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Ambient-stable cafeo4 synthesis process wet - Abstract The aim of this work is to prepare the room-stable calcium ferrate

In order to assess the impact of the proper functioning of wastewater treatment plants (WWTPs) and sanitation networks on the quality of water and surface sediments of the Oued Fez River and its tributaries, and ultimately their outlet in the Sebou River, physico-chemical, geochemical and mineralogical analyses were performed. The components were studied in high- and low-water regimes at eight sites. Seven heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn) were investigated in the sediments, with a decreasing trend being identified as Zn > Cu > Pb > Cr > As > Ni > Cd, and a mobility sequence as Cu > Pb > Zn > Ni > Cr. A comparison of the total heavy metal concentrations in the Oued Fez and Sebou River sediments with those of previous studies indicated a reduction in the harmful and polluting contribution of the Oued Fez to the Sebou River. The heavy metal assessment was achieved using environmental indices and sediment quality guidelines. The obtained results indicate that the presence of heavy metals in the sediment mainly comes from anthropogenic activities. Based on these results and their comparison with those from previous studies, the contribution of WWTPs and sanitation networks to improving the water quality of the middle Sebou River is clearly noteworthy.

International audience; In the plain of Saiss, the most agricultural region of Morocco, the studies concerning the assessment of environmental and human risks related to metal contamination of agricultural soils are severely missing. To overcome the lack of such studies, trace-element analyses were carried out on six sampling sites of agricultural surface soils (66 sampling points), irrigated by superficial watercourses with high heavy metal contents. The average trace-element contents were 78, 55, 33, and 119 (mg kg−1), respectively, for Cr, Cu, Ni, and Zn. These values are above average worldwide soil and geochemical background levels. Multivariate statistical analyses, principal component, and cluster analyses suggest that soil contamination by Cr, Cu, and Zn is mainly due to wastewater irrigation, with the exception of Ni, which is probably of pedo-lithogenic origin. To provide further information on contamination transmission, the bioavailability and distribution of the four heavy metals in the soils were studied by sequential and single extractions. The results indicate that Cu and Zn are potentially available and can constitute a potential risk to the environment. The risk assessment of soil contamination was also carried out using risk assessment code, enrichment factor, contamination factor, degree of contamination, pollution lead index, geoaccumulation index, and potential ecological risk factors. The health risk evaluation by the Hazard Index was used to derive a combined risk of soil ingestion, dermal contact, and inhalation for adults and children. According to these indices, the soils present a moderate-to-high contamination for Cu and Zn elements, respectively. Hazard Index values indicate the relative absence of health risks associated to heavy metals for both adults and children.

A new mixed-valence ironIII-zincII diphosphate, Zn2+Fe3+2(P2O7)2, has been prepared by a dry way and characterized structurally by several techniques. Analysis of the powder diffraction pattern of the synthesized diphosphate showed that it is isostructural with the ironIII-ironII diphosphate, Fe2+Fe3+2(P2O7)2, crystallizing in an orthorhombic symmetry in the Pnma space group. Other physical properties were characterized using Mossbauer spectroscopy and Vibrating Sample Magnetometer measurements, which showed that this new phosphate with Fe3+ ions in VI coordination has a paramagnetic behavior at room temperature. Infrared and Raman spectroscopies were also used in this study to help characterizing structurally the new synthesized material.

This work investigates the recycling of pyrrhotite ash (PA) waste as a method to provide a secondary raw material for clay brick bodies. PA is an industrial waste mainly composed by iron oxide particles (64,9 wt%). It was produced during the production of sulfuric acid from the combustion of pyrrhotite ore. This waste was characterized by X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy and differential thermal analysis. The morphology and distribution of particles size were also studied. Clay bricks containing yellow clay and different content of PA (10–50 wt%) were prepared, fired at 1000 °C and tested to evaluate their technological properties (e.g. linear shrinkage, water absorption, bulk density, apparent porosity and flexural strength). The microstructure of the sintered bricks was also evaluated by scanning electron microscopy (SEM). The test results indicate that the addition up to 30 wt% of PA waste to clay bricks could be used, which would enhance the possibility of its reuse in a safe and sustainable way.

This work is a result of previously done studies on the synthesis of A2FeVIO4 wet ferrate (VI) formula, using chlorine as an oxidant. The major problem of these ferrates is related to their stability over time. This brings us to identify and optimize the critical parameters influencing the preparation of the Na2FeO4 at room stable phase with acceptable performance. The use of water bleach (hypochlorite ClO‾) at a chlorometric degree of 50°F in the synthesis of the Na2FeO4 ambient stable phase promotes the oxidation of iron (II) iron to (VI) in a concentrated NaOH alkaline medium. The synthesis reaction is in the presence of FeSO4 7H2O hydrated iron sulfate at a temperature of about 55°C in order to simplify the synthesis process, to enhance the production of the Fe (VI) and to meet the growing demand of ferrates (VI) for their interest in the treatment of water. Monitoring the degradation of synthesized Na2FeO4 shows its stability up to 12 months, which facilitates storage and transportation. The phases obtained were characterized by IR spectroscopy, and RX by UV spectrophotometer, measuring the optical density at 507 nm.

The iron compounds in the oxidation state (VI) have the specific advantage of being powerful oxidants and bactericides. This feature explains their particular interest in the treatment of water. The aim of this work is to prepare Na2FeO4 stable at ambient in order to optimize the key parameters influencing the performance of the oxidation of iron (II) to iron (VI), as well as to monitor its degradation over time. The synthesis of this phase has been carried out by using the dry reaction Na2O2 with Fe2O3 with a temperature of 700°C for a reaction time of 13 hours with a Na/Fe ratio of 4 to make it possible to simplify the synthesis procedure, to minimize the cost and enhance the production of iron (VI) to meet the growing demand of ferrate (VI) for its interest in water treatment. The obtained phase was characterized by UV spectrophotometer by measuring the optical density at a wavelength of 507 nm.

Ferrate (VI) alkalis are the best known and best studied. The importance of their study is due to their increasingly diverse and innovative applications. The aim of this work is to prepare stable at ambient BaFeO4, to study and optimize the key parameters influencing the performance of the oxidation of iron (III) into iron (VI) and to monitore its degradation over time in order to minimize the cost and improve the production of ferrate (VI) for their interest in the water treatment.. the synthesis of the phase was carried out by dry processing, using the reaction Ba3 (Fe(OH)6)2, H2O, and Ba(OH)2 at a temperature of 850 ° C under flowing oxygen for a period of 12 hours with a ratio of Ba / Fe = 3. The result was characterized by UV spectrophotometer, measuring the optical density at the wavelength of 507 nm.

This work aims at preparing electrochemically the K2FeO4 ambient stable phase and monitoring its degradation with time. The electrochemical method attracted more interest because of the high purity of the obtained product. Thus, we have identified, through the development of electrochemical method for the synthesis of the K2FeO4 ambient stable phase, the optimizing parameters influencing the yield of the oxidation of Fe (II) to Fe (VI) in saturated alkaline (KOH) at a temperature of 60 ° C and at a current density of 1.3 A / dm2 for a time electrolysis of an hour. This yield reached a value of 75%. It was characterized by UV spectrophotometer, measuring the optical density at a wavelength of 507 nm.

Fe (VI) as an oxidant has a higher oxidation potential than ozone, hydrogen peroxide, permanganate or chlorine.Demanding environmental regulations encourage the use of ferrate as a decontaminating agent of choice. Thus, the purpose of this work is to identify and optimize the time and drying temperature of stable to ambient K2FeO4 by wet means facilitating their storage and transport. Wet synthesis is performed by attacking ferric sulfate FeSO4, 7H2O by ClO- hypochlorite with a chlorometric degree of 50 ° F in a concentrated medium KOH, at a temperature of 55 ° C. The drying time is of the order of 12 hours at a temperature of 120 ° C. The obtained result was characterized by UV spectrophotometer by measuring the optical density at a wavelength of 507 nm.

To investigate the relevance of biochemical parameters in biogeochemical mechanisms of the soil, it is important to gather data related to different soil types under different pedogeoclimatic conditions. In this study, we investigated on the calcareous agricultural soils in the Saiss plain (North Morocco). Four agricultural soils exposed to multi-metal (Cr, Cu, Zn and Ni) and organic matter contamination as a result of irrigation with Oued Fez and Oued Sebou waters that are affected by urban and industrial activities around the city of Fez, were studied and compared to a reference site irrigated with uncontaminated water.The study concerned soil physicochemical proprieties and the activity of a range of enzymes (phosphatase (PHOS), arylsulfatase (SULF), urease (UREA), arylamidase (AMID), β-galactosidase (GALA), glucosidase (GLUC) and laccase (LACA)) related to nutrients cycles. Pearson's correlations between these parameters showed that soil enzymatic activities (PHOS, SULF, UREA, GALA, GLUC and LACA) were correlated positively with heavy metals (Cu, Zn and Cr) concentrations in the soil and also with dissolved organic carbon (DOC) and negatively with the aromaticity (AROM) of these compounds. Interestingly, analysis of intra-site correlations showed strong relationships among enzyme activities in the reference soil, while in contaminated soils these activities were largely unrelated to each other.It was concluded that soil irrigation with heavy metal and organic matter contaminated watercourses over decades has resulted in soils with high enzymatic activities function and nutrient turnover but altered relationships among geochemical cycles.

International audience; This article presents a combination of coagulation–flocculation and powder activated carbon (PAC) adsorption as a treatment process for landfill leachate. Leachates were collected from a municipal solid waste landfill in Mediouna site, Casablanca city. Ferric chloride (FeCl3 ) is used here as a coagulant to study the optimum conditions for the removal of chemical oxygen demand (COD), colour, total suspended solids (TSS) and turbidity in jar tests. This coagulant showed the highest removal efficiency in terms of COD (62.5%), turbidity (92.5%), colour (80%) and least sludge volume generation (30% v/v) for an optimum coagulant dose of 12 g Fe3+ L–1. Combining coagulation with adsorption process onto PAC enhances the removal of COD, turbidity and colour reduction by a 77%, a 99% and a 99.7%, respectively. These results show that coagulation-adsorption could be used as a promising hybrid process for the treatment of landfill leachates. Use of combination of coagulation and adsorption process for the landfill leachate treatment from Casablanca city. Available from: https://www.researchgate.net/publication/320016102_Use_of_combination_of_coagulation_and_adsorption_process_for_the_landfill_leachate_treatment_from_Casablanca_city [accessed Nov 20 2017].

Pyrrhotite ash is an industrial waste which is currently stored in large quantities in a large area in southwest of Morocco. The literature review revealed that this waste has been used by some cement industries and has not been the subject of any environmental study or valuation in another area. This work focuses on the environmental study of pyrrhotite ash. This study consists of a dynamic test with renewing lixiviate more particularly the leaching tank test. The protocol used is extracted from the Dutch standard NEN 7345 with modification of the volume of water used and the number of extraction. Quantitative analysis by ICP has shown that pyrrhotite ash releases heavy metals in aqueous medium. However, the concentration of these is very low compared to the limits estimated by the Dutch standard adapted to the Moroccan hydrological context (MBMD), this result encouraged us to find a way to valorise this waste and to make it a raw material for the manufacture of terracotta bricks made of clay.

This thesis deals with the behavior of a priority compound on the basis of the framework Directive on water at European level: tributyltin (TBT) ) and its metabolites (dibutyltin (DBT) and monobutyltin (MBT)). The study is focused on two waste stabilization pond treatment plants (WSP), which is an appropriate treatment to domestic effluents from sparsely urbanized areas.This thesis comes to fill the lack of scientific results on (1) the level of butyltin concentrations in domestic effluents from sparsely urbanized areas, in the input of the WSP and the output after treatment; (2) the efficiency of butyltins elimination by the WSP treatment; (3) the identification of the processes that control the fate of these elements during the treatment.Butyltins are measured in particulate and dissolved matrices and in sludge, by GC-ICP-MS, in all stages of the treatment by lagooning of two villages of the Department of Hérault (34, France): Gigean (6000 p.e.) and Montbazin (4500 p.e.).It is shown that the three butyltin species are consistently present in all samples taken from the two WSP. Butyltins arrive primarily in particulate form in the raw water. During treatment, the processes of sorption onto particulate matter and the settling of the latter at the bottom of each basin are the main factors for the elimination of butyltins. The first anaerobic ponds, characterized by deep depth and long residence times, allow the elimination of more than 60% Gigean (93% at Montbazin) of butyltins. Bottom sludge of each basin show high butyltins concentrations. The resuspension of butyltins is noted in the last maturation ponds, characterized by shallow depth, which may be due to re-thermal stratification. At the outlet, despite significant butyltin removal, concentrations in butyltins remain high (12 to 228 and 1.8 to 15 ng (Sn). L-1, respectively for Montbazin and Gigean).Laboratory batch experiments were conducted to study sorption processes following several experimental protocols. It was thus shown that: (1) the distribution of the butyltin species between solid and liquid phases is different from one test to another according to the operating conditions; (2) the affinity between butyltins and bottom sludge is important, regardless of its provenance. 98% of the butyltins are found in the solid phase, due to their hydrophobicity. The TBT sludge-water partition coefficient is higher than that obtained for other type of solid phases (75000 L.kg-1); (3) the process of sorption is fast.Moreover processes of sorption, desorption and dealkylation of TBT, explaining changes in concentrations of MBT and DBT in the solid phase were identified. Desorption of TBT is fast. It degrades in the liquid phase in DBT which part turns into MBT. The sorption of MBT on sludge has been systematically measured. Therefore, the sorption phenomenon is not completely reversible over time. These results help to explain the dysfunctions observed in WSP, for example after direct inputs of rainwater.This thesis shows the systematic presence of butyltin in waste stabilization pond treatment plants. In-situ data coupled with laboratory tests allow to understand the behaviour of these compounds during this treatment: the solid fraction plays a key role in the processes of sorption-desorption-(bio) degradation of butyltins.; Cette thèse porte sur le comportement d’un composé prioritaire au titre de la Directive Cadre sur l’Eau au niveau européen : le tributylétain (TBT) et ses métabolites (dibutylétain (DBT) et monobutylétain (MBT)). On s’intéresse plus particulièrement aux eaux usées domestiques lors de leur transit dans deux stations d’épuration par lagunage naturel (STEP), traitement adapté aux effluents provenant des zones faiblement urbanisées. Ce travail de thèse vient combler le manque de résultats scientifiques sur (1) le niveau des concentrations en butylétains dans les effluents domestiques des zones peu urbanisées en entrée des stations par lagunage et en sortie après traitement ; (2) l’efficacité du traitement par lagunage à éliminer les butylétains ; (3)l’identification des processus qui contrôlent le devenir de ces éléments au cours du traitement.Les butylétains sont mesurés dans les matrices particulaires, dissoutes et dans les boues, par couplage GC-ICP-MS, dans toutes les étapes du traitement par lagunage de deux communes rurales du département de l’Hérault (34,France) : Gigean (6000 eq-hab.) et Montbazin (4500 eq-hab.). On montre que les trois espèces butylées sont systématiquement présentes dans tous les échantillons prélevés sur les deux STEP. Les butylétains arrivent principalement sous forme particulaire dans les eaux brutes en entrée des stations. Au cours du traitement, les processus de sorption sur les particules en suspension et la décantation de ces dernières au fond de chaque bassin sont les principaux facteurs permettant l’élimination des butylétains. Les premiers bassins anaérobies, de grande profondeur et de long temps de séjour, permettent l’élimination de plus de 60% à Gigean (93% à Montbazin) des butylétains. Les boues de fond de chaque bassin montrent des concentrations élevées en butylétains. La remise en suspension des butylétains est notée dans les derniers bassins de finition, peu profonds, ce qui peut être due à la re-stratification thermique. En sortie de station, malgré les abattements importants, des concentrations non négligeables en butylétains (12 à 228 et 1.8 à 15 ng(Sn).L-1 respectivement pour Montbazin et Gigean) sont rejetées dans le milieu récepteur. Des expériences de sorption basées sur la mise en contact de butylétains avec des boues de fond de bassin diluées ont été effectuées selon plusieurs approches expérimentales. On a ainsi montré que (1) la distribution des espèces MBT, DBT, TBT, entre les phases solide et liquide, est variable d’un test à l’autre selon les conditions opératoires ; (2) l’affinité entre les butylétains et la boue est importante, quelle que soit sa provenance. 98% des butylétains se retrouvent dans la phase solide, du fait de leur hydrophobicité. Le coefficient de distribution Kd entre le TBT et les boues est plus élevé que celui obtenu pour d’autres type de phases solides (75000 L.kg- 1) ; (3) le processus de sorption est rapide. De plus des processus de sorption, désorption et déalkylation du TBT, expliquant les variations des concentrations en MBT et DBT dans la phase solide ont été identifiés. La désorption du TBT est rapide. Il se dégrade dans la phase liquide en DBT dont une partie se transforme en MBT. La sorption du MBT sur les boues a été systématiquement mesurée. Le phénomène de sorption n’est donc pas complètement réversible au cours du temps. Ces résultats contribuent à expliquer les dysfonctionnements observés dans les stations de traitement par lagunage, par exemple lors d’apports directs d’eau de pluie.Cette thèse démontre la présence systématique des butylétains dans les stations d’épuration par lagunage naturel. Les données acquises in-situ couplées à des essais en laboratoire permettent de comprendre le comportement de ces composés lors de ce traitement : la fraction solide joue un rôle clé dans les processus de sorption-désorption-(bio)dégradation des butylétains.

This thesis deals with the behavior of a priority compound on the basis of the framework Directive on water at European level: tributyltin (TBT) ) and its metabolites (dibutyltin (DBT) and monobutyltin (MBT)). The study is focused on two waste stabilization pond treatment plants (WSP), which is an appropriate treatment to domestic effluents from sparsely urbanized areas.This thesis comes to fill the lack of scientific results on (1) the level of butyltin concentrations in domestic effluents from sparsely urbanized areas, in the input of the WSP and the output after treatment; (2) the efficiency of butyltins elimination by the WSP treatment; (3) the identification of the processes that control the fate of these elements during the treatment.Butyltins are measured in particulate and dissolved matrices and in sludge, by GC-ICP-MS, in all stages of the treatment by lagooning of two villages of the Department of Hérault (34, France): Gigean (6000 p.e.) and Montbazin (4500 p.e.).It is shown that the three butyltin species are consistently present in all samples taken from the two WSP. Butyltins arrive primarily in particulate form in the raw water. During treatment, the processes of sorption onto particulate matter and the settling of the latter at the bottom of each basin are the main factors for the elimination of butyltins. The first anaerobic ponds, characterized by deep depth and long residence times, allow the elimination of more than 60% Gigean (93% at Montbazin) of butyltins. Bottom sludge of each basin show high butyltins concentrations. The resuspension of butyltins is noted in the last maturation ponds, characterized by shallow depth, which may be due to re-thermal stratification. At the outlet, despite significant butyltin removal, concentrations in butyltins remain high (12 to 228 and 1.8 to 15 ng (Sn). L-1, respectively for Montbazin and Gigean).Laboratory batch experiments were conducted to study sorption processes following several experimental protocols. It was thus shown that: (1) the distribution of the butyltin species between solid and liquid phases is different from one test to another according to the operating conditions; (2) the affinity between butyltins and bottom sludge is important, regardless of its provenance. 98% of the butyltins are found in the solid phase, due to their hydrophobicity. The TBT sludge-water partition coefficient is higher than that obtained for other type of solid phases (75000 L.kg-1); (3) the process of sorption is fast.Moreover processes of sorption, desorption and dealkylation of TBT, explaining changes in concentrations of MBT and DBT in the solid phase were identified. Desorption of TBT is fast. It degrades in the liquid phase in DBT which part turns into MBT. The sorption of MBT on sludge has been systematically measured. Therefore, the sorption phenomenon is not completely reversible over time. These results help to explain the dysfunctions observed in WSP, for example after direct inputs of rainwater.This thesis shows the systematic presence of butyltin in waste stabilization pond treatment plants. In-situ data coupled with laboratory tests allow to understand the behaviour of these compounds during this treatment: the solid fraction plays a key role in the processes of sorption-desorption-(bio) degradation of butyltins.; Cette thèse porte sur le comportement d’un composé prioritaire au titre de la Directive Cadre sur l’Eau au niveau européen : le tributylétain (TBT) et ses métabolites (dibutylétain (DBT) et monobutylétain (MBT)). On s’intéresse plus particulièrement aux eaux usées domestiques lors de leur transit dans deux stations d’épuration par lagunage naturel (STEP), traitement adapté aux effluents provenant des zones faiblement urbanisées. Ce travail de thèse vient combler le manque de résultats scientifiques sur (1) le niveau des concentrations en butylétains dans les effluents domestiques des zones peu urbanisées en entrée des stations par lagunage et en sortie après traitement ; (2) l’efficacité du traitement par lagunage à éliminer les butylétains ; (3)l’identification des processus qui contrôlent le devenir de ces éléments au cours du traitement.Les butylétains sont mesurés dans les matrices particulaires, dissoutes et dans les boues, par couplage GC-ICP-MS, dans toutes les étapes du traitement par lagunage de deux communes rurales du département de l’Hérault (34,France) : Gigean (6000 eq-hab.) et Montbazin (4500 eq-hab.). On montre que les trois espèces butylées sont systématiquement présentes dans tous les échantillons prélevés sur les deux STEP. Les butylétains arrivent principalement sous forme particulaire dans les eaux brutes en entrée des stations. Au cours du traitement, les processus de sorption sur les particules en suspension et la décantation de ces dernières au fond de chaque bassin sont les principaux facteurs permettant l’élimination des butylétains. Les premiers bassins anaérobies, de grande profondeur et de long temps de séjour, permettent l’élimination de plus de 60% à Gigean (93% à Montbazin) des butylétains. Les boues de fond de chaque bassin montrent des concentrations élevées en butylétains. La remise en suspension des butylétains est notée dans les derniers bassins de finition, peu profonds, ce qui peut être due à la re-stratification thermique. En sortie de station, malgré les abattements importants, des concentrations non négligeables en butylétains (12 à 228 et 1.8 à 15 ng(Sn).L-1 respectivement pour Montbazin et Gigean) sont rejetées dans le milieu récepteur. Des expériences de sorption basées sur la mise en contact de butylétains avec des boues de fond de bassin diluées ont été effectuées selon plusieurs approches expérimentales. On a ainsi montré que (1) la distribution des espèces MBT, DBT, TBT, entre les phases solide et liquide, est variable d’un test à l’autre selon les conditions opératoires ; (2) l’affinité entre les butylétains et la boue est importante, quelle que soit sa provenance. 98% des butylétains se retrouvent dans la phase solide, du fait de leur hydrophobicité. Le coefficient de distribution Kd entre le TBT et les boues est plus élevé que celui obtenu pour d’autres type de phases solides (75000 L.kg- 1) ; (3) le processus de sorption est rapide. De plus des processus de sorption, désorption et déalkylation du TBT, expliquant les variations des concentrations en MBT et DBT dans la phase solide ont été identifiés. La désorption du TBT est rapide. Il se dégrade dans la phase liquide en DBT dont une partie se transforme en MBT. La sorption du MBT sur les boues a été systématiquement mesurée. Le phénomène de sorption n’est donc pas complètement réversible au cours du temps. Ces résultats contribuent à expliquer les dysfonctionnements observés dans les stations de traitement par lagunage, par exemple lors d’apports directs d’eau de pluie.Cette thèse démontre la présence systématique des butylétains dans les stations d’épuration par lagunage naturel. Les données acquises in-situ couplées à des essais en laboratoire permettent de comprendre le comportement de ces composés lors de ce traitement : la fraction solide joue un rôle clé dans les processus de sorption-désorption-(bio)dégradation des butylétains.