Water is one of the fundamental resources for the existence of humans and the environment. Throug... more Water is one of the fundamental resources for the existence of humans and the environment. Throughout time, due to urbanization, expanding population, increased agricultural production, and intense industrialization, significant pollution with persistent contaminants has been noted, placing the water quality in danger. As a consequence, different procedures and various technologies have been tested and used in order to ensure that water sources are safe for use. The adsorption process is often considered for wastewater treatment due to its straightforward design, low investment cost, availability, avoidance of additional chemicals, lack of undesirable byproducts, and demonstrated significant efficacious potential for treating and eliminating organic contaminants. To accomplish its application, the need to develop innovative materials has become an essential goal. In this context, an overview of recent advances in hydrogels based on chitosan and nanocomposites and their application for the depollution of wastewater contaminated with dyes is reported herein. The present review focuses on (i) the challenges raised by the synthesis process and characterization of the different hydrogels; (ii) the discussion of the impact of the main parameters affecting the adsorption process; (iii) the understanding of the adsorption isotherms, kinetics, and thermodynamic behavior; and (iv) the examination of the possibility of recycling and reusing the hydrogels.
A low-cost adsorbent was prepared by using cherry stones powder and chitosan and used to retain R... more A low-cost adsorbent was prepared by using cherry stones powder and chitosan and used to retain Reactive Black 5 dye from aqueous solution. Then, the spent material was submitted to a regeneration process. Five different eluents (water, sodium hydroxide, hydrochloric acid, sodium chloride and ethanol) were tested. Among them, sodium hydroxide was selected for an advanced investigation. Values of three working conditions, namely the eluent volume, its concentration and the desorption temperature, were optimized by Response Surface Methodology-Box–Behnken Design. In the established settings (NaOH volume: 30 mL, NaOH concentration: 1.5 M, working temperature: 40 °C), three successive cycles of adsorption/desorption were conducted. The analysis performed by Scanning Electron Microscopy and by Fourier Transform Infrared Spectroscopy revealed the evolution of the adsorbent throughout the dye elution from the material. Pseudo-second-order kinetic model and Freundlich equilibrium isotherm w...
The treatment of contaminated water is currently a major concern worldwide. This work was directe... more The treatment of contaminated water is currently a major concern worldwide. This work was directed towards the preparation of a composite hydrogel by entrapping cherry stones powder on chitosan, which is known as one of the most abundant natural polymers. The synthesized material was characterized by scanning electron microscopy, by Fourier transform infrared spectroscopy, and by the point of zero charge determination. Its ability to remove two azo dyes models (Acid Red 66 and Reactive Black 5) existing in single form and in binary mixture was evaluated. Response Surface Methodology–Central Composite Design was used to optimize three parameters affecting the process while targeting the lowest final contaminant concentrations. The best results were obtained at pH 2, an adsorbent dose of 100 g/L, and a temperature of 30 °C, when more than 90% of the pollutants from the single component systems and more than 70% of those of the binary mixtures were removed from their aqueous solutions....
Global NEST International Conference on Environmental Science & Technology
Over the past few years, the presence of the pharmaceuticals and their metabolites in the aquatic... more Over the past few years, the presence of the pharmaceuticals and their metabolites in the aquatic environment has become an important public health issue. These molecules are generally released in the aquatic ecosystem through the effluents of conventional wastewater treatment plants which were not designed to treat such kind of pollution. Thus, new efficient strategies are needed for their efficient elimination. This study focuses on the photocatalytic degradation of pharmaceutic compound essentially employed for the treatment of hypertension using TiO2 as catalyst and UVA irradiation. An efficient elimination of 95% was obtained after 10 minutes of irradiation at initial pollutant concentration of 6 mg/L and 1.2 g/L of catalyst. A higher mineralization yield of 87% was reached in 2h of reaction. Results showed that under all studied process conditions the target molecule was degraded according to a pseudo first order kinetics. Obtained data clearly demonstrate the potential applic...
Two types of biosorbents, based on Saccharomyces pastorianus immobilized in calcium alginate, wer... more Two types of biosorbents, based on Saccharomyces pastorianus immobilized in calcium alginate, were studied for the removal of pharmaceuticals from aqueous solutions. Synthetized biocomposite materials were characterized chemically and morphologically, both before and after simulated biosorption. Ethacridine lactate (EL) was chosen as a target molecule. The process performance was interpreted as a function of initial solution pH, biosorbent dose, and initial pharmaceutical concentration. The results exhibited that the removal efficiencies were superior to 90% for both biosorbents, at the initial pH value of 4.0 and biosorbent dose of 2 g/L for all EL initial concentrations tested. Freundlich, Temkin, Hill, Redlich-Peterson, Sips, and Toth isotherms were used to describe the experimental results. The kinetic data were analyzed using kinetic models, such as pseudo-first order, pseudo-second order, Elovich, and Avrami, to determine the kinetic parameters and describe the transport mecha...
In this study, ethacridine lactate removal from aqueous solution using a biosorbent material base... more In this study, ethacridine lactate removal from aqueous solution using a biosorbent material based on residual microbial biomass and natural polymers in fixed-bed continuous column was investigated. Composite beads of Saccharomyces pastorianus residual biomass and calcium alginate were obtained by immobilization technique. The prepared biosorbent was characterized by Fourier transformed infrared spectroscopy, scanning electron microscopy, and analysis of point of zero charge value. Then, laboratory-scale experiments by fixed-bed column biosorption were conducted in continuous system. To this purpose, the column bed high (5 cm; 7.5 cm), initial pollutant concentration (20 mg/L; 40 mg/L), and solution flow through the column (0.6 mL/min; 1.5 mL/min) were considered the main parameters. Recorded breakthrough curves suggest that lower flow rates, greater bed heights, and a lower concentration of ethacridine lactate led to an increased biosorption of the target compound. The biosorption ...
The chemical instability of vitamin C acid is due to the fact that it is a strong reducing agent ... more The chemical instability of vitamin C acid is due to the fact that it is a strong reducing agent and can be deactivated by a wide range of oxidizing agents. In food industry the use of various thermal processes has, in the most cases, a negative impact over the preservation of vitamin C content alongside raw materials conversion into the final products. A comparative study about the variations of vitamin C concentrations in lemons is presented in this paper, variations being produced by the uses of low, medium and respectively high temperature treatments.
This work was aimed to determine the optimal storage conditions able to insure a sufficient flour... more This work was aimed to determine the optimal storage conditions able to insure a sufficient flour maturity degree in order to improve its rheological and technological properties. To this purpose the Response Surface Methodology (RSM) was successfully employed. The effects of three different parameters (storage time, temperature and environmental humidity) on flour and dough rheological characteristics that were determined by farinograph analysis: water absorption, stability time and dough softening degree were studied. The RSM established optimum conditions for wheat flour maturation process were: storage temperature: 28°C, storage time: 21 days, environmental humidity: 68-70%. Under these conditions, for tested flour, the farinograph recordings revealed that water absorption increased with 0.5% comparing with initial product (after grinding process). In terms of dough stability time an augmentation of 20% was registered. Dough softening degree at 10 and 12 min were reduced with 30...
Citric acid is an organic acid produced by carbohydrates fermentation process under microorganism... more Citric acid is an organic acid produced by carbohydrates fermentation process under microorganisms’ action. Its uses in a large variety of fields going from food products to cosmetics and medicines require a good knowledge of its industrial behavior. From this point of view, thermo-physical properties (density, viscosity, thermal heat capacity, thermal conductivity and so on) present a major interest. As consequence, in this paper, different mathematical relations between temperature and concentration and density and dynamic viscosity of aqueous solutions made of anhydrous citric acid were established. The known data were fitted in different equations in order to assess and select suitable mathematical models. Their accuracy was studied using several statistical analysis tools such as correlation coefficient, ANOVA test, relative error etc. Taking into consideration the level of precision and the simplicity of formulation, several equations were generated for each of the studied the...
AbstractThe aim of this study is to characterize and assess the sorption potential of brown peat... more AbstractThe aim of this study is to characterize and assess the sorption potential of brown peat, in relation to colored pollutants from the textile industry wastewater. The objectives of this paper were: the physicochemical, morphological, and mineralogical characterization of brown peat, testing the adsorption capacity of natural and chemically treated peat samples for Astrazone Blue, evaluation of adsorption process from equilibrium isotherm and kinetic point of view. The characteristics of the peat samples were investigated using elemental analysis, scanning electron microscopy and X-ray diffractometry. Experimental data indicated that the brown peat tested confirm a high level of adsorption (removal efficiency >93.00%, adsorption capacity reaching up to 24.27 mg/g) of Astrazone Blue from aqueous solution. The Langmuir and Freundlich adsorption isotherm models were used to find the best equation able to describe the adsorption process. Experimental adsorption data were successfully described by the Langmuir equilibrium isotherm model. This fact is supported by the agreement between the q values obtained using the Langmuir equation ( .32 mg/g), and the ones obtained experimentally (24.27 mg/g). The kinetic studies showed that the pseudo-second-order model described Astrazone Blue sorption kinetics, as confirmed by the high values of R 2 , which are over 0.99 for the whole investigated concentration range (200 to 800 mg/L). The use of brown peat adsorbent is more advantageous compared with other materials since it does not require a preliminary treatment, is low-cost and is an eco-friendly adsorbent. Hence, this peat appears to be a viable material for the decontamination of effluents containing dyes.
Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in sev... more Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in several aquatic environments worldwide; therefore, the elimination of these pollutants is a global challenge. This study aimed to develop a biosorbent based on Saccharomyces pastorianus residual biomass encapsulated in a calcium alginate matrix and to evaluate its biosorption performance to remove Ethacridine Lactate (EL) from aqueous solutions. Firstly, the synthesis and characterization of biosorbent has been carried out. Then, the impact of main parameters on biosorption process were investigated by batch experiments. Finally, the kinetics behavior and equilibrium isotherms were evaluated. The resulted beads have an irregular and elongated shape with about 1.89 mm ± 0.13 mm in size with a homogeneous structure. The best removal efficiency for EL of over 85% was obtained at acidic pH 2 and 25 °C for 50 mg/L initial concentration and 2 g/L biosorbent dose. The pseudo-second-order and intra...
Scientific Study & Research: Chemistry & Chemical Engineering, Biotechnology, Food Industry, 2011
When optimizing the process of grapes juice manufacture not just to obtain an excellent quality, ... more When optimizing the process of grapes juice manufacture not just to obtain an excellent quality, but also to develop a data base is essential to know the evolution of physical properties, such as viscosity or heat capacity elevation. These properties are affected by temperature and dry matter content. The aim of this study was to establish a mathematical relation between these variables. In order to assess and select a suitable mathematical model the known data were fitted in different equations. Tests results have shown that at constant dry matter content the temperature and the viscosity are related by an exponential equation while between temperature and heat capacity variation a "heat capacity" model seems to be the most appropriate.
The present work focused on the fodder yeast production, an attractive source of proteins for the... more The present work focused on the fodder yeast production, an attractive source of proteins for the livestock nutrition through the efficient growth of microorganisms on inexpensive waste substrates. Two agricultural by-products, sugar beet pulp and barley husks, rich in simple carbohydrates (88 g/L and 31.77 g/L for sugar beet hydrolysate and barley husks hydrolysate, respectively) were mixed after acid hydrolysis and used as a carbon and energy source for the "fodder yeast" Candida utilis production. Various nutritional requirements affecting the yeast growth were considered and investigated through an experimental design approach. The Response Surface Methodology was applied in order to optimize the medium composition aiming to increase on the one hand the yield on biomass rich in protein content and the substrate bioconversion on the other hand. Statistical analysis of the mathematical models developed for the studied response functions revealed a good correlation betwee...
This work aimed to study the mathematical variation of three main thermodynamic properties (dynam... more This work aimed to study the mathematical variation of three main thermodynamic properties (dynamic viscosity, thermal conductivity and thermal diffusivity) of pasta dough obtained by mixing wheat semolina and water with dough humidity and deformation speed (for dynamic viscosity), respectively with dough humidity and temperature (for thermal diffusivity and conductivity). The realized regression analysis of existing graphical data led to the development of mathematical models with a high degree of accuracy. The employed statistical tests (least squares, relative error and analysis of variance) revealed that the obtained equations are able to describe and predict the tendency of the dough thermodynamic properties.
Cephalexin (CPX) is recognized as a water pollutant, and it has been listed in a number of countr... more Cephalexin (CPX) is recognized as a water pollutant, and it has been listed in a number of countries with a risk factor greater than one. Herein, the present work focused on the synthesis, characterization and biosorption capacity evaluation of Saccharomyces cerevisiae immobilized in calcium alginate as a biosorbent to remove CPX from aqueous solutions. Biosorbent was characterized by SEM and FTIR techniques. Batch biosorption experiments were conducted in order to evaluate the effect of the initial pH, biosorbent dose and CPX initial concentration. The removal efficiency, in considered optimal conditions (pH = 4, CPX initial concentration = 30 mg/L, biosorbent dose = 1 g/L) was 86.23%. CPX biosorption was found to follow the pseudo–second-order kinetics. The equilibrium biosorption data were a good fit for the Langmuir model with correlation coefficient of 0.9814 and maximum biosorption capacity was 94.34 mg/g. This study showed that the synthesized biosorbent by immobilization tec...
Pharmaceuticals and dyes are a very important part of the nonbiodegradable or hard biodegradable ... more Pharmaceuticals and dyes are a very important part of the nonbiodegradable or hard biodegradable substances present in wastewater. Microorganisms are already known to be effective biosorbents, but the use of free microbial cells involves difficulties in their separation from effluents and limits their application in wastewater treatment. Thus, this study aimed to develop biosorbents by immobilizing Saccharomyces cerevisiae, Saccharomyces pastorianus and Saccharomyces pastorianus residual biomass on natural polymers (alginate and chitosan) and to evaluate the biosorptive potential for removal of pharmaceuticals and dyes from water. Six types of biosorbents were synthesized and characterized by Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy techniques and their biosorptive capacities for three drugs (cephalexin, rifampicin, ethacridine lactate) and two dyes (orange II and indigo carmine) were evaluated. The obtained results show that the removal efficiency de...
In recent years, more and more pollutants (including pharmaceuticals, personal care products, pes... more In recent years, more and more pollutants (including pharmaceuticals, personal care products, pesticides, herbicides, hormones, chemicals) are detected in the aquatic environment. Even if they are encountered in very low concentrations, the toxicological data reveal that they represent a major risk both for the water living organisms and for human beings. Moreover, an important resistance to the classical methods applied at wastewater treatment plants characterizes them. Aeration, coagulation, flocculation, sedimentation, filtration, adsorption, oxidation, activated sludge treatments are often either insufficient or completely ineffective. To overcome these drawbacks, many researches were dedicated to the development of new effective techniques for the removal of these water pollutants. Advanced oxidation methods are widely reported as being of the most efficient ones. In this article, we investigate the utility of the photocatalysis as a sustainable alternative for the enhanced eli...
Environmental Engineering and Management Journal, 2014
The study aimed the diversification of fodder yeast assortments with viable economic effects whil... more The study aimed the diversification of fodder yeast assortments with viable economic effects while reducing the environment pollution by capitalization of wastewaters with high monosaccharides content from pulp and paper industry and residual whey from milk industry. Using the Response Surface Methodology the fabrication recipe has been optimized according to an experimental program based on a mathematical model with biomass, protein and residual sugar as response functions. The culture medium for a mix of Candida utilis and Candida pseudotropicalis strains was composed by 25 g/L fermentable monosaccharides provided by pulp and paper wastewaters and whey, MgSO 4 0.8 g/L, ZnSO 4 1.2 g/L, MnSO 4 1.0 g/L, FeSO 4 0.8 g/L and up to 1053 mg/L nitrogen and 422 mg/L phosphorous from (NH 4) 2 SO 4 and (NH 4) 2 HPO 4. In these conditions, the biomass gain was of 6.45 g/L and the protein content reached a value of 50.64% while the amount of the residual sugar decreased at 2.08 g/L.
Water is one of the fundamental resources for the existence of humans and the environment. Throug... more Water is one of the fundamental resources for the existence of humans and the environment. Throughout time, due to urbanization, expanding population, increased agricultural production, and intense industrialization, significant pollution with persistent contaminants has been noted, placing the water quality in danger. As a consequence, different procedures and various technologies have been tested and used in order to ensure that water sources are safe for use. The adsorption process is often considered for wastewater treatment due to its straightforward design, low investment cost, availability, avoidance of additional chemicals, lack of undesirable byproducts, and demonstrated significant efficacious potential for treating and eliminating organic contaminants. To accomplish its application, the need to develop innovative materials has become an essential goal. In this context, an overview of recent advances in hydrogels based on chitosan and nanocomposites and their application for the depollution of wastewater contaminated with dyes is reported herein. The present review focuses on (i) the challenges raised by the synthesis process and characterization of the different hydrogels; (ii) the discussion of the impact of the main parameters affecting the adsorption process; (iii) the understanding of the adsorption isotherms, kinetics, and thermodynamic behavior; and (iv) the examination of the possibility of recycling and reusing the hydrogels.
A low-cost adsorbent was prepared by using cherry stones powder and chitosan and used to retain R... more A low-cost adsorbent was prepared by using cherry stones powder and chitosan and used to retain Reactive Black 5 dye from aqueous solution. Then, the spent material was submitted to a regeneration process. Five different eluents (water, sodium hydroxide, hydrochloric acid, sodium chloride and ethanol) were tested. Among them, sodium hydroxide was selected for an advanced investigation. Values of three working conditions, namely the eluent volume, its concentration and the desorption temperature, were optimized by Response Surface Methodology-Box–Behnken Design. In the established settings (NaOH volume: 30 mL, NaOH concentration: 1.5 M, working temperature: 40 °C), three successive cycles of adsorption/desorption were conducted. The analysis performed by Scanning Electron Microscopy and by Fourier Transform Infrared Spectroscopy revealed the evolution of the adsorbent throughout the dye elution from the material. Pseudo-second-order kinetic model and Freundlich equilibrium isotherm w...
The treatment of contaminated water is currently a major concern worldwide. This work was directe... more The treatment of contaminated water is currently a major concern worldwide. This work was directed towards the preparation of a composite hydrogel by entrapping cherry stones powder on chitosan, which is known as one of the most abundant natural polymers. The synthesized material was characterized by scanning electron microscopy, by Fourier transform infrared spectroscopy, and by the point of zero charge determination. Its ability to remove two azo dyes models (Acid Red 66 and Reactive Black 5) existing in single form and in binary mixture was evaluated. Response Surface Methodology–Central Composite Design was used to optimize three parameters affecting the process while targeting the lowest final contaminant concentrations. The best results were obtained at pH 2, an adsorbent dose of 100 g/L, and a temperature of 30 °C, when more than 90% of the pollutants from the single component systems and more than 70% of those of the binary mixtures were removed from their aqueous solutions....
Global NEST International Conference on Environmental Science & Technology
Over the past few years, the presence of the pharmaceuticals and their metabolites in the aquatic... more Over the past few years, the presence of the pharmaceuticals and their metabolites in the aquatic environment has become an important public health issue. These molecules are generally released in the aquatic ecosystem through the effluents of conventional wastewater treatment plants which were not designed to treat such kind of pollution. Thus, new efficient strategies are needed for their efficient elimination. This study focuses on the photocatalytic degradation of pharmaceutic compound essentially employed for the treatment of hypertension using TiO2 as catalyst and UVA irradiation. An efficient elimination of 95% was obtained after 10 minutes of irradiation at initial pollutant concentration of 6 mg/L and 1.2 g/L of catalyst. A higher mineralization yield of 87% was reached in 2h of reaction. Results showed that under all studied process conditions the target molecule was degraded according to a pseudo first order kinetics. Obtained data clearly demonstrate the potential applic...
Two types of biosorbents, based on Saccharomyces pastorianus immobilized in calcium alginate, wer... more Two types of biosorbents, based on Saccharomyces pastorianus immobilized in calcium alginate, were studied for the removal of pharmaceuticals from aqueous solutions. Synthetized biocomposite materials were characterized chemically and morphologically, both before and after simulated biosorption. Ethacridine lactate (EL) was chosen as a target molecule. The process performance was interpreted as a function of initial solution pH, biosorbent dose, and initial pharmaceutical concentration. The results exhibited that the removal efficiencies were superior to 90% for both biosorbents, at the initial pH value of 4.0 and biosorbent dose of 2 g/L for all EL initial concentrations tested. Freundlich, Temkin, Hill, Redlich-Peterson, Sips, and Toth isotherms were used to describe the experimental results. The kinetic data were analyzed using kinetic models, such as pseudo-first order, pseudo-second order, Elovich, and Avrami, to determine the kinetic parameters and describe the transport mecha...
In this study, ethacridine lactate removal from aqueous solution using a biosorbent material base... more In this study, ethacridine lactate removal from aqueous solution using a biosorbent material based on residual microbial biomass and natural polymers in fixed-bed continuous column was investigated. Composite beads of Saccharomyces pastorianus residual biomass and calcium alginate were obtained by immobilization technique. The prepared biosorbent was characterized by Fourier transformed infrared spectroscopy, scanning electron microscopy, and analysis of point of zero charge value. Then, laboratory-scale experiments by fixed-bed column biosorption were conducted in continuous system. To this purpose, the column bed high (5 cm; 7.5 cm), initial pollutant concentration (20 mg/L; 40 mg/L), and solution flow through the column (0.6 mL/min; 1.5 mL/min) were considered the main parameters. Recorded breakthrough curves suggest that lower flow rates, greater bed heights, and a lower concentration of ethacridine lactate led to an increased biosorption of the target compound. The biosorption ...
The chemical instability of vitamin C acid is due to the fact that it is a strong reducing agent ... more The chemical instability of vitamin C acid is due to the fact that it is a strong reducing agent and can be deactivated by a wide range of oxidizing agents. In food industry the use of various thermal processes has, in the most cases, a negative impact over the preservation of vitamin C content alongside raw materials conversion into the final products. A comparative study about the variations of vitamin C concentrations in lemons is presented in this paper, variations being produced by the uses of low, medium and respectively high temperature treatments.
This work was aimed to determine the optimal storage conditions able to insure a sufficient flour... more This work was aimed to determine the optimal storage conditions able to insure a sufficient flour maturity degree in order to improve its rheological and technological properties. To this purpose the Response Surface Methodology (RSM) was successfully employed. The effects of three different parameters (storage time, temperature and environmental humidity) on flour and dough rheological characteristics that were determined by farinograph analysis: water absorption, stability time and dough softening degree were studied. The RSM established optimum conditions for wheat flour maturation process were: storage temperature: 28°C, storage time: 21 days, environmental humidity: 68-70%. Under these conditions, for tested flour, the farinograph recordings revealed that water absorption increased with 0.5% comparing with initial product (after grinding process). In terms of dough stability time an augmentation of 20% was registered. Dough softening degree at 10 and 12 min were reduced with 30...
Citric acid is an organic acid produced by carbohydrates fermentation process under microorganism... more Citric acid is an organic acid produced by carbohydrates fermentation process under microorganisms’ action. Its uses in a large variety of fields going from food products to cosmetics and medicines require a good knowledge of its industrial behavior. From this point of view, thermo-physical properties (density, viscosity, thermal heat capacity, thermal conductivity and so on) present a major interest. As consequence, in this paper, different mathematical relations between temperature and concentration and density and dynamic viscosity of aqueous solutions made of anhydrous citric acid were established. The known data were fitted in different equations in order to assess and select suitable mathematical models. Their accuracy was studied using several statistical analysis tools such as correlation coefficient, ANOVA test, relative error etc. Taking into consideration the level of precision and the simplicity of formulation, several equations were generated for each of the studied the...
AbstractThe aim of this study is to characterize and assess the sorption potential of brown peat... more AbstractThe aim of this study is to characterize and assess the sorption potential of brown peat, in relation to colored pollutants from the textile industry wastewater. The objectives of this paper were: the physicochemical, morphological, and mineralogical characterization of brown peat, testing the adsorption capacity of natural and chemically treated peat samples for Astrazone Blue, evaluation of adsorption process from equilibrium isotherm and kinetic point of view. The characteristics of the peat samples were investigated using elemental analysis, scanning electron microscopy and X-ray diffractometry. Experimental data indicated that the brown peat tested confirm a high level of adsorption (removal efficiency >93.00%, adsorption capacity reaching up to 24.27 mg/g) of Astrazone Blue from aqueous solution. The Langmuir and Freundlich adsorption isotherm models were used to find the best equation able to describe the adsorption process. Experimental adsorption data were successfully described by the Langmuir equilibrium isotherm model. This fact is supported by the agreement between the q values obtained using the Langmuir equation ( .32 mg/g), and the ones obtained experimentally (24.27 mg/g). The kinetic studies showed that the pseudo-second-order model described Astrazone Blue sorption kinetics, as confirmed by the high values of R 2 , which are over 0.99 for the whole investigated concentration range (200 to 800 mg/L). The use of brown peat adsorbent is more advantageous compared with other materials since it does not require a preliminary treatment, is low-cost and is an eco-friendly adsorbent. Hence, this peat appears to be a viable material for the decontamination of effluents containing dyes.
Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in sev... more Pharmaceuticals are recognized as emerging water microcontaminants that have been reported in several aquatic environments worldwide; therefore, the elimination of these pollutants is a global challenge. This study aimed to develop a biosorbent based on Saccharomyces pastorianus residual biomass encapsulated in a calcium alginate matrix and to evaluate its biosorption performance to remove Ethacridine Lactate (EL) from aqueous solutions. Firstly, the synthesis and characterization of biosorbent has been carried out. Then, the impact of main parameters on biosorption process were investigated by batch experiments. Finally, the kinetics behavior and equilibrium isotherms were evaluated. The resulted beads have an irregular and elongated shape with about 1.89 mm ± 0.13 mm in size with a homogeneous structure. The best removal efficiency for EL of over 85% was obtained at acidic pH 2 and 25 °C for 50 mg/L initial concentration and 2 g/L biosorbent dose. The pseudo-second-order and intra...
Scientific Study & Research: Chemistry & Chemical Engineering, Biotechnology, Food Industry, 2011
When optimizing the process of grapes juice manufacture not just to obtain an excellent quality, ... more When optimizing the process of grapes juice manufacture not just to obtain an excellent quality, but also to develop a data base is essential to know the evolution of physical properties, such as viscosity or heat capacity elevation. These properties are affected by temperature and dry matter content. The aim of this study was to establish a mathematical relation between these variables. In order to assess and select a suitable mathematical model the known data were fitted in different equations. Tests results have shown that at constant dry matter content the temperature and the viscosity are related by an exponential equation while between temperature and heat capacity variation a "heat capacity" model seems to be the most appropriate.
The present work focused on the fodder yeast production, an attractive source of proteins for the... more The present work focused on the fodder yeast production, an attractive source of proteins for the livestock nutrition through the efficient growth of microorganisms on inexpensive waste substrates. Two agricultural by-products, sugar beet pulp and barley husks, rich in simple carbohydrates (88 g/L and 31.77 g/L for sugar beet hydrolysate and barley husks hydrolysate, respectively) were mixed after acid hydrolysis and used as a carbon and energy source for the "fodder yeast" Candida utilis production. Various nutritional requirements affecting the yeast growth were considered and investigated through an experimental design approach. The Response Surface Methodology was applied in order to optimize the medium composition aiming to increase on the one hand the yield on biomass rich in protein content and the substrate bioconversion on the other hand. Statistical analysis of the mathematical models developed for the studied response functions revealed a good correlation betwee...
This work aimed to study the mathematical variation of three main thermodynamic properties (dynam... more This work aimed to study the mathematical variation of three main thermodynamic properties (dynamic viscosity, thermal conductivity and thermal diffusivity) of pasta dough obtained by mixing wheat semolina and water with dough humidity and deformation speed (for dynamic viscosity), respectively with dough humidity and temperature (for thermal diffusivity and conductivity). The realized regression analysis of existing graphical data led to the development of mathematical models with a high degree of accuracy. The employed statistical tests (least squares, relative error and analysis of variance) revealed that the obtained equations are able to describe and predict the tendency of the dough thermodynamic properties.
Cephalexin (CPX) is recognized as a water pollutant, and it has been listed in a number of countr... more Cephalexin (CPX) is recognized as a water pollutant, and it has been listed in a number of countries with a risk factor greater than one. Herein, the present work focused on the synthesis, characterization and biosorption capacity evaluation of Saccharomyces cerevisiae immobilized in calcium alginate as a biosorbent to remove CPX from aqueous solutions. Biosorbent was characterized by SEM and FTIR techniques. Batch biosorption experiments were conducted in order to evaluate the effect of the initial pH, biosorbent dose and CPX initial concentration. The removal efficiency, in considered optimal conditions (pH = 4, CPX initial concentration = 30 mg/L, biosorbent dose = 1 g/L) was 86.23%. CPX biosorption was found to follow the pseudo–second-order kinetics. The equilibrium biosorption data were a good fit for the Langmuir model with correlation coefficient of 0.9814 and maximum biosorption capacity was 94.34 mg/g. This study showed that the synthesized biosorbent by immobilization tec...
Pharmaceuticals and dyes are a very important part of the nonbiodegradable or hard biodegradable ... more Pharmaceuticals and dyes are a very important part of the nonbiodegradable or hard biodegradable substances present in wastewater. Microorganisms are already known to be effective biosorbents, but the use of free microbial cells involves difficulties in their separation from effluents and limits their application in wastewater treatment. Thus, this study aimed to develop biosorbents by immobilizing Saccharomyces cerevisiae, Saccharomyces pastorianus and Saccharomyces pastorianus residual biomass on natural polymers (alginate and chitosan) and to evaluate the biosorptive potential for removal of pharmaceuticals and dyes from water. Six types of biosorbents were synthesized and characterized by Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy techniques and their biosorptive capacities for three drugs (cephalexin, rifampicin, ethacridine lactate) and two dyes (orange II and indigo carmine) were evaluated. The obtained results show that the removal efficiency de...
In recent years, more and more pollutants (including pharmaceuticals, personal care products, pes... more In recent years, more and more pollutants (including pharmaceuticals, personal care products, pesticides, herbicides, hormones, chemicals) are detected in the aquatic environment. Even if they are encountered in very low concentrations, the toxicological data reveal that they represent a major risk both for the water living organisms and for human beings. Moreover, an important resistance to the classical methods applied at wastewater treatment plants characterizes them. Aeration, coagulation, flocculation, sedimentation, filtration, adsorption, oxidation, activated sludge treatments are often either insufficient or completely ineffective. To overcome these drawbacks, many researches were dedicated to the development of new effective techniques for the removal of these water pollutants. Advanced oxidation methods are widely reported as being of the most efficient ones. In this article, we investigate the utility of the photocatalysis as a sustainable alternative for the enhanced eli...
Environmental Engineering and Management Journal, 2014
The study aimed the diversification of fodder yeast assortments with viable economic effects whil... more The study aimed the diversification of fodder yeast assortments with viable economic effects while reducing the environment pollution by capitalization of wastewaters with high monosaccharides content from pulp and paper industry and residual whey from milk industry. Using the Response Surface Methodology the fabrication recipe has been optimized according to an experimental program based on a mathematical model with biomass, protein and residual sugar as response functions. The culture medium for a mix of Candida utilis and Candida pseudotropicalis strains was composed by 25 g/L fermentable monosaccharides provided by pulp and paper wastewaters and whey, MgSO 4 0.8 g/L, ZnSO 4 1.2 g/L, MnSO 4 1.0 g/L, FeSO 4 0.8 g/L and up to 1053 mg/L nitrogen and 422 mg/L phosphorous from (NH 4) 2 SO 4 and (NH 4) 2 HPO 4. In these conditions, the biomass gain was of 6.45 g/L and the protein content reached a value of 50.64% while the amount of the residual sugar decreased at 2.08 g/L.
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Papers by Andrei Simion