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International audience; Two organic solutes of close molecular weight (approximate to 270 g mol(-1)) and hydrophobicity (logK(ow) approximate to 1.2- 1.5) were selected as model micropollutants to study their reverse osmosis in seawater. Tropaeolin O can be a monovalent/divalent anion whereas Thiamine can be a monovalent/divalent cation. Their charges and hydrophilic/hydrophobic balance can be modulated by playing on the pH and the ionic strength. The TFC-HR (Koch, USA) and SW30 (FilmTec, The Netherlands) membranes have shown a similar overall behavior either for single NaCl or Tropaeolin O filtrations. The comparison of Tropaeolin O/Thiamine rejections by the TFC-HR membrane has shown that membrane/solute electrostatic interactions explained the rejection in single solutions. However, in 30 g L-1 NaCl and synthetic seawater, rejections were more likely due to the hydrophobic/hydrophilic balance of a given solute: the more hydrophobic form being more rejected than the hydrophilic ones. Finally, the ethanol addition (30%) was achieved to study the impact of a second concentrated organics, moreover able to modify the background solvent of the filtration; Tropaeolin O rejection was decreased.

A novel ceramic microfiltration (MF) membrane was prepared from natural phosphate and its properties were thoroughly characterized. An investigation of the effect of sintering temperature on the features of phosphate membrane was carried out in the range from 900 to 1100 °C. The optimized membrane sintered at 1000 °C exhibits 697 L h−1 m-2 bar−1 of permeability, 25.6 % of porosity, 0.26 μm of average pore size and 19.7 MPa of flexural strength. When evaluated for filtration of raw seawater as a potential pretreatment for reverse osmosis desalination, the prepared membrane reduced total organic carbon (TOC) and turbidity by 73 and 98 %, respectively, as well as reducing silt density index (SDI) from 5.41 to 3.25. Furthermore, the fouling mechanism and the flux recovery were also studied. Finally, simple cleaning of the prepared membrane performed after the MF experiment led to recover 74 % of its original water flux.

Drinking water treatment sludge (DWTS) was used for the preparation of ceramic microfiltration membrane. The DWTS powder was firstly characterized to determine its chemical and mineralogical composition, and to understand its thermal behavior. DWTS powder was mixed with clay as binder and starch as porosity agent, then pressed to shape flat membrane, and sintered at different temperatures from 950 to 1150 °C. The optimal sintering temperature (1050 °C) provides ceramic membrane with a porosity of 46.7%, a pore size of 0.92 μm, a mechanical strength of 14.5 MPa and a permeability of 724.5 L/h.m2.bar. This membrane was successfully used to clarify a synthetic baking powder suspension and an textile effluent. DWTS-based membrane was able to remove completely the turbidity from feeds, to reduce significantly the chemical oxygen demand (COD), and to discolor completely textile wastewater. Furthermore, four empirical models were applied to describe the fouling mechanism occurred during filtration experiments.

International audience; The aim of this work is the manufacturing of flat microfiltration membrane made from Moroccan natural kaolinite clay and corn starch as porosity agent. The membrane was prepared by uniaxial pressing technique and sintering at 1,100 degrees C. The effect of starch on membrane features was investigated from 0 to 15 wt.%. The membrane has a diameter of 37.8 mm and a thickness of 2.3 mm. In order to optimize its properties, prepared membrane was characterized in terms of apparent porosity, water absorption, apparent density, mechanical strength, pore size, microstructure, and water permeability measurements. Experimental results showed that the membrane prepared with 10 wt.% of starch is considered as an optimized membrane which has an average pore size of 2.3 mu m, the mechanical strength of 20.2 MPa, and permeability of 2,129 L h(-1)m(-2) bar(-1). The optimized membrane was applied for pretreatment of raw seawater for desalination and clarification of agro-food effluent using dead-end filtration under pressure of 0.12 bar. Filtration results showed that turbidity rejection achieves 73% and 99%, respectively for raw seawater and agro-food model effluent.

International audience; In this work, low-cost and high permeation NaA zeolite membrane was successfully prepared on kaolinite support by in-situ crystallization using secondary growth method. The effect of synthesis conditions including temperature and time of crystallization, and water ratio was studied aiming to improve the quality and the performance of the membrane. The prepared membrane was thoroughly characterized using many techniques such as X-ray diffraction, scanning electron microscopy infrared spectroscopy, Brunauer-Emmett-Teller specific surface area and zeta potential to investigate the layer deposition. The prepared membrane exhibits high permeation flux of 8.49 kg m −2 h−1 and separation factor of 10900 for the dehydration of 90 wt% ethanol by pervaporation at 75 °C.

This study concerns the development and characterization of composite ultrafiltration membrane made of polymer blend of polysulfone (PSf) and polyetherimide (PEI) as membrane layer and flat pozzolan support. The organic layer was deposed on ceramic support by spin/spray-coating method. The effect of PEI content (5–20 wt.%) on membrane proprieties in terms of microstructure and filtration performance was investigated. The prepared membrane was characterized using several techniques such as Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), scanning electron microscope (SEM) and contact angle. The morphology analysis showed that PSf/PEI membrane layer is homogeneous and strongly adherent on the pozzolan support. The thickness layer is uniform and found to be between 10.3 and 11.2 μm. Furthermore, performances of the prepared composite membranes were evaluated by filtration of acid orange 74 (AO74) and methyl orange (MO) solutions at pressure of 3 bar. The optimized membrane (prepared with 20 wt.% of PEI) has water permeability of 24.2 L/h m2 bar and maximum rejection of 96.1 and 75.8% respectively for AO74 and MO. Based on promising filtration results as well as the low cost of prepared membrane, industrial applications for treatment of wastewater particularly colored wastewater generated from textile industries may take place.

International audience; The adoption of fuel cells for portable electronic devices appears to be an efficient promising approach to alleviate the energetic dependence to fossil fuels. Poly-pyrrole (PPy) and nickel nanoparticles (NiNPs) based electro catalyst was synthesized by galvanostatic and potentiostatic modes respectively using the regeneration approach with the aim to accelerate the kinetics of anodic oxidation of ethanol with a low production cost, good catalytic activity, high resistance to poisoning species and long term stability. The electrochemical, morphological, structural, and catalytic features of the nanocomposite were investigated using several techniques such as cyclic voltammetry (CV), electrochemical Impedance spectroscopy (EIS), scanning electron spectroscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The effect of the NiNPs content on the electrocatalytic performance of NiNPs/PPy was investigated which lead to the optimized composition. An excessive amounts of nickel particles reduces the number of active sites of the material causing a sluggishness of the electron transfer path. Consequently, the optimal concentration of nickel which reveals the best electrocatalytic activity of NiNPs/PPy/CPE nanocomposite for ethanol electrooxidation is 6 mM. At this concentration, the value of the anodic current is dramatically amplified from 3.58 mA/cm2 to 20.1 mA/cm2 on the regenerated electrode proving the effectiveness of the regeneration approach on enhancing the current density and magnifying the anodic peak. The regeneration of the electrode reduces the electrocatalyst tolerance towards poisoning intermediate carbonaceous species accumulated on the catalyst surfaces and increased the current density with a good stability for more than 5000s.

Hydroxyapatite (HAp) nanorods are synthesized from phosphogypsum waste (PG) and potassium dihydrogen phosphate (KH2PO4) under hydrothermal conditions. The influence of several synthesis parameters such as temperature (100–200 °C), synthesis time (1–15 h), and solution pH (5–11) on product structure and purity is addressed by X-ray diffraction and Fourier Transformed-Infrared Spectroscopy. Phase-pure HAp nanorods with diameter and length of 18 and 63 nm, respectively, are obtained after 10 h at 200 °C and pH ∼ 11. The influence of Brij-93 surfactant on the morphology of prepared HAp is investigated by transmission and scanning electron microscopy. The aspect ratio and the mean size of HAp crystals increase to 1013 and 205 × 20 nm, respectively, with increasing the concentration of Brij-93 surfactant to 0.01 mol. Hence, the PG recycling could be accomplished using an easy synthesis route with relatively cheap reactants for the production of nanocrytalline HAp.

This work describes the elaboration of flat ceramic microfiltration membrane based on natural perlite for microfiltration of industrial wastewater. The ceramic membrane was obtained by an uniaxial pressing process and sintering at optimized temperature. The sintering temperature was investigated in the range from 850 to 1050 °C. The elaborated membrane of 38.4 mm in diameter and 2.2 ± 0.3 mm in thickness was characterized by environmental scanning electron microscopy (ESEM), porosity, water permeability, mechanical strength, and chemical resistance. The porosity of optimized membrane (sintered at 950 °C) is 52.11% with an average pore size of 1.70 μm. The water permeability reached a value of 1433.46 L/hm2.bar. In addition, the membrane has a mechanical resistance of 21.68 MPa and exhibits good chemical resistance both in an acidic and basic medium. The performance of prepared membrane was evaluated by frontal microfiltration of two industrial wastewater effluents (agro-food and tannery). Experimental results show that retention of turbidity was superior to 97 and 96% respectively for agro-food and tannery effluents. The filtration results are quite promising that could allow using the prepared membrane as an alternative process in industrial wastewater treatment.

This paper reports the preparation and characterization of a low-cost nano-TiO 2 ultrafiltration membrane deposited on a bentonite support. The ultrafiltration layer was obtained by dip-coating process using nano-TiO 2 , followed by sintering at 750 °C. Environmental Scanning Electron Microscope (ESEM) analysis of prepared ultrafiltration membrane showed that the deposited layer is homogeneous and shows a good adhesion on the support presenting a mean thickness of 4 ± 0.2 μm. The average pore diameter and water permeability of the obtained membrane are respectively 10 ± 0.5 nm and 16.08 L/h m 2 bar. The membrane performance was evaluated by filtration of three different dyes: two anionic (Direct red 80 and Acid orange 74) and a cationic one (Methylene blue). Effect of feed pH and dyes concentration on membrane rejection was investigated at a pressure of 4 bar. The experimental filtration results showed that rejection of Direct Red 80, Acid Orange 74 and Methylene Blue achieved maximum values of 98%, 85% and 94% respectively, depending on filtration conditions and each dye characteristics.

Graphical abstract, A new and simple approach for carbaryl determination in natural sample was proposed using Low Silica X (LSX) zeolite modified carbon paste electrode. LSX zeolite with a porous structure was incorporated into carbon paste electrode in the appropriate portion. The prepared electrode was then characterized using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Various experimental parameters as the zeolite amounts, pH, accumulation time, and differential pulse voltammetric parameters were optimized. Under optimal conditions, a linear response was obtained in the range of 1–100 µM of carbaryl using differential pulse voltammetry with detection limit of 0.3 µM (S/N = 3). The sensors showed good selectivity, stability, and reproducibility and has been successfully applied for detection of carbaryl in tomato samples with good recoveries.

Moroccan natural phosphate was tested as an effective adsorbent for the removal of cationic dye rhodamine 6G (Rh6G) as well as anionic dye congo red (CR) from wastewater. The X-ray diffraction, FTIR and EDX characterizations reveal that the sample contains 98 wt% fluoroapatite (Ca 5 (PO 4 ) 3 F) with 1 wt% quartz (SiO 2 ) and 1 wt% calcium carbonate (CaCO 3 ). Nitrogen sorption analysis shows that the BET specific surface area (S BET ) and BJH pore volumes of the sample are 18.8 m 2 /g and 0.1 cm 3 /g, respectively. Batch adsorption experiments of the dyes from aqueous solution were conducted, taking into account the influence of initial dye concentration (100–400 mg/L), adsorbent dosage (1–20 g/L), contact time (5–300 min) and solution pH (3–12). The Langmuir isotherm model best represents the equilibrium adsorption process of the two dyes. The calculated maximum adsorbed quantity q max of CR and Rh6G at dosage 20 g/L and pH value of 5.2 were found 19.81 and 6.84 mg/g, respectively. The adsorption of Rh6G and CR on natural phosphate was found to follow the pseudo-second-order model. Natural phosphate was also tested as an effective adsorbent for a simulated dye effluent under industrial conditions of temperature and pH. Desorption studies were conducted using HCl as an eluent and the highest elution efficiency for both dyes was obtained with a 0.1 M solution. Accordingly, it is demonstrated in this work that natural phosphate is a very efficient adsorbent for both cationic and anionic dyes from contaminated water, and represents a great low-cost alternative to commercial adsorbents due to its abundance as a natural resource in Morocco.

Herein, we report the fabrication of a clay-based ceramic membrane. The corresponding support was prepared by a solid-state method using a clay/banana peels (BP, natural porogen) mixture followed by sintering for 2 h at 1100 °C, and the raw materials were characterized by a range of instrumental characterization techniques. In particular, the influence of BP content on the support properties such as porosity and mechanical strength was examined, and an increase in BP content from 5 to 20 wt% was shown to result in increased support porosity and decreased mechanical strength. The microfiltration membrane was prepared by spin-coating the support with a suspension of clay powder (

The present work reports the preparation and characterization of flat ceramic membrane via dry pressing method made from natural phosphate as based material and kaolinite as additive to enhance membrane characteristics. Response surface methodology based on Box–Behnken design was used to optimize the preparation conditions notably amount of kaolinite (5–15 wt%), sintering temperature (900–1000 °C) and time of sintering (2–4 h). The optimized membrane has 40.2 MPa of flexural strength, 41.3% of porosity, 1045 L h−1 m−2 bar−1 of permeability and 0.35 µm of average pore size. The phosphate/kaolinite membrane was subjected to the filtration of industrial textile wastewater and it showed excellent performance as microfiltration membrane. It is able to remove 98.99% of turbidity, 69.39% of total organic carbon, 74% of chemical oxygen demand and 77.11% of biological oxygen demand.

Nanocrystalline hydroxyapatite (HAp) with high surface area was synthesized by surfactant-assistant hydrothermal method from an industrial waste phosphogypsum. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen sorption characterizations revealed that HAp crystals grow as needle-like particles along the c direction with surface area of 86 and 135 m2/g for the samples synthesized without and with Brij-93 surfactant, respectively. Adsorption of anionic azo dye Congo Red (CR) were conducted on both samples, taking into account the influence of initial dye concentration (100–500 mg/L), adsorbent dosage (0.5–30 g/L), contact time (5–180 min) and solution pH (2–12). Kinetic studies showed that the adsorption of CR followed pseudo-second-order model, i.e., chemisorption is the rate controlling step. Freundlich isotherm was found to be most suitable model for the adsorption of CR, i.e. adsorption is multilayer process. The calculated maximum adsorption capacity of synthesized B93-HAp adsorbent using Brij-93 surfactant was found to be 139 mg/g at pH 5.5 and dosage of 2 g/L. Two predominant mechanisms were observed for CR adsorption, electrostatic attraction and hydrogen bonding as revealed by Fourier transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. The multi-cycle sorption/desorption tests indicated that waste-transformed adsorbent could be regenerated and reused up to 6 cycles. Therefore, this work shows that the conversion of waste materials into adsorbents has a two-fold environmental benefit for both waste management and wastewater treatment.

The development of high performance ultrafiltration membranes using low-cost products and naturally abundant materials has utmost importance for sustainable development and environmental applications. In this work, a new composite membrane was successfully synthesized by deposition of a polypyrrole layer on a flat porous support based on a natural geomaterial. The thin layer of polypyrrole was synthesized by the chemical polymerization of pyrrole. The obtained composite membrane was characterized by Infrared Spectroscopy, X-Ray Diffraction and energy dispersive X-Ray analysis to confirm the polymerization reaction of pyrrole. Scanning electron microscopy and contact angle that the membrane surface has typical cauliflower morphology with 20 μm in thickness and high hydrophobicity (108°). The performance of the polypyrrole membrane in terms of dye permeance and effluent textile treatment was investigated by measurement of the water permeability and congo red rejection from aqueous solutions. Experimentally, the water permeability reaches 10.3 ± 3 L/m2.h.bar, and the polypyrrole membrane removes up to 98 % of congo red at optimized conditions.

γ alumina microporous membranes, produced from a sol–gel process, were grafted by means of chloro-, methoxy- or ethoxy-organosilanes. The grafting conditions were first tested on γ alumina powders which were characterised by means of thermogravimetric analysis and nitrogen adsorption. The membrane material was studied by means of infrared spectrometry, nitrogen adsorption and nitrogen permeation. The performances of grafted and ungrafted membranes were examined for the separation by pervaporation of binary mixtures such as water/ethanol, cyclohexane/toluene, ethanol/cyclohexane and methylethylketone/cyclohexane.

In this work, the ability of chrome shavings and of crust leather buffing dusts to remove dyes from aqueous solutions has been studied. Buffing dusts proved to be a much better adsorbent than chrome shavings for cationic dyes. The adsorption of anionic dyes is very important on two studied wastes. The pH has an obvious influence on the adsorption of dyes. Adsorption of cationic dyes is less favourable under acidic conditions (pH 10.5). The adsorption of anionic dyes on both adsorbents is more favourable under acidic conditions (pH

Seawater desalination by reverse osmosis (RO) is one of the solutions to meet the growing global demand for fresh water. However, at least two major challenges remain: (i) to limit the membrane fouling and (ii) to control the rejection of organic micropollutants present in the water to be treated to ensure the potability of the treated water. The RO membrane fouling can be limited by pre-treating the water to be filtered (physico-chemical treatments, microfiltration) and by increasing the hydrophilicity of the membrane materials. The control of the organic micro-pollutants’rejection requires a better fundamental understanding of the origins of transfers through polymeric RO membranes which are currently the most efficient for desalination. The aim of this work is to contribute to provide answers at these different levels. The thesis work was carried out along 3 axes : (i) development of low-cost microfiltration membrane made of natural Moroccan clay, used as MF membrane for seawater pretreatment and then as a support to develop an ultrafiltration membrane by graphene oxide (GO) grafting. (ii) development of self-supported mixed matrix membranes with PES and GO, used for the filtration of salts, small organic molecules and model effluent. PES/GO membranes fouled less than PES membranes. Their resistance to chlorine was evaluated. (iii) study of the rejection of two model micropollutants (dye, vitamin) in synthetic seawater. The model micropollutants were two organic molecules of close molecular weight (≈ 270 g.mol-1) of opposite charge and comparable hydrophobicity., Le dessalement de l'eau de mer par osmose inverse (OI) est l'une des solutions pour répondre à la demande mondiale croissante d'eau douce. Cependant, il subsiste au moins deux défis majeurs : (i) la limitation du colmatage des membranes et (ii) la maîtrise de la rétention des micropolluants organiques présents dans les eaux à traiter pour assurer la potabilité de l’eau traitée. Le colmatage des membranes d’OI peut être limité en pré-traitant l’eau à filtrer (traitements physicochimiques, microfiltration) et en augmentant l’hydrophilie des matériaux membranaires. La maîtrise de la rétention des micro-polluants organiques passe par une meilleure compréhension fondamentale des origines des transferts à travers les membranes d’OI polymères qui sont actuellement les plus performantes pour le dessalement. Le but de ce travail est de contribuer à apporter des réponses à ces différents niveaux. Les travaux de thèse se sont déroulés selon 3 axes : (i) élaboration de membrane de microfiltration à faible coût en argile naturelle marocaine, utilisée comme membrane MF de prétraitement d’eau de mer puis comme support pour élaborer une membrane d’ultrafiltration par greffage d'oxyde de graphène (GO). (ii) élaboration de membranes auto-supportées à matrice mixte en PES et de GO, utilisées pour la filtration de sels, de petites molécules organiques et d’effluent modèle. Les membranes PES/GO se colmatent moins que les membranes PES. Leur résistance au chlore a été évaluée. (iii) étude de la rétention de deux micropolluants modèles (colorant, vitamine) dans de l’eau de mer synthétique. Les micropolluant modèles était deux molécules organiques de poids moléculaire proche (≈ 270 g.mol-1) de charge opposée et d’hydrophobie comparable.