In this work, a novel Anion exchange membrane (AEM) with simultaneously enhanced Monovalent Anion selectivity and reduced organic fouling properties was synthesized through oxidative self-polymerization and an amide condensation reaction. Using a rapid deposition and polymerization procedure, L-dopa was coated on a commercial AEM surface to form an L-dopa polymer layer (L-PDA) by using CuSO4 and H2O2 as a trigger. This layer was chemically assembled with a 4-amino-benzenesulfonic acid monosodium salt (ABS) via an amide condensation reaction. The resulting Anion exchange membrane L-PDA#ABS, with a unique hydrophilic characteristic and negatively charged thin layer, was found to have a high Monovalent Anion permselectivity of 5.29 (SO42−/Br−) and 4.66 (SO42−/Cl−) in electrodialysis (ED) (10 min, initial concentration of 50 mM Br−, Cl− and SO42−, and current density of 10.00 mA cm−2), while the original AEM had corresponding permselectivities of 1.22 and 1.00. Furthermore, the selective separation efficiency parameter of the L-PDA#ABS AEM in SO42−/Br− and SO42−/Cl− was 66% and 63%, which is higher than those of the original AEM (8% and 2%). Sodium dodecyl benzene sulfonate, bovine serum albumin and humic acid were used as model organic fouling materials; the L-PDA#ABS AEM has a much higher antifouling potential than a commercial reference AEM. The work also demonstrated that the chemically assembled functional layer with high stability was suitable for long term application.
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mussel inspired surface functionalization of aem for simultaneously improved Monovalent Anion selectivity and antibacterial property
Membranes, 2019Co-Authors: Zhihao Zheng, Huimin Ruan, Congjie Gao, Bart Van Der Bruggen, Junbin Liao, Pang Xiao, Jiangnan ShenAbstract:A facile membrane surface modification process for improving permselectivity and antimicrobial property was proposed. A polydopamine (PDA) coating was firstly fabricated on pristine Anion exchange membrane (AEM), followed by in situ reduction of Ag without adding any extra reductant. Finally, 2,5-diaminobenzene sulfonic acid (DSA) was grafted onto PDA layer via Michael addition reaction. The as-prepared AEM exhibited improved permselectivity (from 0.60 to 1.43) and effective inhibition of bacterial growth. In addition, the result of the long-term (90-h continuous electrodialysis) test expressed the excellent durability of the modified layer on membrane surface, because the concentration of Cl− and SO42− in diluted chamber fluctuated ~0.024 and 0.030 mol·L−1 with no distinct decline. The method described in this work makes the full use of multifunctional PDA layer (polymer-like coating, in situ reduction and post-organic reaction), and a rational design of functional AEM was established for better practical application.
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sandwich like structure modified Anion exchange membrane with enhanced Monovalent selectivity and fouling resistant
Journal of Membrane Science, 2018Co-Authors: Liang Hao, Yuliang Jiang, Bart Van Der Bruggen, Yan Zhao, Junbin Liao, Arcadio Sotto, Jiajie Zhu, Jiangnan ShenAbstract:Abstract Surface modification is a critical method for fabricating novel Anion exchange membranes (AEMs) with high Monovalent Anion selectivity and desired antifouling property. In this work, we have modified a commercial AEM with “sandwich”-like structure, composed of upper/bottom bilayers of polydopamine (PDA) and sandwich alternating bilayers of poly (sodium 4-styrene sulfonate) (PSS)/hydroxypropyltrimethyl ammonium chloride chitosan-nano silver particles (HACC-Ag Np), aiming to enhance the Monovalent selectivity and fouling resistant for electrodialysis (ED) application. Our investigations suggest that the permselectivity ( P S O 4 2 − C l − ) of the modified AEM with 4.5 bilayers of PSS can reach 5.1, significantly outperforming that of commercial standard AEM (0.98). Due to the electrostatic repulsion resulted from the negatively charged top layer in sandwich structure and hydrophilia of PDA, the time elapsed until the occurrence of fouling (transition time) of the modified AEM (125 min) is much longer than that of the original one (60 min). In addition, anchored silver nanoparticles in sandwich alternating bilayers endow the modified AEMs with effective antibacterial activities of Escherichia coli. These results are indicative of the desired fouling resistant for ED process. The facile fabrication process and superior performances of modified AEM suggest that the as-prepared “sandwich”-like structure modified AEM is potentially applicable in ED for separation of Monovalent and multivalent Anions.
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one pot approach to prepare internally cross linked Monovalent selective Anion exchange membranes
Journal of Membrane Science, 2018Co-Authors: Jiefeng Pan, Jincheng Ding, Yu Zheng, Congjie Gao, Bart Van Der Bruggen, Jiangnan ShenAbstract:Abstract In this study, high performance internally cross-linked Monovalent selective Anion exchange membranes were prepared via a one-pot approach by simply adding different amounts of sulfamerazine (SF) to partially-quaternized chloromethylated polysulfone (QPSF). The composition and structure of the prepared membranes were studied by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and Atomic force microscopy (AFM). The Monovalent Anion selectivity was evaluated by electrodialysis using a Cl-/SO42- system. The experimental results show that all QPSF-SF-x membranes exhibit excellent Monovalent Anion selectivity ( P SO 4 2 − Cl − = 3.98–15.90) at an average pH level of 6.0 because of the presence of sulfamerazine, which can change the compactness and electronegativity of the QPSF membranes. Especially, the optimized QPSF-SF-0.09 membrane had a permselectivity of 24.55 at pH 10.0 and showed an excellent permselectivity in alkaline condition. Based on an overall consideration of the facile synthesis procedure and the excellent Monovalent ion selectivity of the resulting membranes, this process is expected to inspire the further investigation of Monovalent Anion selective membranes.
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Fluoride Removal from Water by Membrane Capacitive Deionization with a Monovalent Anion Selective Membrane
2018Co-Authors: Jiefeng Pan, Jincheng Ding, Yu Zheng, Congjie Gao, Bart Van Der Bruggen, Jiangnan ShenAbstract:Contamination of groundwater by Monovalent Anions, for instance, fluoride (F–) and nitrite (NO2–), leaves an adverse impact on human health. This study aims at investigating the feasibility of the application of membrane capacitive deionization (MCDI) combined with a Monovalent Anion permselective exchange membrane (PSM) for the removal of fluoride from water. In this study, various parameters (Anion composition and concentration, pH, operating voltage, flow rate, and time) were studied for the purpose of attaining the maximum selectivity. Evaluation of the selectivity for Monovalent Anions was performed with the help of a lab-made MCDI with a model aqueous system (F–/SO42–). As revealed by the empirical findings, the removal of both F– and SO42– Anions increased with the increase in Anion concentration and pH, in addition to the increase in the selectivity for Monovalent Anions (F–). The removal of Anions and selectivity also exhibited an increase with flow rate and operating time. Contrarily, the selectivity declined with the applied voltage. A Monovalent Anion selectivity of 1.43 was obtained subjected to the conditions of 1.0 V operating voltage, together with 10 min adsorption time and 30 mL/min feed flow rate. The results in this study are capable of helping develop the PSMCDI (permselective exchange membrane capacitive deionization) technology and expand its application for the removal of fluoride from drinking water
Miguel Angel Quinones - One of the best experts on this subject based on the ideXlab platform.
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Independent induction of two blue light‐dependent Monovalent Anion transport systems in the plasma membrane of Monoraphidium braunii
Journal of experimental botany, 2002Co-Authors: Cristina Mora, Pedro J Aparicio, Federico G. Witt, Miguel Angel QuinonesAbstract:In the plasma membrane of the green alga Monoraphidium braunii there are at least two Monovalent Anion transport systems. One of them is specific for bicarbonate. This transport system is activated by blue light and its induction is triggered by a decrease in the external CO2 concentration. The second transport system is responsible for nitrate uptake at least. This transport system is also activated by blue light and its induction occurs when there is no ammonium in the external medium. Both transport systems are synthesized independently. Hence, when M. braunii cells grow with nitrate as the only nitrogen source under high CO2, they have a nitrate transport system but lack a bicarbonate transporter. Conversely, cells grown with ammonium under low CO2, have a bicarbonate transport system but lack a nitrate transporter. Both transport systems are induced in cells irradiated with white light in the absence of a carbon source, suggesting that there may be precursors in the plasma membrane that only need the synthesis and assembly of some component(s) to become fully active. The induction of nitrate and nitrite reductases, however, only takes place when a carbon source is supplied to the cells.
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independent induction of two blue light dependent Monovalent Anion transport systems in the plasma membrane of monoraphidium braunii
Journal of Experimental Botany, 2002Co-Authors: Cristina Mora, Pedro J Aparicio, Federico G. Witt, Miguel Angel QuinonesAbstract:In the plasma membrane of the green alga Monoraphidium braunii there are at least two Monovalent Anion transport systems. One of them is specific for bicarbonate. This transport system is activated by blue light and its induction is triggered by a decrease in the external CO2 concentration. The second transport system is responsible for nitrate uptake at least. This transport system is also activated by blue light and its induction occurs when there is no ammonium in the external medium. Both transport systems are synthesized independently. Hence, when M. braunii cells grow with nitrate as the only nitrogen source under high CO2, they have a nitrate transport system but lack a bicarbonate transporter. Conversely, cells grown with ammonium under low CO2, have a bicarbonate transport system but lack a nitrate transporter. Both transport systems are induced in cells irradiated with white light in the absence of a carbon source, suggesting that there may be precursors in the plasma membrane that only need the synthesis and assembly of some component(s) to become fully active. The induction of nitrate and nitrite reductases, however, only takes place when a carbon source is supplied to the cells.
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limiting co2 levels induce a blue light dependent hco3 uptake system in monoraphidium braunii
Journal of Experimental Botany, 2000Co-Authors: Nuria Giraldez, Pedro J Aparicio, Miguel Angel QuinonesAbstract:The in situ photoactivation of an HCO3 uptake system in the green alga Monoraphidium braunii requires the irradiation of the cell suspensions with short wavelength radiation (blue, UVA and/or UVC). Plasma membrane ATPase inhibitors block the uptake of this Monovalent Anion at pH 9. M. braunii cells grown in high CO 2 lack an HCO 3 - uptake system in their plasma membrane, but those grown in low CO 2 can take up this Anion at high rates. Cells grown in high CO 2 , transferred to CO 2 -limiting conditions in the light, start taking up HCO 3 - in 30 min, although they take 90 min to reach maximum rates of HCO 3 - transport. Therefore, this induction process seems to be triggered by low external CO 2 concentration. In fact, increasing or decreasing the external HCO 3 - concentration does not induce the uptake system and only a decrease in CO 2 concentration in the medium triggers the induction process. The appearance of the HCO 3 - transport activity is sensitive to cycloheximide, indicating that cytoplasmic protein biosynthesis is necessary for the induction of the uptake system. Photosynthetically active radiation, but not particularly blue light, is essential for induction of the uptake system to occur and the inhibition of photosynthesis by DCMU blocks it. From these results it can be inferred that when M. braunii cells detect a drop in CO 2 concentration, they induce a blue light-dependent HCO 3 - uptake system.
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Limiting CO2 levels induce a blue light‐dependent HCO3− uptake system in Monoraphidium braunii
Journal of Experimental Botany, 2000Co-Authors: Nuria Giraldez, Pedro J Aparicio, Miguel Angel QuinonesAbstract:The in situ photoactivation of an HCO3 uptake system in the green alga Monoraphidium braunii requires the irradiation of the cell suspensions with short wavelength radiation (blue, UVA and/or UVC). Plasma membrane ATPase inhibitors block the uptake of this Monovalent Anion at pH 9. M. braunii cells grown in high CO 2 lack an HCO 3 - uptake system in their plasma membrane, but those grown in low CO 2 can take up this Anion at high rates. Cells grown in high CO 2 , transferred to CO 2 -limiting conditions in the light, start taking up HCO 3 - in 30 min, although they take 90 min to reach maximum rates of HCO 3 - transport. Therefore, this induction process seems to be triggered by low external CO 2 concentration. In fact, increasing or decreasing the external HCO 3 - concentration does not induce the uptake system and only a decrease in CO 2 concentration in the medium triggers the induction process. The appearance of the HCO 3 - transport activity is sensitive to cycloheximide, indicating that cytoplasmic protein biosynthesis is necessary for the induction of the uptake system. Photosynthetically active radiation, but not particularly blue light, is essential for induction of the uptake system to occur and the inhibition of photosynthesis by DCMU blocks it. From these results it can be inferred that when M. braunii cells detect a drop in CO 2 concentration, they induce a blue light-dependent HCO 3 - uptake system.
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blue light dependent Monovalent Anion uptake
Physiologia Plantarum, 1997Co-Authors: Miguel Angel Quinones, Nuria Giraldez, Federico G. Witt, Pedro J AparicioAbstract:Blue light is one of the most important environmental signals regulating Monovalent Anion transport in plant cells. Inthe unicellular freshwater chlorophyte Monoraphidium braunii, blue light is essential for the activation of HCO 3 - , NO 3 - , NO 2 - and Cl - transport systems. These Anions are taken up when blue light is present but the uptake ceases when this radiation is suppressed, indicating that blue light is a switch signal for the Monovalent Anion transport system(s) of this alga. Similar results have been obtained in other green algae and higher plants. The action spectra for the uptake of NO 3 - and Cl - in M. braunii are very similar and resemble the absorption spectra of flavins or a combination of flavins and pterins. It is proposed that both Anions share the same transport system(s). The uptake of Monovalent Anions consists of a cotransport with H + , thus producing alkalinization of the external medium. The time between the onset of blue light and the beginning of alkalinization can be as short as 2 s. Taken together, the results suggest that the photoreceptor mediating the blue light activation of Monovalent Anion uptake in this green alga is a plasma membrane-bound flavoprotein.
Yan Zhao - One of the best experts on this subject based on the ideXlab platform.
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A chemically assembled Anion exchange membrane surface for Monovalent Anion selectivity and fouling reduction
Journal of Materials Chemistry A, 2019Co-Authors: Yan Zhao, Congjie Gao, Shushan Yuan, Junyong Zhu, Sofie Houtmeyers, Raf Dewil, Bart Van Der BruggenAbstract:Separation and extraction of Monovalent Anions from salt lakes or oceans is very important in view of a sustainable supply of industrial chemical compounds. In this work, a novel Anion exchange membrane (AEM) with simultaneously enhanced Monovalent Anion selectivity and reduced organic fouling properties was synthesized through oxidative self-polymerization and an amide condensation reaction. Using a rapid deposition and polymerization procedure, L-dopa was coated on a commercial AEM surface to form an L-dopa polymer layer (L-PDA) by using CuSO4 and H2O2 as a trigger. This layer was chemically assembled with a 4-amino-benzenesulfonic acid monosodium salt (ABS) via an amide condensation reaction. The resulting Anion exchange membrane L-PDA#ABS, with a unique hydrophilic characteristic and negatively charged thin layer, was found to have a high Monovalent Anion permselectivity of 5.29 (SO42−/Br−) and 4.66 (SO42−/Cl−) in electrodialysis (ED) (10 min, initial concentration of 50 mM Br−, Cl− and SO42−, and current density of 10.00 mA cm−2), while the original AEM had corresponding permselectivities of 1.22 and 1.00. Furthermore, the selective separation efficiency parameter of the L-PDA#ABS AEM in SO42−/Br− and SO42−/Cl− was 66% and 63%, which is higher than those of the original AEM (8% and 2%). Sodium dodecyl benzene sulfonate, bovine serum albumin and humic acid were used as model organic fouling materials; the L-PDA#ABS AEM has a much higher antifouling potential than a commercial reference AEM. The work also demonstrated that the chemically assembled functional layer with high stability was suitable for long term application.
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a durable and antifouling Monovalent selective Anion exchange membrane modified by polydopamine and sulfonated reduced graphene oxide
Separation and Purification Technology, 2018Co-Authors: Yali Jin, Congjie Gao, Yan Zhao, Huimin Liu, Arcadio Sotto, Jiangnan ShenAbstract:Abstract Developing a durable and antifouling Monovalent selective Anion exchange membrane is critical in practical electrodialysis (ED) process. Herein, a commercial Anion exchange membrane was modified by sulfonated reduced graphene oxide (S-rGO) and polydopamine (PDA). Inspired by biological adhesion from mussels, the PDA coating on the surface of S-rGO-PDA membrane enhanced the stability of S-rGO nanosheets due to strong adhesion. The Monovalent Anion selectivity was evaluated by means of the Cl - / SO 4 2 - permeselectivity, and stability property was measured by the ion concentration changes of Cl - and SO 4 2 - for a long time application of ED. Moreover, antifouling property was measured by recording the time course of the potential difference in the presence of sodium dodecyl benzene sulfonate (SDBS). The results show that permselectivity of S-rGO-PDA membrane is 2.50, which is higher than pristine membrane (1.08). In addition, S-rGO-PDA membrane is stable, the permselectivity did not change significantly during 70 h ED process. Besides antifouling property of S-rGO-PDA membranes is improved compared with S-rGO membranes.
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sandwich like structure modified Anion exchange membrane with enhanced Monovalent selectivity and fouling resistant
Journal of Membrane Science, 2018Co-Authors: Liang Hao, Yuliang Jiang, Bart Van Der Bruggen, Yan Zhao, Junbin Liao, Arcadio Sotto, Jiajie Zhu, Jiangnan ShenAbstract:Abstract Surface modification is a critical method for fabricating novel Anion exchange membranes (AEMs) with high Monovalent Anion selectivity and desired antifouling property. In this work, we have modified a commercial AEM with “sandwich”-like structure, composed of upper/bottom bilayers of polydopamine (PDA) and sandwich alternating bilayers of poly (sodium 4-styrene sulfonate) (PSS)/hydroxypropyltrimethyl ammonium chloride chitosan-nano silver particles (HACC-Ag Np), aiming to enhance the Monovalent selectivity and fouling resistant for electrodialysis (ED) application. Our investigations suggest that the permselectivity ( P S O 4 2 − C l − ) of the modified AEM with 4.5 bilayers of PSS can reach 5.1, significantly outperforming that of commercial standard AEM (0.98). Due to the electrostatic repulsion resulted from the negatively charged top layer in sandwich structure and hydrophilia of PDA, the time elapsed until the occurrence of fouling (transition time) of the modified AEM (125 min) is much longer than that of the original one (60 min). In addition, anchored silver nanoparticles in sandwich alternating bilayers endow the modified AEMs with effective antibacterial activities of Escherichia coli. These results are indicative of the desired fouling resistant for ED process. The facile fabrication process and superior performances of modified AEM suggest that the as-prepared “sandwich”-like structure modified AEM is potentially applicable in ED for separation of Monovalent and multivalent Anions.
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Electric-pulse layer-by-layer assembled of Anion exchange membrane with enhanced Monovalent selectivity
Journal of Membrane Science, 2018Co-Authors: Yan Zhao, Jiangnan Shen, Ding Jincheng, Jiajie Zhu, Bart Van Der Brugge, Congjie GaoAbstract:Abstract The present study investigates the electric-pulse layer-by-layer assembled of Anion exchange membrane (AEM) by N-O-sulfonic acid benzyl chitosan (NSBC) and hydroxypropyl trimethyl ammonium chloride chitosan (HACC). The constructed NSBC/HACC layers by electric-pulse deposition method with 7.5 bialyers exhibit substantial influence on Monovalent Anions selectivity. The Monovalent Anion selectivity stems from an increased electrostatic repulsion effect for divalent Anions and hydrophilic property of the membrane surface. Remarkably, the separation efficiency of Cl-/SO42- is increased from − 8.93% (unmodified AEM) to 94.43% (constructed 7.5 bilayers on the surface of AEM by electric-pulse deposition method) during 20 min and the permselectivity value is increased from 0.81 to 47.04. Compare to the traditional electrostatic deposition modification and the electro-deposition modification methods, the multilayer constructed by electric-pulse deposition technology with significantly homogeneous and stable Monovalent selective separation multilayer. Besides, the modified AEM shows the higher selectivity than the commercial Monovalent ion-selective AEMs.
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a facile avenue to modify polyelectrolyte multilayers on Anion exchange membranes to enhance Monovalent selectivity and durability simultaneously
Journal of Membrane Science, 2017Co-Authors: Huimin Liu, Huimin Ruan, Jiefeng Pan, Congjie Gao, Bart Van Der Bruggen, Yan Zhao, Arcadio Sotto, Jiangnan ShenAbstract:Abstract Layer-by-layer deposition of polycations and polyAnions multilayers on the surface of Anion exchange membranes (AEMs) is a simple and versatile method to obtain Monovalent Anion selectivity. However, the stability of the polyelectrolyte multilayers (PEMs) can be compromised by the weak interactions formed between the deposited barrier and the pristine membrane surface. In this sense, cross-linking appears as an efficient method to improve the chemical stability of PEMs by covalent bonding. In this investigation, polyelectrolyte multilayers was coated on commercial AEMs by alternating electro-deposition with polystyrene sulfonate (PSS) and 2-hydro-xypropyltrimethyl ammonium chloride chitosan (HACC). Subsequently, photosensitive molecules (4,4-diazostilbene-2,2-disulfonic acid disodium salt (DAS)) were mixed into the loose multilayers by soaking in the DAS solution and chemical bonds were formed in the membrane by UV irradiation. The chemical composition and structure of the membrane were confirmed and observed by infrared spectroscopy, atomic force microscopy and scanning electron microscopy. The Monovalent selectivity and durability were evaluated by electrodialysis (ED) in a Cl - /SO 4 2- system. The optimized membrane was found to have a stable selectivity during the entire duration of testing (76 h), and while a conventional multilayer modified AEMs completely loses its selectivity after 30 h. Furthermore, the modification process improved the Monovalent Anion selectivity from 0.39 to 4.36. The experimental results demonstrate the effectivity and feasibility of the modified strategy.