Search

This work aimed to study the seasonal impact on the pollutant removal efficiency of constructed wetland (CW) units that treat domestic wastewater in the region of Rabat, Morocco. In this context, four vertical flow-constructed wetlands (VFCWs) were investigated for one year. Each CW unit has a surface area of 1 m² and a depth of 60 cm. The difference between the units is the vegetation. The experiments were conducted on a laboratory scale and outdoors to investigate the direct effect of climate. The purpose of this study was to investigate the performance of CWs with two different plant species (Phragmites australis and Arundo Donax) and plant arrangements (monoculture and polyculture). Since the region of Rabat has a semiarid climate, plants that behave during seasonal changes were explored. The elimination of organic matter showed seasonal variation in the CW systems, with higher rates occurring during the hot season and lower rates occurring during the cold season. The planted system outperformed the unplanted system, and the polyculture system was the most effective, reaching removal rates of 99.47%, 99.58%, and 85.64% for COD, BOD5, and TSS, respectively, in the summer season where the temperature reached its maximum, promoting plant growth as well as microbial activity. The results showed that the VFCWs used in this study are a successful technology for regions that are cost-effective and require little energy.

Olive stones waste is a widely available agricultural waste. That can be used as an alternative feedstock for activated carbon production applied for wastewater treatment. In this study, activated carbon preparation was optimised using a fractional The long-term accumulation and residue of the micropollutant thiamphenicol in aquatic environments have significantly harmed biological systems. Therefore, removing organic micropollutants using activated carbon is a frequent and essential procedure in advanced wastewater treatment. Olive stones can be used as an alternative feedstock for producing activated carbon for wastewater treatment. In this study, the preparation of activated carbon was optimized using a fractional factorial design experiment with five factors: concentration, heating rate, activation temperature, activation time, and impregnation ratio. The specific surface area (SSA) was calculated using the methylene blue method and was considered the response parameter of the synthesis. Thiamphenicol (THI) adsorption tests were conducted in a fixed-bed column after characterizing the optimal activated carbon prepared with phosphoric acid (OACPA). The results showed that the optimal conditions for activated carbon preparation were a solid-liquid ratio of 1:2 for phosphoric acid (74.52%), a temperature of 550°C with a heating rate of 10°C/min, and an activation time of 120 minutes, yielding an activated carbon with an SSA of 53.07 m²/g. The THI removal tests indicated that the flow rate and initial THI concentration were inversely proportional to the THI removal efficiency, whereas the bed height positively affected the removal percentage.

Calcium molybdate (CaMoO4) is of significant interest due to its unique properties and numerous industrial applications, such as catalysis, electrochemistry, and optoelectronics. In this study, we developed an economical and environmentally friendly method to synthesize calcium molybdate from Moroccan phosphogypsum (PG) industrial waste and sodium molybdate, all at room temperature. Comprehensive analysis through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman vibrational spectroscopy, and scanning electron microscopy (SEM) revealed the high purity of the synthesized calcium molybdate, with particle sizes of only 12 nm. Additionally, optical characteristics were studied using ultraviolet-visible spectroscopy (UV-vis), which showed an optical band gap of Egap = 3.96 eV for CaMoO4. These results confirm the successful synthesis of calcium molybdate nanoparticles from Moroccan phosphogypsum, demonstrating an effective pathway to valorize this industrial waste into a valuable material. This approach contributes to environmental sustainability by reducing dependence on rare chemicals while offering innovative solutions for the industry’s sustainable development.

A novel synthesis process and characterization of nano-Calcium fluoride(n-CaF2) single crystal prepared from phosphogypsum waste. The phosphogypsum (CaSO4,•2H2O) powder has been mechanically mixed with NH4F in presence of a controlled amount of water. The mixture still sintered for 48 hours until the formation of nano Calcium fluoride particles. The n-CaF2 particles have been characterized by several techniques, The techniques utilized included X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM).Therefore, it was confirmed that very pure n-CaF2 was obtained with a Ca / F ratio of 0.5 and an average crystalizing size measured according to the Debye-Scherrer equation of 11 nm. Based on the findings reached, The characterization data revealed successful synthesis of n-CaF2 from phosphogypsum. Additionally, the adsorption performance of the elaborated n-CaF2 was tested in Reactive Blue 21 (RB21) anionic dye removal, Adsorption tests were conducted in a batch reactor, focusing on key factors such as contact time, which can significantly influence the adsorption results. adsorption amount, pH, and dye concentration were tested. Hence results show an important adsorption performance of n-CaF2 with Reactive Blue 21 removal rate up to 90%.

The main objective of this study is to evaluate the potential of olive mill wastewater (OMW) as an organic fertilizer through co-composting with various agricultural by-products. OMW was mixed with agricultural by-products, including maize silage, sugar beet pulp, and sugarcane bagasse, in controlled proportions and conditions. The study was conducted at the National Institute of Agricultural Research in Rabat, Morocco. The composting process was monitored over time, focusing on the evolution of key physicochemical parameters and phenol content of each mixture. The results showed that the performance of the composts varied, with the mixture containing sugar beet pulp (SBPO) exhibiting the most promising results, followed by maize silage (MSO) and sugarcane bagasse (SBO). These results suggest that co-composting OMW with agricultural by-products can produce high-quality organic fertilizers, thus reducing the need for inorganic alternatives and providing a sustainable waste management solution in the olive oil industry. It highlights the potential for reducing phenols characteristic of OMW and promoting sustainable agricultural practices. The application of the composts to crops was not tested, highlighting the need for further research in this regard. Future investigations should focus on evaluating the long-term effects of OMW-derived composts on soil health and crop productivity. This study explores a combination of materials that, to our knowledge, has not been previously documented in scientific literature. The results underscore the importance of sustainable waste management practices and their potential role in improving soil fertility and reducing the environmental impact associated with olive oil production.

This in vitro study examines the electrochemical responses and surface degradation of alumina and feldspar dental ceramic materials in acidic environments using cyclic polarization and electrochemical impedance spectroscopy (EIS). Alumina and feldspar demonstrate balanced responses in both Fusayama Artificial Saliva and acidic solutions, indicating effective passivation. SEM/EDX analyses after 168-h immersion reveal significant elemental variations, suggesting complex surface phenomena and chemical reactions leading to oxide layer formation. Alumina exhibits increased Si, O, Al, Na, K, and C counts, while feldspar shows increased Si, O, Al, Na with reduced C and Ca levels, indicating complex reactions. Immersion induces notable elemental composition modifications, with alumina showing remarkable corrosion resistance and feldspar undergoing selective dissolution. This study provides insights into the electrochemical and surface degradation of these materials, emphasizing long-term stability and the need for continuous monitoring of protective layer dynamics in future research on corrosion-resistant dental biomaterials.

This study investigates a controlled synthesis and particle size optimization of nanocalcite particles using phosphogypsum, a waste byproduct from the phosphate fertilizer industry, and cesium carbonate (Cs2CO3), a common carbonate source. The effects of synthesis parameters, including temperature and pH, on the size, morphology, and crystallinity of the synthesized nanocalcite particles were systematically examined. The optimized synthesis conditions for obtaining nanocalcite particles with desired properties are discussed. The synthesized nanocalcite particles were characterized using various techniques, such as XRD, FTIR, and SEM, to analyze their crystal structure, morphology, and elemental composition. Particle sizes were determined using the Debye–Scherrer method, and accordingly, nanometric sizes were achieved. The potential applications of the synthesized nanocalcite particles in cementitious materials, agriculture, and drug delivery are highlighted. This research provides valuable insights into the sustainable synthesis and size optimization of nanocalcite particles from phosphogypsum and Cs2CO3 at a controlled temperature and pH.

Wood wastes have been widely studied for their adsorption properties in recent years. Researchers have mainly been interested in Atlas cedar sawdust. The present work studies four adsorbents after different extraction (hydrodistillation, soxhlet, maceration, and ultrasound) for methylene blue adsorption. The points discussed concern the operating conditions used during adsorption, thermodynamic, kinetic and other models describing the adsorbent-adsorbate system, and the effect of the main operating parameters (adsorbate concentration, treatment pH, and adsorbent concentration) was investigated using the full factorial design. The best adsorbent is the residue of sawdust generated after extraction via maceration: the yield of methylene blue adsorption is 98.42 % and the adsorbed quantity (Qads = 7.84 mg/g) is close to that of powdered activated carbon used for comparison (Qads = 9 mg/g). According to the kinetic result, the second order describes well the adsorption of MB onto the four types of Cedar Sawdust. The thermodynamic study confirms the physisorption process in which the enthalpy was found low to 40 kJ·mol−1.

This paper aims to assess soil fertility and risk contamination parameters in response to increased amendment rates of sewage sludge application, under semi-arid climatic conditions of Morocco, using two soil textures: soil A (clay-silty) and soil B (sandy-clay) over two years. To this end, sewage sludge and soils treatments physicochemical parameters, heavy metals content, degree of pollution and associated risks were evaluated and compared to controlled soils. The results showed that all studied parameters changed significantly (p Pb > Zn > Ni > Cd > Cr. Nevertheless, their concentrations were below the critical values established by the European Union for the agronomic use of soil. The obtained results of assessed parameters indicating SS degree of pollution and associated risks showed a low to a moderate contamination risks of heavy metals. Accordingly, environmental risks of sewage sludge application will be related to increase of heavy metals mainly in a long-term agricultural reuse. Thus, optimal management of sewage sludge application is recommended to ensure sustainability and benefits at the same time to master the contamination risks.

Lately, due to its accessibility and eco-friendliness, walnut shell biochar (WS-BC) is gaining attention as an electrode material component in the electrochemical detection of water pollutants. The overall performance of WS-BC is reliant on the nature of raw biomass and the production methods as well. In our concept, biochar, prepared from raw walnut shell (WS) by pyrolysis, was added to a carbon paste electrode (CPE), and poly-tyrosine (p-Tyr) was electrodeposited on the surface of the BC-doped electrode. The conditions of the elaboration of the electrode, such as pH, potential, and the number of deposition cycles, pH were optimized. The obtained p-Tyr-BC-CPE platform was tested for the determination of cadmium, lead, copper, and mercury ions in water and soil samples, using square wave voltammetry (SWV). The raw WS biomass and its BC were examined by thermal analysis (TG-DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) techniques. The synergistic effects of the coexistence of the WS-BC and the thin film of p-Tyr, for the detection of traces of heavy metal ions were investigated by electrochemical tests. The electrochemical characterization of the unmodified and modified electrodes was performed using the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods, while the Cd2+, Pb2+, Cu2+, and Hg2+ detection experiments were studied using the CV and SWV techniques. The optimized experimental conditions for the p-Tyr-BC-CPE platform were evaluated. The obtained electrochemical results showed that the p-Tyr-BC-CPE platform produced excellent sensitivity toward the heavy metal ions: LOD of 0.086, 0.175, 0.246, and 0.383 nM for Cd(II), Pb(II), Cu(II) and Hg(II), respectively. The modified electrode platform displayed high selectivity, stability, and good reproducibility.

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).

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.

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.

The use of 5-azidomethyl-7-morpholinomethyl-8-hydroxyquinoline (AMH) as a corrosion inhibitor for AISI 321 stainless steel in 5.5 M polluted phosphoric acid was investigated using the hydrogen evolution technique, linear polarization curves, and impedance spectroscopy. Impedance measurements revealed that the dissolution of AISI 321 in 5.5 M polluted phosphoric acid was controlled by an activation mechanism, unchanged even with the addition of AMH at different concentrations. Polarization results showed that the inhibition ability was enhanced with increasing inhibitor concentration. AMH acted as a mixed-type inhibitor by random adsorption on the alloy surface, whatever the nature of the reaction that is taking place. The adsorption of AMH on the AISI 321 surface was also discussed via the Langmuir adsorption isotherm. The influence of elevating the solution temperature on the corrosion inhibition performance was studied. A quantum chemistry study with the DFT method was also conducted, which supplied a logical and exploitable theoretical explanation of the adsorption and the inhibition action of AMH on AISI 321.

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.

Tafel polarization method was used to assess the corrosion inhibitive and adsorption behaviours of amino-tris(methylenephosphonic) acid (ATMP) for C38 carbon steel in 1 M HCl solution in the temperature range from 30 to 60∘C. It was shown that the corrosion inhibition efficiency was found to increase with increase in ATMP concentration but decreased with temperature, which is suggestive of physical adsorption mechanism. The adsorption of the ATMP onto the C38 steel surface was found to follow Langmuir adsorption isotherm model. The corrosion inhibition mechanism was further corroborated by the values of kinetic and thermodynamic parameters obtained from the experimental data.