gael plantard - Academia.edu (original) (raw)

Papers by gael plantard

Advances in Materials and Processing Technologies

Journal of Chemical Technology & Biotechnology, 2020

BACKGROUND: Occurrence of pharmaceutical compounds in wastewater has become a major concern 3 for... more BACKGROUND: Occurrence of pharmaceutical compounds in wastewater has become a major concern 3 for human health and the environment. Therefore, it is challenging to improve the conventional 4 wastewater treatment to remove these compounds. Coupling a biological treatment with an advanced oxidation technology has been widely studied in the literature, but only sequential associations of the 6 two processes have been used. This study proposes an innovative concept based on a real integration of 7 the photocatalytic oxidation process in a continuous recycling loop on a membrane bioreactor. The role 8 of the oxidation is not here to completely degrade pharmaceuticals, but to oxidize them moderately to 9 increase their biodegradability so that they can be eliminated by the biological process. 10 RESULTS: Preliminary experiments on oxidation process indicated that a flux density of 5 W.m-2 was 11 sufficient to increase biodegradability and decrease toxicity of a cocktail of 3 pharmaceuticals. Then 12 performances of a 20-L continuous membrane bioreactor treating wastewater with 7 pharmaceuticals, 13 without and with pre-oxidation at 5 W.m-2 were compared. Pre-oxidation has increased the global 14 removal for some recalcitrant pharmaceuticals (from 3 to 47 % for diclofenac and for 1 to 44 % for 15 furosemide) without affecting neither the removal of carbon, nitrogen and phosphorous by activated 16 sludge neither the removal of already highly removed pharmaceuticals. 17 CONCLUSION: This work proves the feasibility and interest of the innovative concept of a continuous 18 hybrid process coupling a photocatalytic oxidation process and a membrane bioreactor for the treatment 19 of pharmaceuticals in wastewater, with a low cost and size.

Le Centre pour la Communication Scientifique Directe - HAL - Inria, Jun 16, 2019

Le Centre pour la Communication Scientifique Directe - HAL - Université Paris Descartes, Jul 8, 2014

International audienc

Journal of Environmental Chemical Engineering, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Solar Energy, 2020

Thermal activation of new oxidant chemicals like Persulfate (PS) has recently gained attention in... more Thermal activation of new oxidant chemicals like Persulfate (PS) has recently gained attention in driving advanced oxidation processes (AOP) for a number of applications. Persulfate (PS) is an oxidant chemical likely to undergo thermal activation to drive advanced oxidation processes (AOP) with respect to a number of applications. On the other hand, addressing energy demand with carbon free and sustainable energy solutions represents an asset for new technologies in the modern society. This paper then investigates on the removal of pharmaceuticals residues in wastewater (WW), conducted with PS advanced oxidation reactions on a solar thermal pilot equipment. IIndoor preliminary investigations on small scale laboratory experimentations shows how increasing temperature has a direct positive impact on pollutants degradations rate (kapp value ranging from 0.4•10-3 s-1 at ambient to 10.4•10-3 s-1 at 75°C)., However, after an experimental screening methodology, carried out with a screening methodology, lead to 65 °C and 200 µM appear as the appropriate target temperature and PS oxidant dosage to cope with both activation of PS oxidant and degradation of ten target micropollutants typically found in WW stream. Outdoor experimentations on the solar pilot equipment were operated conducted according to a batch running mode at a treatment capacity scale of a cubic meter. 95 % pollutant removal rate is achieved within 2 hours once the temperature has raised up to the target value (65 °C) in the bulk treated WW effluent. Series of treatment cycles under the natural day/night period demonstrate the reproducibility of the performance. As an early step result of the process optimization approach, heat recovery demonstration on the pilot equipment improves significantly the energetic balance over the now innovative thermal solar water treatment.

Waste and Biomass Valorization, 2016

This paper investigates on the sustainable ways of associating activated carbon (AC) and titania ... more This paper investigates on the sustainable ways of associating activated carbon (AC) and titania (TiO 2) into a single material capable of both adsorbing and degrading micropollutants in aqueous solution under UV light. Three main preparation routes were carried out, based on the thermochemical conversion of shea nut shell, an abundant and cost free tropical biomass. N 2 adsorption desorption at 77 K, X-ray diffraction spectroscopy, scanning electron microscopy and energy dispersive spectroscopy were used to assess how each specific preparation route shapes the textural and structural properties of the resulting catalysts. Catalysts obtained from AC impregnation with preformed titania nanoparticles sol (CAT/S) exhibited a regular deposition of TiO 2 nanoparticles in the readily irradiated external macropores providing them with the best performances on phenol photomineralization. Pyrolysis of biomass impregnated with TiO 2 nanoparticles sol leads to catalysts (CAT/SB) with large agglomerates embedded within the AC structure. The third category of catalysts (CAT/G) obtained from the in situ generation of TiO 2 nanoparticles within a titania gel impregnated AC presented a degraded porosity-surface area network, which seems to explain their poor photoactivity. The performances of CAT/S catalysts are maintained after three successive reutilizations and suggest their stability and self regeneration capacity.

Industrial & Engineering Chemistry Research, 2015

The remediation of groundwater contaminated by common pollutant perchloroethylene (PCE) is report... more The remediation of groundwater contaminated by common pollutant perchloroethylene (PCE) is reported. The studied process is adsorption using a fixed-bed column packed with granular activated carbon (GAC). An original setup was designed to perform the isotherms. Small particle sizes and fullscale GAC were tested. Adsorption capacity decreases with increasing particle size in the presence of natural organic matter. Columns running in dynamic-mode PCE in-feed were used to test three operating conditions. Sampling along the columns was used to monitor PCE concentration in the liquid phase at different column lengths. A large dataset was collected. A mathematical model based on mass balance of PCE was adopted to predict the adsorption dynamics under various operating conditions. Global mass transfer coefficients were identified to find the best fit with the experimental data. The model was reliable and accurate over the whole dataset. The performances of the fixed bed were evaluated in terms of operation time, total volume of decontaminated water and degree of GAC utilization. The results showed that a trade-off has to be found between these performance parameters. The model developed here can be used to design full-scale fixed-bed columns and optimize the three key parameters.

Industrial & Engineering Chemistry Research, 2016

Our aim was to assess the feasibility of using solar energy for the thermal regeneration of spent... more Our aim was to assess the feasibility of using solar energy for the thermal regeneration of spent activated carbons (ACs). The context was water treatment, for which ACs are commonly used. The target pollutant was perchloroethylene (PCE). Preliminary experiments were performed to select the best-suited adsorbent among five ACs (Aquacarb, surface area Brunauer–Emmett–Teller, 1100 m2 g–1; micropores areas, 870 m2 g–1). Water properties influence adsorption capacity; this is lower with natural water (groundwater) than with ultrapure water. The competition between natural organic matter (found in groundwater but not in ultrapure water) and the target pollutant accounts for this difference. Groundwater was used in regeneration tests so as to approximate to field conditions. Operating conditions for regeneration were determined: the working temperature ranged between 130 and 400 °C, and the treatment time was set so as to prevent any kinetic limitation. Four regeneration cycles showed the same decrease in adsor...

AIChE Journal, 2015

A study was carried out to develop a kinetic model of the photocatalytic inactivation of E. coli ... more A study was carried out to develop a kinetic model of the photocatalytic inactivation of E. coli using different TiO2 catalysts. The model developed is based on a reaction scheme that involves effectively coupling mass transfer fluxes between bacteria and catalyst surface on one hand and bacterial degradation reaction on the other. The photocatalytic results were derived from experiments led in a batch reactor under both dark and UV irradiation conditions. Using a reference catalyst the robustness of the developed model was tested under solar conditions. The experimental data validated

Solar Energy, 2013

Phytosanitary run off from agricultural fields represents highly disseminated local sources of po... more Phytosanitary run off from agricultural fields represents highly disseminated local sources of pollution and corresponds to relatively small volumes which need to be treated (around 5 m 3 for a farm of a few tens of hectares). The simplicity, the robustness and the low energy consumption of the solar heterogeneous photocatalytic process make it well adapted to this application. Mineralization of phytosanitary effluent with this solar eco-technology was tested with a solar laboratory set up for a few tens of litres. Feasibility was explored step by step with preliminary solar experiments performed on 2,4-dichlorophenol (DCP) followed by solar mineralization carried out on two representative commercial pesticides and three real phytosanitary waste products which were directly collected from a vineyard area. The total organic carbon profiles showed advanced mineralization but the presence of a threshold must be underlined at about 70% of mineralization yield in the case of the two pesticides as well as for the phytosanitary wastewater. A complementary eco-toxicity measurement demonstrated that this threshold is not penalizing regarding the detoxification performance. The kinetic law of mineralization, taking into account the discontinuous solar UV irradiation developed and validated for DCP, was applied with success to the commercial solutions and the wastewater from agricultural activities. Scaling up of the process based on the validated kinetics associated with solar data leads to an annual treatment capacity of 3.5 m 3 for a reactor surface of 1 m 2 .

Chemical Engineering and Processing: Process Intensification, 2012

Heterogeneous photocatalysis is able to degrade organic micropollutants in a non-selective manner... more Heterogeneous photocatalysis is able to degrade organic micropollutants in a non-selective manner and in contrast to existing tertiary processes (UVC, ozonation, membranes), solar photocatalysis permits a treatment process that, energy-wise, is clean, that is to say self-sufficient. In this context, an efficient use of the sunlight represents a major challenge in the conception and the development of this technology adapted for a sustainable water treatment. Basically, such efficiency is highly dependent of the photocatalytic media implemented in the reactor. Within the objective to study the potential of the process intensification, three different options were tested, i.e.: the conventional suspension of a photocatalyst powder; a commercial 2D photocalytic media; aluminum foam with supported photocatalyst. In a first step, for each media, pollutant (2-4 DCP) mineralization kinetics was determined in identical and controlled working conditions with a setup using UV artificial radiations. Thereafter, the model's robustness in artificial controlled conditions was validated with outdoor experiments that take necessary into account the intermittent flux of sunlight. Finally, simulations performed during a full working year demonstrated the major influence of the photocatalytic media selected on the treatment capacity of the process.

Advanced Powder Technology, 2010

A new method for setting the porous particle overall density is proposed. The apparent density of... more A new method for setting the porous particle overall density is proposed. The apparent density of the particle including the solid matter as well as the different internal porosities (from microporous to macroporous pore size ranges) is currently needed for industrial applications as gas storage, heterogeneous catalysis.. . The technique proposed is based on the principle own immersion fluid applied to a granular medium consisting of extremely fine particles playing the role of non-wetting liquid. Here are presented the restrictive theoretical and experimental conditions, which have to be fulfilled by any granular medium before applying this principle. The conventional technique of mercury porosimetry has been used to characterize apparent grain density and validate the obtained results. The technique has been calibrated to be used with particles, which exhibit a different density, size, shape, and surface roughness. In a second part, the proposed method has been applied to a crop of materials including modified activated carbons previously obtained by oxidative transient treatments. The corresponding change in microporous properties has been studied by N 2 physisorption at 77 K. Moreover, the size ranges of the particle over which each technique leads to efficient measurements have been identified.

Journal of Photochemistry and Photobiology A: Chemistry, 2011

In the field of advanced oxidization processes based on solar radiation, heterogeneous solar cata... more In the field of advanced oxidization processes based on solar radiation, heterogeneous solar catalysis involves exciting a photocatalyst with UV rays and one of the major problems encountered is optimizing the use of the sunlight. The work presented here aimed to use an efficient material able to provide a high active specific surface expressed in square meter per unit volume

Journal of Photochemistry and Photobiology A: Chemistry, 2021

Abstract Activated-Carbon/Titania composites (AC/TiO2) is a relevant option to gather the dual ad... more Abstract Activated-Carbon/Titania composites (AC/TiO2) is a relevant option to gather the dual adsorption/photodegradation property within a single material. This work aimed to investigate the composition influence on the adsorption and photodegradation properties of AC/TiO2 composites against caffeine. TiO2 grafted AC powders covering the whole composition scale were synthesized by a one-step mechanical milling process. This original simple elaboration route led to the obtention of powders which particles size and composition were homogeneous and well controlled. When the adsorbent mass ratio varied in the range 0.01−0.75, the adsorption properties, i.e. apparent kinetic and maximum adsorption capacity of the composites increased respectively by 1 and 2-log. At the opposite, the photo-oxidation rate decreased significantly when the adsorbent ratio increased. The simple elaboration route explored produces flexible AC/TiO2 composites with adjustable properties that can easily be managed to meet the requirements of different target applications.

World Academy of Science, Engineering and Technology, International Journal of Environmental and Ecological Engineering, 2015

This work establishes the Anderson localization in both the spectral exponential and the strong d... more This work establishes the Anderson localization in both the spectral exponential and the strong dynamical localization for the multi-particle Anderson tightbinding model with correlated but strongly mixing random external potential. The results are obtained near the lower edge of the spectrum of the multi-particle Hamiltonian. In particular, the exponential decay of the eigenfunctions is proved in the max-norm and the dynamical localization in the Hilbert-Schmidt norm. The proofs need the conditional probability distribution function of the random external stochastic processes to obey the uniform log-Hölder continuity condition.