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Open Journal of Civil Engineering 2024年第2期14卷 155-167页

作者： Malang Bodian Mariétou Barro Diop-Fall Dame Keinde El-Hadji Dieye Modou Gningue Diop Modou Fall laboratoire de chimie Physique organique et dAnalyse Environnementales (LCPOAE) Dpartement de Chimie Univ Cheikh Anta Diop de Dakar Dakar Senegal laboratoire de Matriaux de Gnie Civil (LMGC) Ecole Suprieure Polytechnique de Dakar Univ Cheikh Anta Diop Dakar Sngal

This work first investigates the corrosion-inhibiting behavior of montmorillonite K-10 on reinforcing steel. The corrosion-inhibiting power of the clay (Montmorillonite) is determined in a medium HCl (C = 1N) using free corrosion potential monitoring, Tafel potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results of this study showed a satisfactory corrosion-inhibiting efficiency of around 72.665% for the optimum content of 1%. This is due to the presence of a stable oxide layer that protects the metal against corrosion. To validate the concept of montmorillonite as a corrosion inhibitor in repair mortar, we now turn to the influence of montmorillonite on the mechanical properties of mortars in the hardened state. In this part, montmorillonite K-10 is added to the mortar by partial substitution of the cement by 5% and 10% of the cement mass. The aim of this study is to ensure that the addition of this clay to the mortar composition will not have a negative effect on its compressive and flexural strengths. The results of the compression and flexural tests showed that the presence of montmorillonite in the mortar improved flexural and compressive strengths for the different compositions studied.

关键词： Clay Reinforced Concrete Corrosion Inhibitor Rehabilitation Electrochemical Methods

Phytochemical Screening and Assays of Phenolic Compounds in Senna occidentalis L. Leaf and Seed Extracts

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Food and Nutrition Sciences 2024年第7期15卷 499-508页

作者： Edmond Antoine Badock Lahat Niang Abdoulaye Dramé Célestine Nkounkou-Loumpangou Omar Touré Omar Sokhna Nicolas Cyrille Ayessou Mady Cissé Ecole Suprieure Polytechnique Laboratoire Eau Energie Environnement et Procds Industriels (LE3PI) Universit Cheikh Anta Diop Dakar Sngal Ecole Suprieure Polytechnique Centre dEtudes sur la Scurit Alimentaire et les Molcules Fonctionnelles (CESAM-RESCIF) Universit Cheikh Anta Diop Dakar Sngal laboratoire de Valorisation des Produits de la Biomasse Dpartement de Chimie Universit Cheikh Anta Diop de Dakar Dakar Sngal Unit de chimie du Vgtal et de la Vie Facult des Sciences et Techniques Universit Marien NGOUABI Brazzaville Republic of the Congo laboratoire de chimie organique et Bio-organique Dpartement de Chimie Facult des Sciences et Techniques/UCAD Universit Cheikh Anta Diop Dakar Sngal

Phytochemical screening and assay of secondary metabolites, crude extracts with distilled water, aqueous methanol, aqueous acetone and aqueous ethanol of leaves and seeds of Senna occidentalis L. were studied in this work. The aim was to verify the distribution of secondary metabolites according to S. occidentalis organs. Four leaf samples from four different localities (South, East, West and Central Senegal) and a mixed sample of seeds were used. Functional molecules such as polyphenols, flavonoids and tannins were then assessed in the leaves and seeds using various standard methods. The results show that Senna occidentalis L. leaf and seed samples display an identical and homogeneous profile, regardless of locality. They contain secondary metabolites and the polyphenol content of extracts from southern, eastern, western and central leaves is: 0.620 - 0.539 - 0.811 - 0.573 g GAE/100 g DM;flavonoids: 0.064 - 0.074 - 0.130 - 0.101 g CE/100 g DM and tannins: 0.326 - 0.264 - 0.269 - 0.494 g TAE/100 g DM. The efficacy of S. occidentalis L. infusions in therapy is thus justified by the presence of these metabolites, whose biological properties are well known. It is then possible to explore isolation of active principles of Senna occidentalis L. leaves and even seeds for producing medicines.

关键词： Senna occidentalis L. Total Polyphenols Flavonoids Tannins

Indirect Electroanalysis of 3-Methyl-4-Nitrophenol in Water Using Carbon Fiber Microelectrode Modified with Nickel Tetrasulfonated Phthalocyanine Complex

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Materials Sciences and Applications 2024年第2期15卷 25-35页

作者： Yibor Fabrice Roland Bako Serge Foukmeniok Mbokou Boukaré Kaboré Issa Tapsoba Maxime Pontié laboratoire de chimie Analytique Environnementale et Bio-organique (LCAEBiO) Département de Chimie Université Joseph Ki-Zerbo Ouagadougou Burkina Faso Institut des Sciences et de Technologie Ecole Normale Supérieure Ouagadougou Burkina Faso Group of analysis and Processes Analysis (GA&P) Département de Chimie Université d’Angers Angers France laboratoire de Sciences et Technologies (LaST) Université Thomas SANKARA Ouagadougou Burkina Faso

Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use of a carbon fiber microelectrode modified with a tetrasulfonated nickel phthalocyanine complex for the detection of MNP at a lower potential than that of direct phenol oxidation. The MNP voltammogram showed the presence of an anodic peak at -0.11 V vs SCE, corresponding to the oxidation of the hydroxylamine group generated after the reduction of the nitro group. The effect of buffer pH on the peak current and SWV parameters such as frequency, scan increment, and pulse amplitude were studied and optimized to have better electrochemical response of the proposed sensor. With these optimal parameters, the calibration curve shows that the peak current varied linearly as a function of MNP concentration, leading to a limit of detection (LoD) of 1.1 μg/L. These results show an appreciable sensitivity of the sensor for detecting the MNP at relatively low potentials, making it possible to avoid passivation phenomena.

关键词： 3-Methyl-4-Nitrophenol Carbon Fiber Microelectrode Nickel Tetrasulfonated Phthalocyanine Indirect Electroanalysis Square Wave Voltammetry

Hexavalent Chromium Cr (VI) Removal from Water by Mango Kernel Powder

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Journal of Materials Science and Chemical Engineering 2024年第1期12卷 84-103页

作者： Amadou Sarr Gning Cheikh Gaye Antoine Blaise Kama Pape Abdoulaye Diaw Diène Diégane Thiare Modou Fall laboratoire de chimie Physique organique et d’Analyses Environnementales (LCPOAE) Université Cheikh Anta Diop Dakar Sénégal Equipe chimie des Matériaux Inorganique et organique (ECMIO) Université Alioune Diop Bambey Sénégal Equipe des Matériaux Electrochimie et Photochimie Analytiques (EMEPA) Université Alioune Diop Bambey Sénégal laboratoire de Photochimie et d’Analyse (LPA) Université Cheikh Anta Diop Dakar Sénégal

Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate surface properties and morphology of the adsorbent.

关键词： Adsorption Chromium Mango Kernel Powder Spectroscopy Analysis Water Treatment

A study on wildfire impacts on greenhouse gas emissions and regional air quality in South of Orléans,France

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Journal of Environmental Sciences 2024年第1期135卷 521-533页

作者： Chaoyang Xue Gisèle Krysztofiak Yangang Ren Min Cai Patrick Mercier Frédéric Le Fur Corinne Robin Benoit Grosselin Véronique Daele Max RMcGillen Yujing Mu Valéry Catoire Abdelwahid Mellouki laboratoire de Physique et chimie de l’Environnement et de l’Espace(LPC2E) CNRS–UniversitéOrléans–CNES(UMR 7328)Orléans Cedex 245071France Institut de Combustion AérothermiqueRéactivitéEnvironnement(ICARE)CNRSOrléans Cedex 245071France Research Centre for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Lig’Air-Association de surveillance de la qualitéde l’air en région Centre-Val de Loire Saint-Cyr-en-Val 45590France Mohammed V University RabatMorocco

Wildfire events are increasing globally which may be partly associated with climate change,resulting in significant adverse impacts on local,regional air quality and global *** September 2020,a small wildfire(burned area:36.3 ha)event occurred in Souesmes(Loiret-Cher,Sologne,France),and its plume spread out over 200 km on the following day as observed by the MODIS *** on measurements at a suburban site(~50 km northwest of the fire location)in Orléans and backward trajectory analysis,young wildfire plumes were *** increases in gaseous pollutants(CO,CH_(4),N_(2)O,VOCs,etc.)and particles(including black carbon)were found within the wildfire plumes,leading to a reduced air *** factors,defined as EF(X)=ΔX/ΔCO(where,X represents the target species),of various trace gases and black carbon within the young wildfire plumes were determined accordingly and compared with previous *** in the ambient ions(such as ammonium,sulfate,nitrate,chloride,and nitrite in the particle-and gasphase)and aerosol properties(e.g.,aerosol water content,aerosol p H)were also quantified and ***,we estimated the total carbon and climate-related species(e.g.,CO_(2),CH_(4),N_(2)O,and BC)emissions and compared them with fire emission *** biomass burning emission inventories have uncertainties in estimating small fire burned areas and *** instance,we found that the Global Fire Assimilation System(GFAS)may underestimate emissions(e.g.,CO)of this small wildfire while other inventories(GFED and FINN)showed significant *** that it is the first time to record wildfire plumes in this region,related atmospheric implications are presented and discussed.

关键词： Wildfire Air quality Emission factor Emission inventory VOLTAIRE supersite

Distribution, Mobility, and Health Risks Assessment of Trace Metals in River Sediments from Intense Agricultural Activity Areas in West Africa

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Journal of Materials Science and Chemical Engineering 2024年第8期12卷 12-42页

作者： Ahbeauriet Ahmed Ouattara Maley-Pacôme Soro Albert Brou Kouadio Horo Koné Albert Trokourey Dpartment des Sciences et Technique Universit Alassane Ouattara Bouak Cte dIvoire laboratoire de Thermodynamique et de Physico-chimie du Milieu Universit Nangui Abrogoua Abidjan Cte dIvoire laboratoire de chimie Physique Universit Flix Houphout Boigny Abidjan Cte dIvoire

The economy of West African countries is mainly based on agriculture. However, the trace metal(loid)s contamination status in rivers is relatively unknown in the region. In this work, 45 surface sediments collected from the Bandama, Comoé, and Bia Rivers in south and south eastern Côte d’Ivoire (West Africa), were analyzed for total metal concentrations and chemical speciation. The results showed that the river sediments were considerably contaminated by Cd and moderately contaminated by As, Cu, Pb, and Zn. Significant spatial variations were observed among the stations but not between the rivers. Metals Cd and Cu were likely to cause more ecological risks. The speciation analysis unravelled that the metal(loid)s partitioned mainly in the residual fraction, with the potential mobile fraction varying from 14% to 28%. The study calls for establishment of strict policies relative to the application of fertilizers and agrochemicals and mining activities to protect the environment and human health risks.

关键词： River Sediment Trace Metal (Loid)s Multivariate Analysis Potential Ecological Risk Assessments Sequential Extraction Geochemical Indices

Application of in-situ characterization techniques in modern aqueous batteries

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Rare Metals 2024年第8期43卷 3553-3575页

作者： Jia-Hao Wu Hong-Wei Cai Zhao-Hui deng Jean-Jacques Gaumet Yu Bao Wen Luo department of Physics State Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingSchool of Materials Science and EngineeringWuhan University of TechnologyWuhan430070China laboratoire de chimie Et Physique:Approche Multi-Echelles Des Milieux Complexes(LCP-A2MC)Institut Jean BarriolUniversitéde Lorraine57070MetzFrance department of Medicinal Chemistry Hubei College of Chinese MedicineJingzhou 434020China

The development of high-performance aqueous batteries calls for an in-depth knowledge of their chargedischarge redox and failure mechanism,as well as a systematic understanding of the dynamic evolution of microstructure,phase composition,chemical composition,and local chemical environment of the materials for ***-situ characterization technology is expected to understand and reveal the problems faced by aqueous rechargeable batteries,such as the dissolution of electrode materials,the growth of metal negative electrode dendrites,passivation,corrosion,side reactions and a series of *** on this,typical in-situ characterization techniques and their basic mechanisms are summarized,including in-situ optical visualization,in-situ microscopy techniques(in-situ scanning electron microscopy(SEM),in-situ transmission electron microscopy(TEM)),in-situ X-ray techniques(in-situ X-ray diffraction(XRD),in-situ X-ray photoelectron spectroscopy(XPS),in-situ near-edge structural X-ray absorption spectroscopy(XANES)),and in-situ spectroscopy techniques(in-situ Raman spectroscopy,in-situ Fourier transform infrared(FTIR)).Moreover,some emerging techniques concerning aqueous battery research,especially gas evolution and materials dissolution issues,such as in-situ electrochemical quartz crystal microbalance(EQCM).in-situ fiber-optic sensing,in-situ gas chromatography(GC) are *** last,the applications of advanced in-situ characterizations in future research of aqueous batteries are emphasized and discussed,along with some of the remaining challenges and possible solutions.

关键词： Aqueous battery In-situ characterization Phase transformation Solid electrolyte interphase Zinc dendrite growth

Aqueous Extract of Ceiba pentandra Stimulates the Production of Fetal Hemoglobin in Sickle Cell Patients

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Journal of Biosciences and Medicines 2024年第8期12卷 295-306页

作者： Marie Miezi Nsimba Magain Barihuta Mihatano Blaise Maya Mbamu Aline Diza Lubongo Thoms Nzaji Kolombo Josué Matadi Mukengeshaie José Nzunzu Lami laboratoire de Recherche Bio-organique Dpartement de Chimie Mdicinale et Pharmacognosie Facult des Sciences Pharmaceutiques Universit de Kinshasa Kinshasa Democratic Republic of the Congo laboratoire dAnalyse Biologique Hpital Biamba Marie Mutombo Kinshasa Democratic Republic of the Congo Centre de Phytothrapie Moderne NIECA Commune de Ngaba Kinshasa Democratic Republic of the Congo Traumatology Service Department of Surgery Kinshasa University Hospital University of Kinshasa Kinshasa Democratic Republic of the Congo

Subsequent studies have demonstrated the reversed activity of the aqueous extract of Ceiba pentandra on the deformity of sickled red blood cells in hypoxia conditions. The observation which related to an in vitro study had given rise to hopes as to the management of sickle cell disease (SCD) by the use of this plant species. In this paper, the authors aimed to investigate the effect of the aqueous extract of C. pentandra on the production of fetal hemoglobin in SCD patients. The work carried out hemoglobin electrophoresis, for a period of six months, on blood samples from SCD patients who voluntarily undergone routine treatment, based on the medicinal recipe prepared from the bark of the trunk and branches of C. pentandra, in a hospital center of herbal medicines located in Kinshasa. The medicinal recipe called BEAT-SS is a patented product of the hospital center named Centre de Phytothérapie Moderne NIECA. Blood samples from patients under treatment were taken to evaluate the behavior of different forms of hemoglobin (hemoglobin S, hemoglobin F and hemoglobin A2). Agarose gel electrophoresis with integrated reading was used for the separation of the different forms of hemoglobin, as well as their dosage on each sample of sickle blood. A reduction in the proportion of hemoglobin S and an increase in the proportion of fetal hemoglobin were found in all sickle cell patients during the treatment period. This observation could affirm that the management of sickle cell patients using the recipe prepared from the aqueous extract of C. pentandra could increase the level of fetal hemoglobin in these patients.

关键词： Sickle Cell Disease Hemoglobin S Fetal Hemoglobin Ceiba pentandra

Effect of Seasonal Variations on the Behavior of Flexible Pavements in Burkina Faso: Towards Alternating and Periodic Loading of Multi-Axle Heavy Goods Vehicles for Road Durability

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Journal of Materials Science and Chemical Engineering 2024年第6期12卷 24-42页

作者： Kokoro Kobori Doua Allain Gnabahou Bouto Kossi Imbga laboratoire de chimie Analytique de Physique Spatiale et Energtique Universit Norbert ZONGO Koudougou Burkina Faso laboratoire denergie Thermique Renouvelable Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

Bituminous materials are heat-sensitive, and their mechanical properties vary with temperature. This variation in properties is not without consequences on the performance of flexible road structures under the repeated passage of multi-axles. This study determines the influence of seasonal variations on the rate of permanent deformation, the rut depth of flexible pavements and the effect of alternating loading of heavy goods vehicles following the temperature variations on the durability of roads. Thus, an ambient and pavement surface temperature measurement was carried out in 2022. The temperature profile at different layers of the modelled pavement, the evaluation of deformation rates and rutting depth were determined using several models. The results show that the permanent deformation and rutting rates are higher at the level of the bituminous concrete layer than at the level of the asphalt gravel layer because the stresses decrease from the surface to the depth of the pavement. On the other hand, the variations in these rates, permanent deformations and ruts between the hot and so-called cold periods are more pronounced in the bitumen gravel than in bituminous concrete, showing that gravel bitumen is more sensitive to temperature variations than bituminous concrete despite its higher rigidity. Of these results, we suggested a periodic and alternating loading of the different types of heavy goods vehicles. These loads consist of fully applying the WAEMU standards with a tolerance of 15% during periods of high and low temperatures. This regulation has increased 2 to 3 times in the durability of roadways depending on the type of heavy goods vehicle.

关键词： Pavement Rutting Permanent deformation Multi-Axle Seasonal

Theoretical and Experimental Quantification of Solar Radiation through a Tracking System

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Open Journal of Applied Sciences 2024年第9期14卷 2648-2660页

作者： Guy Christian Tubreoumya Eloi Salmwendé Tiendrebeogo Tchardja Combary Téré Dabilgou Jacques Nebié Boubou Bagré Alfa Oumar Dissa Antoine Bere laboratoire de Physique et de chimie de lEnvironnement (LPCE) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire de Mathmatiques et PhySique (LA.M.P.S) Universit de Perpignan Via Domitia (UPVD) Perpignan France

This work deals with the estimation of solar radiation through a solar tracker aimed at evaluating the effect of solar tracking on the solar deposit in Burkina Faso. Using a two-axis solar tracking system, we experimentally measured solar radiation at our Joseph KI-ZERBO University site and compared it with that obtained by a numerical simulation run using Fortran programming software based on a mathematical model by Brichambaut. The results obtained from the mathematical and experimental studies show that, with a solar tracker, on a clear-sky day, solar irradiation is between 800 W·m−2 and 1000 W·m−2 between about 8 a.m. and 4 p.m., i.e. a duration of 8 hours of insolation. Analysis of the numerical and experimental results shows very good quantitative and qualitative agreement, with an average relative error of 18%.

关键词： Tracking System Solar Radiation Dual Axis Energy Efficiency