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37 results on '"Membrane Materials and Processes"'

1. Kosmotropes and chaotropes: Specific ion effects to tailor layer-by-layer membrane characteristics and performances

Author

Anna Casimiro, Cees Weijers, Daniëlle Scheepers, Zandrie Borneman, Kitty Nijmeijer, Membrane Materials and Processes, and EIRES Eng. for Sustainable Energy Systems

Subjects
History, Polymers and Plastics, LbL membranes, Kosmotropes, Filtration and Separation, General Materials Science, Chaotropes, Business and International Management, Physical and Theoretical Chemistry, Specific ion effects, Biochemistry, Industrial and Manufacturing Engineering, Nanofiltration
Abstract

So-called specific ion effects strongly impact physicochemical phenomena in among others, morphologies of polymeric membranes. This can be correlated to the identity of the ions, rather than just to their charge or concentration. We use this effect to tune the properties of layer-by-layer membranes prepared with the polyelectrolytes polydiallyldimethylammonium chloride and polystyrene sodium sulfonate. To systematically study this, membranes were prepared using different salts (NaBr, NH4Cl, MgCl2, NaCl, LiCl, MgSO4, NaH2PO4, (NH4)2SO4, Na2SO4). The specific ion effects were evaluated thanks to the classification of salts and PEs into kosmotropes (well hydrated) and chaotropes (poorly hydrated) following the law of matching water affinities (LMWA). The impact of the type of anions and cations on the multilayer formation and membrane performances was evaluated. Membranes prepared with kosmotropic salts achieved stable performances after only 4 bilayers, and almost 6 times higher water permeabilities than membranes prepared with chaotropic salts without compromising and often even improving the membrane's size exclusion behaviour. The salts used tuned the membranes charge: Kosmotropic salts delivered negatively charged membranes with Na2SO4 and MgCl2 retentions till 97% and 10% respectively, while chaotropic salts formed more positively charged membranes with reversed behaviour with Na2SO4 and MgCl2 rejection of 20 and 89%.

Published
2023
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2. Bottom-up design of porous electrodes by combining a genetic algorithm and a pore network model

Author

van Gorp, Rik, van der Heijden, Maxime, Amin Sadeghi, Mohammad, Gostick, Jeffrey, Forner-Cuenca, Antoni, Membrane Materials and Processes, EIRES Eng. for Sustainable Energy Systems, EIRES Chem. for Sustainable Energy Systems, and EIRES System Integration

Subjects
Genetic algorithm, General Chemical Engineering, Environmental Chemistry, Pore network model, General Chemistry, Porous electrode microstructure, Redox flow batteries, Electrochemical storage, Pore-scale modeling, Industrial and Manufacturing Engineering
Abstract

The microstructure of porous electrodes determines multiple performance-defining properties, such as the available reactive surface area, mass transfer rates, and hydraulic resistance. Thus, optimizing the electrode architecture is a powerful approach to enhance the performance and cost-competitiveness of electrochemical technologies. To expand our current arsenal of electrode materials, we need to build predictive frameworks that can screen a large geometrical design space while being physically representative. Here, we present a novel approach for the optimization of porous electrode microstructures from the bottom-up that couples a genetic algorithm with a previously validated electrochemical pore network model. In this first demonstration, we focus on optimizing redox flow battery electrodes. The genetic algorithm manipulates the pore and throat size distributions of an artificially generated microstructure with fixed pore positions by selecting the best-performing networks, based on the hydraulic and electrochemical performance computed by the model. For the studied VO2+/VO2+ electrolyte, we find an increase in the fitness of 75 % compared to the initial configuration by minimizing the pumping power and maximizing the electrochemical power of the system. The algorithm generates structures with improved fluid distribution through the formation of a bimodal pore size distribution containing preferential longitudinal flow pathways, resulting in a decrease of 73 % for the required pumping power. Furthermore, the optimization yielded an 47 % increase in surface area resulting in an electrochemical performance improvement of 42 %. Our results show the potential of using genetic algorithms combined with pore network models to optimize porous electrode microstructures for a wide range of electrolyte composition and operation conditions.

Published
2023

3. On the impact of the type of anion on the properties of solid-state electrolytes

Author

Anna Casimiro, Kitty Nijmeijer, Membrane Materials and Processes, and EIRES Chem. for Sustainable Energy Systems

Subjects
Polymers and Plastics, Organic Chemistry, sodium salts, Materials Chemistry, solid-state electrolytes, crown-ethers, ionic conductivity, anions
Abstract

Solid-state batteries are a valuable option for sustainable energy storage. Their performance is strongly dependent on the ionic conductivity of the solid-state electrolyte (SSE). The mechanism of ion conduction in solid polymer electrolytes has been extensively studied in terms of flexibility of the polymer chains and their interactions with mobile cations that hop between conduction sites carrying the charge. The role of the counterion (i.e. anion) interacting with both the polymer and the cation has not been explored in detail. In this study we show however, that the anion can severely impact the conduction as well. The effect of the anion (I−, SCN−, BF4− and PF6−) on the thermal, structural and electrical properties of a solid polymer electrolyte (15C5BA polymer) was investigated. The results clearly show that the nature of the anions can be used as a parameter to actually tune the properties of the polymer electrolyte.

Published
2022

4. Time-dependent plasticization behavior of polyimide membranes at supercritical conditions

Author

Kitty Nijmeijer, Menno Houben, Zandrie Borneman, Machiel van Essen, Membrane Materials and Processes, EIRES Eng. for Sustainable Energy Systems, and EIRES Chem. for Sustainable Energy Systems

Subjects
Materials science, Synthetic membrane, CO plasticization, Filtration and Separation, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Biochemistry, General Materials Science, Physical and Theoretical Chemistry, Physics::Atmospheric and Oceanic Physics, chemistry.chemical_classification, Polyimide membrane, Sorption, Polymer, Permeation, Time-dependency, 021001 nanoscience & nanotechnology, Supercritical fluid, 0104 chemical sciences, Membrane, chemistry, Chemical engineering, Permeability (electromagnetism), Astrophysics::Earth and Planetary Astrophysics, 0210 nano-technology, Glass transition, Supercritical CO
Abstract

The time-dependent CO2-induced plasticization behavior of glassy Matrimid® 5218 polymer membranes at supercritical conditions up to 120 bar was investigated. Glassy polyimide membranes were conditioned with both gaseous CO2 and liquid-like sc-CO2. The plasticization behavior during permeation and sorption was correlated with the intrinsic membrane properties and the CO2 fluid properties. In the gaseous region the CO2 concentration increased slightly over time, while in the liquid-like sc-CO2 region the CO2 concentration remained constant over time and showed no hysteresis, indicating an induced glass transition. Contrary to the CO2 sorption the CO2 permeability showed more pronounced time-dependent behavior which increases with feed pressure because of polymer membrane plasticization. Despite the strong time-dependency, the CO2 permeability was independent of the feed pressure in the liquid-like sc-CO2 region. This difference in time-dependent behavior between sorption and permeation is due to the presence of a concentration gradient during permeation experiments. In addition, the permeability showed significant hysteresis. Exposure to liquid-like sc-CO2 resulted in a highly plasticized membrane and changed the permeation behavior at all subsequent feed pressures, due to slow polymer chain relaxation rates. Clearly, these relationships proof that the permeation history is a critical aspect for time-dependent plasticization phenomena at high CO2 pressures.

Published
2021
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5. Predicting reverse electrodialysis performance in the presence of divalent ions for renewable energy generation

Author

Zandrie Borneman, Michel Saakes, Kitty Nijmeijer, Diego Pintossi, Catarina Simões, Membrane Materials and Processes, EIRES Eng. for Sustainable Energy Systems, and EIRES Chem. for Sustainable Energy Systems

Subjects
Materials science, 020209 energy, Energy Engineering and Power Technology, 02 engineering and technology, Ion, 020401 chemical engineering, Stack (abstract data type), Reverse electrodialysis, Reversed electrodialysis, 0202 electrical engineering, electronic engineering, information engineering, Magnesium, SDG 7 - Affordable and Clean Energy, 0204 chemical engineering, Magnesium ion, Ion transporter, Fouling, Renewable Energy, Sustainability and the Environment, Sulfate, Fuel Technology, Membrane, Nuclear Energy and Engineering, Chemical engineering, Uphill transport, Seawater, SDG 7 – Betaalbare en schone energie, Model
Abstract

Reverse electrodialysis (RED) is an electro-membrane process to harvest renewable energy from salinity gradients. RED process models have been developed in the past, but they mostly assume that only NaCl is present in the feedwaters, which results in unrealistically high predictions. In the present work, an existing simple model is extended to accommodate the presence of magnesium ions and sulfate in the feedwaters, and potentially even more complex mixtures. All power loss mechanisms deriving from the presence of multivalent ions are included in the new model: increased membrane electrical resistance, uphill transport of multivalent ions from the river to the seawater compartment, and membrane permselectivity loss. This new model is validated with experimental and literature data of membrane electrical resistance (at 10 mol. % MgCl2 for the CEMs and 25 mol. % Na2SO4 for the AEMs), RED stack performance (up to 50 mol. % MgCl2 or Na2SO4 in the feedwaters), and ion transport (at 10 mol. % MgCl2 or Na2SO4 in the feedwaters) showing very good agreement between model predictions and experimental data. Finally, we showed that the developed model not only describes experimental data but can also predict RED performances under a variety of conditions and cross-flow configurations (single-stage with and without electrode segmentation, multi-stage in co-current and counter-current mode) and feedwater compositions (only NaCl, with Na2SO4, with MgCl2, and with MgSO4). It thus provides a very valuable tool to design and evaluate RED process systems.

Published
2021

6. Permeation of supercritical CO2 through dense polymeric membranes

Author

Kitty Nijmeijer, Zandrie Borneman, Marije Dunnewold, Andrew Shamu, Henk Miedema, and Membrane Materials and Processes

Subjects
Materials science, General Chemical Engineering, 02 engineering and technology, 010402 general chemistry, Thermal diffusivity, Polydimethylsiloxane (PDMS), Widom line, 01 natural sciences, Permeability, chemistry.chemical_compound, Supercritical carbon dioxide, Nafion, Dense membranes, Physical and Theoretical Chemistry, Solubility, Permeation, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Supercritical fluid, 0104 chemical sciences, Permeability (earth sciences), Membrane, chemistry, Chemical engineering, Sorption, 0210 nano-technology
Abstract

Supercritical carbon dioxide (scCO2) is used in the food industry as a water-extracting drying agent. Once saturated with water, the scCO2 needs to be regenerated. A promising way of drying scCO2 is by using H2O permeable membranes. Ideally, these membranes demonstrate low CO2 permeability. Here, we investigated the CO2 permeability of three types of dense membranes, Nafion, Natural Rubber and PDMS, of which the latter in more detail because of its ease of handling. The experimental conditions, temperature and pressure, resulting in minimum CO2 permeability (=losses) were explored. Even though the absolute CO2 permeability depends on the intrinsic membrane material properties, its trend with increasing feed pressure is defined by the (supercritical) behavior of CO2, notably its density as a function of temperature and pressure. The data points to transitions within the supercritical regime, from the gaseous-like supercritical state to the liquid-like supercritical state, graphically visualized by the Widom line for CO2 density. Sorption measurements with PDMS membranes confirm this behavior that follows the diffusion-solution theory. In the gaseous state, the (normalized) permeability follows the (normalized) solubility, indicating a constant CO2 diffusivity. With increasing pressure and when entering the liquid-like (supercritical) regime, the diffusivity drops, resulting in a (normalized) permeability that starts to lag behind the (normalized) solubility.

Published
2019
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7. Role of anion exchange membrane fouling in reverse electrodialysis using natural feed waters

Author

W.M. de Vos, Kitty Nijmeijer, Timon Rijnaarts, Michel Saakes, J. Moreno, Membrane Science & Technology, and Membrane Materials and Processes

Subjects
Humic acids, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Colloid and Surface Chemistry, Reverse electrodialysis, Reversed electrodialysis, medicine, Organic matter, SDG 7 - Affordable and Clean Energy, chemistry.chemical_classification, Ion exchange, Fouling, Chemistry, Membrane fouling, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Anion exchange membranes, Membrane, Chemical engineering, Seawater, Natural water, Swelling, medicine.symptom, 0210 nano-technology, SDG 7 – Betaalbare en schone energie
Abstract

Reverse electrodialysis (RED) is a process to harvest renewable energy from salinity gradients. Under lab conditions with artificial salt solutions, promising results have been achieved in recent years. However, in large scale industrial applications, natural waters are used and that poses challenges such as fouling. Fouling of anion exchange membranes (AEMs) by organic matter (e.g. humic acids) has been identified as a possible cause that lowers RED performance with natural waters. In this work, natural river and seawater at the Afsluitdijk (The Netherlands) are used to study the RED performance of six different AEMs. These AEMs are characterized before and after RED experiments with natural waters. The effect of natural fouling is found to be specific for each AEM and highly dependent on their respective chemistries and associated membrane properties. Firstly, aromatic AEMs with a low swelling degree showed a permselectivity decrease as well as membrane resistance increase. Secondly, aliphatic AEMs with a medium swelling degree experienced only a membrane resistance increase. Finally, only a decrease in permselectivity was observed for aliphatic AEMs with large swelling degrees. Subsequently, the effect of AEM fouling is compared to the observed decrease in RED performance and this shows that AEM fouling can only explain a minor part of the losses in open circuit voltage (OCV). The RED power densities dropped by 15–20% over 12 days, independent of the AEMs selected, while the reduced AEM performance could only explain 2–4% of this reduction in power density. This demonstrates that next to AEM fouling, also other factors, such as spacer fouling, are expected to be the dominant fouling mechanism, reducing the performance to a much larger extent.

Published
2019

8. Multistage electrodialysis for desalination of natural seawater

Author

Zandrie Borneman, Marrit van der Wal, G.J. Doornbusch, Kitty Nijmeijer, Michele Tedesco, Jan W. Post, Membrane Materials and Processes, EIRES Eng. for Sustainable Energy Systems, and EIRES Chem. for Sustainable Energy Systems

Subjects
Multivalent ions, Nacl solutions, Chemistry, Magnesium, Mechanical Engineering, General Chemical Engineering, Sodium, chemistry.chemical_element, Electrodialysis, General Chemistry, Multistage, Desalination, Ion, Energy consumption, Membrane, Chemical engineering, General Materials Science, Seawater, SDG 7 - Affordable and Clean Energy, Natural seawater, SDG 7 – Betaalbare en schone energie, Water Science and Technology
Abstract

Electrodialysis (ED) is receiving increasing attention as promising technology for seawater desalination. However, most of the ED investigations are typically performed using artificial NaCl solutions, while the effect of multivalent ions (such as Mg2+ and Ca2+) on membrane scaling and resistance has been so far overlooked. In this work, we investigate the influence of multivalent ions in seawater on the desalination performance of multistage ED. In particular, natural seawater was used as feed solution, and two different strategies were compared, i.e. by using conventional cation exchange membranes (CEMs), as well as CEMs with preferential removal of multivalent ions. For both CEMs, we found that the removal of calcium and magnesium was higher compared to that of sodium and no effect due to operation at low current density was observed. More magnesium was removed with the multivalent ion permeable CEM. Starting from ~27 g/l (i.e. inlet concentration of the natural seawater source), the upscaled multistage ED system produced a continuous diluate concentration of 1.9 g/l. The system performance was stable over 18 days, with an average energy consumption of 3 kWh/m3, demonstrating the potential of multistage ED seawater desalination.

Published
2021

9. Electrode segmentation in reverse electrodialysis

Author

Wim Brilman, Michel Saakes, Diego Pintossi, Kitty Nijmeijer, Zandrie Borneman, Catarina Simões, Membrane Materials and Processes, EIRES Eng. for Sustainable Energy Systems, EIRES Chem. for Sustainable Energy Systems, and Sustainable Process Technology

Subjects
Work (thermodynamics), Renewable energy, Materials science, General Chemical Engineering, UT-Hybrid-D, Electrode segmentation, 02 engineering and technology, 7. Clean energy, 020401 chemical engineering, Stack (abstract data type), Reverse electrodialysis, Reversed electrodialysis, General Materials Science, SDG 7 - Affordable and Clean Energy, 0204 chemical engineering, Water Science and Technology, Power density, Salinity gradient energy, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, 6. Clean water, Power (physics), Energy efficiency, Electrode, Optoelectronics, 0210 nano-technology, business, SDG 7 – Betaalbare en schone energie, Efficient energy use
Abstract

Reverse electrodialysis harvests energy from salinity gradients establishing a renewable energy source. High energy efficiencies are fundamental to up-scale the process and to minimize feedwater pre-treatment and pumping costs. The present work investigates electrode segmentation to strategically optimize the output power density and energy efficiency. Electrode segmentation allows the current density to be tuned per electrode segment. Segmentation experiments were performed with a dedicated electrode configuration in a cross-flow stack using a wide range of residence times. Moreover, an experimentally validated model was extended and used to further compare single and segmented electrode configurations. While operating the electrode segments, the highest efficiencies were obtained when considering the overall power, i.e. not maximized by segment. Results show that at a given net power density (0.92 W·m−2), electrode segmentation increases the net energy efficiency from 17% to 25%, which is a relative increase of 43%. Plus, at 40% net energy efficiency the net power output for a segmented electrode configuration (0.67 W·m−2) is 39% higher than in a single electrode configuration. Higher power density reduces capital investment and higher energy efficiency reduces operating costs. Electrode segmentation increases these parameters compared to a single electrode and can be potentially applied for up-scaling.

Published
2020

10. Understanding the role of the porous electrode microstructure in redox flow battery performance using an experimentally validated 3D pore-scale lattice Boltzmann model

Author

Sai Gu, Vladimir Yufit, Nigel P. Brandon, Qiong Cai, Oluwadamilola O. Taiwo, Antoni Forner-Cuenca, Fikile R. Brushett, Duo Zhang, Membrane Materials and Processes, and EIRES System Integration

Subjects
Materials science, Lattice Boltzmann methods, Energy Engineering and Power Technology, 02 engineering and technology, Electrolyte, 010402 general chemistry, Electrochemistry, 01 natural sciences, Porous electrodes, SDG 7 - Affordable and Clean Energy, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Composite material, Porosity, X-ray computed tomography, Pressure drop, Lattice Boltzmann model, Renewable Energy, Sustainability and the Environment, Electrochemical performance, Redox flow battery, 021001 nanoscience & nanotechnology, Microstructure, Flow battery, 0104 chemical sciences, Electrode, 0210 nano-technology, SDG 7 – Betaalbare en schone energie
Abstract

The porous structure of the electrodes in redox flow batteries (RFBs) plays a critical role in their performance. We develop a framework for understanding the coupled transport and reaction processes in electrodes by combining lattice Boltzmann modelling (LBM) with experimental measurement of electrochemical performance and X-ray computed tomography (CT). 3D pore-scale LBM simulations of a non-aqueous RFB are conducted on the detailed 3D microstructure of three different electrodes (Freudenberg paper, SGL paper and carbon cloth) obtained using X-ray CT. The flow of electrolyte and species within the porous structure as well as electrochemical reactions at the interface between the carbon fibers of the electrode and the liquid electrolyte are solved by a lattice Boltzmann approach. The simulated electrochemical performances are compared against the experimental measurements with excellent agreement, indicating the validity of the LBM simulations for predicting the RFB performance. Electrodes featuring one single dominant peak (i.e., Freudenberg paper and carbon cloth) show better electrochemical performance than the electrode with multiple dominant peaks over a wide pore size distribution (i.e., SGL paper), whilst the presence of a small fraction of large pores is beneficial for pressure drop. This framework is useful to design electrodes with optimal microstructures for RFB applications.

Published
2020

11. Printed luminescent solar concentrators: artistic renewable energy

Author

Michael G. Debije, Emily L. Bugg, Teun J.L. Wagenaar, Maxime van der Heijden, Jeroen ter Schiphorst, Marx L.M.K.H.Y.K. Cheng, Renee L. Hageman, Stimuli-responsive Funct. Materials & Dev., Membrane Materials and Processes, ICMS Core, and EIRES Chem. for Sustainable Energy Systems

Subjects
business.industry, Computer science, 020209 energy, Mechanical Engineering, Model study, 0211 other engineering and technologies, 02 engineering and technology, Building and Construction, Solar energy, Engineering physics, Sustainable energy, Renewable energy, Electricity generation, 021105 building & construction, 0202 electrical engineering, electronic engineering, information engineering, SDG 7 - Affordable and Clean Energy, Electrical and Electronic Engineering, business, Inkjet printing, SDG 7 – Betaalbare en schone energie, Civil and Structural Engineering
Abstract

The built environment and its direct surroundings show great potential for sustainable energy harvesting but often face the challenge of being integrated with solar energy generators in an aesthetically pleasing manner. In this work, we demonstrate the inkjet printing of luminescent solar concentrators with striking imagery as a promising solution where energy generation and aesthetic possibilities of transparent surfaces become possible. Inkjet printing is used to create a variety of unique patterns for enhanced aesthetics, while a model study explores the effect of patterning and use of multiple colors with this technique on the output of the device.

Published
2020

12. Performance mapping of cation exchange membranes for hydrogen-bromine flow batteries for energy storage

Author

Kitty Nijmeijer, Wiebrand Kout, Zandrie Borneman, Yohanes Antonius Hugo, Friso Sikkema, and Membrane Materials and Processes

Subjects
Hydrogen bromine flow batteries, Water uptake, Materials science, Hydrogen, 020209 energy, Ionic bonding, chemistry.chemical_element, Filtration and Separation, 02 engineering and technology, Biochemistry, Energy storage, Reinforcement, chemistry.chemical_compound, Perfluorosulfonic acid membranes, Membrane, chemistry, Chemical engineering, Bromide, Cation exchange membranes, Proton transport, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Physical and Theoretical Chemistry, Reactive material, Power density
Abstract

Electricity storage is essential for the transition to sustainable energy sources. Hydrogen-bromine flow batteries (HBFBs) are promising cost-effective energy storage systems. In HBFBs, proton exchange membranes are required to separate the two reactive materials, enabling proton transport for charge balancing. In this paper, we present a comprehensive overview of the key properties and an experimental performance map of cation exchange membranes for HBFBs. Our study shows that membrane water uptake is an important property due to its strong correlation with membrane resistance and bromide species crossover. Long chain perfluorosulfonic acid (LC PFSA) membranes are shown to have a better power density–crossover tradeoff and a higher stability than other types of functionalized membranes. The good power density-crossover tradeoff of LC PFSA membranes is the result of the high level of separation of hydrophobic and hydrophilic domains in the membrane, leading to well-connected ionic pathways for proton transport. Reinforcement of long chain LC PFSA membranes further improves their tradeoff because it mechanically constrains the swelling (lower water uptake), resulting in a lower crossover but a similar peak power density. Consequently, reinforced LC PFSA membranes are the most promising option for HBFBs.

Published
2018
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13. Towards controlled fouling and rejection in dead-end microfiltration of nanoparticles : role of electrostatic interactions

Author

Antoine Kemperman, Krzystof W Trzaskus, DC Kitty Nijmeijer, Wiebe M. de Vos, Membrane Materials and Processes, and Membrane Science & Technology

Subjects
Chromatography, Fouling, Chemistry, Microfiltration, Membrane fouling, Nanoparticle, Silica, Filtration and Separation, Biochemistry, law.invention, Membrane technology, Membrane, Chemical engineering, law, Hollow fiber membrane, 2023 OA procedure, General Materials Science, Physical and Theoretical Chemistry, Stability, Filtration
Abstract

Membrane technology proves to be effective in the removal of nano-sized contaminants from water. However, not much is known on the filtration and fouling behavior of manufactured nanoparticles.The high surface-area-to-volume ratio of nanoparticles, significantly increases the effect of surface interactions on the stability of nanoparticle suspensions. Also, the stability of nanoparticle suspensions and their tendency to aggregate strongly affects the fouling mechanism during membrane filtration of nanoparticles. In this experimental study, fouling development and rejection mechanisms of mono-disperse silica model nanoparticles were investigated in great detail.A microfiltration hollow fiber membrane was employed in dead-end filtration mode for the filtration of commercially available silica nanoparticles under constant pressure. By applying a low concentration of nanoparticles and a large difference between the membrane pore size (∼200 nm) and the nominal size of the nanoparticles (22 nm), a detailed investigation of the fouling mechanisms was allowed. Five subsequent fouling stages were postulated: adsorption, unrestricted transport through pores, pore blocking, cake filtration and cake maturation. Higher concentrations of nanoparticles did not change the behavior of these fouling stages, but were found to lead to their acceleration. Fouling severity and occurrence of dynamic transitions between these fouling stages were quantitatively evaluated. The presence of salts, pH and valency of the cation strongly influenced nanoparticle properties and interactions and thus occurrence and character of the fouling stages. Lower repulsive interactions between the nanoparticles accelerate fouling by faster pore blockage and aggregation on the membrane surface. Porosity and permeability of the formed filtration cake layer are strongly dependent on the repulsive interactions between nanoparticles, with a lower repulsion leading to denser cake layers. This paper clearly shows that fouling development and rejection of nanoparticles by microfiltration membranes easily can be adjusted by tuning the electrostatic interactions between the suspended nanoparticles

Published
2015

14. Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: A novel platform for eco-friendly biofouling mitigation

Author

Roni Nugraha, Yusuf Wibisono, Antoine Kemperman, Mohsen Golabi, Wetra Yandi, Emile Cornelissen, Kitty Nijmeijer, Thomas Ederth, Membrane Materials and Processes, and Membrane Science & Technology

Subjects
Environmental Engineering, Biofouling, Hydrogel, Charge, Two-phase flow, Feed spacer, Spiral-wound membrane, Polypropylenes, Hydrogel, Polyethylene Glycol Dimethacrylate, Water Purification, Escherichia coli, Fysik, Reverse osmosis, Waste Management and Disposal, Water Science and Technology, Civil and Structural Engineering, Chromatography, Fouling, Chemistry, Ecological Modeling, Membranes, Artificial, Pollution, Environmentally friendly, Membrane, Chemical engineering, Biofilms, Self-healing hydrogels, 2023 OA procedure, Physical Sciences, Water treatment, Nanofiltration, Filtration
Abstract

Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG(10)MA), cationic (polyDMAEMA) and anionic (polySPMA) hydrogels have been successfully grafted onto polypropylene (PP) feed spacers via plasma-mediated UV-polymerization. These coatings maintained their chemical stability after 7 days incubation in neutral (pH 7), acidic (pH 5) and basic (pH 9) environments. Anti-biofouling properties of these coatings were evaluated by Escherichia coli attachment assay and nanofiltration experiments at a TMP of 600 kPag using tap water with additional nutrients as feed and by using optical coherence tomography. Especially the anionic polySPMA-coated PP feed spacer shows reduced attachment of E. coli and biofouling in the spacer-filled narrow channels resulting in delayed biofilm growth. Employing this highly hydrophilic coating during removal of biofouling by two-phase flow cleaning also showed enhanced cleaning efficiency, feed channel pressure drop and flux recoveries. The strong hydrophilic nature and the presence of negative charge on polySPMA are most probably responsible for the improved antifouling behavior. A combination of polySPMA-coated PP feed spacers and two-phase flow cleaning therefore is promising and an environmentally friendly approach to control biofouling in NF/RO systems employing spiral-wound membrane modules. Funding Agencies|Dutch Ministry of Economic Affairs; Ministry of Infrastructure and Environment; European Union Regional Development Fund; Province of Fryslan; Northern Netherlands Provinces; European Community [237997]

Published
2015
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15. Monovalent-ion-selective membranes for reverse electrodialysis

Author

Michel Saakes, Willem van Baak, Enver Güler, DC Kitty Nijmeijer, Faculty of Science and Technology, Membrane Science & Technology, and Membrane Materials and Processes

Subjects
chemistry.chemical_classification, Electrodialysis reversal, Ion exchange, Chemistry, Inorganic chemistry, Filtration and Separation, Electrodialysis, Biochemistry, Divalent, Ion, Membrane, Reversed electrodialysis, General Materials Science, Physical and Theoretical Chemistry, Selectivity
Abstract

Reverse electrodialysis (RED) is a process that can be used to generate energy from salinity gradients. Since its application in practice requires the use of natural seawater and river water, the presence of multivalent ions is inevitable, but this currently limits RED performance. Membranes with selectivity for monovalent ions may overcome this limitation. Standard ion exchange membranes have low monovalent-ion selectivity. We used a relatively fast method to coat a standard commercial anion exchange membrane to improve its monovalent-ion selectivity. The coating layer was formed by copolymerization of 2-acryloylamido-2-methylpropanesulfonic acid (AMPS) as the active polymer and N,N-methylenebis(acrylamide) (MBA) as the crosslinker, using UV irradiation. The monovalent ion selectivity of the resulting membranes was comparable to that of commercial monovalent-selective membranes. Furthermore, the modified membranes with their negatively charged coating showed increased hydrophilicity and exhibited sufficient antifouling potential against organic foulants. When they were tested in an RED stack, their performance was found to depend especially on the proportion of the divalent ions (sulfate) in the river water stream. However, the use of the currently available monovalent selective membranes was not found to be very effective for obtaining higher gross power densities in RED

Published
2014
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16. Transport limitations in ion exchange membranes at low salt concentrations

Author

Kitty Nijmeijer, Sybrand J. Metz, Matthias Wessling, Piotr Długołęcki, Benoît Anet, Membrane Materials and Processes, Membrane Science & Technology, and Faculty of Science and Technology

Subjects
Microbial fuel cell, Ion exchange, Capacitive deionization, Chemistry, Inorganic chemistry, Chronopotentiometry, Ion transport number, Analytical chemistry, Filtration and Separation, Electrodialysis, METIS-260394, Biochemistry, IR-71501, Membrane, Limiting current density, Reversed electrodialysis, General Materials Science, Membrane resistance, Physical and Theoretical Chemistry, Ion transporter, Ion exchange membrane
Abstract

In this work we show that the electrical resistance of ion exchange membranes strongly depends on the solution concentration: especially at low solution concentrations (

Published
2010
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17. Adsorptive membranes for bilirubin removal

Author

Matthias Wessling, M.E. Avramescu, Zandrie Borneman, W F C Sager, Membrane Science & Technology, Faculty of Science and Technology, and Membrane Materials and Processes

Subjects
Ethylene, Microfiltration, Clinical Biochemistry, Serum albumin, eval, Biochemistry, Analytical Chemistry, IR-49425, chemistry.chemical_compound, Adsorption, Humans, Bovine serum albumin, Aqueous solution, Chromatography, biology, Chemistry, Membranes, Artificial, Bilirubin, Cell Biology, General Medicine, METIS-221778, Membrane, Microscopy, Electron, Scanning, biology.protein, Adsorptive membranes
Abstract

In this study, we employed ethylene vinyl alcohol (EVAL) adsorptive membranes with bovine serum albumin (BSA) as bioligand for affinity supports for bilirubin (BR) retention. Microfiltration membranes were prepared from ternary or quaternary water/(1-octanol)/DMSO/EVAL systems. To obtain active binding sites for BSA, the EVAL membranes were either chemically functionalized in aqueous and organic medium and by plasma dischargement or physically activated by entrapping of active particles. Static BR removal was determined for all EVAL-BSA membranes. BR retentions relevant for human plasma were gained for the mixed adsorber membranes and additionally investigated in the dynamic mode.

Published
2004
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18. Sustainable production of organic acids from chitin biomass catalyzed by Keggin-type heteropolyacid under hydrothermal condition.

Author

Chang Y, Wang Y, Feng Y, Zhu X, and Zang H

Subjects
Catalysis, Formates chemistry, Acetic Acid chemistry, Temperature, Chitin chemistry, Biomass
Abstract

The "shell biorefinery," which valorizes the shell waste chitin into fine chemicals, has developed rapidly in recent years. Herein, we present a novel base-free heteropolyacid-catalyzed oxidation method for the transformation of chitin biomass into organic acid. After a series of optimization experiments, a 5.93 % yield of formic acid and 25.09 % yield of acetic acid were achieved in the presence of 0.5 equivalent of Mo-V-P heteropolyacids (H 4 PMo 11 VO 40 ·2H 2 O) and air at 180 °C under hydrothermal conditions for 4 h. Meanwhile, we have demonstrated that the Keggin-type heteropolyacid catalysts are capable of efficiently converting microcrystalline chitin into organic acids. The synthesized heteropolyacids are well characterized with FT-IR, XRD, ICP-AES, and TGA. The possible reaction pathway was speculated accordingly. This method offers several advantages, including readily available raw materials, simple operation, and relatively higher yield., Competing Interests: Declaration of competing interest Hongjun Zang reports financial support was provided by Tianjin science and technology commission (No. 18JCYBJC87200). Hongjun Zang reports a relationship with Tianjin science and technology commission that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Published
2024
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19. Direct conversion of chitin derived N-acetyl-D-glucosamine into 3-acetamido-5-acetylfuran in deep eutectic solvents.

Author

Wang K, Xiao Y, Wu C, Feng Y, Liu Z, Zhu X, and Zang H

Subjects
Deep Eutectic Solvents, Glucosamine, Solvents chemistry, Choline chemistry, Chitin, Acetylglucosamine
Abstract

3-Acetylamino-5-acetylfuran (3A5AF) is an important nitrogen-containing fine chemical with broad application prospects and high research value. Herein, we report a novel method for the conversion of N-acetyl-d-glucosamine (NAG) to 3A5AF in the choline chloride-based deep eutectic solvents (DESs). The catalytic activities of various DESs have been smoothly screened, and DES 2 (choline chloride/PEG-200/boronic acid = 1/1/0.5) displayed the best catalytic performance. In the absence of any additional solvent, catalyst and additive, product 3A5AF was obtained in 18.3% yield after reacting at 180 °C for 15 min under atmospheric condition. In addition, DES 2 showed a good reusability. The possible reaction pathway was elucidated on the basis of the results of LC-MS and 13 C NMR spectra. This study provided a new perspective for the application of DES in the conversion of chitin biomass., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Published
2023
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20. Valorization of chitin biomass into N-containing chemical 3-acetamido-5-acetylfuran catalyzed by simple Lewis acid.

Author

Zang H, Feng Y, Zhang M, Wang K, Du Y, Lv Y, Qin Z, and Xiao Y

Subjects
Biomass, Spectroscopy, Fourier Transform Infrared, Catalysis, Chitin chemistry, Lewis Acids
Abstract

3-Acetamido-5-acetylfuran(3A5AF) is a nitrogen-containing fine chemical and has broad application prospects and high research value. Herein, we report a mild and efficient method for the synthesis of 3A5AF from N-acetyl-d-glucosamine (NAG). The influence of solvent, temperature and additive on the catalytic performance was also studied. The Lewis acids with high catalytic efficiency have been smoothly screened. The highest yield (41.57%) of 3A5AF was obtained in the presence of B 2 O 3 and MgCl 2 ·6H 2 O at 180 °C for 60 min under normal atmospheric conditions. The reaction pathway was explored by LC-MS, 1 H NMR, 13 C NMR and FT-IR spectra. Compared with the microwave method and hydrothermal method, the optimized reaction condition was relatively mild. Moreover, the catalyst MgCl 2 ·6H 2 O is low-cost and environmentally friendly., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

Published
2022
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21. Novel bacterial cellulose membrane biosynthesized by a new and highly efficient producer Komagataeibacter rhaeticus TJPU03.

Author

He X, Meng H, Song H, Deng S, He T, Wang S, Wei D, and Zhang Z

Subjects
Acetobacteraceae genetics, Acetobacteraceae metabolism, Carbohydrate Conformation, Cellulose chemistry, Cellulose isolation & purification, Particle Size, Phylogeny, Acetobacteraceae chemistry, Cellulose biosynthesis
Abstract

Bacterial cellulose(BC) is a kind of extracellular polymer synthesized by bacteria and it has very wide applications in many fields. However, the application of BC in a large commercial scale can still not be fulfilled due to the low yield and demanding for BC membranes with very different properties. To this end, a new BC-producer Komagataeibacter rhaeticus TJPU03 was isolated from rotten orange peel, which produced 8.28 ± 0.27 g/L(dry weight) in standard HS medium at the 10th day. The membrane is easier to be purified by one-step alkaline treatment and the produced BC(K-BC) membranes possess homogeneous, looser and more porous three-dimensional network composed by thinner cellulose fibrils. However, the wet K-BC possesses stronger mechanical properties and exhibits lower toxicity and higher cytocompatibility to mammalian cell. Owing to the more porous and homogeneous network, K-BC possesses high loading capacity of cell and protein drugs. Also, it exhibits sustained-controlled release ability for proteinaceous drug. The high yield of this strain and the special characteristics of K-BC predict this strain to be a very promising BC-producer and broad applications of K-BC in the fields of wound healing, scaffolds of tissue engineering, tissue repair and regeneration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Published
2020
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22. Efficient conversion of N-acetyl- D -glucosamine into nitrogen-containing compound 3-acetamido-5-acetylfuran using amino acid ionic liquid as the recyclable catalyst.

Author

Wang J, Zang H, Jiao S, Wang K, Shang Z, Li H, and Lou J

Abstract

Chitin is the most widely distributed oceanic biomass resources. Its monomer unit, N-acetyl- D -glucosamine (NAG), contains precious atomic nitrogen and represents a potential feedstock for the manufacture of regenerative organic nitrogen chemicals. Herein, the conversion of NAG to the platform chemical, 3-acetamido-5-acetylfuran (3A5AF), catalyzed by amino acid ionic liquids, was investigated. The reaction, catalyzed by a very small amount of glycine chloride ionic liquid without any additives, could yield 43.22% 3A5AF in 10 min. By adding CaCl 2 , a higher yield up to 52.61% was obtained. This work demonstrated the conversion of chitin biomass to 3A5AF in higher yield without using a boron-based catalyst for the first time. Moreover, the ionic liquid catalyst exhibited excellent recyclability, and afforded 43.22-36.59% yield over during eight cycles. This research provides new and green procedures to convert shellfish fishery waste into value-added platform chemicals., (Copyright © 2019. Published by Elsevier B.V.)

Published
2020
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23. Removal of antibiotics (sulfamethazine, tetracycline and chloramphenicol) from aqueous solution by raw and nitrogen plasma modified steel shavings.

Author

Tran VS, Ngo HH, Guo W, Ton-That C, Li J, Li J, and Liu Y

Abstract

The removal of sulfamethazine (SMT), tetracycline (TC) and chloramphenicol (CP) from synthetic wastewater by raw (M 3 ) and nitrogen plasma modified steel shavings (M 3 -plN 2 ) was investigated using batch experiments. The adsorption kinetics could be expressed by both pseudo-first-order kinetic (PFO) and pseudo-second-order kinetic (PSO) models, where correlation coefficient r 2 values were high. The values of PFO rate constant k 1p and PSO rate constant k 2p decreased as SMT-M 3 >SMT-M 3 -plN 2 >TC-M 3 -plN 2 >TC-M 3 >CP-M 3 >CP-M 3 -plN 2 and SMT-M 3 >SMT-M 3 -plN 2 >TC-M 3 >TC-M 3 -plN 2 >CP-M 3 >CP-M 3 -plN 2 , respectively. Solution pH, adsorbent dose and temperature exerted great influences on the adsorption process. The plasma modification with nitrogen gas cleaned and enhanced 1.7-fold the surface area and 1.4-fold the pore volume of steel shavings. Consequently, the removal capacity of SMT, TC, CP on the adsorbent rose from 2519.98 to 2702.55, 1720.20 to 2158.36, and 2772.81 to 2920.11μg/g, respectively. Typical chemical states of iron (XPS in Fe2p3 region) in the adsorbents which are mainly responsible for removing antibiotics through hydrogen bonding, electrostatic and non- electrostatic interactions and redox reaction were as follows: Fe 3 O 4 /Fe 2+ , Fe 3 O 4 /Fe 3+ , FeO/Fe 2+ and Fe 2 O 3 /Fe 3+ ., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Published
2017
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24. Carbon nanotube-reinforced mesoporous hydroxyapatite composites with excellent mechanical and biological properties for bone replacement material application.

Author

Li H, Song X, Li B, Kang J, Liang C, Wang H, Yu Z, and Qiao Z

Subjects
Bone Substitutes, Bone and Bones, Cell Adhesion, Durapatite, Osteoblasts, Porosity, Nanotubes, Carbon
Abstract

Carbon nanotube (CNT)-reinforced mesoporous hydroxyapatite (HA) composites with excellent mechanical and biological properties were fabricated successfully by the in situ chemical deposition of mesoporous HA on homogeneously dispersed CNTs. The CNTs are first synthesized in situ on HA nanopowders by chemical vapor deposition, and then, the HA particles with mesoporous structures are deposited in situ onto the as-grown CNTs by using cetyl trimethyl ammonium bromide as templates to form mesoporous HA encapsulated CNTs (CNT@meso-HA). The modification of CNTs by mesoporous HA leads to strong CNT-HA interfacial bonding, resulting in efficient load transfer between CNT and HA and improved mechanical properties of CNT/HA composites. More importantly, the mesoporous HA structure has a high specific surface area and large surface roughness that greatly promote the cell adhesion and proliferation, resulting in better biocompatibility and improved osteoblast viability (MC3T3-E1) compared to those fabricated by traditional methods. Therefore, the obtained CNT@meso-HA composites are expected to be promising materials for bone regeneration and implantation applications., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Published
2017
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25. Hydrothermal conversion of N-acetyl-d-glucosamine to 5-hydroxymethylfurfural using ionic liquid as a recycled catalyst in a water-dimethyl sulfoxide mixture.

Author

Zang H, Yu S, Yu P, Ding H, Du Y, Yang Y, and Zhang Y

Subjects
Catalysis, Furaldehyde chemical synthesis, Furaldehyde chemistry, Molecular Structure, Recycling, Acetylglucosamine chemistry, Dimethyl Sulfoxide chemistry, Furaldehyde analogs & derivatives, Imidazoles chemistry, Ionic Liquids chemistry, Temperature, Water chemistry
Abstract

Here, N-acetyl-d-glucosamine (GlcNAc), the monomer composing the second most abundant biopolymer, chitin, was efficiently converted into 5-hydroxymethylfurfural (5-HMF) using ionic liquid (IL) catalysts in a water/dimethyl sulfoxide (DMSO) mixture solvent. Various reaction parameters, including reaction temperature and time, DMSO/water mass ratios and catalyst dosage were optimized. A series of ILs with different structures were analyzed to explore their impact on GlcNAc conversion. The substrate scope was expanded from GlcNAc to d-glucosamine, chitin, chitosan and monosaccharides, although 5-HMF yields obtained from polymers and other monosaccharides were generally lower than those from GlcNAc. Moreover, the IL N-methylimidazolium hydrogen sulfate ([Hmim][HSO 4 ]) exhibited the best catalyst performance (64.6% yield) when GlcNAc was dehydrated in a DMSO/water mixture at 180 °C for 6 h without the addition of extra catalysts. To summarize, these results could provide knowledge essential to the production of valuable chemicals that are derived from renewable marine resources and benefit biofuel-related applications., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Published
2017
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26. New fluorescence probe for Fe³⁺ with bis-rhodamine and its application as a molecular logic gate.

Author

Yan F, Zheng T, Guo S, Shi D, Han Z, Zhou S, and Chen L

Subjects
Cell Line, Ferric Compounds chemistry, Fluorescence, Fluorescent Dyes chemistry, Humans, Iron chemistry, Molecular Imaging methods, Molecular Probe Techniques, Molecular Structure, Spectrophotometry, Ultraviolet, Sulfur chemistry, Iron analysis, Molecular Probes chemistry, Rhodamines chemistry
Abstract

A bis-rhodamine based fluorescent probe R1 for naked-eye detection of Fe(3+) with enhanced sensitivity compared to a mono-rhodamine derivative that shows selectivity for Hg(2+), has been synthesized. The 1:1 stoichiometric structure of R1 and Fe(3+) is confirmed using a Job's plot estimation and density functional theory calculations. The reversibility of R1 is verified through its spectral response toward Fe(3+) and S(2-) titration experiments. Using Fe(3+) and S(2-) as chemical inputs and the fluorescence intensity signal as outputs, R1 can be utilized as an INHIBIT logic gate at molecular level. Fluorescent imaging for Fe(3+) in living HL-7702 cells have also been successfully performed., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Published
2015
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27. Highly sensitive Fe₃O₄ nanobeads/graphene-based molecularly imprinted electrochemical sensor for 17β-estradiol in water.

Author

Li Y, Zhao X, Li P, Huang Y, Wang J, and Zhang J

Subjects
Graphite, Limit of Detection, Molecular Imprinting methods, Polymerization, Sensitivity and Specificity, Spectrum Analysis, Raman, Water analysis, Water Pollutants, Chemical analysis, X-Ray Diffraction, Electrochemical Techniques instrumentation, Electrochemical Techniques methods, Estradiol analysis, Ferrosoferric Oxide chemistry, Nanostructures chemistry
Abstract

A novel molecularly imprinted electrochemical sensor based on Fe3O4 nanobeads immobilized on graphene (Fe3O4-MIP@RGO) has been developed for detecting 17β-estradiol (17β-E2) in water using reversible addition fragmentation chain transfer (RAFT) polymerization technique. 17β-E2 can be detected by this electrochemical sensor through the response current change before and after binding 17β-E2. The Fe3O4-MIP@RGO-based sensor amplifies the response current in differential pulse voltammetry measurement, allowing the detection limit reaching 0.819 nM in a wide linear range from 0.05 to 10 μM. Moreover, Fe3O4-MIP@RGO-based sensor exhibits high selectivity and sensitivity towards 17β-E2. This MIP electrochemical sensor has a promising potential in the detection of 17β-E2 in water., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Published
2015
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28. Highly luminescent organosilane-functionalized carbon dots as a nanosensor for sensitive and selective detection of quercetin in aqueous solution.

Author

Zou Y, Yan F, Zheng T, Shi D, Sun F, Yang N, and Chen L

Subjects
Citric Acid chemistry, Luminescence, Quercetin chemistry, Solubility, Solutions, Water chemistry, Carbon chemistry, Nanostructures chemistry, Quercetin analysis, Silanes chemistry
Abstract

The organosilane-functionalized carbon dots (SiCDs) were synthesized using citric acid with N-(b-aminoethyl)-g-aminopropyl methyldimethoxy silane (AEAPMS). The as-synthesized SiCDs were characterized by IR, TEM, XPS, NMR and fluorescence. The SiCDs showed a strong emission at 455 nm with excitation at 365 nm. The SiCDs exhibited analytical potential as sensing probes for quercetin (QCT) determination. pH effect, temperature effect, interferences, and analytical performance of the method were investigated. It suggested that SiCDs exhibited high sensitivity and selectivity toward QCT: the linear ranges of SiCDs were estimated to be 0-40 μM while the limit of detection (LOD) was calculated to be 79 nM., (Copyright © 2015. Published by Elsevier B.V.)

Published
2015
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29. Adsorption of phthalic acid esters (PAEs) by amphiphilic polypropylene nonwoven from aqueous solution: the study of hydrophilic and hydrophobic microdomain.

Author

Zhou X, Wei J, Zhang H, Liu K, and Wang H

Subjects
Adsorption, Amines chemistry, Epoxy Compounds chemistry, Esters, Hydrophobic and Hydrophilic Interactions, Methacrylates chemistry, Solutions, Textiles, Water Purification methods, Dibutyl Phthalate chemistry, Diethylhexyl Phthalate chemistry, Polypropylenes chemistry, Water Pollutants, Chemical chemistry
Abstract

A kind of amphiphilic polypropylene nonwoven with hydrophilic and hydrophobic microdomain was prepared through electron beam induced graft polymerization and subsequent ring opening reaction and then utilized in the adsorption of phthalic acid esters (PAEs). To elucidate the superiority of such amphiphilic microdomain, a unique structure without hydrophilic part was constructed as comparison. In addition, the adsorption behaviors including adsorption kinetics, isotherms and pH effect were systematically investigated. The result indicated that the amphiphilic structure and the synergy between hydrophilic and hydrophobic microdomain could considerably improve the adsorption capacities, rate and affinity. Particularly the existence of hydrophilic microdomain could reduce the diffusion resistance and energy barrier in the adsorption process. These adsorption results showed that the amphiphilic PP nonwoven have the potential to be used in environmental application., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Published
2014
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30. A rhodamine derivative as selective fluorescent and colorimetric chemosensor for mercury (II) in buffer solution, test strips and living cells.

Author

Wang M, Yan FY, Zou Y, Yang N, Chen L, and Chen LG

Subjects
Buffers, Cations, Divalent analysis, Cell Line, Colorimetry methods, Drinking Water analysis, Humans, Limit of Detection, Models, Molecular, Optical Imaging methods, Spectrometry, Fluorescence methods, Fluorescent Dyes chemistry, Mercury analysis, Rhodamines chemistry
Abstract

In this paper, we reported a new rhodamine derivative bearing 2,4-dichloroquinazoline as a selective fluorescent chemosensor for Hg(2+). The ring-opening process of spirolactam enabled the large fluorescent enhancement and colorimetric change by Hg(2+) induced configuration transformation of the rhodamine. Moreover, the fluorescence changes of the chemosensor were dramatically specific for Hg(2+) in the presence of other metal ions, which could meet the selective requirements for practical application. Under optimized experimental conditions, the linear response range covered the concentration range of Hg(2+) from 0 to 1.0×10(-6)M, and the limit of detection was calculated to be 2.7×10(-8)M. In addition, the probe was also successfully applied to the determination of Hg(2+) in water samples, test strips and living cells., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Published
2014
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31. Preparation and adsorption of bovine serum albumin-imprinted polyacrylamide hydrogel membrane grafted on non-woven polypropylene.

Author

Zhao K, Lin B, Cui W, Feng L, Chen T, and Wei J

Subjects
Adsorption, Calorimetry, Differential Scanning, Microscopy, Electron, Scanning, Spectroscopy, Fourier Transform Infrared, Thermogravimetry, Acrylic Resins chemistry, Membranes, Artificial, Polypropylenes chemistry, Serum Albumin, Bovine chemistry
Abstract

Bovine serum albumin (BSA) imprinted polypropylene (PP) fiber-grafted polyacrylamide (PAM) hydrogel membrane (PP-g-PAM MIP) was prepared using non-woven PP fiber as matrix, BSA as template molecule, and acrylamide (AM) as functional monomer via UV radiation-reduced polymerization in an aqueous phase. SEM, FT-IR, DSC and TG were used to characterize the PP grafted PAM hydrogel. Influence factors on the adsorption capacity of PP-g-PAM MIP were investigated, such as monomer concentration, cross-linker concentration, template molecule amount and pH values in BSA solution. The adsorption and recognition properties of PP-g-PAM MIP were evaluated and the results showed that the PP-g-PAM MIP exhibited an obvious improvement in terms of adsorption capacity for BSA as compared with non-imprinted ones. PP-g-PAM MIPs could recognize the template protein using Lys, Ova, BHb, and Glo as control proteins, and the selectivity factor (β) was above 2.0. The imprinting efficiency of PP-g-PAM MIP tended to be stable after three cycles and maintained 76% of the initial value of the imprinting efficiency even after five repetitions, which was more excellent than that of PAM microsphere. The PP-g-PAM MIP is low cost and easy to be prepared, which would show its potential applications in the fields of extracting and testing required proteins from cells or particulate samples., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Published
2014
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32. Schwertmannite as a new Fenton-like catalyst in the oxidation of phenol by H2O2.

Author

Wang WM, Song J, and Han X

Subjects
Catalysis, Hydrogen-Ion Concentration, Microscopy, Electron, Transmission, Oxidation-Reduction, Hydrogen Peroxide chemistry, Iron Compounds chemistry, Phenol chemistry
Abstract

In this study, schwertmannite was prepared through a hydrothermal method and used as a new Fenton-like catalyst in the oxidation of phenol by H2O2. The synthesized iron oxide had a formula of Fe8O8(OH)4.5(SO4)1.75 with a weak crystalline structure as well as a high specific surface area of 325.52 m(2) g(-1). However, schwertmannite has not been used as a Fenton-like catalyst so far, and its catalytic mechanism in the oxidation of phenol is still unknown. This study confirmed that schwertmannite had a good catalytic activity in the oxidation of phenol via a OH radical mechanism. The free radicals could be generated on the schwertmannite surface by ≡ Fe(III) species and in bulk solution by dissolved Fe(III) over a wide pH range. The synthesized schwertmannite also showed a high catalytic ability in the oxidation of phenol in the presence of 0.5M nitrate, chloride or sulfate anions at initial pH 5.0, indicating its potential application in the treatment of high salinity wastewater. In addition, phenol removal percentage could still reach 98% after schwertmannite was successively used for 12 cycles, indicating the good reusability of this catalyst, although a phase transformation of schwertmannite to goethite was observed., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Published
2013
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33. Abiotic oxidation of Mn(II) induced oxidation and mobilization of As(III) in the presence of magnetite and hematite.

Author

Ren HT, Jia SY, Wu SH, Liu Y, Hua C, and Han X

Subjects
Adsorption, Oxidation-Reduction, Arsenic chemistry, Ferric Compounds chemistry, Ferrosoferric Oxide chemistry, Manganese chemistry, Water Pollutants, Chemical chemistry
Abstract

Manganese (hydr)oxides are powerful oxidants mediating the transformation of As(III) to As(V) under natural conditions, however, the presence of Mn(II) on the oxidation of As(III) in the pH range of 7.0-9.0 has not been reported so far. In this study, abiotic oxidation of Mn(II) to amorphous Mn(III, IV) (hydr)oxides (MnOx) on magnetite and hematite was confirmed, and the impact of newly formed MnOx on the fate of As(III) was investigated. With the addition of Mn(II) into As(III)-preloaded systems, the dissolved and the adsorbed As(III) was oxidized to As(V) at high pH, and Mn(II) mobilized the adsorbed As(III) and As(V) in hematite system. High production of dissolved As(V) and significant mobilization of As(III) were even more significant in hematite suspension (total As was 18.96 mgL(-1) after 60 h at pH 8.62) with simultaneous addition of Mn(II) and As(III), while magnetite showed a higher capacity for the retention of As(III) and As(V). It could therefore be deduced that the newly formed MnOx on iron oxides could oxidize the dissolved and the adsorbed As(III) to As(V). In addition, the MnOx formed at high pH would take up the sorption sites previously occupied by the adsorbed As(III), and then mobilized a fraction of the adsorbed As(III) into solution. The present study reveals that MnOx formed via abiotic oxidation on iron oxides plays an important role in the oxidation and mobilization of both dissolved and adsorbed As(III) in aquatic environment., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Published
2013
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34. Temperature-sensitivity and cell biocompatibility of freeze-dried nanocomposite hydrogels incorporated with biodegradable PHBV.

Author

Zhang Q, Chen L, Dong Y, and Lu S

Subjects
Acrylic Resins pharmacology, Biodegradation, Environmental, Calorimetry, Differential Scanning, Cell Proliferation drug effects, Hep G2 Cells, Humans, Hydrogels chemistry, Kinetics, Microscopy, Electron, Scanning, Phase Transition drug effects, Silicates pharmacology, X-Ray Diffraction, Biocompatible Materials pharmacology, Freeze Drying, Hydrogels pharmacology, Materials Testing, Nanocomposites chemistry, Polyesters pharmacology, Temperature
Abstract

The structure, morphology, thermal behaviors and cytotoxicity of novel hydrogels, composed of poly(N-isopropylacrylamide)(PNIPAM) and biodegradable polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) under nanoclay hectorite "Laponite XLG" severed as physical cross-linker, were characterized by X-ray diffraction, scanning electron microscopy, gravimetric method, differential scanning calorimetry, and cell culture experiments. It was found that, due to the introduction of hydrophobic PHBV, the homogeneity of interior pore in the pure PNIPAM nanocomposite hydrogel was disrupted, the transparency and swelling degree gradually decreased. Although the weight ratio between PHBV and NIPAM increased from 5 to 40 wt.%, the volume phase transition temperature (VPTTs) of hydrogel were not altered compared with the pure PNIPAM nanocomposite hydrogel. No matter what PHBV content, the PHBV/PNIPAM/Hectorite hydrogels always exhibit good stimuli-responsibility. In addition, human hepatoma cells(HepG2) adhesion and spreading on the surface of PHBV-based hydrogels was greatly improved than that of pure PNIPAM nanocomposite hydrogel at 37 °C due to the introduction of PHBV., (Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.)

Published
2013
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35. A rhodamine based fluorescent probe for Hg2+ and its application to cellular imaging.

Author

Yan F, Cao D, Yang N, Wang M, Dai L, Li C, and Chen L

Subjects
Animals, Cations, Divalent analysis, Cell Line, Fibroblasts cytology, Fluorescent Dyes chemical synthesis, Limit of Detection, Mice, Microscopy, Fluorescence methods, Rhodamines chemical synthesis, Spectrometry, Fluorescence methods, Fibroblasts chemistry, Fluorescent Dyes chemistry, Mercury analysis, Molecular Imaging methods, Rhodamines chemistry
Abstract

A new rhodamine-based fluorescent probe (Rh-F) for detection of Hg(2+) ions was synthesized, which could bind Hg(2+) in aqueous ethanol (7:3, v/v) at pH 7.0 with detectable change in color and fluorescence. The response is based on a ring opening reaction and formation of a 1:1 complex, while ring-opening process of spirolactam enables large fluorescent enhancement and colorimetric change upon the addition of Hg(2+). The response is reversible and linear in the range between 200nM and 1000nM, with a detection limit of 4.2nM. Selectivity and competition experiments with various other metal ion revealed that Rh-F possesses highly selective fluorescent response to Hg(2+). Furthermore, the probe was successfully applied to fluorescent imaging of Hg(2+) in L-929 cells confirm that Rh-F can be used as a fluorescent probe for monitoring Hg(2+) in living cells., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Published
2013
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36. Evaluation of the influence of homopolymerization on the removal of water-insoluble organics by grafted polypropylene fibers.

Author

Li S and Wei J

Subjects
Adsorption, Chemical Hazard Release, Polymerization, Ultraviolet Rays, Water Pollutants, Chemical chemistry, Water Purification methods, Environmental Restoration and Remediation methods, Polypropylenes chemistry, Water Pollutants, Chemical analysis
Abstract

Lauryl acrylate (LA) grafted polypropylene (PP) fibers (PP-g-LA) were prepared via ultraviolet radiation and used to adsorb insoluble organics from aqueous solutions. The grafted fibers showed a maximum adsorption capacity of 18.85 g/g for benzene, while the adsorption capacity of the original PP fiber was only 8.21 g/g. However, graft polymerization is usually accompanied by the homopolymerization phenomenon, which is detrimental to practical applications of the grafted fiber. Homopolymerization negatively affected the adsorption capacities and the reusabilities of the grafted fibers, which decreased with increasing rates of homopolymerization. The adsorption capacity of grafted fiber with a homopolymerization rate of 18.40% was maintained above 85% of its initial adsorption capacity after being regenerated 10 times, while the adsorption capacity of the grafted fiber with a homopolymerization rate of 70.51% was approximately 40% of its initial capacity after 10 regenerations., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Published
2012
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37. Sulfur removal from fuel using zeolites/polyimide mixed matrix membrane adsorbents.

Author

Lin L, Wang A, Dong M, Zhang Y, He B, and Li H

Subjects
Adsorption, Microscopy, Electron, Scanning, Spectroscopy, Fourier Transform Infrared, Hydrocarbons chemistry, Imides chemistry, Membranes, Artificial, Sulfur isolation & purification, Zeolites chemistry
Abstract

A novel membrane adsorption process was proposed for the sulfur removal from fuels. The mixed matrix membranes (MMMs) adsorbents composed of polyimide (PI) and various Y zeolites were prepared. By the detailed characterization of FT-IR, morphology, thermal and mechanical properties of MMMs adsorbents, combining the adsorption and desorption behavior research, the process-structure-function relationship was discussed. Field-emission scanning electron microscope (FESEM) images show that the functional particles are incorporated into the three-dimensional network structure. MMMs adsorbents with 40% of zeolites content possess better physical properties, which was confirmed by mechanical strength and thermo stability analysis. Influence factors including post-treatment, content of incorporated zeolites, adsorption time, temperature, initial sulfur concentration as well as sulfur species on the adsorption performance of MMMs adsorbents have been evaluated. At 4 wt.% zeolites content, adsorption capacity for NaY/PI, AgY/PI and CeY/PI MMMs adsorbents come to 2.0, 7.5 and 7.9 mg S/g, respectively. And the regeneration results suggest that the corresponding spent membranes can recover about 98%, 90% and 70% of the desulfurization capacity, respectively. The distinct adsorption and desorption behavior of MMMs adsorbents with various functional zeolites was markedly related with their various binding force and binding mode with sulfur compounds., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Published
2012
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