Anthony Szymczyk

Université de Rennes 1 | UR1 · Institut des Sciences Chimiques de Rennes (ISCR) - UMR CNRS 6226

Organic solvent nanofiltration (OSN) has recently proved to be a promising separation process thanks to the development of membrane materials with suitable resistance toward organic solvents. Among those materials, P84 polyimide membranes are currently the most used in OSN while PIM-1 membranes have recently attracted attention due to their high pe...

Rare earth elements are considered as raw substances for several high technological material, they are extracted and furnished by a limited number of country, while the need for these critical elements continue to grow strongly to incite exploration of a new resources. In this purposes, we propose in our work, an alternative way to achieve rare ear...

High energy consumption during harvesting is one of the main bottlenecks for sustainable microalgae production. Membranes can efficiently separate microalgae from liquids with low energy consumption, but membrane fouling remains an important issue. Flocculation prior to membrane filtration can increase membrane fluxes and decrease fouling, thus off...

Oxidative modification is a facile method to improve the desalination performance of thin-film composite membranes. In this study, we comparatively investigated the modification mechanisms induced by sulfate radical (SO4• -) and hydroxyl radical (HO•) for polyamide reverse osmosis (RO) membrane. The SO4• -- and HO•-based membrane modifications were...

Safe water provision in low-income countries is constrained by limited financial resources, and the problem is worsened during natural disasters. Thus, there is a need to develop efficient low-cost technologies for point-of-use water treatment. This work reports on the development of new ceramic microfiltration membranes made from mixtures of inexp...

In this work, a molecular scale study of the interactions between a polymer with intrinsic microporosity (PIM-1) membrane and toluene, methanol and their mixtures was performed by means of molecular dynamics simulations. From the radial distribution functions we highlight specific interactions between the hydroxyl group of methanol and the aromatic...

In this work, the relationship between the water flux through nanoporous two-dimensional hexagonal Boron Nitride (h-BN) and surface tension was investigated from equilibrium and pressure-driven molecular dynamics simulations by considering the most popular rigid water models. From the surface tension calculation, the contact angle was evaluated and...

This study assesses the feasibility of designing a hybrid ozonation / nanofiltration membrane process that can simultaneously oxidize and reject contaminants while exhibiting reduced membrane fouling. An innovative monophasic configuration, in which a pre-ozonated water was mixed at the membrane cell inlet to the water to be treated doped with H2O2...

Despite the growing interest in membrane filtration for biorefining of microalgae, few works have dealt with membrane regeneration after fouling by such specific vegetable products. The current procedure still requires large volumes of cleaning solutions, which leads to additional energy and water consumption with a substantial environmental impact...

The use of characterization techniques helps membrane scientists and engineers to follow a membrane throughout its life. Characterization tests can inspect membrane samples right after fabrication in order to check if a membrane batch meets expectations. Later, they become vital for rationalizing membrane separation performance and propensity to fo...

The present work examines, for the first time, the use of thiolated graphene oxide (TGO), in polyelectrolyte composite membranes as an effective approach to enhance the MFC performance. A new composite membrane based on a sulfonated polyethersulfone (SPES) hybrid with GO, sulfonated GO (SGO), and TGO was fabricated and assessed in MFC. The blend me...

Biomimetic forward osmosis membranes with a polyamide-based active layer containing polymersomes incorporating aquaporins were exposed to various free chlorine doses (free chlorine concentration x exposure time) and pH. Membrane chlorination was found to decrease the apolar/polar balance of the membrane surface energy and to increase its negative s...

In this work the parallel component of the static dielectric permittivity, ϵ II of ionic liquids ultraconfined into flexible carbon nanotubes of radius of 1.2 nm and 2.4 nm is evaluated from molecular dynamics simulations. We show an enhancement of ϵ II with respect to bulk value and a counter-intuitive temperature dependence. Indeed an increase of...

According to the developed bioinspired method in the one-step procedure, the material with the petal effect was switched to lotus one. Therefore, highly hydrophobic and super-hydrophobic materials with tunable adhesive properties and fractal-like structures were successfully produced with high efficiency (67-84%). The work's essence was to modify c...

The transport phenomena across polymeric membrane may be enhanced by applying various strengths inside or outside the system. Recently, polymer inclusion membrane (PIM) has been considered one of the most popular methods that acts as a sink for the contaminant and immobilizes it. In the literature, there is no report about how to achieve the synthe...

Membranes have a lot of potential for harvesting microalgae, but membrane fouling is hampering their breakthrough. In this study, the effects of charge and corrugated surface on membrane filtration performance were investigated. The clean water permeance (CWP), the microalgae harvesting efficiency and the membrane flux for a microalgal broth were d...

Rare earths are critical elements in our modern societies and the ever-increasing demand raises fears of supply risks in the coming years. This work dealt with the feasibility of extracting rare earth elements (REEs) from an industrial waste product from the exploitation of phosphate ores of “Djebel Onk” in Tébessa eastern region of Algeria. The so...

Harvesting efficiency is one of the key issues restricting the further commercialization of microalgae. Traditional biofilm studies only tend to focus on enhancing biofilm formation, while neglecting the subsequent harvesting of the biofilm. In this study, a win–win strategy for high-density microalgal cultivation and low-cost harvesting through bi...

Ozone is a strong oxidant applied in water treatment for disinfection and organic and inorganic pollutants removal. It can be coupled with membrane processes as a pre-treatment or post-treatment as well as in a hybrid configuration. In this study, we investigated the resistance of three commercial polymer nanofiltration membranes (NP10, NF90 and NF...

Recycling rare earth elements (REEs) contained in electronic waste is of utmost importance due to their ever-increasing use in the high-tech sector. In this context, the use of non-polluting techniques represents a real challenge for scientists. In this work, we demonstrated that a clean and energy-efficient process, diffusion dialysis, has great p...

Thanks to its unique features, membrane distillation (MD) has been particularly applied for desalination but also for niches applications with feed solutions containing a mixture of volatile molecules. For such solutions, the complex interplay of the solutes and solvent physicochemical and operating parameters makes it challenging to predict the se...

State-of-the-art desalination and water purification processes use reverse osmosis and nanofiltration membranes. Their thin polyamide (PA) top-layers ensure concurrent high water permeances and salt rejections, but are also intrinsically sensitive to chlorine, originating from disinfectant added upstream. The chlorine resistance of PA-based membran...

p> Thanks to its unique features, membrane distillation (MD) has been particularly applied for desalination but also for niches applications with feed solutions containing a mixture of volatile molecules. For such solutions, the complex interplay of the solutes and solvent physicochemical and operating parameters makes it challenging to predict t...

The desalination performance (water permeability and salt rejection) of both uncharged and charged multi‐walled carbon nanotubes (MWCNTs) is computationally assessed by means of pressure‐driven molecular dynamics simulations. It is shown that the performance of these materials surpass that of the widely used polyamide reverse osmosis membranes and...

Heterogeneous catalysts were synthesized with a glass foam support mainly composed of recycled glass and impregnated with zerovalent ruthenium nanoparticles (aiming to 0.1 wt.% ruthenium). Different glass foams were developed, playing on the nature and quantity of foaming/doping agents as well as the operating conditions (heat temperature and time...

The only methods to increase water supply beyond what is available from the hydrological cycle are desalination and water reuse. Of particular relevance for water purification are micro‐ and ultrafiltration membranes with a porous barrier enabling separation of particles mainly based on size, and nanofiltration and reverse osmosis membranes with a...

Tangential electrokinetic measurements are widely used to characterize membrane fouling as the membrane zeta potential is partly governed by the presence of foulant materials on its surface. However, in the case of porous materials as micro- (MF) and ultrafiltration (UF) membranes, a part of the streaming current flows through the porosity of the m...

In this study, novel polyethersulfone (PES) membranes were blended for the first time with nano­ composites from the system (ZnO­TiO 2 ­SiO 2 ­CeO 2). The obtained composite membranes by wet­ phase inversion method were subsequently characterized and finally used for the filtration of lysozyme solutions. The incorporation of 0.25 wt.% of the ternar...

We report a new approach to fabricate an efficient 3D glucose bioanode based on the co-immobilization of the enzyme glucose dehydrogenase (GDH), its cofactor NADP, and Multiwall Carbon Nanotubes (MWCNTs) coated with poly (methylene green) (PMG). The MWCNT-PMG composite was obtained by chemical polymerization of methylene green (MG) monomer on the M...

In this work, PES (polyethersulfone) /PVP (Polyvinylpyrrolidone) blend membranes and PES (Polyethersulfone) /ZnO (Zinc Oxide) mixed-matrix membranes (MMMs) were fabricated by a phase-inversion method. The membranes were characterized by several techniques including FTIR-ATR, porosity, water permeability and membrane performance in lysozyme solution...

Membrane technology is currently still excluded from separations in more aggressive feeds due to limited chemical robustness. To extent its applicability, a novel thin-film composite (TFC)membrane was synthesized via the homopolymerization of epoxide monomers, resulting in robust poly(epoxyether)top-layers with >90% rose bengal (MW = 1017 Da)and 70...

More than 80% of the energy consumed in the world comes from fossil fuels alone. However, fermentative production of bioethanol has recently gained a considerable interest as an alternative and renewable fuel. Among the different biomasses, the use of macro-algae hydrolysate as the fermentation substrate has been shown to be interesting. However, a...

Ultrafiltration (UF) membrane processes have become an established technology in the treatment and reuse of secondary effluents from the sewage treatment plant. However, without pre-treatment, secondary treated wastewater effluent shows high fouling potential and hence reduces the performance of UF membrane filtration significantly. This study inve...

Ultrafiltration (UF) membrane processes have become an established technology in the treatment and reuse of secondary effluents from the sewage treatment plant. However, without pre-treatment, secondary treated wastewater effluent shows high fouling potential and hence reduces the performance of UF membrane filtration significantly. This study inve...

The main purpose of this research was to develop an effective and inexpensive pretreatment for ultrafiltration (UF) membrane process in order to treat a primary effluent for its reuse in several applications by avoiding biological treatment. For that the impacts of reuse alum sludge liquid recovered by the drinking water treatment plant of Boudouao...

Recently, many works have been focused on the wetting properties of water on hexagonal boron nitride (hBN) monolayers given their potential application as reverse osmosis membrane in desalination processes. Among interfacial properties contact angle and surface tension are probably the most studied. In this work, we investigated the computational p...

Over the past decades, desalination by reverse osmosis (RO) membranes has attracted increasing attention. Although RO has proven its efficiency, it remains, however, relatively costly because of the use of high-pressure pumps and the low water permeability of conventional cross-linked polymer membranes. One route to improve the desalination perform...

In this work, the electrical resistance method was used to get an insight of the liquid transport through the polymers with excess of fractional free volume. The dense films based on the first generation of polymers of intrinsic microporosity, disubstituted polyacetylenes PMP and PTMSP, were used; water-ethanol binary mixtures allowed to adjust the...

Following current strong demands from, among others, paper, food and mining industries, a novel type of nanofiltration membrane was developed, which displays excellent performance in terms of selectivity/flux with a unique combination of chemical stability over the full (0–14) pH-range and thermal stability up to 120 °C. The membrane consists of po...

The influence of membrane surface charge on biofouling community composition during activated sludge filtration in a membrane bioreactor was investigated in this study using polyacrylonitrile-based membranes. Membranes with different surface properties were synthesized by phase inversion followed by a layer-by-layer modification. Various characteri...

Pressure-driven ion transport through conical and hourglass-shape (double conical) nanopores is investigated theoretically by solving the Poisson, Nernst-Planck and Navier-Stokes equations numerically. Due to the electrostatic asymmetry in conical nanopores, these latter exhibit nanofiltration rectification properties, i.e. they reject salts differ...

Chlorination remains a big hurdle in membrane technology as the most commonly used membranes for water purification consist of a polyamide top-layer, which is not fully resistant towards chlorine-induced oxidation. In this work, DOW FILMTECTM BW30 membrane elements were systematically chlorinated with NaOCl at pilot-scale under acidic conditions (p...

The new type of efficient pervaporative separation hybrid materials based on cellulose acetate propionate (CAP) and doped with 1-methyl-3-(4-vinylbenzyl)-1H-imidazol-3-ium chloride polymerizable ionic liquid (PIL) monomers (12.3–44.4 wt.%) were elaborated for dehydration of propan-2-ol. Broad material and physicochemical characterization of membran...

Polyethersulfone/sulfonated polyetheretherketone (PES/sPEEK) supported osmotic thin film composite (TFC) membranes were fabricated with a focus on the optimization of the support layer of the TFC membrane by the phase inversion process. The polymer solution was cast directly on a glass substrate without any backing fabric to prepare the support lay...

Phosphorus sorption capacity was investigated in surface sediments derived from an abandoned zinc-lead mine area located in northeastern Algeria. The forms and the distribution of phosphorus in the raw sediment were identified using the sequential chemical extractions method. Batch experiments were done to study the adsorption kinetics and isotherm...

This work presents the design of a membrane distillation (MD) unit coupled to a refrigeration device. The operation of an MD pilot plant is first tested then simulated using EES solver. The range of hot water feed temperature provided by the condenser of the refrigeration device may vary from 25 to 65. °C as needed by the MD unit. The results of th...

Sodium hypochlorite is widely used to clean/sanitize PES/PVP membranes. However, this strong oxidant is responsible for accelerated polymer ageing, thus impairing PES/PVP membrane lifespan. This work aimed at getting a better understanding of the role of PVP in the degradation of PES/PVP membranes. As the precise chemical composition of commercial...

In this work we have examined a computational approach in predicting the interactions between uncharged organic solutes and polyamide membranes. We used three model organic molecules with identical molecular weights (100.1 g/mol), 4-aminopiperidine, 3,3-dimethyl-2-butanone (pinacolone) and methylisobutyl ketone for which we obtained experimental da...

In this work, molecular dynamics simulations were used to determine the surface tension profile of water on graphene and boron nitride (BN) multilayers, and to predict water permeation through nanoporous graphene and BN membranes. For both graphene and BN multilayers a decrease in surface tension ($\gamma$) was evidenced as the number of layers inc...

Over the past decade many works have focused on various aspects of the dynamics of liquids confined at the nanoscale such as e.g. water flow enhancement through carbon nanotubes (CNTs). Transport of room temperature ionic liquids (RTILs) through various nanochannels has also been explored and some conflicting findings about their translational dyna...

Up to now, the SEDE (Steric Electric and Dielectric Exclusion) model was used to describe solute rejection in nanofiltration or membrane potential measurements. This model uses four fitting parameters: pore size, thickness to membrane porosity ratio, volume charge density (X) and dielectric constant of the solution inside pores (ep). Because these...

Up to now, the SEDE (Steric Electric and Dielectric Exclusion) model was used to describe solute rejection in nanofiltration or membrane potential measurements. This model uses four fitting parameters: pore size, thickness to membrane porosity ratio, volume charge density (X) and dielectric constant of the solution inside pores (ep). Because these...

This manuscript encompasses the investigation into the solvent resistant nanofiltration (SRNF) performance of multilayer membranes prepared from weak polyelectrolytes. These weak polyelectrolytes are unique in that the charge density is not fixed and depends on the coating pH, adding an extra variable as tuning parameter for SRNF performance. The w...

Transport of fluids inside porous materials is relevant to many fields of application. Non-equilibrium molecular dynamics simulation is a powerful technique to explore fluid transport through porous media at the molecular scale. In this work, we compared two commonly used methods for studying pressure-driven transport. The first method was based on...

A new method for determining the electrical conductivity of ion-exchange membranes was implemented with four commercial membranes (AMX, CMX, MK-40 and MA-41). It is based on lateral resistance measurements without direct contact between electrodes and membranes. The cell configuration made it possible to determine the membrane conductivity over a w...

Over the last decades only a few atomistic simulations were performed to investigate water transport through polyamide reverse osmosis membranes at the molecular scale. In most reported simulations water uptake by the membrane was fixed on the basis of scarce experimental data available in the literature but it has never been predicted directly fro...

This study focused on the impact of ageing solution pH (200 ppm TFC sodium hypochlorite) on the electrokinetic properties of a commercial PES/PVP UF membrane. PVP oxidation, leading to an increase in the negative charge density of aged membranes, was pointed out whatever the ageing solution pH although different mechanisms might be involved dependi...

Some of the recent publications in nanofiltration modelling converge on the importance of dielectric effects and numerous models have been developed in order to take them into account. However several works reported lately in the literature suggest a screening of image charges effect at high electrolyte concentration and the predominance of the Bor...

Pressure-driven molecular dynamics simulations were carried out to investigate both structural and transport properties of a sodium chloride solution through a highly cross-linked polyamide membrane. Transport properties were characterized from the calculation of water permeability and salt rejection while the local structure was analyzed through h...

Single cooling and desalination technologies require a high amount of energy to produce cooling and fresh water, respectively. Coupling these systems seems to be attractive not only to reduce their energy consumption rates and to gain more flexibility in operation but also for environmental considerations. Besides, using solar energy to drive these...

Nowadays, it is well established that the physical properties of confined liquids strongly differ from those in bulk phase. While dynamical and structural properties were strongly explored, dielectric properties are poorly studied despite their importance in the understanding and the modelling of molecular mechanism in a number of nano-applications...

Recently, it has been highlighted that Volatile Organic Compounds (VOCs) could be removed through through the coupling of an absorption step in a solvent followed by biodegradation mainly at the liquid/liquid (solvent/water) interface. Among the solvents fulfilling the required characteristics (non toxicity and no biodegradability, high affinity fo...

The dielectric properties of sodium chloride solutions confined in a hydrophilic nanocavity were investigated by means of molecular dynamics simulations. Unlike what is observed in the bulk phase, three dielectric regimes were evidenced, namely an anomalous increase in the dielectric permittivity at low concentrations (with respect to confined pure...

Using molecular dynamics simulations, the influence of the surface charge density of a nanotube on the static dielectric permittivity ε of confined water was reported. Whereas the dielectric anisotropy between the radial and axial directions of water confined in hydrophilic and hydrophobic membranes and the increase in axial dielectric permittivity...

The objective of the present work is to correlate the evolution of membrane characteristics due to contact with hypochlorite used as cleaning agent to its selectivity towards model solutes. Accelerated ageing experiments were performed by soaking the membrane at ambient temperature in hypochlorite solutions. The total free chlorine concentration of...

Polyelectrolyte multilayer membranes have proved to be promising materials for ion nanofiltration. In this work we implement a continuum mesoscopic transport model developed in previous works (Langmuir 2010, 26, 1214; J. Phys. Chem. B 2010, 114, 10143) to investigate pressure-driven transport of electrolyte mixtures through such kind of membranes....

Polyethersulfone (PES) / polyvinylpyrrolidone (PVP) membranes are widely used in various industrial fields such as drinking water production and in the dairy industry. However, the use of oxidants to sanitize the processing equipments is known to impair the integrity and lifespan of polymer membranes. In this work we showed how thorough electrokine...

In this work, the local dielectric permittivity () of water confined into the MIL-53(Cr) metal-organic framework was investigated using molecular dynamics simulations. A dielectric anisotropy of confined water was found, given the confinement effect, which is in good agreement with recent experiments [JACS, 133, 5736, 2011]. In addition, we found a...

In this study, hexafluoroalcohol-containing polyamide layer (HFAPA) was prepared on top of a conventional polyamide under-layer (REFPA) via sequential interfacial polymerization (SIP) to improve RO separation behavior, and the performance of the resulting bilayer membrane was thoroughly optimized by investigating the effect of cross-contamination i...

Molecular dynamics simulations were carried out to investigate the effect of the pore length on the structural, dielectric and dynamic properties of water confined in a silica cylindrical nanopore of 6 Å in radius where the planar silica/water interfaces were taken into account explicitly. Four different pore lengths and two sizes of reservoirs wer...

By means of molecular simulations we shed light on the interplay of surface, confinement and salt effects on the structure and dynamics of water and ions highly confined within a hydrophilic silica nanotube. By a local description of the hydrogen bonding network, the structure and the dynamics we disentangle the confinement and the surface effects....

Tangential streaming current measurements were performed to investigate the surface charge properties and the charge formation mechanism of various NF /RO membranes. Unlike what is usually done in electrokinetic studies of membranes, experiments were conducted with degassed background solutions under a controlled atmosphere by means of nitrogen gas...

Computer simulations were employed to build an atomistic model of a highly cross-linked fully aromatic polyamide membrane relevant to reverse osmosis materials. The methodology used to construct the membrane accounts explicitly for the solid/liquid interface and enables the control of the membrane cross-linking degree. A membrane cross-linked to mo...

We report molecular dynamics simulations of aqueous sodium chloride solutions in order to investigate the salt concentration dependence of the dielectric permittivity, the structure and the dynamics of these solutions. Different models have been applied over a large range of salt concentrations: the DRUDE oscillator model with a negative DRUDE part...

The electronic continuum (EC) model uses a scaling of the charges of the ions in order to model implicitly the polarization into nonpolarizable models. This scaling procedure is applied here to two standard nonpolarizable force fields to investigate the salt concentration dependence of the surface tension and density of NaCl aqueous solutions. The...

The influence of the surface polarity of cylindrical silica nanopores and the presence of Na+ ions as compensating charges on the structure and dynamics of confined water has been investigated by molecular dynamics simulations. A comparison between three different matrixes has been included: a protonated nanopore (PP, with SiOH groups), a deprotona...

Reverse osmosis (RO) is an attractive process for the detoxification of distillery condensates before their recycling at the fermentation stage. However, transfer mechanisms through dense NF and RO membranes are still not well understood for the organic solutes to eliminate, and rejection results could be disappointing. This study aims at correlati...

This article discusses macroscopic modeling of the transport mechanisms of ions through nanofiltration membranes. The modeling is based on mechanistic approaches that consider nanofiltration membranes as bundles of (nano)pores and ionic transport as resulting from hindered diffusion, electromigration, and convection. The governing equations are pre...