The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. T...The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions（Cd（Ⅱ） and Pb（Ⅱ）） followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd（Ⅱ） and Pb（Ⅱ） biosorption onto dried activated sludge was their binding with amide I group.展开更多
A sensor array comprising 9 potentiometric chemical sensors and some pattern recognition tools for the data processing has been applied in order to characterize the groundwater in the plain of Kairouan Region (Tunisia...A sensor array comprising 9 potentiometric chemical sensors and some pattern recognition tools for the data processing has been applied in order to characterize the groundwater in the plain of Kairouan Region (Tunisia). A total of 17 groundwater samples were collected from three different villages and analyzed for their chemical components. Nine chemical parameters were determined: Potassium, Sodium, Calcium, Ammonium, Cadmium, Chlorides, Nitrates, Fluoride and pH. Multi-sensor responses measured in each water sample were diagnosed by Principal Component Analysis (PCA) and Cluster Analysis (CA). PCA is a procedure for reducing data redundancy. CA is used to detect spatial similarity among sampling sites. This methodology is simple, rapid and the obtained results demonstrate that the electronic tongue technique based on the sensor array combined with pattern recognition method could be a useful tool for the characterization and the classification of wells water samples.展开更多
An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by h...An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by heavy metals and by pesticides. Inhibition activities were observed with different mixtures of pesticides + heavy metals. The quantification limits for Cd2+ and Hg2+ are 10-20 M in mixture and in pure solution. The quantification limits of parathion-methyl, paraoxon-methyl and triazine are respectively 10-20 M, 10-18 M and 10-20 M in mixture and pure solutions. These results show that there is no synergistic effect between the two families of pollutants. Qualitative contamination of effluent samples and their purification after passing through a municipal wastewater treatment plant were observed by our bi-enzymatic biosensor and confirmed by classical analytical techniques for heavy metal ions.展开更多
In order to treat the polluted discharge from El-Jadida,Morocco,a method of electrocoagulation using aluminum electrodes was used.This approach was coupled for the first time with high-frequency electrochemical impeda...In order to treat the polluted discharge from El-Jadida,Morocco,a method of electrocoagulation using aluminum electrodes was used.This approach was coupled for the first time with high-frequency electrochemical impedance spectroscopy(EIS).Significant pollutant abatementwas observed after 30 min,at a current density of 190.5 A·m^(-2),with a specific electrical energy consumption of 1.58 kW·h(per gram of eliminated carbon organic demand(COD))and specific aluminum consumption of 0.11 g·g^(-1):electrocoagulation proved to be particularly effective,achieving 85.7%elimination of COD and a decrease of total dissolved solid(TDS)and electrical conductivity(EC)levels from 2430 mg·L^(-1)to 1773 mg·L^(-1)and from 4230μS·cm^(-1)to 3210μS·cm^(-1),respectively.As for USP and ORP,they decreased from 2.5 to 1.87 and from 244.6 mV to 51 mV,respectively.The inductance of the electrocoagulation system measured by EIS was modeled through an electrical equivalent circuit.When the applied intensity increased,the coagulation resistance increased suddenly when the applied electrical current reached 0.2 A(current density:95.2 A·m^(-2)).At this point,the rate of COD abatement versus SEEC(specific electrical energy consumption decreases which shows that the EC process should be combined with another process to improve its efficiency,such as ultrasound.展开更多
Nowadays, at a time of growing concern for sustainable development and compliance with environmental standards and legislation, the detection of heavy metal contaminants in environmental matrices represents a difficul...Nowadays, at a time of growing concern for sustainable development and compliance with environmental standards and legislation, the detection of heavy metal contaminants in environmental matrices represents a difficult but important task. The current major limitation lies in the poor detection limits of the targeted pollutant＇s trace concentrations by the available conventional techniques. In order to elaborate a novel ＂living＂ self assembled electrochemical 3-D biosensor, the authors propose a new concept to overcome this shortcoming. The advantages of the properties of polyelectrolyte-functionalized NBs （nanobeads） are combined along with the use of non covalently strongly bound micro-organisms. The designed 3-D biosensor is all the more promising as it has showed a significantly improved sensitivity. In fact, the detection limits of the tested heavy metals （cadmium and mercury） were as low as 1.0 × 10^-12 mol.L-1 and six to seven orders of magnitude lower than those provided by conventional 2-D biosensors. Furthermore, it is potentially applicable to a wide range of bioreceptor-pollutant detection systems.展开更多
In this work, we have developed an electrochemical sensor for nitrite detection, based on a polyoxometalate (POM) namely mono-lacunary keggin anion [SiW11O39]8﹣ cited as (SiW11). Electrochemical characterization of S...In this work, we have developed an electrochemical sensor for nitrite detection, based on a polyoxometalate (POM) namely mono-lacunary keggin anion [SiW11O39]8﹣ cited as (SiW11). Electrochemical characterization of SiW11 shows two-step reduction processes, with formal potentials of ﹣0.5 V (I) and ﹣0.68 V (II). Oppositely charged polyelectrolyte (poly (allylamine hydrochloride) (PAH)) and (SiW11) were assembled alternately to modify glassy carbon electrode. The electrochemical behavior of the modified electrode was studied in detail using cyclic voltammetry (CV). The results showed that SiW11/PAH/GC electrode present good electrocatalytic activity for the reduction of nitrite. The sensor showed a dynamic range from 100 μM to 3.6 mMof nitrite and no interference from other classical anions. Experimental factors that affect electron-transfer rate in these films, such as pH effect and layers number, were systematically analyzed.展开更多
A simple electrochemical sensor for dopamine detection, is based on molecularly imprinted and electropolymerized over-oxidized polypyrrole (OPPy). The MIP-based electrode is obtained by electrocopolymerization of pyrr...A simple electrochemical sensor for dopamine detection, is based on molecularly imprinted and electropolymerized over-oxidized polypyrrole (OPPy). The MIP-based electrode is obtained by electrocopolymerization of pyrrole (0.1 M) in the presence of the template molecular (dopamine, DA) (10<sup>-3</sup> M). The square wave voltammetry (SWV) is used for the detection of dopamine in buffer solution. The current peak obtained at the MIP electrode was proportional to the logarithm of the DA concentration in the range of 10<sup>-11</sup> to 5 × 10<sup>-8</sup> M with a detection limit of 10<sup>-11</sup> M. The proposed sensor was used for the detection of DA in spiked blood serum, satisfactory results were obtained.展开更多
L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for...L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for the modification of a glassy carbon electrode (GCE), for the sensitive detection of L-tryptophan (Trp). After spectroscopic and morphological characterization of the extracted NFC, the GC electrode modification was monitored through cyclic voltammetry. The NFC-modified electrode exhibited good analytical performance in detecting Trp with a wide linear range between 7.5 × 10−4 mM and 10−2 mM, a detection limit of 0.2 µM, and a high sensitivity of 140.0 µA∙mM−1. Additionally, the NFC/GCE showed a good reproducibility, good selectivity versus other amino acids, uric acid, ascorbic acid, and good applicability to the detection of Trp in urine samples.展开更多
In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a...In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a self-assembled monolayer of a thiol (cysteamine) carrying terminal amine groups on gold electrodes. Glutarardehyde, a homobifunctional cross-linker, was used as a coupling reagent for the covalent linking of avidin to the amine groups of cysteamine. The attachment of the biotin labeled antibodies (anti-Human IgG) to the subsequent modified gold electrode was achieved by affinity interactions tacking advantage of the strong avidin-biotin bridge. The stepwise assembly process of the electrode was interrogated by means of cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurements. The response of the antibody modified electrode to their target antigens was investigated in the presence of BSA (bovin serum albumin) in order to alleviate non-specific adsorption problems. A proposed electrical model was used to analyse the experimental data. The resulting immunosensor has a linear dynamic range of 100 - 900 ng?ml<sup>–</sup>1 of antigen and a detection limit of 100 ng?ml<sup>–</sup>1.展开更多
Rare earth elements (REEs) are beneficial in developing modern technologies, especially electronics. Their extractions from natural deposits and their recycling require chemical processes that should be monitored rega...Rare earth elements (REEs) are beneficial in developing modern technologies, especially electronics. Their extractions from natural deposits and their recycling require chemical processes that should be monitored regarding efficiency and environmental sustainability. The purpose of this study is to develop impedimetric sensors for the sensitive detection of the rare earth elements La and Ce by modifying a platinum electrode with four isosorbide-based oligo (ether sulfone)s. These oligomers, functionalized with different end groups (hydroxyl, fluor, amine, maleimide), were obtained with satisfactory yields, starting from isosorbide and bis (4-fuorophenyl) sulphone monomers. The resulting oligomers were characterized by NMR, DSC, and ATG analysis. The dihydroxy-oligo (ether sulfone) modified sensor showed the highest analytical performance compared to the other oligomers. The detection limit is 10−9 M for La and 3 × 10−9 M for Ce which is lower than that of most of the published electrochemical sensors.展开更多
基金The National New Century Scholarship (No. NCET-05-0387) the France-China P2R Programs and the Specialized Research Fundfor the Doctoral Program of Higher Education (No. 20050247016)
文摘The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions（Cd（Ⅱ） and Pb（Ⅱ）） followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd（Ⅱ） and Pb（Ⅱ） biosorption onto dried activated sludge was their binding with amide I group.
文摘A sensor array comprising 9 potentiometric chemical sensors and some pattern recognition tools for the data processing has been applied in order to characterize the groundwater in the plain of Kairouan Region (Tunisia). A total of 17 groundwater samples were collected from three different villages and analyzed for their chemical components. Nine chemical parameters were determined: Potassium, Sodium, Calcium, Ammonium, Cadmium, Chlorides, Nitrates, Fluoride and pH. Multi-sensor responses measured in each water sample were diagnosed by Principal Component Analysis (PCA) and Cluster Analysis (CA). PCA is a procedure for reducing data redundancy. CA is used to detect spatial similarity among sampling sites. This methodology is simple, rapid and the obtained results demonstrate that the electronic tongue technique based on the sensor array combined with pattern recognition method could be a useful tool for the characterization and the classification of wells water samples.
文摘An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by heavy metals and by pesticides. Inhibition activities were observed with different mixtures of pesticides + heavy metals. The quantification limits for Cd2+ and Hg2+ are 10-20 M in mixture and in pure solution. The quantification limits of parathion-methyl, paraoxon-methyl and triazine are respectively 10-20 M, 10-18 M and 10-20 M in mixture and pure solutions. These results show that there is no synergistic effect between the two families of pollutants. Qualitative contamination of effluent samples and their purification after passing through a municipal wastewater treatment plant were observed by our bi-enzymatic biosensor and confirmed by classical analytical techniques for heavy metal ions.
基金financial support from POC4 allergies project(768686)which received funding from ERA PerMed ERA-NET,and the financial support from Bionanosens project(951887)which received funding from the European Union's Horizon 2020.
文摘In order to treat the polluted discharge from El-Jadida,Morocco,a method of electrocoagulation using aluminum electrodes was used.This approach was coupled for the first time with high-frequency electrochemical impedance spectroscopy(EIS).Significant pollutant abatementwas observed after 30 min,at a current density of 190.5 A·m^(-2),with a specific electrical energy consumption of 1.58 kW·h(per gram of eliminated carbon organic demand(COD))and specific aluminum consumption of 0.11 g·g^(-1):electrocoagulation proved to be particularly effective,achieving 85.7%elimination of COD and a decrease of total dissolved solid(TDS)and electrical conductivity(EC)levels from 2430 mg·L^(-1)to 1773 mg·L^(-1)and from 4230μS·cm^(-1)to 3210μS·cm^(-1),respectively.As for USP and ORP,they decreased from 2.5 to 1.87 and from 244.6 mV to 51 mV,respectively.The inductance of the electrocoagulation system measured by EIS was modeled through an electrical equivalent circuit.When the applied intensity increased,the coagulation resistance increased suddenly when the applied electrical current reached 0.2 A(current density:95.2 A·m^(-2)).At this point,the rate of COD abatement versus SEEC(specific electrical energy consumption decreases which shows that the EC process should be combined with another process to improve its efficiency,such as ultrasound.
文摘Nowadays, at a time of growing concern for sustainable development and compliance with environmental standards and legislation, the detection of heavy metal contaminants in environmental matrices represents a difficult but important task. The current major limitation lies in the poor detection limits of the targeted pollutant＇s trace concentrations by the available conventional techniques. In order to elaborate a novel ＂living＂ self assembled electrochemical 3-D biosensor, the authors propose a new concept to overcome this shortcoming. The advantages of the properties of polyelectrolyte-functionalized NBs （nanobeads） are combined along with the use of non covalently strongly bound micro-organisms. The designed 3-D biosensor is all the more promising as it has showed a significantly improved sensitivity. In fact, the detection limits of the tested heavy metals （cadmium and mercury） were as low as 1.0 × 10^-12 mol.L-1 and six to seven orders of magnitude lower than those provided by conventional 2-D biosensors. Furthermore, it is potentially applicable to a wide range of bioreceptor-pollutant detection systems.
文摘In this work, we have developed an electrochemical sensor for nitrite detection, based on a polyoxometalate (POM) namely mono-lacunary keggin anion [SiW11O39]8﹣ cited as (SiW11). Electrochemical characterization of SiW11 shows two-step reduction processes, with formal potentials of ﹣0.5 V (I) and ﹣0.68 V (II). Oppositely charged polyelectrolyte (poly (allylamine hydrochloride) (PAH)) and (SiW11) were assembled alternately to modify glassy carbon electrode. The electrochemical behavior of the modified electrode was studied in detail using cyclic voltammetry (CV). The results showed that SiW11/PAH/GC electrode present good electrocatalytic activity for the reduction of nitrite. The sensor showed a dynamic range from 100 μM to 3.6 mMof nitrite and no interference from other classical anions. Experimental factors that affect electron-transfer rate in these films, such as pH effect and layers number, were systematically analyzed.
文摘A simple electrochemical sensor for dopamine detection, is based on molecularly imprinted and electropolymerized over-oxidized polypyrrole (OPPy). The MIP-based electrode is obtained by electrocopolymerization of pyrrole (0.1 M) in the presence of the template molecular (dopamine, DA) (10<sup>-3</sup> M). The square wave voltammetry (SWV) is used for the detection of dopamine in buffer solution. The current peak obtained at the MIP electrode was proportional to the logarithm of the DA concentration in the range of 10<sup>-11</sup> to 5 × 10<sup>-8</sup> M with a detection limit of 10<sup>-11</sup> M. The proposed sensor was used for the detection of DA in spiked blood serum, satisfactory results were obtained.
文摘L-tryptophan is an essential amino acid for human health. Nanofibrillated cellulose (NFC) from marram grass (Ammophila arenaria) extracted from plants harvested in the center of Tunisia was used for the first time for the modification of a glassy carbon electrode (GCE), for the sensitive detection of L-tryptophan (Trp). After spectroscopic and morphological characterization of the extracted NFC, the GC electrode modification was monitored through cyclic voltammetry. The NFC-modified electrode exhibited good analytical performance in detecting Trp with a wide linear range between 7.5 × 10−4 mM and 10−2 mM, a detection limit of 0.2 µM, and a high sensitivity of 140.0 µA∙mM−1. Additionally, the NFC/GCE showed a good reproducibility, good selectivity versus other amino acids, uric acid, ascorbic acid, and good applicability to the detection of Trp in urine samples.
文摘In this work an impedimetric immunosensor based on affinity immobilization method of a biotin labelled anti-human IgG antibody, used as a model system, was reported. The experimental procedure involves the growth of a self-assembled monolayer of a thiol (cysteamine) carrying terminal amine groups on gold electrodes. Glutarardehyde, a homobifunctional cross-linker, was used as a coupling reagent for the covalent linking of avidin to the amine groups of cysteamine. The attachment of the biotin labeled antibodies (anti-Human IgG) to the subsequent modified gold electrode was achieved by affinity interactions tacking advantage of the strong avidin-biotin bridge. The stepwise assembly process of the electrode was interrogated by means of cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurements. The response of the antibody modified electrode to their target antigens was investigated in the presence of BSA (bovin serum albumin) in order to alleviate non-specific adsorption problems. A proposed electrical model was used to analyse the experimental data. The resulting immunosensor has a linear dynamic range of 100 - 900 ng?ml<sup>–</sup>1 of antigen and a detection limit of 100 ng?ml<sup>–</sup>1.
文摘Rare earth elements (REEs) are beneficial in developing modern technologies, especially electronics. Their extractions from natural deposits and their recycling require chemical processes that should be monitored regarding efficiency and environmental sustainability. The purpose of this study is to develop impedimetric sensors for the sensitive detection of the rare earth elements La and Ce by modifying a platinum electrode with four isosorbide-based oligo (ether sulfone)s. These oligomers, functionalized with different end groups (hydroxyl, fluor, amine, maleimide), were obtained with satisfactory yields, starting from isosorbide and bis (4-fuorophenyl) sulphone monomers. The resulting oligomers were characterized by NMR, DSC, and ATG analysis. The dihydroxy-oligo (ether sulfone) modified sensor showed the highest analytical performance compared to the other oligomers. The detection limit is 10−9 M for La and 3 × 10−9 M for Ce which is lower than that of most of the published electrochemical sensors.
