Baba NGOM - Academia.edu (original) (raw)

Papers by Baba NGOM

Research paper thumbnail of Experimental determination and modeling of desorption isotherms and isosteric heat of onion

It is essential to know the desorption isotherms to control the drying processes of agricultural ... more It is essential to know the desorption isotherms to control the drying processes of agricultural products, food. The objective of this work is to determine the sorption isotherms of the local onion: the Violet de Galmi cultivated in the Niayes area. Desorption isotherms were studied for water activities ranging from 0.05 to 0.9 and for temperatures of 40 °C, 50 °C and 60 °C using the static gravimetric method. Six saturated salt solutions were used (KOH, K2CO3, NaBr, CuCl2, KCl and NaCl). The results show that the desorption isotherms of onion are type II and the equilibrium water content is temperature dependent. The experimental results are then smoothed by five models: Guggenheim-Anderson-De Boer (GAB), Brunauer-Emmett and Teller (BET), Henderson, Oswin and Peleg for the description of the equilibrium state of this product. From the modeling, it was concluded that both the Peleg model and the GAB model describe the desorption isotherms of onion well, but the Peleg model has the smallest relative errors, thus defining the Peleg model as the best model. From the results obtained, the isosteric heat of desorption is determined using the Clausius-Clapeyron equation.

Research paper thumbnail of Differential Gene Expression and Bioinformatics Analysis of Copper Resistance Gene afe_1073 in Acidithiobacillus ferrooxidans

Biological Trace Element Research, Jan 24, 2013

Copper resistance of acidophilic bacteria is very significant in bioleaching of copper ore since ... more Copper resistance of acidophilic bacteria is very significant in bioleaching of copper ore since high concentration of copper are harmful to the growth of organisms. Copper resistance gene afe_1073 was putatively considered to be involved in copper homeostasis in Acidithiobacillus ferrooxidans ATCC23270. In the present study, differential expression of afe_1073 in A. ferrooxidans strain DY26 and DC was assessed with quantitative reverse transcription polymerase chain reaction. The results showed the expression of afe_1073 in two strains increased with the increment of copper concentrations. The expression of DY26 was lower than that of DC at the same copper concentration although A. ferrooxidans strain DY26 possessed higher copper resistance than strain DC. In addition, bioinformatics analysis showed AFE_1073 was a typical transmembrane protein P1b1-ATPase, which could reduce the harm of Cu + by pumping it out from the cell. There were two mutation sites in AFE_1073 between DY26 and DC and one may change the hydrophobicity of AFE_1073, which could enhance the ability of DY26 to pump out Cu +. Therefore, DY26 needed less gene expression of afe_1073 for resisting copper toxicity than that of DC at the same copper stress. Our study will be beneficial to understanding the copper resistance mechanism of A. ferrooxidans.

Research paper thumbnail of The effect of the introduction of exogenous strain Acidithiobacillus thiooxidans A01 on functional gene expression, structure and function of indigenous consortium during pyrite bioleaching

Bioresource Technology, Sep 1, 2011

At. ferrooxidans (CMS) 9 K 2.0 30 Peng et al. (2006) L. ferriphilum (YSK) 9 K 1.6 40 Gao et al. (... more At. ferrooxidans (CMS) 9 K 2.0 30 Peng et al. (2006) L. ferriphilum (YSK) 9 K 1.6 40 Gao et al. (2007) At. thiooxidans (A01) 9 K + Sulfur (10 g/L) 2.0 30 Fu et al. (2008) At. caldus (S1) 9 K (without FeSO 4) + Sulfur (10 g/L) 2.0 45 Zhou et al. (2007) Acidiphilium spp. (DX1-1) 9 K (without FeSO 4) + Glucose (10 g/L) 3.5 30 Zhang et al. (2007) F. thermophilum (L1) 9 K + Yeast extract (0.1 g/L) 1.0 45 Zhou et al. (2008) S. thermosulfidooxidnas (ST) 9 K + Yeast extract (0.2 g/L) 1.5 45 Unpublished 9 K medium (g/L): (NH 4) 2 SO 4 (3), KCl (0.1), K 2 HPO 4 (0.5), MgSO 4 Á7H 2 O (0.5), Ca(NO 3) 2 (0.01), FeSO 4 Á7H 2 O (44.7).

Research paper thumbnail of Changes in the composition of an acid mine drainage microbial community upon successive transfers in medium containing low-grade copper sulfide

Bioresource Technology, 2011

A consortium of microorganisms from acid mine drainage samples was cultured in modified 9 K mediu... more A consortium of microorganisms from acid mine drainage samples was cultured in modified 9 K medium containing low-grade copper sulfide. The culture was maintained for sixty days and then transferred to fresh medium. This process was repeated three more times and a final consortium exhibiting a copper extraction rate of 89.3% was obtained. RFLP and microarrays analysis of 16S rRNA sequences retrieved from the consortia showed that Acidithiobacillus caldus, Leptospirillum ferriphilum, Sulfobacillus sp., Acidiphilium sp., and Sulfolobus spp. were represented in higher numbers in the consortia obtained in the copper-containing medium than in the original consortium. In contrast, a decrease in Acidithiobacillus ferrooxidans, Alicyclobacillus sp., Pseudomonas sp., and Sulfobacillus thermosulfidooxidans was observed. The abundance of genes related to sulfur metabolism from At. caldus and Sulfolobus spp., iron oxidation from Leptospirillum sp. and metal resistance from most of the detected microorganisms increased as the consortium was successively transferred into fresh medium.

Research paper thumbnail of Numerical Modelling of the Saloum Continental Terminal (Ct) Aquifer (Senegal)

Research paper thumbnail of Contribution to the Hydrochemical Study of Groundwater from the Continental Terminal in Saloum

Journal of Water Resource and Protection

This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum... more This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum river. This study aims to participate in the knowledge of the physicochemical quality and to help understand the origins and processes of the mineralization of the water of the Continental Terminal (CT). Physicochemical treatments show an average pH of 6.61 indicating a slightly acidic water overall. The electrical conductivity varies between 37.4 and 12,320 µS·cm −1 with an average of 729.3 µS·cm −1. High conductivities are recorded around the ocean and the Saloum River, indicating higher mineralized waters in these areas. The geochemical study and multivariate statistical analysis indicate three groups of the sampled waters. Group 1 is mainly formed of the Ca-HCO 3 , Na-HCO 3 , Ca-Cl and Na-Cl facies. This group is the most common one and is found throughout the southern Saloum area. Group 2, mainly made up of the Ca-HCO 3 and Na-HCO 3 facies, is located in the center, east, west and north of the zone. The mineralization of these two groups is believed to be of carbonate, evaporitic and/or anthropogenic origin. Group 3 is formed from the Na-Cl facies. This group is located in the north and west of the area (near the ocean and the Saloum river). This group 3 suggests pollution of marine and anthropogenic origin. The calculated base indices suggest cationic exchanges between the waters and the formations of the water table of the terminal continental.

Research paper thumbnail of Evaluation of the inhibitory action of essential oil from Eucalyptus globulus leaves on the corrosion of mild carbon steel in 1M HCl medium

Ovidius University Annals of Chemistry

The present work aims to valorize an aromatic and medicinal plant of Eucalyptus globulus found in... more The present work aims to valorize an aromatic and medicinal plant of Eucalyptus globulus found in the region of Dakar, Senegal. To do so, we first extracted the essential oil contained in the leaves of the plant harvested in October 2020. We obtained the essential oil by hydrodistillation using a Clevenger type extractor with a yield of 1.70% of the dry plant mass. This value is quite appreciable compared to the different values in the literature. The essential oil extracted from the leaves of Eucalyptus globulus was tested as a green inhibitor on carbon steel type XC38 in 1M HCl acid medium by the mass loss method. The results obtained led to a maximum inhibitory efficiency of 89.03% for a concentration of 1.6 g/L of essential oil at room temperature of 298 K. The effect of temperature on the inhibitory behavior of the essential oil was also studied over a range of 298 K to 338 K. In this temperature range, a loss of efficiency was observed with increasing temperature, reaching a v...

Research paper thumbnail of Contribution to the Hydrochemical Study of Groundwater from the Continental Terminal in Saloum

Journal of Water Resource and Protection

This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum... more This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum river. This study aims to participate in the knowledge of the physicochemical quality and to help understand the origins and processes of the mineralization of the water of the Continental Terminal (CT). Physicochemical treatments show an average pH of 6.61 indicating a slightly acidic water overall. The electrical conductivity varies between 37.4 and 12,320 µS·cm −1 with an average of 729.3 µS·cm −1. High conductivities are recorded around the ocean and the Saloum River, indicating higher mineralized waters in these areas. The geochemical study and multivariate statistical analysis indicate three groups of the sampled waters. Group 1 is mainly formed of the Ca-HCO 3 , Na-HCO 3 , Ca-Cl and Na-Cl facies. This group is the most common one and is found throughout the southern Saloum area. Group 2, mainly made up of the Ca-HCO 3 and Na-HCO 3 facies, is located in the center, east, west and north of the zone. The mineralization of these two groups is believed to be of carbonate, evaporitic and/or anthropogenic origin. Group 3 is formed from the Na-Cl facies. This group is located in the north and west of the area (near the ocean and the Saloum river). This group 3 suggests pollution of marine and anthropogenic origin. The calculated base indices suggest cationic exchanges between the waters and the formations of the water table of the terminal continental.

Research paper thumbnail of Etude Des Possibilites De Mise Au Point Dun Combustible a Base De Dechets Agricoles : Cas De La Litiere De Filao

International Journal of Advanced Research, 2022

Lobjectif de cette etude est une valorisation energetique de la litiere de filao par le biais de ... more Lobjectif de cette etude est une valorisation energetique de la litiere de filao par le biais de la production de combustible en vue de le substituer au bois de chauffe. Nous avons fait la caracterisation physicochimique de la litiere de filao et determiner les pouvoirs calorifiques inferieurs avant et apres carbonisation en utilisant differents liants : la melasse, lamidon, les feuille de baobab et la farine. Les resultats obtenus montrent linfluence des liants sur la variation du PCI et ce dernier est superieur a celui du bois de chauffe. Des briquettes ont ete realisees apres carbonisation de la litiere de filao avec comme liants la melasse et lamidon .Nous avons note que le PCI du bio charbon est superieur au precedent. Des essais de compression ont ete faits pour apprehender la resistance des briquettes pour chaque pourcentage de liant. Cela nous a permis de choisir la melasse comme liant avec une proportion de 20 % presentant un pouvoir calorifique de 25427,8KJ/kg et une meill...

Research paper thumbnail of Characterization of the Physicochemical and Chemical Parameters of the Surface Waters of Keur Momar Sarr in the Louga Region (Senegal)

Water brings to every living being a good health and the well-being of his organism. It allows th... more Water brings to every living being a good health and the well-being of his organism. It allows them to meet their basic needs and especially their diet. But, for a beneficial use, the optimal quality of the water is crucial. Here in Senegal most of the regions are fed by the lake Lac de Guiers and the latter is threatened by industrial discharges, hydroagricultural activities that cause a gradual degradation of its quality. In this study, we made a characterization of the physicochemical parameters of the waters of Keur Momar Sarr in order to have visibility on the evolution of ions, temperature, pH, conductivity etc. Then, a comparative study between certain measured chemical elements and the standards of discharges or potability was made. The results obtained show that the surface waters of Keur Momar Sarr are of excellent quality with a dominance of a chlorinated and sulphated calcium facies. We observed a dominance of chloride ion at the anion level and magnesium ion at the cati...

Research paper thumbnail of Design and Realization of a UV-C Based Disinfection Tools Monitored by Mobile Application

Open Journal of Applied Sciences, 2022

In many outbreaks, patients and healthcare workers are particularly at risk from nosocomial infec... more In many outbreaks, patients and healthcare workers are particularly at risk from nosocomial infections as a result of non-effective disinfection methods. With increasing incidence of viral infections such as severe acute respiratory syndrome, in one hand, and the increase in the rate of antibiotic resistant bacteria associated with nosocomial infections in other hand, there is a need to design novel engineering tools for inactivation of nosocomial pathogens. Ultraviolet germicidal irradiation (UVGI) is considered as a promising method to inactivate bacteria and viruses. This paper presents UV-C Based disinfection tools monitored by mobile application, designed for hospital and Epidemic Treatment Center. The evolution of the irradiation intensity over time was evaluated, and the theorical disinfection duration for several nosocomial pathogens was determined. In the case of SARS-CoV2, less than 12 minutes were needed to achieve 99.99% viral reduction in a room of 36 sqm.

Research paper thumbnail of Techniques for Tracking Microbial Community Structure and Function in Natural Environment and Engineered Systems

Microbial community activity impact on changes in environment and bioprocesses efficiency, howeve... more Microbial community activity impact on changes in environment and bioprocesses efficiency, however their structure and function are also strongly affected by the condition of their surrounding environment. Understanding mechanisms underlying microbes-environments interactions would allow the predictions of environmental changes and optimization of existing microbe-engineered systems. Therefore linking microbial community structure to function and environmental changes has been one of the biggest challenges for scientific committee in this last decade. Addressing such challenge requires microbial population analysis under various conditions over time and space. Thus, it is important to master and comprehend appropriate methods for analyzing microbial community diversity, structure and function in various environments. In this paper number of techniques is presented, and their advantages and disadvantages are evaluated.

Research paper thumbnail of Study and Proposal for a Hyperfluorinated Brackish Water Treatment System in the Fatick Region, Case of Diouroup (Senegal)

American Journal of Analytical Chemistry, 2021

Groundwater is the main resource for human consumption in many countries, especially in developin... more Groundwater is the main resource for human consumption in many countries, especially in developing countries. This groundwater is often brackish and hyperfluorinated, which leads to diseases such as dental and bone fluorosis, etc. The water from the Diouroup water drainage facilities, like those from many other water drainage facilities in the regions of Fatick, Kaolack, Diourbel and the area of Touba, is facing this problem. To solve these problems, several physicochemical and membrane methods have been implemented. In this work we have briefly outlined some of these methods and we have chosen one of them, low pressure reverse osmosis. In addition, this technique is very simple to operate and maintain. Reverse osmosis provides good quality water in a single step, without the need for additional sterilization or remineralization treatments. We then carried out simulations with the Reverse Osmosis System Analysis (ROSA) software. For reasonable operating parameters, we have noticed a low feed pressure of 11.58 bars, a good average flow of raw water of 27.79 L/m 2 /h and a recovery rate of the first pass of 75.01%. The results obtained also showed a good quality of the permeate which respects the recommendations of the World Health Organization (WHO) on drinking water. The fluorides of 0.59 mg/L have a recovery rate of 90.8% while the chlorides of 59.09 mg/L have a recovery rate of 92.12% as for the Total Dissolved Solids of 184.90 mg/L for an abatement of 92%. Finally, the low energy consumption of the process makes it possible to consider it in coupling with an electric supply by photovoltaic solar collectors for isolated sites.

Research paper thumbnail of Review on Essential Oils and Their Corrosion-inhibiting Properties

American Journal of Applied Chemistry, 2021

Natural and aromatic substances contained in plants which can be extracted by hydro-distillation ... more Natural and aromatic substances contained in plants which can be extracted by hydro-distillation or by cold extraction, more commonly known as essential oils are used today in several fields including cosmetic, perfumery, food processing, traditional medicine, agriculture etc. More recently, a strong use of these products extracted from plants as a corrosion inhibitor of metals and alloys in an acidic environment has been observed, given the number of works that have been published in recent decades. This review represents a general study on essential oils for a better understanding of these natural products, but also a non-exhaustive study of the published research works on the use of essential oils as a corrosion inhibitor of metals and alloys, in particular mild steels in acidic environments. Most of these studies have revealed great potentials of essential oils in inhibiting the corrosion of metals in aggressive environment, such as acidic environment. Thus, they have proposed alternatives to artificial metal corrosion inhibitor known to cause environmental pollution and public health issues. This review is a contribution to research efforts carried out by scientific community to find green corrosion inhibitors. It lays the basis for future research work aimed to investigate on the corrosion inhibition properties of essential oils extracted from Senegalese local plants.

Research paper thumbnail of Construction of Control Charts for Monitoring Various Parameters Related to the Management of the COVID-19 Pandemic

Journal of Biosciences and Medicines, 2021

To monitor the quality characteristics of a process, appropriate graphical and statistical tools ... more To monitor the quality characteristics of a process, appropriate graphical and statistical tools must be used. These tools are capable of showing the evolution over time of the behavior of the quality characteristics (measurable or countable) and detecting situations that seem to present certain anomalies. The control chart is one of these tools widely used in quality management. In the process of managing the COVID-19 pandemic, this tool will make it possible to know at all times whether the parameters monitored such as the positivity rate, the recovery rate, and the mortality rate, are under control and to act accordingly. Monitoring cure and mortality rates will also show us the effectiveness of the treatments used.

Research paper thumbnail of Evolution and Prospect of Dakar Drinking Water Consumption

Journal of Water Resource and Protection, 2019

In Dakar, there has been a considerable deficit in the drinking water supply for more than a deca... more In Dakar, there has been a considerable deficit in the drinking water supply for more than a decade. The distribution is poorly controlled in this region. And yet, there is no lack of supply sources or solutions. With a drinking water deficit of 300,000 m 3 /d to fill, the State of Senegal proposed two (02) options: firstly, the construction of a second Plan at Keur Momar Sarr on the Guiers Lake with a capacity of 75,000 m 3 /d coupled with a third pipeline between Keur Momar Sarr and Thiès (KMS3); secondly, the construction of a seawater desalination Plant with a capacity of 75,000 m 3 /d. In this article, we studied the evolution of the drinking water consumption and the statistical data relating to population growth, which is the key element in the drinking water consumption evolution in Dakar. We were able to extract the equations from the trend curves that made it possible to predict a population growth. The results obtained with the equations and the curves show that the real needs for drinking water in Dakar are proportional to population growth.

Research paper thumbnail of Comparison of Indigenous and Exogenous Mesophilic Bacteria for the Bioleaching of Low Grade Copper Ores

Advanced Materials Research, 2013

Using indigenous microorganisms in biomining processes assures few ecological distortions and les... more Using indigenous microorganisms in biomining processes assures few ecological distortions and less time consumption for adaptation. However, there is a debate as to whether an indigenous microbial community is more efficient than one composed of microbial strains selected for specific physiological traits. In order to provide thoughtful opinions in such a debate, a cross-comparison of six strains isolated from two different regions: Chambishi Copper Mine (Zambia) and Dexing Copper Mine (China), was conducted. Physiological properties and leaching performancesof Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum in pure and mixed culture were studied. The results showed that strains within species presented similar traits while copper resistance was not species-specific. In terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the exogenous. In addition, microbial c...

Research paper thumbnail of Cross-Comparison of Leaching Strains Isolated from Two Different Regions: Chambishi and Dexing Copper Mines

BioMed Research International, 2014

A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zam... more A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa) and Dexing copper mine (China, Asia), was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions:Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans, andLeptospirillum ferriphilum. Prior to their study in bioleaching, the different strains were characterized and compared at physiological level. The results revealed that, except for copper tolerance, strains within species presented almost similar physiological traits with slight advantages of Chambishi strains. However, in terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the foreign microorganisms. In addition, microbial community analysis revealed that the different mixed cultures shared almos...

Research paper thumbnail of Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media

Archives of Microbiology, 2014

In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and... more In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and used in double-layer agar plate to efficiently isolate and purify leaching bacteria. Unlike Acidiphilium sp., the yeast strain was tetrathionate tolerant and could metabolize a great range of organic compounds including organic acids. These properties allowed the yeast strain to enable and fasten the growth of iron and sulfur oxidizers on double-layer agar plate. The isolates were identified as Acidithiobacillus ferrooxidans FOX1, Leptospirillun ferriphilum BN, and Acidithiobacillus thiooxidans ZMB. These three leaching bacteria were inhibited by organic acids such as acetic and propionic acids; however, their activities were enhanced by Candida digboiensis NB under dissolved organic matter stress.

Research paper thumbnail of Experimental determination and modeling of desorption isotherms and isosteric heat of onion

It is essential to know the desorption isotherms to control the drying processes of agricultural ... more It is essential to know the desorption isotherms to control the drying processes of agricultural products, food. The objective of this work is to determine the sorption isotherms of the local onion: the Violet de Galmi cultivated in the Niayes area. Desorption isotherms were studied for water activities ranging from 0.05 to 0.9 and for temperatures of 40 °C, 50 °C and 60 °C using the static gravimetric method. Six saturated salt solutions were used (KOH, K2CO3, NaBr, CuCl2, KCl and NaCl). The results show that the desorption isotherms of onion are type II and the equilibrium water content is temperature dependent. The experimental results are then smoothed by five models: Guggenheim-Anderson-De Boer (GAB), Brunauer-Emmett and Teller (BET), Henderson, Oswin and Peleg for the description of the equilibrium state of this product. From the modeling, it was concluded that both the Peleg model and the GAB model describe the desorption isotherms of onion well, but the Peleg model has the smallest relative errors, thus defining the Peleg model as the best model. From the results obtained, the isosteric heat of desorption is determined using the Clausius-Clapeyron equation.

Research paper thumbnail of Differential Gene Expression and Bioinformatics Analysis of Copper Resistance Gene afe_1073 in Acidithiobacillus ferrooxidans

Biological Trace Element Research, Jan 24, 2013

Copper resistance of acidophilic bacteria is very significant in bioleaching of copper ore since ... more Copper resistance of acidophilic bacteria is very significant in bioleaching of copper ore since high concentration of copper are harmful to the growth of organisms. Copper resistance gene afe_1073 was putatively considered to be involved in copper homeostasis in Acidithiobacillus ferrooxidans ATCC23270. In the present study, differential expression of afe_1073 in A. ferrooxidans strain DY26 and DC was assessed with quantitative reverse transcription polymerase chain reaction. The results showed the expression of afe_1073 in two strains increased with the increment of copper concentrations. The expression of DY26 was lower than that of DC at the same copper concentration although A. ferrooxidans strain DY26 possessed higher copper resistance than strain DC. In addition, bioinformatics analysis showed AFE_1073 was a typical transmembrane protein P1b1-ATPase, which could reduce the harm of Cu + by pumping it out from the cell. There were two mutation sites in AFE_1073 between DY26 and DC and one may change the hydrophobicity of AFE_1073, which could enhance the ability of DY26 to pump out Cu +. Therefore, DY26 needed less gene expression of afe_1073 for resisting copper toxicity than that of DC at the same copper stress. Our study will be beneficial to understanding the copper resistance mechanism of A. ferrooxidans.

Research paper thumbnail of The effect of the introduction of exogenous strain Acidithiobacillus thiooxidans A01 on functional gene expression, structure and function of indigenous consortium during pyrite bioleaching

Bioresource Technology, Sep 1, 2011

At. ferrooxidans (CMS) 9 K 2.0 30 Peng et al. (2006) L. ferriphilum (YSK) 9 K 1.6 40 Gao et al. (... more At. ferrooxidans (CMS) 9 K 2.0 30 Peng et al. (2006) L. ferriphilum (YSK) 9 K 1.6 40 Gao et al. (2007) At. thiooxidans (A01) 9 K + Sulfur (10 g/L) 2.0 30 Fu et al. (2008) At. caldus (S1) 9 K (without FeSO 4) + Sulfur (10 g/L) 2.0 45 Zhou et al. (2007) Acidiphilium spp. (DX1-1) 9 K (without FeSO 4) + Glucose (10 g/L) 3.5 30 Zhang et al. (2007) F. thermophilum (L1) 9 K + Yeast extract (0.1 g/L) 1.0 45 Zhou et al. (2008) S. thermosulfidooxidnas (ST) 9 K + Yeast extract (0.2 g/L) 1.5 45 Unpublished 9 K medium (g/L): (NH 4) 2 SO 4 (3), KCl (0.1), K 2 HPO 4 (0.5), MgSO 4 Á7H 2 O (0.5), Ca(NO 3) 2 (0.01), FeSO 4 Á7H 2 O (44.7).

Research paper thumbnail of Changes in the composition of an acid mine drainage microbial community upon successive transfers in medium containing low-grade copper sulfide

Bioresource Technology, 2011

A consortium of microorganisms from acid mine drainage samples was cultured in modified 9 K mediu... more A consortium of microorganisms from acid mine drainage samples was cultured in modified 9 K medium containing low-grade copper sulfide. The culture was maintained for sixty days and then transferred to fresh medium. This process was repeated three more times and a final consortium exhibiting a copper extraction rate of 89.3% was obtained. RFLP and microarrays analysis of 16S rRNA sequences retrieved from the consortia showed that Acidithiobacillus caldus, Leptospirillum ferriphilum, Sulfobacillus sp., Acidiphilium sp., and Sulfolobus spp. were represented in higher numbers in the consortia obtained in the copper-containing medium than in the original consortium. In contrast, a decrease in Acidithiobacillus ferrooxidans, Alicyclobacillus sp., Pseudomonas sp., and Sulfobacillus thermosulfidooxidans was observed. The abundance of genes related to sulfur metabolism from At. caldus and Sulfolobus spp., iron oxidation from Leptospirillum sp. and metal resistance from most of the detected microorganisms increased as the consortium was successively transferred into fresh medium.

Research paper thumbnail of Numerical Modelling of the Saloum Continental Terminal (Ct) Aquifer (Senegal)

Research paper thumbnail of Contribution to the Hydrochemical Study of Groundwater from the Continental Terminal in Saloum

Journal of Water Resource and Protection

This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum... more This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum river. This study aims to participate in the knowledge of the physicochemical quality and to help understand the origins and processes of the mineralization of the water of the Continental Terminal (CT). Physicochemical treatments show an average pH of 6.61 indicating a slightly acidic water overall. The electrical conductivity varies between 37.4 and 12,320 µS·cm −1 with an average of 729.3 µS·cm −1. High conductivities are recorded around the ocean and the Saloum River, indicating higher mineralized waters in these areas. The geochemical study and multivariate statistical analysis indicate three groups of the sampled waters. Group 1 is mainly formed of the Ca-HCO 3 , Na-HCO 3 , Ca-Cl and Na-Cl facies. This group is the most common one and is found throughout the southern Saloum area. Group 2, mainly made up of the Ca-HCO 3 and Na-HCO 3 facies, is located in the center, east, west and north of the zone. The mineralization of these two groups is believed to be of carbonate, evaporitic and/or anthropogenic origin. Group 3 is formed from the Na-Cl facies. This group is located in the north and west of the area (near the ocean and the Saloum river). This group 3 suggests pollution of marine and anthropogenic origin. The calculated base indices suggest cationic exchanges between the waters and the formations of the water table of the terminal continental.

Research paper thumbnail of Evaluation of the inhibitory action of essential oil from Eucalyptus globulus leaves on the corrosion of mild carbon steel in 1M HCl medium

Ovidius University Annals of Chemistry

The present work aims to valorize an aromatic and medicinal plant of Eucalyptus globulus found in... more The present work aims to valorize an aromatic and medicinal plant of Eucalyptus globulus found in the region of Dakar, Senegal. To do so, we first extracted the essential oil contained in the leaves of the plant harvested in October 2020. We obtained the essential oil by hydrodistillation using a Clevenger type extractor with a yield of 1.70% of the dry plant mass. This value is quite appreciable compared to the different values in the literature. The essential oil extracted from the leaves of Eucalyptus globulus was tested as a green inhibitor on carbon steel type XC38 in 1M HCl acid medium by the mass loss method. The results obtained led to a maximum inhibitory efficiency of 89.03% for a concentration of 1.6 g/L of essential oil at room temperature of 298 K. The effect of temperature on the inhibitory behavior of the essential oil was also studied over a range of 298 K to 338 K. In this temperature range, a loss of efficiency was observed with increasing temperature, reaching a v...

Research paper thumbnail of Contribution to the Hydrochemical Study of Groundwater from the Continental Terminal in Saloum

Journal of Water Resource and Protection

This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum... more This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum river. This study aims to participate in the knowledge of the physicochemical quality and to help understand the origins and processes of the mineralization of the water of the Continental Terminal (CT). Physicochemical treatments show an average pH of 6.61 indicating a slightly acidic water overall. The electrical conductivity varies between 37.4 and 12,320 µS·cm −1 with an average of 729.3 µS·cm −1. High conductivities are recorded around the ocean and the Saloum River, indicating higher mineralized waters in these areas. The geochemical study and multivariate statistical analysis indicate three groups of the sampled waters. Group 1 is mainly formed of the Ca-HCO 3 , Na-HCO 3 , Ca-Cl and Na-Cl facies. This group is the most common one and is found throughout the southern Saloum area. Group 2, mainly made up of the Ca-HCO 3 and Na-HCO 3 facies, is located in the center, east, west and north of the zone. The mineralization of these two groups is believed to be of carbonate, evaporitic and/or anthropogenic origin. Group 3 is formed from the Na-Cl facies. This group is located in the north and west of the area (near the ocean and the Saloum river). This group 3 suggests pollution of marine and anthropogenic origin. The calculated base indices suggest cationic exchanges between the waters and the formations of the water table of the terminal continental.

Research paper thumbnail of Etude Des Possibilites De Mise Au Point Dun Combustible a Base De Dechets Agricoles : Cas De La Litiere De Filao

International Journal of Advanced Research, 2022

Lobjectif de cette etude est une valorisation energetique de la litiere de filao par le biais de ... more Lobjectif de cette etude est une valorisation energetique de la litiere de filao par le biais de la production de combustible en vue de le substituer au bois de chauffe. Nous avons fait la caracterisation physicochimique de la litiere de filao et determiner les pouvoirs calorifiques inferieurs avant et apres carbonisation en utilisant differents liants : la melasse, lamidon, les feuille de baobab et la farine. Les resultats obtenus montrent linfluence des liants sur la variation du PCI et ce dernier est superieur a celui du bois de chauffe. Des briquettes ont ete realisees apres carbonisation de la litiere de filao avec comme liants la melasse et lamidon .Nous avons note que le PCI du bio charbon est superieur au precedent. Des essais de compression ont ete faits pour apprehender la resistance des briquettes pour chaque pourcentage de liant. Cela nous a permis de choisir la melasse comme liant avec une proportion de 20 % presentant un pouvoir calorifique de 25427,8KJ/kg et une meill...

Research paper thumbnail of Characterization of the Physicochemical and Chemical Parameters of the Surface Waters of Keur Momar Sarr in the Louga Region (Senegal)

Water brings to every living being a good health and the well-being of his organism. It allows th... more Water brings to every living being a good health and the well-being of his organism. It allows them to meet their basic needs and especially their diet. But, for a beneficial use, the optimal quality of the water is crucial. Here in Senegal most of the regions are fed by the lake Lac de Guiers and the latter is threatened by industrial discharges, hydroagricultural activities that cause a gradual degradation of its quality. In this study, we made a characterization of the physicochemical parameters of the waters of Keur Momar Sarr in order to have visibility on the evolution of ions, temperature, pH, conductivity etc. Then, a comparative study between certain measured chemical elements and the standards of discharges or potability was made. The results obtained show that the surface waters of Keur Momar Sarr are of excellent quality with a dominance of a chlorinated and sulphated calcium facies. We observed a dominance of chloride ion at the anion level and magnesium ion at the cati...

Research paper thumbnail of Design and Realization of a UV-C Based Disinfection Tools Monitored by Mobile Application

Open Journal of Applied Sciences, 2022

In many outbreaks, patients and healthcare workers are particularly at risk from nosocomial infec... more In many outbreaks, patients and healthcare workers are particularly at risk from nosocomial infections as a result of non-effective disinfection methods. With increasing incidence of viral infections such as severe acute respiratory syndrome, in one hand, and the increase in the rate of antibiotic resistant bacteria associated with nosocomial infections in other hand, there is a need to design novel engineering tools for inactivation of nosocomial pathogens. Ultraviolet germicidal irradiation (UVGI) is considered as a promising method to inactivate bacteria and viruses. This paper presents UV-C Based disinfection tools monitored by mobile application, designed for hospital and Epidemic Treatment Center. The evolution of the irradiation intensity over time was evaluated, and the theorical disinfection duration for several nosocomial pathogens was determined. In the case of SARS-CoV2, less than 12 minutes were needed to achieve 99.99% viral reduction in a room of 36 sqm.

Research paper thumbnail of Techniques for Tracking Microbial Community Structure and Function in Natural Environment and Engineered Systems

Microbial community activity impact on changes in environment and bioprocesses efficiency, howeve... more Microbial community activity impact on changes in environment and bioprocesses efficiency, however their structure and function are also strongly affected by the condition of their surrounding environment. Understanding mechanisms underlying microbes-environments interactions would allow the predictions of environmental changes and optimization of existing microbe-engineered systems. Therefore linking microbial community structure to function and environmental changes has been one of the biggest challenges for scientific committee in this last decade. Addressing such challenge requires microbial population analysis under various conditions over time and space. Thus, it is important to master and comprehend appropriate methods for analyzing microbial community diversity, structure and function in various environments. In this paper number of techniques is presented, and their advantages and disadvantages are evaluated.

Research paper thumbnail of Study and Proposal for a Hyperfluorinated Brackish Water Treatment System in the Fatick Region, Case of Diouroup (Senegal)

American Journal of Analytical Chemistry, 2021

Groundwater is the main resource for human consumption in many countries, especially in developin... more Groundwater is the main resource for human consumption in many countries, especially in developing countries. This groundwater is often brackish and hyperfluorinated, which leads to diseases such as dental and bone fluorosis, etc. The water from the Diouroup water drainage facilities, like those from many other water drainage facilities in the regions of Fatick, Kaolack, Diourbel and the area of Touba, is facing this problem. To solve these problems, several physicochemical and membrane methods have been implemented. In this work we have briefly outlined some of these methods and we have chosen one of them, low pressure reverse osmosis. In addition, this technique is very simple to operate and maintain. Reverse osmosis provides good quality water in a single step, without the need for additional sterilization or remineralization treatments. We then carried out simulations with the Reverse Osmosis System Analysis (ROSA) software. For reasonable operating parameters, we have noticed a low feed pressure of 11.58 bars, a good average flow of raw water of 27.79 L/m 2 /h and a recovery rate of the first pass of 75.01%. The results obtained also showed a good quality of the permeate which respects the recommendations of the World Health Organization (WHO) on drinking water. The fluorides of 0.59 mg/L have a recovery rate of 90.8% while the chlorides of 59.09 mg/L have a recovery rate of 92.12% as for the Total Dissolved Solids of 184.90 mg/L for an abatement of 92%. Finally, the low energy consumption of the process makes it possible to consider it in coupling with an electric supply by photovoltaic solar collectors for isolated sites.

Research paper thumbnail of Review on Essential Oils and Their Corrosion-inhibiting Properties

American Journal of Applied Chemistry, 2021

Natural and aromatic substances contained in plants which can be extracted by hydro-distillation ... more Natural and aromatic substances contained in plants which can be extracted by hydro-distillation or by cold extraction, more commonly known as essential oils are used today in several fields including cosmetic, perfumery, food processing, traditional medicine, agriculture etc. More recently, a strong use of these products extracted from plants as a corrosion inhibitor of metals and alloys in an acidic environment has been observed, given the number of works that have been published in recent decades. This review represents a general study on essential oils for a better understanding of these natural products, but also a non-exhaustive study of the published research works on the use of essential oils as a corrosion inhibitor of metals and alloys, in particular mild steels in acidic environments. Most of these studies have revealed great potentials of essential oils in inhibiting the corrosion of metals in aggressive environment, such as acidic environment. Thus, they have proposed alternatives to artificial metal corrosion inhibitor known to cause environmental pollution and public health issues. This review is a contribution to research efforts carried out by scientific community to find green corrosion inhibitors. It lays the basis for future research work aimed to investigate on the corrosion inhibition properties of essential oils extracted from Senegalese local plants.

Research paper thumbnail of Construction of Control Charts for Monitoring Various Parameters Related to the Management of the COVID-19 Pandemic

Journal of Biosciences and Medicines, 2021

To monitor the quality characteristics of a process, appropriate graphical and statistical tools ... more To monitor the quality characteristics of a process, appropriate graphical and statistical tools must be used. These tools are capable of showing the evolution over time of the behavior of the quality characteristics (measurable or countable) and detecting situations that seem to present certain anomalies. The control chart is one of these tools widely used in quality management. In the process of managing the COVID-19 pandemic, this tool will make it possible to know at all times whether the parameters monitored such as the positivity rate, the recovery rate, and the mortality rate, are under control and to act accordingly. Monitoring cure and mortality rates will also show us the effectiveness of the treatments used.

Research paper thumbnail of Evolution and Prospect of Dakar Drinking Water Consumption

Journal of Water Resource and Protection, 2019

In Dakar, there has been a considerable deficit in the drinking water supply for more than a deca... more In Dakar, there has been a considerable deficit in the drinking water supply for more than a decade. The distribution is poorly controlled in this region. And yet, there is no lack of supply sources or solutions. With a drinking water deficit of 300,000 m 3 /d to fill, the State of Senegal proposed two (02) options: firstly, the construction of a second Plan at Keur Momar Sarr on the Guiers Lake with a capacity of 75,000 m 3 /d coupled with a third pipeline between Keur Momar Sarr and Thiès (KMS3); secondly, the construction of a seawater desalination Plant with a capacity of 75,000 m 3 /d. In this article, we studied the evolution of the drinking water consumption and the statistical data relating to population growth, which is the key element in the drinking water consumption evolution in Dakar. We were able to extract the equations from the trend curves that made it possible to predict a population growth. The results obtained with the equations and the curves show that the real needs for drinking water in Dakar are proportional to population growth.

Research paper thumbnail of Comparison of Indigenous and Exogenous Mesophilic Bacteria for the Bioleaching of Low Grade Copper Ores

Advanced Materials Research, 2013

Using indigenous microorganisms in biomining processes assures few ecological distortions and les... more Using indigenous microorganisms in biomining processes assures few ecological distortions and less time consumption for adaptation. However, there is a debate as to whether an indigenous microbial community is more efficient than one composed of microbial strains selected for specific physiological traits. In order to provide thoughtful opinions in such a debate, a cross-comparison of six strains isolated from two different regions: Chambishi Copper Mine (Zambia) and Dexing Copper Mine (China), was conducted. Physiological properties and leaching performancesof Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum in pure and mixed culture were studied. The results showed that strains within species presented similar traits while copper resistance was not species-specific. In terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the exogenous. In addition, microbial c...

Research paper thumbnail of Cross-Comparison of Leaching Strains Isolated from Two Different Regions: Chambishi and Dexing Copper Mines

BioMed Research International, 2014

A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zam... more A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa) and Dexing copper mine (China, Asia), was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions:Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans, andLeptospirillum ferriphilum. Prior to their study in bioleaching, the different strains were characterized and compared at physiological level. The results revealed that, except for copper tolerance, strains within species presented almost similar physiological traits with slight advantages of Chambishi strains. However, in terms of leaching efficiency, native strains always achieved higher cell density and greater iron and copper extraction rates than the foreign microorganisms. In addition, microbial community analysis revealed that the different mixed cultures shared almos...

Research paper thumbnail of Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media

Archives of Microbiology, 2014

In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and... more In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and used in double-layer agar plate to efficiently isolate and purify leaching bacteria. Unlike Acidiphilium sp., the yeast strain was tetrathionate tolerant and could metabolize a great range of organic compounds including organic acids. These properties allowed the yeast strain to enable and fasten the growth of iron and sulfur oxidizers on double-layer agar plate. The isolates were identified as Acidithiobacillus ferrooxidans FOX1, Leptospirillun ferriphilum BN, and Acidithiobacillus thiooxidans ZMB. These three leaching bacteria were inhibited by organic acids such as acetic and propionic acids; however, their activities were enhanced by Candida digboiensis NB under dissolved organic matter stress.