Ivo Vankelecom

KU Leuven | ku leuven · Centre for Surface Chemistry and Catalysis (COK)

Although microalgal biomass and environmental benefits of microalgae surpass those of many other feedstocks, the costs associated with up- and downstream technologies still hinder their further development. Membrane technology is an emerging technology that has been applied in the microalgae industry for cultivation, harvesting, and biorefinery, an...

Membrane-based water treatment processes have been established as a powerful approach for clean water production. However, despite the significant advances made in terms of rejection and flux, provision of sustainable and energy-efficient water production is restricted by the inevitable issue of membrane fouling, known to be the major contributor t...

Biogas serves a reliable renewable resource and energy carrier with growing potentials based on the number and size of plants in operation and planned for future. The technical viability of membranes for biogas valorization has attracted attention towards further advancements from the materials and process perspectives. The present review aims to m...

Mixed-matrix membranes (MMMs) have been investigated to render energy-intensive separations more efficiently by combining the selectivity and permeability performance, robustness, and nonaging properties of the filler with the easy processing, handling, and scaling up of the polymer. However, truly combining all in one single material has proven ve...

Most cellulose triacetate (CTA)-based studies for forward osmosis (FO) have greatly focused on achieving asymmetric membranes with a highly porous sublayer along with a dense selective layer. Such membranes can achieve better fluxes due to improved mass transfer and reduced internal concentration polarization. In this work, patterning of the CTA-me...

This study assesses the influence during interfacial polymerization on polyamide thin film composite (TFC) morphology and performance of varying monomer concentrations and organic phases with widely varying physico-chemical characteristics (interfacial tensions (IFT) with water, viscosity and monomer equilibrium partitioning). These physico-chemica...

Polyvinylidene difluoride (PVDF) based membranes have been used extensively for wastewater treatment due to their chemical and mechanical stability. However, membrane fouling remains a critical factor limiting the widespread use of membrane processes. To mitigate membrane fouling, patterned PVDF membranes were prepared via spray-modified non-solven...

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...

Gas-separation membranes are a critical industrial component for a low-carbon and energy-efficient future. As a result, many researchers have been testing membrane materials over the past several decades. Unfortunately, almost all membrane-based testing systems are home-built, and there are no widely accepted material standards or testing protocols...

Background The present study aims to explore the feasibility of using flocculation combined with filtration for microalgae harvesting, i.e., Chlorella vulgaris. This is important because microalgae have small sizes and its broth is stable, which makes it difficult to be harvested. The aforementioned facts cause the harvesting cost to be relatively...

Numerous studies have been carried out to improve the membrane performance and stability of solvent-resistant nanofiltration membranes. This research aims at studying the influence of molecular structure on the membrane performance in a step-wise fashion, making it possible to specifically fine-tune membranes towards their application. For this pur...

Unravelling synthesis-morphology-performance relations of thin-film polyamide (PA) selective layers prepared via interfacial polymerization (IP) is essential for tailor-made membrane design. Here, an approach is outlined, which links synthesis and morphology in terms of interfacial instability of a system undergoing IP, with the notion that a trans...

Design and preparation of mixed-matrix membranes (MMMs) with minimum defects and high performance for desired gas separations is still challenging as it depends on a variety of MMM synthesis parameters. In this study, 6FDA-DAM:DABA based MMMs using MOF-808 as filler were prepared to examine the impact of multiple variables on the preparation proces...

Solvent-resistant UV-cured supports consisting of a semi-interpenetrating network of polysulfone (PSf) and cross-linked poly-acrylate were successfully synthesized for the first time using an alternative, non-reprotoxic, and biodegradable solvent. Tamisolve® NxG is a high-boiling, dipolar aprotic solvent with solubility parameters similar to those...

Polymer membranes have attracted interest in many areas, such as desalination, water treatment, gas separation, and energy storage and generation. Membrane fabrication requires large amounts of solvents for polymer dissolution. These solvents often show toxicity and need to be replaced by greener solvents to avoid adverse effects on human health an...

Controlling the metal-organic framework (MOF)-matrix interface is a useful strategy to improve the gas separation performance of mixed matrix membranes (MMMs). Although polymer blending has been investigated to enhance MMM performances, its true strength, i.e., aligning polymer and additive chemistries to improve interfacial compatibility and ultim...

Nanofiltration (NF) is currently an important branch of membrane technology as it allows the separation of small organic solutes and divalent ions from water. The most commonly applied NF membranes are synthesized either through a process called phase inversion, giving rise to a rather thick (μm‐range) membrane, or through interfacial polymerizatio...

Membrane separation technology is rapidly emerging as an alternative to traditional gas separation processes, and increasingly challenging separations require a constant search for new and better-performing materials. This paper reports the gas separation performance of a poly (vinyl alcohol) (PVA) membrane blended with 53 wt% of the ionic liquid 1...

Metal‐organic framework (MOF) films can be made by cathodic electrodeposition, where a Brønsted base is formed electrochemically which deprotonates the MOF linkers that are present in solution as undissociated/partially dissociated weak acids. However, the co‐deposition of metal and the narrow range of possible metal nodes limit the scope of this m...

Metal–organic framework (MOF) films were made by cathodic electrodeposition using hydrogen peroxide as a pro-base whose single-electron reduction happens at much higher potentials thus preventing the co-deposition of metal and extending the range of possible metal nodes. Abstract Metal–organic framework (MOF) films can be made by cathodic electrod...

Since the advent of thin-film composite polyamide membranes brought forth a breakthrough in desalination and water purification membranes nearly half a century ago, recent years have only witnessed marginal improvements in the water-salt selectivity of these membranes. The slow progression is partly attributable to limited understanding of membrane...

The COVID-19 pandemic has resulted in an increased demand for air-filtration based personal protective equipment. Existing filter masks are mostly based on melt-blow fabrics, which had production upscaling issues because of long lead-times for additional production equipment and the limited number of polymer materials that can be used. Phase invers...

Consistent structure-performance relationships for the design of MOF (metal-organic framework)-based mixed-matrix membranes (MMMs) for gas separation are currently scarce in MMM literature. An important step in establishing such relationships could...

In this work, the effectiveness of metal-organic frameworks (MOFs) with sheet-like morphologies was assessed as function of the MOF microporosity and MOF-matrix compatibility. Zeolitic imidazolate frameworks (ZIFs, a MOF subclass) with sheet-like/platelet morphologies were incorporated in Matrimid/PBI matrices resulting in mixed matrix membranes (M...

Organic solvent nanofiltration (OSN) is gradually expanding from academic research to industrial implementation. The need for membranes with low and sharp molecular weight cutoffs that are able to operate under aggressive OSN conditions is increasing. However, the lack of comparable and uniform performance data frustrates the screening and membrane...

γ-Valerolactone (GVL) was selected as a renewable green solvent to prepare membranes via the process of phase inversion. Water and ethanol were screened as sustainable non-solvents to prepare membranes for nanofiltration (NF). Scanning electron microscopy was applied to check the membrane morphology, while aqueous rose Bengal (RB) and magnesium sul...

In this review, for the first time, the conjugation of the major types of enzymes used in biorefineries and the membrane processes to develop different configurations of MBRs, was analyzed for the production of biofuels, phytotherapics, food ingredients, etc. In particular, the aim is to critically review all the works related to the application of...

Thin films of crystalline and porous metal–organic frameworks (MOFs) have great potential in membranes, sensors, and microelectronic chips. While the morphology and crystallinity of MOF films can be evaluated using widely available techniques, characterizing their pore size, pore volume, and specific surface area is challenging due to the low amoun...

Thin films of crystalline porous materials have great potential in membranes, sensors, and microelectronics. Still, characterizing their pore size, pore volume, and specific surface area is challenging. In article number 2006993, Rob Ameloot and co‐workers discuss positron annihilation lifetime spectroscopy, represented by the bees lighting up insi...

Polyamide (PA) thin-film composite (TFC) membranes are commonly applied in reversed osmosis (RO) and nanofiltration (NF) applications due to their thin, dense top-layer, and high selectivity. Recently, the conventional organic phase (i.e., hexane) during interfacial polymerization (IP) was replaced by less toxic ionic liquids (ILs) which led to exc...

High throughput (HT) screening techniques for pressure-driven membrane processes allow simultaneous screening of multiple membrane samples under similar conditions, and are thus labour-, time- and consumables efficient. HT-modules have so far all been set-up in dead-end configuration. A new filtration set-up for cross-flow filtration has now been d...

Membranes have a lot of potential for harvesting microalgae, but mainly membrane fouling and high harvesting costs linked to low fluxes are hampering their breakthrough. Patterned membranes can reduce fouling by enchancing local turbulences close to the membrane surface on one hand, and by increasing the active area per m² of installed membrane on...

Cellulose acetate (CA) is an attractive membrane polymer for CO2 capture market. However, its low CO2 permeability hampers its application as part of a membrane for most relevant types of CO2 containing feeds. This work investigates the enhancement of CA separation performance by incorporating ionic liquid-like pendants (1-methylimidazol, 1-methylp...

Highly efficient PDMS based membranes with a new type of fluorinated MOF-808 were successfully prepared and used for the first time in pervaporation (PV). Two types of ligands i.e. trifluoroacetic acid (TFA) and pentafluoropropionic acid (PFPA) were used during the MOF synthesis. These ligands with slightly different size and chemical character inf...

A novel fluorinated soft thermoplastic elastomer (sTPE) for microfluidics is presented. It allows the rapid fabrication of microfluidic devices through a 30‐second hot embossing cycle at 220°C followed by self‐sealing through simple conformal contact at room temperature, or with baking. The material shows high chemical resistance, particularly in c...

Mixed matrix membranes (MMM) incorporating metal-organic framework (MOF) fillers have gained increasing attention in addressing environmental and sustainability challenges. Hierarchical materials combining pore sizes of different length scales are expected to facilitate molecular diffusion and mass transfer for the optimization of catalysis and sep...

A novel synthesis method of partially crosslinking a polymer solution prior to casting, has been successfully developed for the preparation of solvent-tolerant nanofiltration (STNF) membranes. STNF merges solvent resistant nanofiltration (SRNF) with aqueous nanofiltration. The feed solution consists of a mixture of solvent(s) and water, requiring a...

There is no efficient wastewater treatment solution for removing organic micropollutants (OMP), which, therefore, are continuously introduced to the Earth's surface waters. This creates a severe risk to aquatic ecosystems and human health. In emerging water treatment processes based on ion-exchange membranes (IEM), transport of OMPs through membran...

In this study, novel asymmetric integral cation exchange membranes were prepared by the wet phase inversion of sulfonated polysulfone (SPSf) solutions. SPSf with different degrees of sulfonation (DS) was synthesized by variation in the amount of chlorosulfonic acid utilized as a sulfonating agent. The characterization of SPSf samples was performed...

Highly stable porous membranes made of commercial polyacrylonitrile (PAN) were developed for high pressure application in aprotic solvents. The membranes prepared by NIPS method from the casting solution with PAN concentration of 15 or 18 wt% in DMSO demonstrated good mechanical stability towards the transmembrane pressure of 30 bar and MWCO of 22...

In this work, the influence of the zeolitic imidazolate framework 78 (ZIF‑78) morphology, with 1D pores, on the mixed matrix membrane (MMM) CO2/N2 mixed gas separation performance is investigated as well as the influence of the feed composition and pressure. Low aspect ratio and a high aspect ratio ZIF‑78 particles are synthesized and incorporated...

A template‐mediated MOF‐CVD (metal—organic framework‐chemical vapor deposition) method was developed for the syntheses of MOFs in both powder and thin‐film forms. The time‐resolved in situ synchrotron small‐angle X‐ray scattering reveals that introducing template vapor into the MOF‐CVD process precludes transformation into a dense phase, thus resul...

The landscape of possible polymorphs for some metal‐organic frameworks (MOFs) can pose a challenge for controlling the synthesis outcome. In this work, we demonstrate how a template can enable such control in the vapor‐assisted formation of zeolitic imidazolate framework (ZIF) powders and thin films. Introducing a small amount of ethanol or dimethy...

Ion-exchange membrane (IEM)-based processes are used in the industry or in the drinking water production to achieve selective separation. The transport mechanisms of organic solutes/micropollutants (i.e., paracetamol, clofibric acid, and atenolol) at a single-membrane level in diffusion cells were similar to that of salts (i.e., diffusion, convecti...

Preparation of multilayer films using the layer-by-layer (LbL) technique via hydrogen bonding has recently gained increasing research interest and has potential in diverse areas of research, especially in the biomedical field. However, the scope of these hydrogen-bonded multilayer films in separation science is quasi-unexplored. In this work, ultra...

One of the key issues in membrane technology is to avoid fouling formed on the membrane surface. Patterned surfaces have been suggested as one of the ways to reduce fouling. In this report, both experimental and simulation studies were performed using membranes with rectangular and triangular patterns, synthesized via the recently developed s-NIPS...

Zeolitic imidazolate frameworks (ZIFs), a subclass of metal-organic frameworks (MOFs), have been widely investigated as additive in mixed matrix membranes (MMMs), but systematic studies to identify critical intrinsic ZIF-type parameters that determine the MMM performance are lacking. Therefore, three isoreticular gmelinite (GME) ZIFs, i.e., ZIF-68,...

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...

The detailed structures and distribution of enzymatically active magnetic-responsive dynamic layers (EnzSP) were investigated for the first time in a crossflow superparamagnetic biocatalytic membrane reactor (XF-BMRSP). The trade-off between a higher mass transfer rate, lower fouling tendency, and preventing washout of the dynamic layer, highly dep...

The introduction of patterns on a membrane-solute interface has been suggested as an effective method to tackle the reduced flux and fouling issues. Herein, the effectiveness of using spray-modified non-solvent induced phase separation (s-NIPS) to create a variety of micrometer-level structured interfaces is now studied. Circular, triangular and re...

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...

Poly(ionic liquid)s are an innovative class of materials with promising properties in gas separation processes that can be used to boost the neat polymer performances. Nevertheless, some of their properties such as stability and mechanical strength have to be improved to render them suitable as materials for industrial applications. This work explo...

Key issues for membrane technology in harvesting microalgae are to reach high fluxes and to alleviate fouling by microalgal cells and extracellular organic matter. To achieve this goal, negatively charged patterned membranes were prepared from polysulfone/sulfonated polysulfone (PSf/sPSf) blends using a spray-modified phase inversion method, and th...

Patterned membranes have been attractive for the mitigation of fouling in membrane processes, but existing patterning methods are rather in-effective in terms of scalability and performance due to pore-size reduction and patterning at the non-selective membrane side. Polyvinylidene fluoride (PVDF) was used now to synthesize patterned membranes via...

Arthrospira platensis (A. platensis), one of the successfully commercialized microalgae, can generate abundant extracellular polysaccharides (EPS). Separating the EPS from the culture medium is important to recycle the medium and further process the polysaccharide resource. To separate EPS from spent Arthrospira platensis culture medium, a negative...

Flocculation of two different fresh-water green microalgae, Chlorella vulgaris and Dictyosphaerium sp., was explored using chitosan, FeCl3 and NaOH as flocculants. The most optimal dosage of each flocculant under certain pH was determined. Both chitosan and FeCl3 gave a higher flocculation efficiency then flocculation induced by pH increase. Floccu...

Crosslinked PVDF is a versatile, thermally and chemically ultrastable material for membrane applications. However, widespread use of this material is hampered by 3 major drawbacks: (1) long crosslinking times, (2) harsh crosslinking conditions and (3) expensive chemicals. In this work, a tremendous increase in the PVDF crosslinking efficiency was a...

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...

The applicability of state-of-the-art water purification membranes in harsh feed streams is limited due to their insufficient chemical robustness. Epoxide chemistry has been recently introduced to achieve pH- and chlorine-stable nanofiltration (NF). This study further investigated the influence of interfacial polymerization (IP) synthesis parameter...

Energy‐efficient indoors temperature and humidity control can be realised using the reversible adsorption and desorption of water in porous materials. Stable microporous aluminium‐based metal‐organic frameworks (MOFs) present promising water sorption properties for this goal. The development of synthesis routes that make use of available and afford...

Thermally induced decarboxylation cross-linking of carboxylic acid bearing polyimides has been recently introduced to create cross-linked polymer membranes with enhanced gas permeability. The main focus has been on the cross-linking of high permeability/low selectivity 6FDA copolymers with a relatively low amount of carboxylic acid groups. In contr...

Highly stable, well suspended TiO2 nanoparticles (NPs) were synthesized by a sol-gel method and directly mixed with an aqueous amine solution to react at the interface with trimesoyl chloride, forming polyamide (PA) thin film nanocomposite (TFN) membranes with a uniform distribution of the nanoparticles in the PA film. Besides the presence of TiO2...

Membrane deformation under an applied hydraulic pressure, often termed compaction, is observed in almost all pressure-driven membrane processes. Most notably, compaction decreases water permeability in conventional reverse osmosis (RO) and is expected to critically hinder high-pressure reverse osmosis (HPRO) for hypersaline brine desalination. In t...

Membranes with a wave pattern on the membrane surface are now proposed for the first time to alleviate microalgal fouling and increase the membrane flux. The membrane morphology was observed via scanning electron microscope, and the clean water permeance, microalgae harvesting efficiency and membrane flux in a real broth were determined to investig...

Ionic liquids (ILs) were used as the organic reagent phase in interfacial polymerization (IFP) to prepare thin film composite (TFC) membranes with a crosslinked polyimide (PI) as support for use in forward osmosis (FO). In a very straightforward and environmentally benign method, phase inversion, PI cross-linking, and amine monomer impregnation ste...

To improve the performance of the currently available solvent-resistant nanofiltration (SRNF) membranes, a new, unique approach was developed. In this approach, the concept of PIMs is combined with the fabrication of thin film composite membranes by interfacial polymerization (IFP) ànd the possibility to tune the molecular structure of the monomers...

Phenol and its derivatives, which naturally occur in lignocellulose, can be considered as a renewable feedstock not only for aromatic, but also for alicyclic compounds, such as primary and N-substituted cyclohexylamines. So far, the latter are mostly produced from non-renewable starting materials like benzene via problematic nitration/reduction or...

Non-aqueous redox flow batteries (RFBs) based on redox-active organic molecules are regarded as a promising technology for large-scale grid energy storage. 1,4-Diaminoanthraquinones (DAAQs) are particularly interesting as active species because they can have up to five different electrochemically accessible oxidation states, but their practical usa...

Redox flow batteries (RFBs) are currently of interest as energy storage devices with great potential. For non-aqueous RFBs, low-cost redox pairs with good reversibility and high solubility in the organic solvents are exploited to improve battery performance. In this work, two metal complexes, containing cheap and abundant cerium, were proposed with...

A simple solvent- and catalyst-free method is presented for the synthesis of the large-pore metal-organic framework (MOF) MAF-6 (RHO-Zn(eIm)2) based on the reaction of ZnO with 2-ethylimidazole vapor at temperatures ≤ 100 °C. By translating this method to a chemical vapor deposition (CVD) protocol, crystalline films of a large-pore material could b...

Conventional CO2 separation in the petrochemical industry via cryogenic distillation or amine-based absorber-stripper units is energy intensive and environmentally unfriendly. Membrane-based gas separation technology, on the other hand, has contributed significantly to the development of energy-efficient systems for e.g. natural gas purification. T...

Solvent resistant nanofiltration is a promising process for homogeneous metal catalyst recovery. However, catalyst rejections are determined using various set-ups with different hydrodynamics, which questions the comparison of the results. The analysis of the membrane performance is another issue even when comparing membranes made of the same mater...

The optimal operational parameters of a second generation magnetically induced m