The investigations on the removal of ibuprofen (IBU) in a hybrid system coupling ozonation and nanofiltration with functionalized catalytic ceramic membrane are presented. The gaseous ozone into feed water in concentration of 11 g Nm-3 was supplied. Positive influence of catalytic ozonation on ibuprofen decomposition was observed. The application of catalytic nanofiltration membrane led to the ibuprofen removal of 91% after the first 15 min from the beginning of the O3/NF process, while at the same time, for the pristine membrane, it was equal to 76%. The investigations revealed incomplete degradation of drug under pH 3 after 2 h, i.e., 89%. On the other hand, the addition of inorganic salts did not affect the catalytic ibuprofen removal efficiency. Under acidic pH, the highest permeate flux decline (26%) was noted, whereas no differences between permeate flux measured under natural and alkaline conditions were observed. During the treatment process, three IBU by-products were detected, which significantly affected the permeate toxicity; however, after 2 h of catalytic nanofiltration, the product of treatment process was found as non-toxic.

Rice husk is a global agricultural co-product and is already the subject of several studies, notably for wastewater treatment. Rice husk is composed of 3 types of components: amorphous silica, organic biopolymers and others (salts, oxides...). Depending on the treatment, rice husk becomes either a carbon-free material or a mixed car-bon/silica biochar. In this paper, a thorough characterisation of rice husk was carried out by SEM, TEM, TGA, XRF, XRD, XPS, FTIR, SAXS, SANS, NMR and N2 adsorption-desorption. The results show that silica can be present as dense silica or silica nanoparticles and that native organic matter can be converted to turbostratic carbon. This carbon "drowns" the silica nanoparticles and prevents them from sintering. Particular attention is paid to impurities which play a crucial role in several properties. They are present in different forms, such as CaCO3, KCl or Al2O3 or in the silica lattice. They can be removed, but if retained, they induce sintering and crystallisation of the silica nanoparticles, resulting in a decrease in specific surface area from 330 m(2).g(- 1) to 15 m(2).g(- 1). Moreover, the sorption efficiency of the materials is strongly dependent on the presence of impurities since the extraction rate drops drastically from 99% to <0.5% when the impurities are removed. The maximum capacity reached for nickel is 11.7 mg.g(- 1).

This study was carried out to determine the best conditions for the preparation of magnetic activated carbons (mACs) from Sargassum sp. as both adsorbents and catalytic supports. Coupling of adsorption and catalytic ozonation for removal and degradation of antibiotics was implemented for several cycles of use in order to assess the efficiency and the stability of these mACs. The mAC prepared by the post-impregnation method (activated carbon with Sargassum sp. + FeCl2.4H2O pyrolyzed at 200 degrees C for 120 min) showed better adsorption capacity of a mixed solution of antibiotics (95.3, 48.3, 13.4 mg g-1 for tetracycline (Tc), penicillin (Pen) and erythromycin (Ery) respectively after 3 cycles of use) than the mAC prepared by the pre-impregnation method (Sargassum sp. + FeCl2.4H2O pyrolyzed at 664 degrees C for 65 min). Whereas the evaluation of the degradation under ozone after mAC saturation by adsorption showed a better degradation after 3 cycles of reuse higher than 96 % for Ery, and higher than 99 % for Tc and Pen for the mAC prepared by the pre-impregnation method. Their physicochemical properties were characterized by different techniques, in particular X ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), analysis of the surface acid-base groups by Boehm method, pore analysis and specific surface area measurement (using the Brunauer-Emmett-Teller method) by nitrogen adsorption, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The use of Sargassum sp. is therefore promising for the preparation of efficient bio-sourced mACs for the removal of organic pollutants from polluted waters.

Photocatalytically active silicon carbide (SiC)-based mesoporous layers (pore sizes between 5 and 30 nm) were synthesized from preceramic polymers (polymer-derived ceramic route) on the surface and inside the pores of conventional macroporous α-alumina supports. The hybrid membrane system obtained, coupling the separation and photocatalytical properties of SiC thin films, was characterized by different static and dynamic techniques, including gas and liquid permeation measurements. The photocatalytic activity was evaluated by considering the degradation efficiency of a model organic pollutant (methylene blue, MB) under UV light irradiation in both diffusion and permeation modes using SiC-coated macroporous supports. Specific degradation rates of 1.58 × 10−8 mol s−1 m−2 and 7.5 × 10−9 mol s−1 m−2 were obtained in diffusion and permeation modes, respectively. The performance of the new SiC/α-Al2O3 materials compares favorably to conventional TiO2-based photocatalytic membranes, taking advantage of the attractive physicochemical properties of SiC. The developed synthesis strategy yielded original photocatalytic SiC/α-Al2O3 composites with the possibility to couple the ultrafiltration SiC membrane top-layer with the SiC-functionalized (photocatalytic) macroporous support. Such SiC-based materials and their rational associations on porous supports offer promising potential for the development of efficient photocatalytic membrane reactors and contactors for the continuous treatment of polluted waters.

A preliminary study was carried out on the morphological design of tubular single-channel alumina membranes prepared by stereolithography, an additive manufacturing process. The geometry of the ring-patterned inner surface of membranes was optimized using computational fluid dynamics calculations and validated in microfiltration tests with aqueous suspensions of P. aeruginosa. Patterning of the inner surface of tubular membranes helped reduce cake formation at a higher value of the average crossflow velocity. The results highlight benefits of stereolithography-based approach to the morphological design of ceramic membranes.

Sintering is a very important process in materials science and technological applications. Despite breakthroughs in achieving optimized piezoelectric properties, fundamentals of K0.5 Na0.5 NbO3 (KNN) sintering are not yet fully understood, facing densification versus grain growth competition. At present, microscale events during KNN sintering under reducing atmospheres are real-time monitored using a High Temperature-Environmental Scanning Electron Microscope. A two contacting KNN particles model satisfying the Kingery and Berg's bulk diffusion model is reported. Dynamic events like individual grain growth and grain elimination process are explored through a postanalysis of recorded image series. The diffusion coefficient for oxygen vacancies of 10-8 cm2 s-1 and average boundary mobility of 10-9 cm4 J-1 s-1 are reported for the KNN ceramics. Moreover, the local pore shrinkage is consistent with the Kingery and François's concept of pore stability except that pore curvatures are not all concave, convex or flat due to anisotropic grain-boundary energies. The global grain growth kinetics are described using parabolic and/or cubic laws. The effect of atmospheres and microstructure evolution on the intrinsic and extrinsic contributions to the dielectric response using Rayleigh's law is also explored. These results bring a new breath for KNN sintering studies in order to adapt the sintering process.

Self-oscillating filtration membranes having a lifelike pulsatile flow are prepared thanks to a synchronized coupling between a chemical oscillator and a responsive membrane. Commercial alumina membranes are superficially functionalized with pH-responsive poly(methacrylic acid) (PMAA) chains synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of MAA in the presence of a catechol-based RAFT agent. The grafting of PMAA onto alumina, mediated through catechol chemisorption, is analyzed by X-ray photoelectron spectroscopy, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, and static water contact angle. Bromate- sulfite-ferrocyanide (BSF) is used as a chemical oscillator, enabling autonomous cyclic pH modulation between 3.5 and 6.5. The pH oscillations are setup in the conditions of membrane filtration inside a filtration cell thanks to a careful study of the bifurcation diagram showing the required conditions to reach the oscillation domain. Since PMAA has a pK(a) around 5.8, a periodic extension-contraction of the polymer chains is obtained during membrane filtration, which leads to a synchronized change in the membrane pore size. Chemically powered autonomous pulsatile flow with an impressive permeability cycles is observed with an effective chemomechanical feedback action of the membrane pore size change on the chemical oscillator mechanism.

A photocatalytically active layer composed of TiO2 (Evonik P25) was successfully deposited on the macroporous (3 mu m pore size) permeate side of an asymmetric porous alumina membrane with the aid of a smectite (a synthetic hectorite, Sumecton SWF) by dipping the membranes into an aqueous suspension containing P25 and the smectite. After the heat treatment at 400 degrees C, the coated hybrid was adhered on the macroporous support enough to be applied for the photocatalytic decomposition of organics (methylene blue and phenol as model molecules) in water. The water permeance of the membranes after the coating with the P25-smectite hybrid was reduced by only 24% compared with that of the pristine membrane, showing that the advantages of the present method for the preparation of the photocatalyst layer on the surface of the macroporous alumina without significant infiltration of the suspension into the support pores. The amount of MB and phenol degraded using the P25-SWF hybrid was equal to 0.007 and 0.023 mmol.L-1, respectively, when the reaction was carried out using the four single-channel tubular membrane reactor at transmembrane pressures of 250 mbar. The implemented photocatalytic membrane reactor can easily be up-scaled by increase the size of the membrane module, with more tubes and longer tubes (lengths up to 1 m are commercially available), paving the way to potential technological applications for the continuous treatment of polluted waters.

Photocatalytic degradation of sulphur containing organics in water was substantially accelerated by the in-situ removal of sulphur oxide species formed by the dye degradation as metal sulfate precipitates. The significant enhancement of the degradation of methylene blue (C16H18ClN3S) and acid yellow 42 (C32H24N8Na2O8S2), as examples of sulphur containing organics, was achieved when the reactions were conducted in the presence of alkaline earth cations (such as Ca2+, Sr2+, and Ba2+).

Micropollutants elimination in water becomes a global concern and represents an important issue for a possible reuse or a release to the environment. Hybrid processes combining membrane filtration and catalytic ozonation offer promising opportunities for micropollutant removal. A ceramic commercial nanofilter with a very low molecular weight cut-off of 200 Da was functionalized by sol-gel deposition of a mesoporous maghemite (gamma-Fe2O3) thin layer. Preliminary experiments enabled to determine the maximum temperature usable for the thermal strengthening of the catalytic layer without significant permeance change. The catalytic activity of the iron oxide equivalent powder was tested in batch reactor with ozone and para-chlorobenzoic acid (pCBA) which quickly reacts with hydroxyl radicals formed with ozone at the catalyst surface, and only very slowly with ozone itself. The operational performance of the functionalized ceramic membrane was evaluated in a dedicated pilot. The obtained results unequivocally show the catalytic activity of this functionalized membrane.

Thermochemical splitting of H2O and CO2 applying redox materials constitutes a sustainable option for synthetic fuel production and CO2 valorization. It consists of two-step process based on the creation of oxygen vacancies in non-stoichiometric oxides during solar-driven thermal reduction, followed by the material re-oxidation with H2O and/or CO2 to generate syngas (H2/CO), the building block for a wide variety of synthetic hydrocarbon fuels. In this work, a monolithic solar reactor was designed and tested integrating reticulated porous ceria (open-cell foams) heated by concentrated solar energy. The influence of various operating parameters on the thermochemical reactor performance was investigated. Increasing the temperature or decreasing the pressure in the reduction step was found to enhance the maximum reduction extent reached by the redox material (CeO2-δ), thereby improving the fuel production capacity. In addition, a decrease of the oxidation temperature led to higher fuel production rate, despite an increase of the temperature swing between the reduction and oxidation steps. Increasing the oxidant concentration also sharply enhanced the oxidation rate. Peak CO production rate approaching 10 mL/min/g was achieved with ceria foams (exhibiting micron-sized grains forming an interconnected macroporous network within the struts) during their reoxidation upon free cooling with pure CO2 stream (after reduction at 1400 °C), thus strongly outperforming (by a factor of about x8) the previous maximum values reported to date. This result was attributed to the fine and stable granular microstructure of the reticulated ceria foams. The solar reactor reliability and robustness during high-temperature two-step redox cycling were demonstrated with an average cycle production of 5.1 mL/g of H2 and CO, and peak solar-to-fuel efficiencies above 8%. The highly reactive reticulated foams with 10 and 20 ppi (pore per inch) were cycled for about 69 h (51 cycles) of continuous on-sun operation without any decrease in performance, thus evidencing their noteworthy thermochemical and microstructural stability.

Hranfa's marl, a local natural mineral, is selected for the decontamination by adsorption of aqueous effluents in textile industry. Its physicochemical characterization is first performed. It is composed mainly of Calcite, Quartz, Ankerite and Muscovite. Its specific surface area is 40 m2g-1. Its adsorption performance is then tested in batch conditions using an industrial organic dye, Bemacid Red E-TL, as a model pollutant. The measured adsorption capacity of Hranfa's marl is 16 mg g-1 which is comparable to that of other types of natural adsorbents. A hybrid process is tested coupling adsorption of the dye on marl in suspension and microfiltration. An adsorption reactor is inserted into the circulation loop of a microfiltration pilot using ceramic membranes. This makes possible a continuous extraction of the treated water provided that a periodic replacement of the saturated adsorbent is done. The breakthrough curve obtained by analyzing the dye concentration in the permeate is close to the ideal one considering that no dye will cross the membrane as long as the adsorbent load is not saturated. These first experimental data provide proof of concept for such a hybrid process.