Carbonate mounds of the Moroccan Mediterranean margin: Facies and environmental controls

Sedimentological and geochemical studies of boxcores from the Brittlestar Ridge I and Cabliers carbonate mounds, along the Moroccan Mediterranean margin, show that sediments are composed of cold water scleratian corals and micritic mud, muddy micrite or muddy allochem limestone matrix, outlining seven different facies that can be attributed to “cluster reefs”. The mixed siliciclastic/carbonate sediments have been derived from both extra- and intrabasinal sources. Extra-basinal sources may be the geological formations outcropping in the Moroccan hinterland and Sahara, the latter including corals and associated bioclasts. Sediments were transported by wind and rivers and redistributed by bottom currents and local upwelling. Our results confirm the role of tectonics in the genesis of these carbonate mounds and reveal that their developments during the Holocene (10.34–0.91ka BP) was controlled by climatic fluctuations (e.g. Holocene Climate Optimum and Little Ice Age), eustatic sea level change, and hydrodynamic regime

Valorisation des DEEE par l’extraction des terres rares, métaux précieux et matières plastiques

The approach proposed in this work present clean processes for the treatment and recycling of waste electrical and electronic equipment, under the protection of the environment paradigm, especially for computers and mobile phones which are classified in category 3: “it and telecommunication equipment” according to the European directive 2002/96/EC through the extraction of precious metals, rare earths and possibly plastic granulates. The proposed solution is adapted to the specificities of Morocco by implementing a scheme of appropriate ecological treatment consists of: 1) Processing of non-ferrous pyrometallurgical aggregates isolated, 2) Recovery of gold from gold coins by hydrometallurgical 3) Identification of rare earth from monitors 4) Manufacture of hydraulic plaster from residual waste (mixture of plastics, resins and ceramics). This work also focuses the possibility of rationalizing the consumption of natural resources by minimizing the need for raw material (e.g. Cu, Al, Au, Pd, plastics,) by the transformation of electrical and electronic waste (WEEE) in resources.L’approche proposée dans le présent travail a pour but d’élaborer des procédés propres pour le traitement et la valorisation des déchets d’équipements électriques et électroniques, en particulier les ordinateurs et les téléphones mobiles classés dans la catégorie 3 : « Equipements informatiques et de télécommunication » selon la directive européenne 2002/96/ce. La valorisation consiste en l’extraction des métaux précieux, des terres rares et éventuellement de granulats de plastiques. La solution proposée est adaptée aux spécificités du Maroc par la mise en œuvre d’un schéma de traitement écologique approprié qui consiste en : 1) Traitement pyrométallurgique de granulats non ferreux isolés, 2) Récupération de l’or à partir des pièces dorées par voie hydrométallurgique, 3) Identification des terres rares dans les écrans, 4) Fabrication d’enduit hydraulique à partir de déchets ultimes (mélange de plastiques, résines et céramiques). Le présent travail se focalise aussi sur la possibilité de rationaliser la consommation des ressources naturelles en minimisant les besoins en matière première (par exemple : Cu, Al, Au, Pd, plastiques,...) par la transformation des déchets électriques et électroniques (DEEE) en ressources

Effects of Different Rates of Liquid Sewage Sludge Amendment on Nutrient Content of the Soil in Rabat, Morocco

The objective of this study was to evaluate different rates of the liquid sewage sludge fertilizer developed by a treatment plant in Skhirat, Rabat, Morocco on improving soil fertility indicators. The results revealed that the application of liquid sludge on the soil increased soil pH from 7.3 to 7.7, electrical conductivity from 227.1 to 416.21 µS.cm−1, and other nutrients such as soil organic matter from 9.0 to 21.4%, Kjeldahl nitrogen (TKN) from 0.1 to 0.7%, and total organic carbon (TOC) from 2.4 to 16.5%; the phosphorus ranged 79.1 to 127.8 mg.kg−1 in a dose-dependent manner in amended soil compared to untreated controls. However, the results also showed increase in heavy metal content in the following order: Zn > Cu > Pb > Ni > Cd, (Zn = 136.69 mg.kg−1, Cu = 69.05 mg.kg−1, Pb = 17.91 mg.kg−1, Ni = 4.73 mg.kg−1, Cd = 0.03 mg.kg−1); nevertheless, we noticed that their concentrations were lower than the critical values established by the European Union for the agronomic use of the soil

Benefits and Risks of Liquid Sewage Sludge Recycling in Agricultural Spreading – A Case Study of WWTP of Skhirat, Morocco

The sewage sludge recycling as an agricultural land resource has received a great deal of attention worldwide. This practice has highly increased because of ever-increasing municipal wastewater production and the awareness of its fertilizing potential as amendment resources. However, there is a concern about land spreading linked mainly to health associated risks due to the presence of diverse pollutants. Thus, sewage spreading management is a key factor the guarantees benefits and avoids risks. The present work aimed to investigate the benefits and risks of sewage sludge (SS) application on agricultural land. To this end, physicochemical main parameters and bacteriological indicators, fecal coliform (FC) and fecal streptococcus (FS), of the sewage sludge generated form WWTP of Skhirat, Morocco, were performed during the period 2018–2019. The obtained results of physicochemical parameters reveal high concentration of organic matter in SS, which reach 96.3 mg/l, and in nutrients. Indeed, total Kjeldahl nitrogen TKN reaches a maximum of 3791 mg/l, potassium K+ reaches 58.71 mg/l. In addition, the average content of FC and FS are around 5.40 CFU/ml and 5.85 CFU/ml, respectively, whereas total phosphorus reaches 508.25 mg/l. In addition, concentrations of micronutrients such as Cl-, SO42-, Ca2+, Mg2+, and Na+ were high, which is interesting and could benefit for both soils and plant. Furthermore, this sewage sludge contains high concentration of heavy metals, mainly zinc and copper which could limit reuse in land spreading. The obtained results were compared to the applied standards and directives established within the framework of the agricultural spreading

Electrochemical and Thermodynamic Investigation on Corrosion Inhibition of C38 Steel in 1M Hydrochloric Acid Using the Hydro-Alcoholic Extract of Used Coffee Grounds

The present work investigates the influence of temperature on C38 steel corrosion in a 1 M HCl medium with and without different concentrations of a hydro-alcoholic extract of used coffee grounds (HECG). The potentiodynamic polarization technique and the electrochemical impedance spectroscopy were performed in temperatures ranging from 293.15 to 323.15 K. It was observed that the inhibition efficiency decreased with increased temperature and inhibitor concentration. The HECG adsorption process on C38 steel surface was found to be spontaneous and obeyed to Langmuir isotherm at all studied temperatures. The associated thermodynamic parameters of adsorption led to suggest the occurrence of physical adsorption of the HECG compounds on the C38 steel surface

Bioenergy Generation and Wastewater Purification with Li_0.95Ta_0.76Nb_0.19Mg_0.15O₃ as New Air-Photocathode for MFCs

MFC is a promising technology that can be used for simultaneous electricity generation and wastewater treatment. Power energy generation of a ferroelectric cathodic ceramic, Li0.95Ta0.76Nb0.19Mg0.15O3 (LTNMg), has been measured in microbial fuel cells, integrating a single chamber fed by industrial wastewater (CODinitial = 471 mg L−1, and pHinitial = 7.24 at T = 27 °C). In this process, the mixed multicomponent oxide material has been prepared and characterized by XRD, PSD, TEM, and UV-Vis spectroscopy. The catalytic activity has been investigated by COD determination, analysis of heavy metals, and polarization measurement. The results show a high COD reduction efficiency, which reaches 95.70% after a working time of 168 h with a maximal power density of 228 mW m−2. In addition, the maximum value of generated voltage in the open-circuit potential (OCP) of this MFC configuration has been increased from 340 mV in the absence of a light source to 470 mV under irradiation, indicating the presence of a promoting photocatalytic effect of LTNMg, which improved the process of the cathodic electron transfer inside the MFC device

BaTiO₃ Functional Perovskite as Photocathode in Microbial Fuel Cells for Energy Production and Wastewater Treatment

Microbial fuel cells (MFCs) provide new opportunities for the sustainable production of energy, converting organic matter into electricity through microorganisms. Moreover, MFCs play an important role in remediation of environmental pollutants from wastewater with power generation. This work focuses on the evaluation of ferroelectric perovskite materials as a new class of non-precious photocatalysts for MFC cathode construction. Nanoparticles of BaTiO3 (BT) were prepared and tested in a microbial fuel cell (MFC) as photocathode catalytic components. The catalyst phases were synthesized, identified and characterized by XRD, SEM, UV–Vis absorption spectroscopy, P-E hysteresis and dielectric measurements. The maximum absorption of BT nanoparticles was recorded at 285 nm and the energy gap (Eg) was estimated to be 3.77 eV. Photocatalytic performance of cathodes coated with BaTiO3 was measured in a dark environment and then in the presence of a UV–visible (UV–Vis) light source, using a mixture of dairy industry and domestic wastewater as a feedstock for the MFCs. The performance of the BT cathodic component is strongly dependent on the presence of UV–Vis irradiation. The BT-based cathode functioning under UV–visible light improves the maximum power densities and the open circuit voltage (OCV) of the MFC system. The values increased from 64 mW m−2 to 498 mW m−2 and from 280 mV to 387 mV, respectively, showing that the presence of light effectively improved the photocatalytic activity of this ceramic. Furthermore, the MFCs operating under optimal conditions were able to reduce the chemical oxygen demand load in wastewater by 90% (initial COD = 2500 mg L−1)

ZrP2O7 as a Cathodic Material in Single-Chamber MFC for Bioenergy Production

The present work is the first investigation of the electrocatalytic performances of ZrP2O7 as a cathode in a single-chamber Microbial Fuel Cell (MFC) for the conversion of chemical energy from wastewater to bioelectricity. This catalyst was prepared by a coprecipitation method, then characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), ultraviolet–visible–near-infrared spectrophotometry (UV–Vis–NIR), and cyclic voltammetry analyses. The acid–basic characteristics of the surface were probed by using 2-butanol decomposition. The conversion of 2-butanol occurs essentially through the dehydrating reaction, indicating the predominantly acidic character of the solid. The electrochemical test shows that the studied cathode material is electroactive. In addition, the ZrP2O7 in the MFC configuration exhibited high performance in terms of bioelectricity generation, giving a maximum output power density of around 449 mW m−2; moreover, it was active for wastewater treatment, reducing the chemical oxygen demand (COD) charge to 50% after three days of reaction

Study of the corrosion inhibition of C38 steel in a 1M HCl medium by the etanoic extract of Rumex Nervosus Vahl leaves

The efficacy of Rumex Nervosus Vahl Leaves Ethanolic extract (RNVLE) to inhibit C38 steel corrosion in one molar hydrochloric acid medium was examined using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Polarization measurements revealed mixed-type inhibitor behavior. The inhibitory efficacy assessed by both polarization and (EIS) techniques was consistent, with an IE value of (96.0 %) and (95.5 %) at 2g/L of RNVLE, respectively. The RNVLE adsorption on the C38 metal surfaces in 1M HCl follows the Langmuir adsorption isotherm. The calculated free energy (G°ads equal to -16.1 KJ mol-1) explained that RNVLE controls the corrosion process by physisorption. The effect of immersion time was also investigated. This study demonstrated that RNVLE can be considered an excellent inhibitor up to 6 hours and after this time; it is considered a lower quality inhibitor although it still has sufficient inhibitory ability. SEM-EDX (Scanning Electron Microscopy and X-ray Energy Dispersive Spectroscopy) analysis revealed that the extract molecules adsorb on the metal's surface. These findings indicate that RNVLE can be used as an effective corrosion inhibitor for C38 steel in 1M HCl solution