Georges Grevillot

Bio: Georges Grevillot is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topic(s): Adsorption & Activated carbon. The author has an hindex of 17, co-authored 45 publication(s) receiving 909 citation(s). Previous affiliations of Georges Grevillot include University of Lorraine & École nationale supérieure des industries chimiques.

Adsorption and electrothermal desorption of organic vapors using activated carbon adsorbents with novel morphologies

Abstract: Novel morphologies of activated carbons such as monolith, beads and fiber cloth can effectively capture organic vapors from industrial sources. These adsorbent materials are also unique because they can undergo direct electrothermal regeneration to recover the adsorbed organic vapors for potential re-use. This investigation compares and contrasts the properties of these adsorbents when using electrothermal–swing adsorption. The adsorption systems consisted of an organic vapor generation system, an electrothermal–swing adsorption vessel, a gas detection unit, and a data acquisition and control system. The activated carbon monolith (ACM) had the lowest pressure drop, highest permeability, highest electrical resistivity and lowest cost as compared to the activated carbon beads (ACB) and the activated carbon fiber cloth (ACFC). ACB had the largest throughput ratio and lowest length of unused bed as compared to the other adsorbents. However, ACFC had the largest adsorption capacity for toluene when compared to ACM and ACB. ACFC was also faster to regenerate and had a larger concentration factor than ACM and ACB. These results describe relevant physical, electrical, adsorption and cost properties for specific morphologies of the adsorbents to more effectively capture and recover organic vapors from gas streams.

Activated Carbon Fiber Cloth Electrothermal Swing Adsorption System

Abstract: Capture and recovery of hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from gas streams using physical adsorption onto activated carbon fiber cloth (ACFC) is demonstrated on the bench-scale. This system is regenerated electrothermally, by passing an electric current directly through the ACFC. The adsorbate desorbs from the ACFC, rapidly condenses on the inside walls of the adsorber, and then drains from the adsorber as a pure liquid. Rapid electrothermal desorption exhibits such unique characteristics as extremely low purge gas flow rate, rapid rate of ACFC heating, rapid mass transfer kinetics inherent to ACFC, and in-vessel condensation. An existing system was scaled up 500%, and the new system was modeled using material and energy balances. Adsorption isotherms using methyl ethyl ketone (MEK) and ACFC were obtained while electricity passed through the ACFC and at temperatures above MEK's boiling point. These isotherms agreed within 7% to Dubinin-Radushkevich modeled isotherms that were extrapolated from independently determined gravimetric measurements obtained at lower temperatures. Energy and material balances for the electrothermal desorption of organic vapors and ACFC agree to within 7% of experimentally measured values. These results allow the modeling of electrothermal desorption of organic vapors from gas streams with in-vessel condensation to optimize operating conditions of the system during regeneration of the adsorbent.

Temperature-swing gas separation with electrothermal desorption step

Abstract: Results of an experimental investigation of a new method for heating adsorbent beds in the desorption step owing to Joule's heat generated inside the adsorbent particles by passing an electric current through them are presented. Desorption of a previously saturated bed and cyclic separation with the electric potential applied to a fibrous activated carbon bed was performed.

Adsorption Isotherms of VOCs onto an Activated Carbon Monolith: Experimental Measurement and Correlation with Different Models

Abstract: A new material, activated carbon monolith, can be used as an adsorbent to remove volatile organic compounds (VOCs). Vapor−solid adsorption isotherms of three VOCs (toluene, 1-butanol, and ethyl ace...

Electrothermal swing adsorption of toluene on an activated carbon monolith - Experiments and parametric theoretical study

Abstract: The purpose of the present work is to investigate electrothermal swing adsorption (ESA) process with an activated carbon monolith as adsorbent. Experiments are performed with toluene as VOC. Several parameters are investigated both experimentally and through a mathematical model. It is shown that the monolith, as a carbon material, behaves as a semi-conductor. Its resistivity decreases as temperature and amount adsorbed increase. This leads to different types of evolution of dissipated electrical power during desorption at constant current intensity. The concentration of the desorbed VOC as a function of time has the shape of a peak followed by a tail. This shape is interpreted as a dispersive wave in the sense of the equilibrium theory of adsorption columns. The performance of the process is strongly dependent on the operating conditions. The maximal (that is initial) concentration increases almost linearly with current intensity and purge gas flow rate, and increases also with preheating duration. The purge gas flow rate has mainly an effect of dilution. The efficiency of desorption (% VOC desorbed) is almost constant in average with different preheating times. It increases with current intensity and gas purge flow rate.

Carbon capture and storage (CCS): the way forward

Abstract: Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

Adsorption of VOCs onto engineered carbon materials: A review

Abstract: Volatile organic compounds (VOCs) severely threaten human health and the ecological environment because most of them are toxic, mutagenic, and carcinogenic. The persistent increase of VOCs together with the stringent regulations make the reduction of VOC emissions more imperative. Up to now, numerous VOC treatment technologies have emerged, such as incineration, condensation, biological degradation, absorption, adsorption, and catalysis oxidation et al. Among them, the adsorption technology has been recognized as an efficient and economical control strategy because it has the potential to recover and reuse both adsorbent and adsorbate. Due to their large specific surface area, rich porous structure, and high adsorption capacity, carbonaceous adsorbents are widely used in gas purification, especially with respect to VOC treatment and recovery. This review discusses recent research developments of VOC adsorption onto a variety of engineered carbonaceous adsorbents, including activated carbon, biochar, activated carbon fiber, carbon nanotube, graphene and its derivatives, carbon-silica composites, ordered mesoporous carbon, etc. The key factors influence the VOC adsorption are analyzed with focuses on the physiochemical characters of adsorbents, properties of adsorbates as well as the adsorption conditions. In addition, the sources, health effect, and abatement methods of VOCs are also described.

Facile synthesis of ultrahigh-surface-area hollow carbon nanospheres for enhanced adsorption and energy storage.

Abstract: Well-defined, large surface area nanostructures are promising functional materials but can be difficult to fabricate. Here the authors show how to prepare ultrahigh-surface-area hollow carbon nanospheres, via a controlled carbonization route, and assess their organic vapour adsorption and electrochemical performance.

Enzyme immobilization by adsorption: a review

Abstract: Endowed with unparalleled high catalytic activity and selectivity, enzymes offer enormous potential as catalysts in practical applications. These applications, however, are seriously hampered by enzymes’ low thermal and chemical stabilities. One way to improve these stabilities is the enzyme immobilization. Among various tested methods of this process that make use of different enzyme-carrier interactions, immobilization by adsorption on solid carriers has appeared most common. According to these findings, in this review we present a comparative analysis of the literature reports on the recent trends in the immobilization of the enzymes by adsorption. This thorough study was prepared in order to provide a deeper understanding of the process. Both carriers, carrier modifiers and procedures developed for effective adsorption of the enzymes are discussed. The review may thus be helpful in choosing the right adsorption scheme for a given enzyme to achieve the improvement of its stability and activity for a specific application.

Nanosized hydroxyapatite and other calcium phosphates: chemistry of formation and application as drug and gene delivery agents.

Abstract: The first part of this review looks at the fundamental properties of hydroxyapatite (HAP), the basic mineral constituent of mammalian hard tissues, including the physicochemical features that govern its formation by precipitation. A special emphasis is placed on the analysis of qualities of different methods of synthesis and of the phase transformations intrinsic to the formation of HAP following precipitation from aqueous solutions. This serves as an introduction to the second part and the main subject of this review, which relates to the discourse regarding the prospects of fabrication of ultrafine, nanosized particles based on calcium phosphate carriers with various therapeutic and/or diagnostic agents coated on and/or encapsulated within the particles. It is said that the particles could be either surface-functionalized with amphiphiles, peptides, proteins, or nucleic acids or injected with therapeutic agents, magnetic ions, or fluorescent molecules. Depending on the additive, they could be subsequently used for a variety of applications, including the controlled delivery and release of therapeutic agents (extracellularly or intracellularly), magnetic resonance imaging and hyperthermia therapy, cell separation, blood detoxification, peptide or oligonucleotide chromatography and ultrasensitive detection of biomolecules, and in vivo and in vitro gene transfection. Calcium phosphate nanoparticles as carriers of therapeutic agents that would enable a controlled drug release to treat a given bone infection and at the same be resorbed in the body so as to regenerate hard tissue lost to disease are emphasized hereby as one of the potentially attractive smart materials for the modern medicine.