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The effect of two lacunary Keggin polyoxometalates (K7[PW11O39].14H2O and K9[AlW11O39].15H2O) on the corrosion inhibition of XC38 steel in 0.1 M NaCl was investigated. Electrochemical methods (polarization curves and electrochemical impedance spectroscopy) showed that the presence of controlled amounts of these compounds improved protection of the steel against corrosion. These results were supported by surface analysis, where only a minor amount of rust was produced on metal surface in the presence of polyoxometalates (POMs). The lacunary POMs were more efficient compared to their saturated species, highlighting the key role played by the lacuna on the inhibition process. Efficiency of POMs (both saturated and lacunary) was explained by their ability to increase the Fe(II)/Fe(III) molar ratio in greenish protective oxide layer formed upon steel oxidation. The mechanism proposed clearly explains the higher efficiency observed with lacunary POMs, in relation to their ability to react with free Fe(III) to yield a substituted structure.
Odilon Romaric Wamba Tchio; Martin Pengou; Cédric Baumier; Sylvain Franger; Anne‐Lucie Teillout; Israël Martyr Mbomekallé; Pedro De Oliveira; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. Comparison between Lacunary and Saturated Keggin Polyoxometalates as Steel Corrosion Inhibitors in Chloride Solution: Contribution of the Lacuna in the Inhibition Mechanism. ChemistrySelect 2020, 5, 10135 -10143.
AMA StyleOdilon Romaric Wamba Tchio, Martin Pengou, Cédric Baumier, Sylvain Franger, Anne‐Lucie Teillout, Israël Martyr Mbomekallé, Pedro De Oliveira, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni. Comparison between Lacunary and Saturated Keggin Polyoxometalates as Steel Corrosion Inhibitors in Chloride Solution: Contribution of the Lacuna in the Inhibition Mechanism. ChemistrySelect. 2020; 5 (32):10135-10143.
Chicago/Turabian StyleOdilon Romaric Wamba Tchio; Martin Pengou; Cédric Baumier; Sylvain Franger; Anne‐Lucie Teillout; Israël Martyr Mbomekallé; Pedro De Oliveira; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. 2020. "Comparison between Lacunary and Saturated Keggin Polyoxometalates as Steel Corrosion Inhibitors in Chloride Solution: Contribution of the Lacuna in the Inhibition Mechanism." ChemistrySelect 5, no. 32: 10135-10143.
The trachyte which was the subject of this work was subjected to physicochemical and electrochemical characterizations. X-ray diffraction, Fourier transform infrared (FT-IR), X-ray fluorescence, EDX analysis, scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy were used. The physicochemical characterization have indicated the presence of elements such as Albite (Na (AlSi3O8); Microcline (K(AlSi3O8); Muscovite (KAl2(Si3Al)O10 (OH)2) and Diopside Aluminum (Ca(MgFeAl)SiAl)2O6). X-ray fluorescence revealed presence of certain chemical elements in the form of oxide (SiO2: 65.24 wt%; Al2O3: 15.49 wt%; Fe2O3: 5.31 wt%; Ca0: 0.02 wt%; MgO: 0.01 wt%; SO3: 0.03 wt%; Na2O: 3.45 wt%; K2O: 5.65 wt% and P2O5: 0.029 wt%). FTIR and EDX confirmed the results obtained by X-ray and X-ray fluorescence. Presence of quartz, particles of trachyte in the form of clusters of fine aggregates and platelets in the form of rods with irregular contours was confirmed by scanning electron microscopy. Electrochemical characterization showed that our material has affinity with K3Fe(CN)6 and Ru(NH3)6Cl3, but this affinity is much more pronounced with K3Fe(CN)6. Modifying glassy carbon electrode with a fine fraction of the trachyte significantly increased sensitivity of the electrode of these species. SiO2/Al2O3 ratio confirmed mechanical resistance of our material and would predestine it in the manufacture of geopolymer binders. Sum% SiO2 + % Al2O3 + % Fe2O3 greater than 70 wt% indicated possibility of using material as pozzolanic materials. High level of alumina, low content of alkaline elements (K2O, Na2O) allow the use of trachyte as a raw material for manufacture of refractory products. This information would allowed us to consider the use of our material for electroanalytical, industrial purposes.
Lemankréo Dai-Yang; Martin Pengou; Hervé Leclerc Tcheumi; Dawai Nguihdama; Abdoul Wahabou; Beaufils Ngana Ngatchou; Odilon Romaric Tchio Wamba; Hervé Tchakouté Kouamo; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. Physico-Chemical and Electrochemical Characterizations of a Trachyte in the Far North Region of Cameroon for Possible Electroanalytical and Environmental Purposes. Journal of Inorganic and Organometallic Polymers and Materials 2020, 31, 542 -551.
AMA StyleLemankréo Dai-Yang, Martin Pengou, Hervé Leclerc Tcheumi, Dawai Nguihdama, Abdoul Wahabou, Beaufils Ngana Ngatchou, Odilon Romaric Tchio Wamba, Hervé Tchakouté Kouamo, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni. Physico-Chemical and Electrochemical Characterizations of a Trachyte in the Far North Region of Cameroon for Possible Electroanalytical and Environmental Purposes. Journal of Inorganic and Organometallic Polymers and Materials. 2020; 31 (2):542-551.
Chicago/Turabian StyleLemankréo Dai-Yang; Martin Pengou; Hervé Leclerc Tcheumi; Dawai Nguihdama; Abdoul Wahabou; Beaufils Ngana Ngatchou; Odilon Romaric Tchio Wamba; Hervé Tchakouté Kouamo; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. 2020. "Physico-Chemical and Electrochemical Characterizations of a Trachyte in the Far North Region of Cameroon for Possible Electroanalytical and Environmental Purposes." Journal of Inorganic and Organometallic Polymers and Materials 31, no. 2: 542-551.
Increasing use of silver nanoparticles (AgNPs) in different consumer products provokes interest in understanding interactions of AgNPs with biological molecules, e.g., proteins. The adsorption of AgNPs and bovine serum albumin (BSA) onto self‐assembled monolayer of mercaptohexylpyridinium (MHP) on gold surface is described. A quartz crystal microbalance coupled with electrochemical measurements were used to study interactions between AgNPs and BSA. It was found that AgNPs adsorbed on MHP can be considered as highly elastic (stiff) film since the dissipation ΔD ∽ 0. Measurements of the mass loss and the increase in dissipation in parallel with the electrochemical oxidation/reduction of AgNPs shows that albumin adsorption on AgNPs highly diminish electrochemical Ag/AgCl conversion. The formation of a less rigid Ag layer than the original MHP‐AgNPs film is also indicated. The 3D assemblies nanostructure observed with SEM revealed clustering of particles after the redox process. This article is protected by copyright. All rights reserved.
Patrick Marcel Seumo Tchekwagep; Jildiz Hamit Eminovski; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Thomas Arnebrant; Tautgirdas Ruzgas. Adsorption of Bovine Serum Albumin on Silver Nanoparticle Layer Deposited on Mercaptohexylpyridinium‐Coated Quartz Crystal Microbalance with Dissipation Gold Electrode: Studied by Electrochemical Quartz Crystal Microbalance with Dissipation. physica status solidi (a) 2020, 217, 1 .
AMA StylePatrick Marcel Seumo Tchekwagep, Jildiz Hamit Eminovski, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni, Thomas Arnebrant, Tautgirdas Ruzgas. Adsorption of Bovine Serum Albumin on Silver Nanoparticle Layer Deposited on Mercaptohexylpyridinium‐Coated Quartz Crystal Microbalance with Dissipation Gold Electrode: Studied by Electrochemical Quartz Crystal Microbalance with Dissipation. physica status solidi (a). 2020; 217 (13):1.
Chicago/Turabian StylePatrick Marcel Seumo Tchekwagep; Jildiz Hamit Eminovski; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Thomas Arnebrant; Tautgirdas Ruzgas. 2020. "Adsorption of Bovine Serum Albumin on Silver Nanoparticle Layer Deposited on Mercaptohexylpyridinium‐Coated Quartz Crystal Microbalance with Dissipation Gold Electrode: Studied by Electrochemical Quartz Crystal Microbalance with Dissipation." physica status solidi (a) 217, no. 13: 1.
This work focuses on the comparison between the mechanical and microstructural properties of poly(sialate-siloxo) networks based on metakaolins from halloysite and kaolin. Poly(sialate-siloxo) networks were prepared using three metakaolins as aluminosilicate sources. Sodium waterglass from rice husk ash and commercial sodium waterglass were used as chemical reagents. The obtained results showed that metakaolins from kaolins have plate shapes with coarse particle sizes whereas the one from halloysite has a spherical morphology and smaller particle sizes. The IR spectra of poly(sialate-siloxo) networks from calcined halloysite indicate the higher value of the wavenumber of the main band. The XRD patterns of all poly(sialate-siloxo) networks show the broad hump structure with higher intensity between 18 and 40°(2θ). The XRD patterns of poly(sialate-siloxo) networks show the band of the unreacted metakaolin at about 20.45°(2θ). This band is more pronounced on the XRD patterns of geopolymer cements from calcined halloysite. The obtained poly(sialate-siloxo) networks based on metakaolins from halloysite and kaolin have a compact, homogenous and denser microstructures. The compressive strength values of the poly(sialate-siloxo) networks using calcined kaolin are ranging from 58.43 to 66.52 MPa whereas those using calcined halloysite are between 72.29 and 88.50 MPa. The compressive strength values of poly(sialate-siloxo) networks using calcined halloysite are higher compared to those from calcined kaolin. The higher compressive strength values of the geopolymer cements from calcined halloysite could be attributed to the fine and spherical particle sizes of calcined halloysite. This implies that the shape and the fine particle sizes of the raw materials influence the properties of the poly(sialate-siloxo) networks. Metakaolin from halloysite can be used as an aluminosilicate source for producing poly(sialate-siloxo) network with higher mechanical properties.
Hervé K. Tchakouté; Sorelle J.K. Melele; Aubin T. Djamen; Cyriaque R. Kaze; Elie Kamseu; Charles N.P. Nanseu; Cristina Leonelli; Claus H. Rüscher. Microstructural and mechanical properties of poly(sialate-siloxo) networks obtained using metakaolins from kaolin and halloysite as aluminosilicate sources: A comparative study. Applied Clay Science 2020, 186, 105448 .
AMA StyleHervé K. Tchakouté, Sorelle J.K. Melele, Aubin T. Djamen, Cyriaque R. Kaze, Elie Kamseu, Charles N.P. Nanseu, Cristina Leonelli, Claus H. Rüscher. Microstructural and mechanical properties of poly(sialate-siloxo) networks obtained using metakaolins from kaolin and halloysite as aluminosilicate sources: A comparative study. Applied Clay Science. 2020; 186 ():105448.
Chicago/Turabian StyleHervé K. Tchakouté; Sorelle J.K. Melele; Aubin T. Djamen; Cyriaque R. Kaze; Elie Kamseu; Charles N.P. Nanseu; Cristina Leonelli; Claus H. Rüscher. 2020. "Microstructural and mechanical properties of poly(sialate-siloxo) networks obtained using metakaolins from kaolin and halloysite as aluminosilicate sources: A comparative study." Applied Clay Science 186, no. : 105448.
In this work, the plant alkaloid Voacangine, isolated from the bark of Tabernaemontana contorta, was examined as a corrosion inhibitor for steel in 1 M hydrochloric acid. The study was carried out using a comparative approach where several independent methods (spectroscopic solution analysis, electrochemical impedance, potentiodynamic polarisation and mass loss measurements) were performed in order to strengthen the validity of the results. All the findings revealed to be in close agreement with each other. Voacangine was determined to be a mixed corrosion inhibitor and to closely follow Langmuir-type adsorption onto active corrosion sites on the metal surface. The maximal inhibition efficiency was 90% which is lower than other comparable species. This deficiency was ascribed to the presence of a basic nitrogen group causing a degree of steric hindrance for the adsorption.
Bertrand Ngoune; Martin Pengou; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. A comparative study using solution analysis, electrochemistry and mass change for the inhibition of carbon steel by the plant alkaloid Voacangine. Corrosion Engineering, Science and Technology 2019, 55, 138 -144.
AMA StyleBertrand Ngoune, Martin Pengou, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni. A comparative study using solution analysis, electrochemistry and mass change for the inhibition of carbon steel by the plant alkaloid Voacangine. Corrosion Engineering, Science and Technology. 2019; 55 (2):138-144.
Chicago/Turabian StyleBertrand Ngoune; Martin Pengou; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. 2019. "A comparative study using solution analysis, electrochemistry and mass change for the inhibition of carbon steel by the plant alkaloid Voacangine." Corrosion Engineering, Science and Technology 55, no. 2: 138-144.
The aiming target of this study is to improve the reactivity of the soda–lime–silica glass solution as a hardener for producing metakaolin-based geopolymer cements. The hardeners with molar ratios SiO2/Na2O equal to 1.5 from rice husk ash and waste glass were prepared. Due to the low dissolution of waste glass, the molar ratio SiO2/Na2O in soda–lime–silica glass solution is less than 1.5 suggesting thus the lower soluble silica content. In order to compensate for the deficiency of soluble silica in soda–lime–silica glass solution, the hardener from rice husk ash is added to the soda–lime–silica glass solution at different percentage such as 0, 20, 30, 40, 50, 60, 70, 80 and 100 wt%. The reactivity of the obtained hardeners was evaluated by using them for producing geopolymer cements. The X-ray pattern and infrared spectrum of residual waste glass indicate the higher intensity of the broad hump structure and the higher value of the wavenumber of the main band, respectively. This corresponds to the higher amount of glass phase contained in the residual waste glass. It was found that the values of the compressive strengths and the apparent density increase with increasing the addition of hardener from rice husk ash to the one from waste glass. The micrographs of geopolymer cements from hardeners containing 40, 50 and 100 wt% of sodium waterglass from rice husk ash are homogeneous and compact microstructure. This implies the formation of the higher connectivity and the long chain of poly(sialate-siloxo) network. The new approach for the preparation of a reactive hardener from the waste glass is found promising for the significant reduction of the greenhouse gas emitted during the production of geopolymers.
Sorelle J. K. Melele; Charles Banenzoué; Daniel Fotio; Hervé K. Tchakouté; Claus H. Rüscher; Charles Peguy Nanseu-Njiki. Improvement of the reactivity of soda–lime–silica glass solution as a hardener for producing geopolymer materials. SN Applied Sciences 2019, 1, 1208 .
AMA StyleSorelle J. K. Melele, Charles Banenzoué, Daniel Fotio, Hervé K. Tchakouté, Claus H. Rüscher, Charles Peguy Nanseu-Njiki. Improvement of the reactivity of soda–lime–silica glass solution as a hardener for producing geopolymer materials. SN Applied Sciences. 2019; 1 (10):1208.
Chicago/Turabian StyleSorelle J. K. Melele; Charles Banenzoué; Daniel Fotio; Hervé K. Tchakouté; Claus H. Rüscher; Charles Peguy Nanseu-Njiki. 2019. "Improvement of the reactivity of soda–lime–silica glass solution as a hardener for producing geopolymer materials." SN Applied Sciences 1, no. 10: 1208.
Alkaloid extract from Rauvolfia macrophylla Stapf (AERMS) was studied as the corrosion inhibitor for C38 steel in 1 M HCl and 0.5 M H2SO4 using electrochemistry and surface analysis. The corrosion inhibition was efficient and proceeds via adsorption of AERMS on the steel surface due to the active functional groups present in the molecules. AERMS acts as a mixed inhibitor in HCl and as a cathodic inhibitor in H2SO4. In H2SO4 corrosive medium, the presence of iodides improves the adsorption of the alkaloid molecules by reducing the surface charge of the electrode and thus substantially decreases the corrosion rate. Two pure alkaloids (tetrahydroalastonine (THA) and perakine (PER)) were quantitatively isolated from AERMS, and their anticorrosive properties for C38 steel in 1 M HCl and 0.5 M H2SO4 were evaluated. THA showed the highest efficiency while the performance of PER was less important compared to the extract. This confirms that the efficiency of AERMS was the result of the complementary action of the chemical compounds present in the extract.
Bertrand Ngoune; Martin Pengou; Armel Megha Nouteza; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. Performances of Alkaloid Extract from Rauvolfia macrophylla Stapf toward Corrosion Inhibition of C38 Steel in Acidic Media. ACS Omega 2019, 4, 9081 -9091.
AMA StyleBertrand Ngoune, Martin Pengou, Armel Megha Nouteza, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni. Performances of Alkaloid Extract from Rauvolfia macrophylla Stapf toward Corrosion Inhibition of C38 Steel in Acidic Media. ACS Omega. 2019; 4 (5):9081-9091.
Chicago/Turabian StyleBertrand Ngoune; Martin Pengou; Armel Megha Nouteza; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. 2019. "Performances of Alkaloid Extract from Rauvolfia macrophylla Stapf toward Corrosion Inhibition of C38 Steel in Acidic Media." ACS Omega 4, no. 5: 9081-9091.
The suitability of metallic iron (Fe(0)) for water defluoridation is yet to be understood. Fluoride removal ([F] = 20.0 mg L) and Orange II discoloration ([Orange II] = 10.0 mg L) by Fe(0)/HO batch systems are compared herein. A steel wool (SW) and a granular iron (GI) are used as Fe(0) specimens. Each essay tube contains 0.5 g sand and 0.1 g of the used Fe(0). Investigated systems were: (i) SW/sand at pH 5.0, (ii) GI/sand at pH 5.0 and (iii) SW/sand at pH 8.0. Prior to contaminant addition, Fe(0) was allowed to pre-corrode within the systems for up to 46 days. The systems were then equilibrated for 30 days with a mixture of the two model contaminants. Result confirmed (i) the higher efficiency of SW over GI in removing both contaminants, (ii) the higher efficiency of Fe(0) for Orange II discoloration and (iii) the positive impact of initial low pH values on the efficiency of Fe(0)/HO systems. The major output of this research is that conventional Fe(0)/HO systems are not suitable for quantitative water defluoridation. It is suggested that ways to avoid defluoridation using Fe must be explored. One affordable opportunity is blending fluoride-polluted water with carefully harvested rainwater.
Arnaud Igor Ndé-Tchoupé; Charles Péguy Nanseu-Njiki; Rui Hu; Achille Nassi; Chicgoua Noubactep; Tobias Licha. Characterizing the reactivity of metallic iron for water defluoridation in batch studies. Chemosphere 2019, 219, 855 -863.
AMA StyleArnaud Igor Ndé-Tchoupé, Charles Péguy Nanseu-Njiki, Rui Hu, Achille Nassi, Chicgoua Noubactep, Tobias Licha. Characterizing the reactivity of metallic iron for water defluoridation in batch studies. Chemosphere. 2019; 219 ():855-863.
Chicago/Turabian StyleArnaud Igor Ndé-Tchoupé; Charles Péguy Nanseu-Njiki; Rui Hu; Achille Nassi; Chicgoua Noubactep; Tobias Licha. 2019. "Characterizing the reactivity of metallic iron for water defluoridation in batch studies." Chemosphere 219, no. : 855-863.
Inadequate access to safe drinking water is one of the most pervasive problems currently afflicting the developing world. Scientists and engineers are called to present affordable but efficient solutions, particularly applicable to small communities. Filtration systems based on metallic iron (Fe0) are discussed in the literature as one such viable solution, whether as a stand-alone system or as a complement to slow sand filters (SSFs). Fe0 filters can also be improved by incorporating biochar to form Fe0-biochar filtration systems with potentially higher contaminant removal efficiencies than those based on Fe0 or biochar alone. These three low-cost and chemical-free systems (Fe0, biochar, SSFs) have the potential to provide universal access to safe drinking water. However, a well-structured systematic research is needed to design robust and efficient water treatment systems based on these affordable filter materials. This communication highlights the technology being developed to use Fe0-based systems for decentralized safe drinking water provision. Future research directions for the design of the next generation Fe0-based systems are highlighted. It is shown that Fe0 enhances the efficiency of SSFs, while biochar has the potential to alleviate the loss of porosity and uncertainties arising from the non-linear kinetics of iron corrosion. Fe0-based systems are an affordable and applicable technology for small communities in low-income countries, which could contribute to attaining self-reliance in clean water supply and universal public health.
Charles Péguy Nanseu-Njiki; Willis Gwenzi; Martin Pengou; Mohammad Azizur Rahman; Chicgoua Noubactep. Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here? Water 2019, 11, 429 .
AMA StyleCharles Péguy Nanseu-Njiki, Willis Gwenzi, Martin Pengou, Mohammad Azizur Rahman, Chicgoua Noubactep. Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here? Water. 2019; 11 (3):429.
Chicago/Turabian StyleCharles Péguy Nanseu-Njiki; Willis Gwenzi; Martin Pengou; Mohammad Azizur Rahman; Chicgoua Noubactep. 2019. "Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here?" Water 11, no. 3: 429.
Because of its chemical properties, sawdust displays poor anionic exchange capacity. Here we demonstrate that sawdust modification with methylene blue (MB) dye represents an interesting and facile alternative to render this natural biomaterial capable to accumulate anionic species. MB adsorption onto sawdust was monitored by cyclic voltammetry and experimental parameters carefully optimized. Under the ideal experimental conditions (composition of accumulation and desorption solution, accumulation and desorption time and the nature of the electrolytic solution), the adsorbed MB showed poor mobility, which results in the absence of the characteristic electrochemical signal of MB. The ability of the material to accumulate anionic species was thus evaluated using Fe(CN)63− as a model anions. The slow Fe(CN)63−/4− system recorded onto the electrode modified by pristine sawdust (P/SFE) become fast and reversible after immobilization of MB onto P/SFE (MB/SFE). Electrochemical impedance spectroscopy confirms this result through the spectacular decrease of charge transfer resistance after MB adsorption (from 83 kΩ on P/SFE to 637 Ω on MB/SFE). MB/SFE was applied to the electroanalysis of nitrites and a sensitivity of 7.4 μA mM−1 was obtained. Although this sensitivity was less important compared to that obtained on glassy carbon electrode (9.4 μA mM−1), the dye modified electrode displays by far the best reproducibility even at higher nitrite concentration.
Beaufils Ngatchou Ngana; Gustave Kenne Dedzo; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. Cationic Dye Modified Sawdust as Electrode Modifier for Electrochemical Detection of Anions. Electroanalysis 2019, 31, 383 -389.
AMA StyleBeaufils Ngatchou Ngana, Gustave Kenne Dedzo, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni. Cationic Dye Modified Sawdust as Electrode Modifier for Electrochemical Detection of Anions. Electroanalysis. 2019; 31 (2):383-389.
Chicago/Turabian StyleBeaufils Ngatchou Ngana; Gustave Kenne Dedzo; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni. 2019. "Cationic Dye Modified Sawdust as Electrode Modifier for Electrochemical Detection of Anions." Electroanalysis 31, no. 2: 383-389.
In the present work, silver colloid was produced by chemical reduction of silver salt (silver nitrate) using citrates in aqueous solution. UV‐Vis spectrophotometry indicated the formation of nanoparticles. The surface plasmon resonance peak in absorption spectra of the silver colloidal solution showed an absorption maximum at 435 nm. The dynamic light scattering and zeta potential measurements showed that the size and the zeta potential of the synthesized nanoparticles were about 98 nm and −50 mV respectively. The nanoparticles have been used to modify the gold electrode for use as a potential electrochemical sensor for the analysis of arsenic in aqueous solution. The cyclic voltammogram recorded using gold electrode modified with AgNPs depicted a well‐defined reduction peak of arsenic compared to bare gold electrode. The enhancement of the signal is essentially due to the large surface area attributed to silver nanoparticles. Linear sweep voltammetry has been used to optimize the analytical conditions of arsenic in aqueous solution: it came out that the detection of arsenic in 0.1 M HNO3 was optimal while the electrode was conditioned at −0.6 v during 300 s. Under these optimum conditions, a calibration curve was plotted in the concentration range of 0.05 μM to 0.2 μM and the detection limit was estimated at 1.38×10−8 M, calculated from a ratio signal/noise 3.
Baudelaire Matangouo Sonkoue; Patrick Marcel Seumo Tchekwagep; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. Electrochemical Determination of Arsenic Using Silver Nanoparticles. Electroanalysis 2018, 30, 2738 -2743.
AMA StyleBaudelaire Matangouo Sonkoue, Patrick Marcel Seumo Tchekwagep, Charles Péguy Nanseu-Njiki, Emmanuel Ngameni. Electrochemical Determination of Arsenic Using Silver Nanoparticles. Electroanalysis. 2018; 30 (11):2738-2743.
Chicago/Turabian StyleBaudelaire Matangouo Sonkoue; Patrick Marcel Seumo Tchekwagep; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. 2018. "Electrochemical Determination of Arsenic Using Silver Nanoparticles." Electroanalysis 30, no. 11: 2738-2743.
Honoré Dieudonné Bassala; Gustave Kenne Dedzo; Charles Baudouin Njine Bememba; Patrick Seumo; Joel Donkeng Dazie; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. Investigation of the efficiency of a designed electrocoagulation reactor: Application for dairy effluent treatment. Process Safety and Environmental Protection 2017, 111, 122 -127.
AMA StyleHonoré Dieudonné Bassala, Gustave Kenne Dedzo, Charles Baudouin Njine Bememba, Patrick Seumo, Joel Donkeng Dazie, Charles Péguy Nanseu-Njiki, Emmanuel Ngameni. Investigation of the efficiency of a designed electrocoagulation reactor: Application for dairy effluent treatment. Process Safety and Environmental Protection. 2017; 111 ():122-127.
Chicago/Turabian StyleHonoré Dieudonné Bassala; Gustave Kenne Dedzo; Charles Baudouin Njine Bememba; Patrick Seumo; Joel Donkeng Dazie; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. 2017. "Investigation of the efficiency of a designed electrocoagulation reactor: Application for dairy effluent treatment." Process Safety and Environmental Protection 111, no. : 122-127.
Gustave Kenne Dedzo; Emmanuel Pameté Yambou; Melissa Ramel Topet Saheu; Gaelle Ngnie; Charles Peguy Nanseu-Njiki; Christian Detellier; Emmanuel Ngameni. Hydrogen evolution reaction at PdNPs decorated 1:1 clay minerals and application to the electrocatalytic determination of p -nitrophenol. Journal of Electroanalytical Chemistry 2017, 801, 49 -56.
AMA StyleGustave Kenne Dedzo, Emmanuel Pameté Yambou, Melissa Ramel Topet Saheu, Gaelle Ngnie, Charles Peguy Nanseu-Njiki, Christian Detellier, Emmanuel Ngameni. Hydrogen evolution reaction at PdNPs decorated 1:1 clay minerals and application to the electrocatalytic determination of p -nitrophenol. Journal of Electroanalytical Chemistry. 2017; 801 ():49-56.
Chicago/Turabian StyleGustave Kenne Dedzo; Emmanuel Pameté Yambou; Melissa Ramel Topet Saheu; Gaelle Ngnie; Charles Peguy Nanseu-Njiki; Christian Detellier; Emmanuel Ngameni. 2017. "Hydrogen evolution reaction at PdNPs decorated 1:1 clay minerals and application to the electrocatalytic determination of p -nitrophenol." Journal of Electroanalytical Chemistry 801, no. : 49-56.
Metallic iron (Fe0)-based filtration systems have the potential to significantly contribute to the achievement of the United Nations (UN) Sustainable Development Goals (SDGs) of substantially improving the human condition by 2030 through the provision of clean water. Recent knowledge on Fe0-based safe drinking water filters is addressed herein. They are categorized into two types: Household and community filters. Design criteria are recalled and operational details are given. Scientists are invited to co-develop knowledge enabling the exploitation of the great potential of Fe0 filters for sustainable safe drinking water provision (and sanitation).
Elham Naseri; Arnaud Igor Ndé-Tchoupé; Hezron T. Mwakabona; Charles Péguy Nanseu-Njiki; Chicgoua Noubactep; Karoli N. Njau; Kerstin D. Wydra. Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision. Sustainability 2017, 9, 1224 .
AMA StyleElham Naseri, Arnaud Igor Ndé-Tchoupé, Hezron T. Mwakabona, Charles Péguy Nanseu-Njiki, Chicgoua Noubactep, Karoli N. Njau, Kerstin D. Wydra. Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision. Sustainability. 2017; 9 (7):1224.
Chicago/Turabian StyleElham Naseri; Arnaud Igor Ndé-Tchoupé; Hezron T. Mwakabona; Charles Péguy Nanseu-Njiki; Chicgoua Noubactep; Karoli N. Njau; Kerstin D. Wydra. 2017. "Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision." Sustainability 9, no. 7: 1224.
Guy Bertrand Tamne; Ede Bodoki; Robert Săndulescu; Radu Oprean; Emmanuel Ngameni; Charles Peguy Nanseu-Njiki. Removal of Nitroaniline From Water/Ethanol by Electrocoagulation Using Response Surface Methodology. CLEAN – Soil, Air, Water 2016, 44, 430 -437.
AMA StyleGuy Bertrand Tamne, Ede Bodoki, Robert Săndulescu, Radu Oprean, Emmanuel Ngameni, Charles Peguy Nanseu-Njiki. Removal of Nitroaniline From Water/Ethanol by Electrocoagulation Using Response Surface Methodology. CLEAN – Soil, Air, Water. 2016; 44 (4):430-437.
Chicago/Turabian StyleGuy Bertrand Tamne; Ede Bodoki; Robert Săndulescu; Radu Oprean; Emmanuel Ngameni; Charles Peguy Nanseu-Njiki. 2016. "Removal of Nitroaniline From Water/Ethanol by Electrocoagulation Using Response Surface Methodology." CLEAN – Soil, Air, Water 44, no. 4: 430-437.
The biosorption characteristics of Cd (II) ions from synthetic wastewater using raw Ayous wood sawdust (Triplochiton scleroxylon), r-AS, immobilized by sodium alginate were investigated with respect to pH, biomass quantity, contact time, initial concentration of heavy metal, temperature and stirring rate. The experimental data fitted well with the Langmuir isotherm, suggesting that monolayer adsorption of the cadmium ions onto alginate-Ayous sawdust composite (a-ASC). The obtained monolayer adsorption capacity of a-ASC for Cd (II) was 6.21 mg/g. From the Dubinin-Radushkevich isotherm model, a 5.39 kJ/mol value for the mean free energy was calculated, indicating that Cd (II) biosorption could include an important physisorption stage. Thermodynamic calculations showed that the Cd (II) biosorption process was feasible, endothermic and spontaneous in nature under examined conditions. The results indicated that a-ASC could be an alternative material replacing more costly adsorbents used for the removal of heavy metals.
Jacques Romain Njimou; Andrada Maicaneanu; Cerasella Indolean; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. Removal of Cd (II) from synthetic wastewater by alginate–Ayous wood sawdust ( Triplochiton scleroxylon ) composite material. Environmental Technology 2016, 37, 1 -13.
AMA StyleJacques Romain Njimou, Andrada Maicaneanu, Cerasella Indolean, Charles Péguy Nanseu-Njiki, Emmanuel Ngameni. Removal of Cd (II) from synthetic wastewater by alginate–Ayous wood sawdust ( Triplochiton scleroxylon ) composite material. Environmental Technology. 2016; 37 (11):1-13.
Chicago/Turabian StyleJacques Romain Njimou; Andrada Maicaneanu; Cerasella Indolean; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. 2016. "Removal of Cd (II) from synthetic wastewater by alginate–Ayous wood sawdust ( Triplochiton scleroxylon ) composite material." Environmental Technology 37, no. 11: 1-13.
Sawdust samples of ayous wood (Triplochiton scleroxylon) have been submitted to a warm pretreatment with NaOH and functionalized in dimethylformamide (DMF) by grafting with two amino organosilanes. The reagents were chosen for their ability to bind hydronium ions in acidic medium: 3-aminopropyltriethoxysilane (APTES) and 3-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS). The resulting materials were characterized by Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (NMR) spectroscopies, which revealed the Si-O-C covalent bond and the polymerization of the grafted silanes through siloxane bridges (Si-O-Si) leading to the stabilization of the structure. The cyclic voltammetry analyses were performed on a glassy carbon modified with native or functionalized sawdust films in contact with electrochemical probes ([Fe(CN)6]3- and [Ru(NH3)6]3+). By means of this method, the permselectivity and accumulation capacity of these functionalized materials could be evaluated. The presence of silanes in the functionalized sawdust leads to a progressive accumulation of anionic species, while the cationic species were repelled when the solution is gradually acidified.
Charles Baudouin Njine-Bememba; Gustave Kenne Dedzo; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. Amination of pretreated ayous (Triplochiton scleroxylon) sawdust with two organosilanes: characterization, stability, and permselective property. Holzforschung 2015, 69, 347 -356.
AMA StyleCharles Baudouin Njine-Bememba, Gustave Kenne Dedzo, Charles Péguy Nanseu-Njiki, Emmanuel Ngameni. Amination of pretreated ayous (Triplochiton scleroxylon) sawdust with two organosilanes: characterization, stability, and permselective property. Holzforschung. 2015; 69 (3):347-356.
Chicago/Turabian StyleCharles Baudouin Njine-Bememba; Gustave Kenne Dedzo; Charles Péguy Nanseu-Njiki; Emmanuel Ngameni. 2015. "Amination of pretreated ayous (Triplochiton scleroxylon) sawdust with two organosilanes: characterization, stability, and permselective property." Holzforschung 69, no. 3: 347-356.
Gold electrodes were modified with silver nanoparticles and Ag/AgCl redox conversion was recorded by cyclic voltammetry in protein containing electrolyte solution. The charge of the reduction peak decreased with the increase of the total protein concentration. This correlation was better for solutions containing bovine serum albumin as a standard than for the samples of human saliva. The results of these electroanalytical measurements show that the method can be used to determine protein concentration in electrolyte solution in the range from 0.01 to 0.2 mg mL−1, though reproducibility of analysis of real samples must be further improved.
Patrick Marcel Seumo Tchekwagep; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Ravi Danielsson; Thomas Arnebrant; Tautgirdas Ruzgas. Determination of Total Protein Concentration in Solution Using Gold Electrode Modified with Silver Nanoparticles. Electroanalysis 2014, 27, 253 -257.
AMA StylePatrick Marcel Seumo Tchekwagep, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni, Ravi Danielsson, Thomas Arnebrant, Tautgirdas Ruzgas. Determination of Total Protein Concentration in Solution Using Gold Electrode Modified with Silver Nanoparticles. Electroanalysis. 2014; 27 (1):253-257.
Chicago/Turabian StylePatrick Marcel Seumo Tchekwagep; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Ravi Danielsson; Thomas Arnebrant; Tautgirdas Ruzgas. 2014. "Determination of Total Protein Concentration in Solution Using Gold Electrode Modified with Silver Nanoparticles." Electroanalysis 27, no. 1: 253-257.
Patrick Marcel Seumo Tchekwagep; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Thomas Arnebrant; Tautgirdas Ruzgas. Quantification of BSA concentration by using Ag electrochemistry in chloride solution: extension of the linear range. Electrochimica Acta 2014, 135, 351 -355.
AMA StylePatrick Marcel Seumo Tchekwagep, Charles Peguy Nanseu-Njiki, Emmanuel Ngameni, Thomas Arnebrant, Tautgirdas Ruzgas. Quantification of BSA concentration by using Ag electrochemistry in chloride solution: extension of the linear range. Electrochimica Acta. 2014; 135 ():351-355.
Chicago/Turabian StylePatrick Marcel Seumo Tchekwagep; Charles Peguy Nanseu-Njiki; Emmanuel Ngameni; Thomas Arnebrant; Tautgirdas Ruzgas. 2014. "Quantification of BSA concentration by using Ag electrochemistry in chloride solution: extension of the linear range." Electrochimica Acta 135, no. : 351-355.
Laboratory experiments were carried out to investigate the mechanisms of electrochemical disinfection of artificial wastewater contaminated by Escherichia coli culture (5 × 105 UFC/100 mL) using electrocoagulation. In order to go deeply into the mechanism of the process, the behaviors of two dissolved-type electrodes (ordinary steel and aluminum) and a non-dissolved-type (carbon graphite) electrode were compared. The ordinary steel electrode was found more efficient for E. coli cells destruction compared to aluminum and carbon graphite electrodes. In order to determine the most favorable condition for the treatment, the effect of various supporting electrolytes including, sodium chloride, sodium sulfate and sodium nitrate, was scrutinized. E. coli is inactivated by 5 log units for a charge loading of 37.30 F/m3 for sodium sulfate, 24.87 F/m3 for sodium nitrate and 12.43 F/m3 for sodium chloride. It thus appears that the most favorable supporting electrolyte type for this method of disinfection is sodium chloride, a fact which can be explained by the formation of disinfectant by-products such as chlorine dioxide, hypochlorite ions and perchlorate ions. From the results obtained, electrocoagulation applied to the elimination of E. coli proceeds through three combined effects: the electric field, the actions of oxidants electrogenerated during the process and the adsorption by the metallic hydroxides formed in solution.
A. C. Ndjomgoue-Yossa; C. P. Nanseu-Njiki; I. M. Kengne; E. Ngameni. Effect of electrode material and supporting electrolyte on the treatment of water containing Escherichia coli by electrocoagulation. International Journal of Environmental Science and Technology 2014, 12, 2103 -2110.
AMA StyleA. C. Ndjomgoue-Yossa, C. P. Nanseu-Njiki, I. M. Kengne, E. Ngameni. Effect of electrode material and supporting electrolyte on the treatment of water containing Escherichia coli by electrocoagulation. International Journal of Environmental Science and Technology. 2014; 12 (6):2103-2110.
Chicago/Turabian StyleA. C. Ndjomgoue-Yossa; C. P. Nanseu-Njiki; I. M. Kengne; E. Ngameni. 2014. "Effect of electrode material and supporting electrolyte on the treatment of water containing Escherichia coli by electrocoagulation." International Journal of Environmental Science and Technology 12, no. 6: 2103-2110.