Georgios Karanikolos

Khalifa University | KU · Department of Chemical Engineering

Polymer-enhanced CO2 foam (PEF) is an emerging technology for gas mobility control and CO2 storage in geologic formations to mitigate anthropogenic emissions. The foam generated by surfactants alone is prone to film rupture and low endurance, particularly in Middle Eastern carbonates under harsh conditions of high temperature and salinity. Adding p...

Metal–organic frameworks (MOFs) have emerged as promising candidates for CO2 adsorption due to their ultrahigh-specific surface area and highly tunable pore-surface properties. However, their large-scale application is hindered by processing issues associated with their microcrystalline powder nature, such as dustiness, pressure drop, and poor mass...

Amine-functionalized mesoporous silica materials have attracted considerable attention as robust adsorbents for large-scale CO2 capture and direct air capture (DAC). Amine grafting increases selective affinity at low pressures, yet also often reduces the adsorbent's pore volume and surface area, affecting the kinetics and capacity upon CO2 adsorpti...

Self-standing 3D-printed gyroid monoliths of zeolite 13X were fabricated for the first time for carbon dioxide adsorption. Gyroid sheet-based triply periodic minimal surface (TPMS) lattices provide high surface area per unit volume, smooth surfaces with no discontinuities, and low pressure drop compared to powder and beads, which are essential in g...

Water is readily available nearly anywhere as vapor. Thus, atmospheric water harvesting (AWH) technologies are seen as a promising solution to support sustainable water production. This work reports a novel semi-interpenetrating network, which integrates poly(pyrrole) doped with a hygroscopic salt and 2D graphene-based nanosheets optimally assemble...

The global challenge of climate change, driven predominantly by the rise in atmospheric carbon dioxide (CO2) levels owing to human activities, requires effective CO2 mitigation strategies such as carbon capture and storage (CCS) [1,2]. In this work, a cylindrical monolith featuring triply periodic minimum surface (TPMS) based gyroid sheet geometry...

This work presents the synthesis of N‐doped nanoporous carbon materials using the Ionic Liquid (IL) 1‐butyl‐3‐methylimidazolium tricyanomethanide [BMIM][TCM] as a fluidic carbon precursor, employing two carbonization pathways: templated precursor and pyrolysis/activation. Operando monitoring of mass loss during pyrolytic and activation treatments p...

Controlling the emission of greenhouse gases such as CO 2 by adsorption has been extensively investigated over various solid adsorbents to achieve effectual capture. The present work studied the fabrication of mesoporous nanosilica materials, KCC-1, KCC-2, KCC-3, and their corresponding amine-functionalized NH 2-KCC, as potential adsorbents for CO...

MOF-based hybrid adsorbents for carbon capture are gaining increased attention as they can enhance key performance properties and scalability of MOFs. Yet, structuring these complex materials into mm-sized shaped particles to be used in actual process while maintaining the performance characteristics of the original powdered hybrids is challenging....

Olefin and paraffin gases are important products of the petrochemical refining industry wherein their effective separation could provide high economic gains and competitiveness in the emerging energy markets amidst state-of-the-art technology. Important chemicals such as polyethylene and polypropylene are derived from raw materials in the form of l...

Biowaste utilization as a carbon source and its transformation into porous carbons have been of great interest to promote environmental remediation owing to biowaste's cost-effectiveness and useful physicochemical properties. In this work, crude glycerol (CG) residue from waste cooking oil transesterification was employed to fabricate mesoporous cr...

Development of paraffin-selective adsorbents for the separation of ethane/ethylene mixtures, as an alternative technology to the energy-intensive cryogenic distillation, is challenging. Herein, we report surface-functionalized mesoporous silica adsorbents exhibiting reverse selectivity prepared by controlled in-situ synthesis of paraffin-selective...

Stimuli-responsive metal–organic frameworks (MOFs) are highly versatile porous materials with the ability to respond to different external stimuli, including temperature, pressure, pH, and light. The MOF properties can switch reversibly under specific light irradiation, opening the doors to various applications. This review focuses on design strate...

Ordered hierarchical nanostructured silica (OHNS) adsorbents were prepared, and their surface was controllably modified by aminosilanization using two different aminosilanes, one bearing one primary amine unit per molecule (4-aminobutyltriethoxysilane, ABTS) and the other bearing both a primary and a secondary amine (N-(2-aminoethyl)-3-aminopropylm...

Metal-organic frameworks (MOFs) are three-dimensional network structures synthesized by the assembly of organic ligands with metal ions or clusters. They currently constitute one of the most promising adsorbent categories for CO2 capture given their high specific surface area and porosity, chemical versatility, and facile chemistry supporting strat...

Solar-assisted thin film evaporation is a promising step toward achieving renewable-energy powered desalination. Electrospun nanofiber membranes (ENMs) have high porosity, surface area, mechanical strength, and tunable nanofiber structure, which make them suitable for membrane desalination. In this work, electrospun poly(vinylidene fluoride-co-hexa...

Carbon dioxide foam injection is a promising enhanced oil recovery (EOR) method, being at the same time an efficient carbon storage technology. The strength of CO 2 foam under reservoir conditions plays a crucial role in predicting the EOR and sequestration performance, yet, controlling the strength of the foam is challenging due to the complex phy...

This paper deals with the permeation properties of binary gas mixtures (CO2/He, CO2/H2) through a carbon molecular sieve membrane (CMSM). The permeation properties of binary gas mixtures were determined via an improved time lag technique, and the permeation flux of an individual component was determined by selectively capturing the CO2 in the perme...

Carbon dioxide (CO2) is the top contributor to global warming. On the other, soot particles formed during fuel combustion and released into the atmosphere are harmful and also contribute to global warming. It would therefore be highly advantageous to capture soot and make use of it as a feedstock to synthesize carbon-based materials for application...

MXenes belong to a new class of two dimensional (2D) functional nanomaterials, mainly encompassing transition‐metal carbides, nitrides and carbonitrides, with unique physical, chemical, electronic and mechanical properties for various emerging applications across different fields. To date, the potentials of MXenes for biomedical application such as...

In this study, Zeolite-Ag2S nanohybrid material was synthesized by a sonication process combined with a hydrothermal method. The structure and morphology of hybrid nanomaterial was studied using XRD, SEM, TEM, BET and XPS analysis. Such microscopy studies show the uniform distribution of Ag2S in the zeolite matrix. For the comparison study, structu...

Isomorphic substitution of zeolite and zeotype materials plays a dominant role in tuning the performance of the materials in adsorption and catalysis. Here, aluminophosphate AlPO4-5 crystals (AFI-type) with variable content of incorporated iron or magnesium were hydrothermally synthesized, characterized, and tested for water adsorption. The metal i...

Freshwater resources are being heavily depleted and not replenished at the same high rate, thus, atmospheric water vapor harvesting has earned growing interest. Development of high-performing desiccant or adsorbent materials offering high sorption capacity and selectivity as well as regeneration capability in atmospheric conditions is crucial to ta...

Adsorbents and membranes consisting of carbon nanotube (CNT) pores with diameters of molecular dimensions are highly desirable for hydrogen storage and selective, high-flux membrane separation. However, fabrication of such materials with precise pore sizes and monodispersity as well as evaluation of the mechanisms associated to adsorption and molec...

Ethylene is an important feedstock for the production of many key-valued compounds, especially polymers. About 60% of the total ethylene produced is utilized for the production of polyethylene, while ethylene is normally produced by steam cracking of naphtha along with traces of ethane, which is undesirable. Considering the energy-intensive nature...

A Cu-BTC metal–organic framework hybrid with graphene oxide (GO) having ultralow GO content (1 wt %) was developed in situ and was explored as a medium for hydrogen storage at ambient temperature. The structural integration of both counterparts in the Cu-BTC/GO hybrid was attained through interaction of the Cu centers with the oxygen-bearing groups...

https://www.ku.ac.ae/uv-radiation-of-graphene-oxide-improves-carbon-capture-efficiency-in-metal-organic-frameworks https://www.thegraphenecouncil.org/blogpost/1501180/Graphene-News-and-Updates?tag=Anish+Varghese https://www.thegraphenecouncil.org/blogpost/1501180/465756/Carbon-capture-technology-can-be-further-improved-for-efficiency-by-simply-ir...

The CO2 Enhanced Oil Recovery (CO2-EOR) process was monitored in real time at the nanoscale by neutron scattering. This was achieved by in situ injection of supercritical CO2 into a limestone sample loaded with deuterated n-decane. The experimental results show directly the decane displacement upon supercritical CO2 injection. The structure of CO2...

Isomorphic substitution of zeolite and zeotype materials plays a dominant role in tuning the performance of the materials in adsorption and catalysis. Here, aluminophosphate AlPO 4-5 crystals (AFI-type) with variable content of incorporated iron or magnesium were hydrothermally synthesized, characterized, and tested for water adsorption. The metal...

Conventional foam modelling techniques require tuning of too many parameters and long computational time in order to provide accurate predictions. Therefore, there is a need for alternative methodologies for the efficient and reliable prediction of the foams’ performance. Foams are susceptible to various operational conditions and reservoir paramet...

Ability to capture carbon dioxide from diverse sources and conditions is vital in mitigating the impact of continuously increasing CO2 levels into the atmosphere. Here, we developed a novel adsorbent based on Cu-BTC metal-organic framework (HKUST-1) and UV-irradiated graphene oxide (UV-GO) by in-situ growth, and assessed its CO2 capture performance...

Covalent Triazine Frameworks (CTFs) are a class of porous organic frameworks with tunable properties obtainable through rational design targeting a wide range of applications. In the present work, we developed a series of CTFs with phosphazene core for CO2 adsorption. The CTFs were synthesized using building blocks of hexakis(oxy)hexabenzonitrile p...

The mitigation of carbon dioxide emissions using hybrid-slurry systems evolved over recent years as an alternative for conventional processes for CO2 capture. The hybrid systems capture CO2 by both of adsorption and absorption processes. Generally, this review discusses the concept, provides illustrations, preparation techniques, transport mechanis...

C4 hydrocarbons are valuable fractions of the oil and gas processing industry due to their market size and importance as raw materials in the manufacture of several products. C4s are derived from fluid catalytic cracking (FCC) and from natural gas fractionation, and are often produced as mixture of associated hydrocarbons that are typically recover...

The development of efficient zeolite-based adsorbents with high water uptake capacity is an essential requirement for water adsorption and moisture removal technologies. In the present study, zeolite-Y samples with interconnected hierarchical micro-mesoporous network were synthesized by employing a bifunctional cationic polymer (namely, polydiallyd...

Polysulfone (PSF)-based mixed-matrix membranes (MMMs) were developed through incorporation by solvent casting of poly(ethylene glycol)-grafted carbon nanotubes (PEG-g-CNTs) into the polymer matrix. Single-gas permeability and the respective perm-selectivity values of the resulting MMMs for CO2, CH4, and N2 along with mixed-gas selectivities were de...

In this work, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membranes were loaded with tungsten oxide (WO3) nanoparticles, surface coated with polydopamine (PDA) hierarchical structures, and tested in oil/water separation, photothermal water evaporation, and degradation of ampicillin. The electrospun nanofiber me...

Cu-BTC (HKUST-1) metal-organic framework (MOF) in crystalline powder form was prepared by using a copper mesh as the metal source without involving any additional metal precursor, and its performance was evaluated for CO2 capture. The crystalline structure, morphology, textural characteristics and surface chemical properties of the synthesized HKUS...

A significant portion of the global energy is nowadays dedicated to separation and purification processes, most of which exhibit limited efficiency mainly due to thermodynamic limitations. As an alternative, membrane-based technologies show increasing potential due to the fact that membranes can combine selective separation at the molecular level,...

In the race for viable solutions that could slow down carbon emissions and help in meeting the climate change targets a lot of effort is being made towards the development of suitable CO2 adsorbents with high surface area, tunable pore size and surface functionalities that could enhance selective adsorption. Here, we explored the use of silsesquiox...

Metal substitution in aluminophosphates is known to induce unique structural and surface characteristics that can tune catalytic performance. Si, Co, Fe and Mg substituted AlPO4-5 (MeAPO-5) catalysts were hydrothermally prepared, characterized, and evaluated for ethanol - acetic acid esterification. Textural evaluation revealed that the Co and Si a...

Metal substitution in aluminophosphates is known to induce unique structural and surface characteristics that can tune catalytic performance. Si, Co, Fe and Mg substituted AlPO4-5 (MeAPO-5) catalysts were hydrothermally prepared, characterized, and evaluated for ethanol - acetic acid esterification. Textural evaluation revealed that the Co and Si a...

To follow the low-carbon environmental directives, it is imperative to develop sustainable carbon capture technologies. From an industrial viewpoint, carbon capture by adsorption shows increasing potential by virtue of energy and cost benefits. In this work, graphene oxide (GO)-based adsorbents, namely self-supported GO foam (GOF) and Cu-BTC metal-...

Bottom-up" additive manufacturing (AM) is the technology whereby a digitally designed structure is built layer-by-layer, i.e., differently than by traditional manufacturing techniques based on subtractive manufacturing. AM, as exemplified by 3D printing, has gained significant importance for scientists, among others, in the fields of catalysis and...

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Aluminophosphate, AlPO4-5, an AFI zeotype framework consisting of one-dimensional parallel micropores, and metal-substituted AlPO4-5 were prepared and studied for CO2 adsorption. Preparation of AlPO4-5 by using different activation methods (calcination and pyrolysis), incorporation of different metals/ions (Fe, Mg, Co, and Si) into the framework us...

Adsorption- and membrane-based processes and materials for capture and separation of CO2 are gaining increased attention as alternatives to overcome current limitations of the traditional amine based absorption. In this study, hybrid nanostructures of metal organic frameworks (MOFs) and graphene oxide (GO) were synthesized, functionalized and used...

Gas separation and purification using polymeric membranes is a promising technology that constitutes an energy-efficient and eco-friendly process for large scale integration. However, pristine polymeric membranes typically suffer from the trade-off between permeability and selectivity represented by the Robeson's upper bound. Mixed matrix membranes...

This work aims at elucidating the most active modes of copper incorporation towards H2S adsorption. Various synthesis methodologies were followed, notably, incorporation via isomorphic substitution, liquid ion exchange (LIE), vapor phase ion exchange (VIE), and nanoparticles inclusion during hydrothermal synthesis, for the introduction of copper in...

Zeolitic imidazolate frameworks (ZIFs) feature a rigid porous structure where the interplay of pore merits and wall functionality, determined by the different imidazolate functional groups, results in superior CO2 capture ability. In this work, the vibrational properties of ZIF-68 and ZIF-69, two characteristic complex gmelinite (GME) type ZIFs com...

Highly effective antimicrobial agents are needed to control the emergence of new bacterial strains, their increased proliferation capability, and antibacterial resistance that severely impact public health, and several industries including water, food, textiles, and oil and gas. Recently, bimetallic nanoparticles, formed via integration of two diff...

Efforts to capture CO2 from anthropogenic sources as well as from the air are being continuously intensified as to battle the greenhouse gas effects and climate change. Capture by liquid solvent absorption, mainly involving amines, is the common industrial practice, yet capture relying on solid adsorbents is increasingly gaining interest due to its...

Development of novel and more efficient materials for capturing CO2 from various sources is of high priority as to combat the climate change effects due to increasing CO2 levels in the atmosphere. In this work, a UV-irradiated graphene oxide foam (UV-GOF) was developed and studied for CO2 adsorption. The characteristics of the prepared GOF and UV-G...

HKUST-1, a Cu-based metalorganic framework (MOF), was synthesized solvothermally, functionalized with polyethyleneimine (PEI), and hybridized with graphene oxide (GO) and functionalized GO for H2S removal. MOF synthesis approach, molecular weight of amines, and the content of GO in the hybrid adsorbents were systematically varied. The adsorbent mat...

CO2 emissions from the consumption of fossil fuels are continuously increasing, thus impacting Earth’s climate. In this context, intensive research efforts are being dedicated to develop materials that can effectively reduce CO2 levels in the atmosphere and convert CO2 into value-added chemicals and fuels, thus contributing to sustainable energy an...

Isomorphic substitution of zeolite and zeotype materials can affect significantly their application performance. The work presented herein assesses the impact of cobalt and silicon substitution at low and high H2O/Al2O3 of the reaction mixture by a combination of experimental and density functional theory (DFT) calculations. The presence of cobalt...

Highly ordered and highly cooperative water with properties of both solid and liquid states has been observed by means of neutron scattering in hydrophobic one-dimensional channels with van der Waals diameter of 0.78 nm. We have found that in initial stages of adsorption water molecules occupy niches close to pore walls, followed later by the filli...

The adsorption of water in one-dimensional channels in porous aluminophosphate material AlPO4-5 has been studied by a combination of gravimetric analysis techniques, neutron and X-ray diffraction and neutron spectroscopy. Molecular structure of AlPO4-5 consists of 12-membered rings of alternating, corner-sharing AlO4 and PO4 tetrahedra connected by...