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Papers by firas kamar

Research paper thumbnail of Author Correction: Full factorial design and dynamic modelling of silent and ultrasound-assisted lead and cadmium removal by porous biosorbent

Research paper thumbnail of Full factorial design and dynamic modelling of silent and ultrasound-assisted lead and cadmium removal by porous biosorbent

Scientific Reports

Present work aimed to analyse single and competitive lead and cadmium batch adsorption, using exp... more Present work aimed to analyse single and competitive lead and cadmium batch adsorption, using experimental studies and mathematical modelling. The experiments were conducted in silent and ultrasound-assisted systems, in aqueous environment, using grinded hazelnut shells as porous biosorbent. The influence of process factors (pH, adsorbent concentration, adsorbent particle size, and initial species concentration in liquid phase) on species removal efficiency was evaluated when process equilibrium was attained. The statistical study, following a 24 factorial experimental design, allowed the development of a model to predict variables influence. Based on the obtained results a deeper analysis of the separation efficiency, depending on process factors, was conducted. The dynamic study was performed based on experimentally obtained removal rates, modelled considering species diffusion, with reversible kinetics of sorption inside solid particles. Hence, the dynamics of removal efficiency ...

Research paper thumbnail of Removal of lead and cadmium ions from aqueous solution using walnut shells as low-cost adsorbent materials

In this study Caulerpa racemosa has been characterized and used for the removal of Cd(II) and Pb ... more In this study Caulerpa racemosa has been characterized and used for the removal of Cd(II) and Pb (II) from aqueous solutions. The effect of pH, adsorbent dosage, contact time and temperature on adsorption process was studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. racemosa biomass. The adsorption data can be well described by Langmuir isotherm. The monolayer biosorption capacity of C. racemosa biomass for Pb(II) and Cd(II) ions was found to be 34.5 mg/g and 29 mg/g, respectively. Kinetics data of both metal ions were best described by pseudo second order model.The thermodynamic studies indicated that the adsorption was spontaneous and exothermic in nature. The analysis with FTIR indicated that possible functional groups involved in metal sorption by this alga were O-H bending, N-H stretching, C-N stretching, CO and S=O stretching.

Research paper thumbnail of Modelling of Lead and Cadmium Removal by Porous Biosorbent in Silent and Ultrasound-assisted Systems

Present work aimed to analyse experimentally, statistically and using mathematical modelling the ... more Present work aimed to analyse experimentally, statistically and using mathematical modelling the behaviour of single and competitive lead and cadmium batch adsorption. The process was conducted in silent, and ultrasound (US)-assisted systems, in aqueous environment, on grinded hazelnut shells (HS) as sustainable and cost-effective porous biosorbent. The dynamic study was based on experimentally obtained removal rates, modelled considering species diffusion with reversible kinetics of sorption inside solid particles. The influence of process factors (pH, adsorbent concentration, adsorbent particle size, and initial species concentration in liquid phase) on species removal efficiency was studied when process equilibrium was attained. The study, following a 24 factorial experimental design, allowed the development of a statistical model to predict variables influences. Based on the obtained results a deeper analysis of separation efficiency depending on process factors was conducted. H...

Research paper thumbnail of Comparative Removal of Lead, Copper and Cadmium Ions from Wastewater in Single and Ternary Batch Biosorption Systems onto Dry Walnut Shells

FIRAS HASHIM KAMAR1,2, AURELIA CRISTINA NECHIFOR1 , GHANIM M. ALWAN3, MIHAELA EMANUELA CRACIUN1, ... more FIRAS HASHIM KAMAR1,2, AURELIA CRISTINA NECHIFOR1 , GHANIM M. ALWAN3, MIHAELA EMANUELA CRACIUN1, GHEORGHE NECHIFOR1* 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Gheorghe Str., 011061, Bucharest, Romania 2 Institute of TechnologyBaghdad, Middle Technical University, Iraq 3 Department of Chemical Engineering, University of Technology, Iraq

Research paper thumbnail of Zinc, Cooper and Cadmium Solvent Extraction at Equilibrium in Liquid-liquid Systems

CRISTINA MODROGAN1*, ALEXANDRA RALUCA MIRON1, IRINA PINCOVSCHI2, CRISTINA COSTACHE1, FIRAS HASHIM... more CRISTINA MODROGAN1*, ALEXANDRA RALUCA MIRON1, IRINA PINCOVSCHI2, CRISTINA COSTACHE1, FIRAS HASHIM KAMAR3 1University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Departament of Analytical Chemistry and Environmental Engineering, 1-7 Polizu Str., 011061, Bucharest, Romania 2 University Politehnica from Bucharest, Department of Hydraulics, Hydraulic Machinery and Environmental Engineering, 313 Splaiul Independentei, 060042, Bucharest, Romania

Research paper thumbnail of Study of the Single and Binary Batch Systems to Remove Copper and Cadmium Ions from Aqueous Solutions using Dry Cabbage Leaves as Biosorbent Material

FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, GHEORGHE NECHIFOR1*, MUTHANA HASSAN SALLOMI3,... more FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, GHEORGHE NECHIFOR1*, MUTHANA HASSAN SALLOMI3, ABDULRAZAQ D. JASEM4 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Ghe. Polizu Str., 011061, Bucharest, Romania 2Institute of TechnologyBaghdad, Middle Technical University, Iraq 3Environment Directorate of Baghdad, Ministry of Environment, Iraq 4Ibn Albetar Research Center, Corporation of Research and Industrial Development, Ministry of Industry and Mineral, Iraq

Research paper thumbnail of Study on Adsorption of Lead Ions from Industrial Wastewater by Dry Cabbage Leaves

FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, MOHANAD JASIM MOHAMMED RIDHA3, MUSTAFA BASIM ... more FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, MOHANAD JASIM MOHAMMED RIDHA3, MUSTAFA BASIM MOHAMMED ALTAIEEMI1, GHEORGHE NECHIFOR1* . 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Gheorghe Polizu Str., 011061, Bucharest, Romania 2 Institute of TechnologyBaghdad, Middle Technical University, Iraq. 3 Department of Environmental Engineering, College of Engineering, Baghdad University, Iraq

Research paper thumbnail of Caseinase Production and Media Optimization from Bacillus subtilis

Caseinase is involved in the breakdown of milk protein casein and converts casein into smaller si... more Caseinase is involved in the breakdown of milk protein casein and converts casein into smaller simple sugars which can be easily utilized by the body for the production of ATP and Fat. Casein can be an instant energy source to the body and involves in muscle building. Caseinase enzyme can be extensively used at the industrial scale for Milk, Textile, Dairy, Paper industry and several other medical purposes. In view of the importance of caseinase, the current research deals with the isolation and identification of caseinase producing bacteria from soil. This is followed by the production of enzyme and its purification. The study also includes its kinetic characterization using the parameters Temperature, pH as well as Carbon and Nitrogen Sources. The organism which was isolated from soil and capable of producing the caseinase enzyme was identified to be Bacillus subtilis based on the Biochemical tests and 16S rRNA sequencing result. The optimal carbon and nitrogen sources were identi...

Research paper thumbnail of Ultrasound enhanced removal of lead from wastewater by hazelnut shell: an experimental design methodology

International Journal of Environmental Science and Technology, 2018

The present work aimed to investigate the possibility to enhance Pb(II) removal from wastewater b... more The present work aimed to investigate the possibility to enhance Pb(II) removal from wastewater by ultrasound-assisted adsorption using unmodified hazelnut shell, as locally and readily available agricultural waste. The main objective was to optimize operational parameters, to allow efficient (fast and low-cost) lead removal. Thus, parameters as contact time, initial Pb(II) concentration and wastewater temperature were investigated in batch operation and optimized using response surface methodology. The obtained results indicated high adsorption efficiency, between 91.6 and 97.3%, even for very short contact time (4-10 min) and for relatively large particles of grounded shell (particle size between 0.5 and 0.63 mm). Furthermore, it was found that the initial Pb(II) concentration is the most important factor in this process: a higher initial concentration of Pb(II) determined a higher removal efficiency. The linear forms of Langmuir and Freundlich isotherms were applied for different values of temperature and initial Pb(II) concentration. In all cases, based on the obtained values of the correlation coefficient, Langmuir model fitted better the isotherms of ultrasound-assisted adsorption. Overall, this study can be regarded as positive background for ultrasound-assisted adsorption as industrial-scale application.

Research paper thumbnail of Removal of Hexavalent Chromium Ions from the Simulated Wastewater Using Electrocoagulation Process

SIMI 2018, 2018

The removal of hexavalent chromium (Cr +6) ions from simulated wastewater was investigated by usi... more The removal of hexavalent chromium (Cr +6) ions from simulated wastewater was investigated by using batch electrocoagulation. The influence of several variables on the removal process was studied such as a type of electrodes, initial pH, initial concentration of Cr +6 ions, electrolysis time, sodium chloride concentration and current density. The experimental results showed that the removal efficiency of Cr +6 ions was more effective when using iron electrode comparing with the aluminium electrodes. The maximum removal of Cr +6 ions was 96.58% at pH 6.0, initial ion concentration 40 mg/L, electrolysis time 15 min, sodium chloride concentration 2 g/L, and the current density 30 mA/cm 2 .

Research paper thumbnail of Comparison of an Artificial Neural Network and a Multiple Linear Regression in Predicting the Heat of Combustion of Diesel Fuel Based on Hydrocarbon Groups

Revista de Chimie

A comparison between artificial neural network (ANN) and multiple linear regression (MLR) models ... more A comparison between artificial neural network (ANN) and multiple linear regression (MLR) models was employed to predict the heat of combustion, and the gross and net heat values, of a diesel fuel engine, based on the chemical composition of the diesel fuel. One hundred and fifty samples of Iraqi diesel provided data from chromatographic analysis. Eight parameters were applied as inputs in order to predict the gross and net heat combustion of the diesel fuel. A trial-and-error method was used to determine the shape of the individual ANN. The results showed that the prediction accuracy of the ANN model was greater than that of the MLR model in predicting the gross heat value. The best neural network for predicting the gross heating value was a back-propagation network (8-8-1), using the Levenberg�Marquardt algorithm for the second step of network training. R = 0.98502 for the test data. In the same way, the best neural network for predicting the net heating value was a back-propagati...

Research paper thumbnail of Use of Artificial Neural Network for Modeling and Prediction of Reactive Red Dye Removal from Wastewater Using Banana Peels Bio-sorbent

Revista de Chimie

Bio-sorption of red dye from aqueous solutions onto banana peels was investigated. Effects of ini... more Bio-sorption of red dye from aqueous solutions onto banana peels was investigated. Effects of initial pH, bio-sorbent dose, initial concentration, contact time, and temperature were studied and they found of 3, 0.4 g/100 mL, 50 mg/L, 100 min and 298 K respectively with removal efficiency of 93.44%. Artificial neural network was used for prediction of adsorption efficiency and its outputs showed a better fit than other traditional isotherm models. The negative values of DG� and DH� indicate that the bio-sorption of red dye was favored and exothermic. The sensitivity analysis signified that the pH was the most influential variable.

Research paper thumbnail of Removal of Dyes from Wastewater by Ceramic Membrane

Revista de Chimie

The current study aimed to investigate the elimination of dyes from sewerage, using microfiltrati... more The current study aimed to investigate the elimination of dyes from sewerage, using microfiltration membrane mechanism. Three dyes were applied, acid yellow-23, disperse blue -79 and acid orange -7. Experiments were performed with feed concentration (40 -120) ppm, feed flow rate (25 -65) l/h and time (0.25 -1.5) h. The membrane used ceramic membrane, constructed as a candle. It was discovered that water flow diminishes with an elevation in running time, feeding oil concentration and enhancing with elevation in the feed flow rate. In addition, it was determined that the elimination (rejection) rate of dyes enhances with elevation in the flow rate, and the elimination (rejection) rate diminishes as time passes. In cross flow microfiltration, the rejection concentration (concentrate) goes up as time passes, with high feed concentration and flow rate. It was also discovered that the modal infusion concentration declines with high feed concentration and working time. In addition, it was ...

Research paper thumbnail of Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

Revista de Chimie

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the remova... more The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ...

Research paper thumbnail of Determination of Ethanol in Fermented Broth by Headspace Gas Chromatography using Capillary Column

Revista de Chimie

The gas chromatography (GC) method in analytical chemistry is a quick and accurate method to dete... more The gas chromatography (GC) method in analytical chemistry is a quick and accurate method to detect volatile components like ethanol. A method for determining volatile components known as Headspace chromatography (HS-GC) was developed along with an internal standard method (ISM) to identify ethanol in fermented broth in the laboratory. The aim of this research is determining the concentration of ethanol in fermented broth using capillary column (ZB-1). This method can analyze ethanol concentrations in the fermented medium broth ranging from 10 to 200 g/L. The validation of this method was done in order to obtain the results to be of high precision and the significant, precision was represented as the relative standard deviation (RSD) which was less than 5%, accuracy was less than 4 % and significance level was p [ 0.05. It was found that this method exhibited good reproducibility.

Research paper thumbnail of Isotherm and Kinetic Models for Bio-sorption of Cadmium Ions from Aqueous Solutions using Dry Peanut Shells and Hazelnut Shells

Revista de Chimie

This work is aiming to investigate the removal Cd(II) ions from the aqueous solution using two ty... more This work is aiming to investigate the removal Cd(II) ions from the aqueous solution using two types of biosorbent materials: peanut shells (PS) and hazelnut shells (HS). The effect of several variables on the batch bio-sorption was studied. The process was carried out at room temperature, shacking speed 200 rpm and using fixed adsorbent diameters of 0.75 mm. The highest removal efficiency of Cd(II) ions onto PS was 91.45% in the best conditions (pH=3, initial concentration of Cd(II) ions 50 mg/ L, amount adsorbent was 0.75 g, contact time was 120 min), while the highest removal efficiency when using HS was 85.62% at pH= 4, and contact time of 160 minutes using the same initial concentration of Cd(II) ions as well as the same amount of absorbent material. Isotherm was studied for bio-sorption of Cd(II) ions using these two adsorbents, and the pseudo- first and second order models were used to study bio-sorption kinetics. The results of the infrared spectroscopy (FTIR) of (PS) and (H...

Research paper thumbnail of Utilization of Waste of Enzymes Biomass as Biosorbent for the Removal of Dyes from Aqueous Solution in Batch and Fluidized Bed Column

Revista de Chimie

The biosorption performance of both batch and liquid-solid fluidized bed operations of dead funga... more The biosorption performance of both batch and liquid-solid fluidized bed operations of dead fungal biomass type (Agaricusbisporus ) for removal of methylene blue from aqueous solution was investigated. In batch system, the adsorption capacity and removal efficiency of dead fungal biomass were evaluated. In fluidized bed system, the experiments were conducted to study the effects of important parameters such as particle size (701-1400�m), initial dye concentration(10-100 mg/L), bed depth (5-15 cm) and solution flow rate (5-20 ml/min) on breakthrough curves. In batch method, the experimental data was modeled using several models (Langmuir,Freundlich, Temkin and Dubinin-Radushkviechmodels) to study equilibrium isotherms, the experimental data followed Langmuir model and the results showed that the maximum adsorption capacity obtained was (28.90, 24.15, 21.23 mg/g) at mean particle size (0.786, 0.935, 1.280 mm) respectively. In Fluidized-bed method, the results show that the total ion u...

Research paper thumbnail of Experimental and Theoretical Studies for Tobacco Leaf Extract as an Eco-friendly Inhibitor for Steel in Saline Water

Journal of Bio- and Tribo-Corrosion

Research paper thumbnail of Aqueous Phase Biosorption of Pb(II), Cu(II), and Cd(II) onto Cabbage Leaves Powder

International Journal of Chemical Reactor Engineering, 2016

In this study, the biosorption of lead (Pb(II)), copper (Cu(II)), and cadmium (Cd(II)) ions from ... more In this study, the biosorption of lead (Pb(II)), copper (Cu(II)), and cadmium (Cd(II)) ions from aqueous solution using waste of cabbage leaves powder (CLP) was investigated as a function of pH, shaking time, initial metal concentration, and biosorbent dose. The maximum removal efficiency at optimum condition in single biosorption system was 95.67, 92.42, and 88.92 % for Pb(II), Cu(II), and Cd(II) ions, respectively. These values reduced in ternary systems in the same sequence. Langmuir and extended Langmuir isotherm models were found to be the best fit of the isotherm data for single and ternary biosorption systems, respectively. The kinetic data of the three metals were better fit by the pseudo-second-order model with higher coefficient of determination and more closely predicted uptake. In addition, the results showed that the intraparticle diffusion was the dominating mechanism. Thermodynamic study showed that the biosorption of Pb(II), Cu(II), and Cd(II) onto CLP was a chemical...

Research paper thumbnail of Author Correction: Full factorial design and dynamic modelling of silent and ultrasound-assisted lead and cadmium removal by porous biosorbent

Research paper thumbnail of Full factorial design and dynamic modelling of silent and ultrasound-assisted lead and cadmium removal by porous biosorbent

Scientific Reports

Present work aimed to analyse single and competitive lead and cadmium batch adsorption, using exp... more Present work aimed to analyse single and competitive lead and cadmium batch adsorption, using experimental studies and mathematical modelling. The experiments were conducted in silent and ultrasound-assisted systems, in aqueous environment, using grinded hazelnut shells as porous biosorbent. The influence of process factors (pH, adsorbent concentration, adsorbent particle size, and initial species concentration in liquid phase) on species removal efficiency was evaluated when process equilibrium was attained. The statistical study, following a 24 factorial experimental design, allowed the development of a model to predict variables influence. Based on the obtained results a deeper analysis of the separation efficiency, depending on process factors, was conducted. The dynamic study was performed based on experimentally obtained removal rates, modelled considering species diffusion, with reversible kinetics of sorption inside solid particles. Hence, the dynamics of removal efficiency ...

Research paper thumbnail of Removal of lead and cadmium ions from aqueous solution using walnut shells as low-cost adsorbent materials

In this study Caulerpa racemosa has been characterized and used for the removal of Cd(II) and Pb ... more In this study Caulerpa racemosa has been characterized and used for the removal of Cd(II) and Pb (II) from aqueous solutions. The effect of pH, adsorbent dosage, contact time and temperature on adsorption process was studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. racemosa biomass. The adsorption data can be well described by Langmuir isotherm. The monolayer biosorption capacity of C. racemosa biomass for Pb(II) and Cd(II) ions was found to be 34.5 mg/g and 29 mg/g, respectively. Kinetics data of both metal ions were best described by pseudo second order model.The thermodynamic studies indicated that the adsorption was spontaneous and exothermic in nature. The analysis with FTIR indicated that possible functional groups involved in metal sorption by this alga were O-H bending, N-H stretching, C-N stretching, CO and S=O stretching.

Research paper thumbnail of Modelling of Lead and Cadmium Removal by Porous Biosorbent in Silent and Ultrasound-assisted Systems

Present work aimed to analyse experimentally, statistically and using mathematical modelling the ... more Present work aimed to analyse experimentally, statistically and using mathematical modelling the behaviour of single and competitive lead and cadmium batch adsorption. The process was conducted in silent, and ultrasound (US)-assisted systems, in aqueous environment, on grinded hazelnut shells (HS) as sustainable and cost-effective porous biosorbent. The dynamic study was based on experimentally obtained removal rates, modelled considering species diffusion with reversible kinetics of sorption inside solid particles. The influence of process factors (pH, adsorbent concentration, adsorbent particle size, and initial species concentration in liquid phase) on species removal efficiency was studied when process equilibrium was attained. The study, following a 24 factorial experimental design, allowed the development of a statistical model to predict variables influences. Based on the obtained results a deeper analysis of separation efficiency depending on process factors was conducted. H...

Research paper thumbnail of Comparative Removal of Lead, Copper and Cadmium Ions from Wastewater in Single and Ternary Batch Biosorption Systems onto Dry Walnut Shells

FIRAS HASHIM KAMAR1,2, AURELIA CRISTINA NECHIFOR1 , GHANIM M. ALWAN3, MIHAELA EMANUELA CRACIUN1, ... more FIRAS HASHIM KAMAR1,2, AURELIA CRISTINA NECHIFOR1 , GHANIM M. ALWAN3, MIHAELA EMANUELA CRACIUN1, GHEORGHE NECHIFOR1* 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Gheorghe Str., 011061, Bucharest, Romania 2 Institute of TechnologyBaghdad, Middle Technical University, Iraq 3 Department of Chemical Engineering, University of Technology, Iraq

Research paper thumbnail of Zinc, Cooper and Cadmium Solvent Extraction at Equilibrium in Liquid-liquid Systems

CRISTINA MODROGAN1*, ALEXANDRA RALUCA MIRON1, IRINA PINCOVSCHI2, CRISTINA COSTACHE1, FIRAS HASHIM... more CRISTINA MODROGAN1*, ALEXANDRA RALUCA MIRON1, IRINA PINCOVSCHI2, CRISTINA COSTACHE1, FIRAS HASHIM KAMAR3 1University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Departament of Analytical Chemistry and Environmental Engineering, 1-7 Polizu Str., 011061, Bucharest, Romania 2 University Politehnica from Bucharest, Department of Hydraulics, Hydraulic Machinery and Environmental Engineering, 313 Splaiul Independentei, 060042, Bucharest, Romania

Research paper thumbnail of Study of the Single and Binary Batch Systems to Remove Copper and Cadmium Ions from Aqueous Solutions using Dry Cabbage Leaves as Biosorbent Material

FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, GHEORGHE NECHIFOR1*, MUTHANA HASSAN SALLOMI3,... more FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, GHEORGHE NECHIFOR1*, MUTHANA HASSAN SALLOMI3, ABDULRAZAQ D. JASEM4 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Ghe. Polizu Str., 011061, Bucharest, Romania 2Institute of TechnologyBaghdad, Middle Technical University, Iraq 3Environment Directorate of Baghdad, Ministry of Environment, Iraq 4Ibn Albetar Research Center, Corporation of Research and Industrial Development, Ministry of Industry and Mineral, Iraq

Research paper thumbnail of Study on Adsorption of Lead Ions from Industrial Wastewater by Dry Cabbage Leaves

FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, MOHANAD JASIM MOHAMMED RIDHA3, MUSTAFA BASIM ... more FIRAS HASHIM KAMAR1, 2, AURELIA CRISTINA NECHIFOR1, MOHANAD JASIM MOHAMMED RIDHA3, MUSTAFA BASIM MOHAMMED ALTAIEEMI1, GHEORGHE NECHIFOR1* . 1University Politehnica of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Gheorghe Polizu Str., 011061, Bucharest, Romania 2 Institute of TechnologyBaghdad, Middle Technical University, Iraq. 3 Department of Environmental Engineering, College of Engineering, Baghdad University, Iraq

Research paper thumbnail of Caseinase Production and Media Optimization from Bacillus subtilis

Caseinase is involved in the breakdown of milk protein casein and converts casein into smaller si... more Caseinase is involved in the breakdown of milk protein casein and converts casein into smaller simple sugars which can be easily utilized by the body for the production of ATP and Fat. Casein can be an instant energy source to the body and involves in muscle building. Caseinase enzyme can be extensively used at the industrial scale for Milk, Textile, Dairy, Paper industry and several other medical purposes. In view of the importance of caseinase, the current research deals with the isolation and identification of caseinase producing bacteria from soil. This is followed by the production of enzyme and its purification. The study also includes its kinetic characterization using the parameters Temperature, pH as well as Carbon and Nitrogen Sources. The organism which was isolated from soil and capable of producing the caseinase enzyme was identified to be Bacillus subtilis based on the Biochemical tests and 16S rRNA sequencing result. The optimal carbon and nitrogen sources were identi...

Research paper thumbnail of Ultrasound enhanced removal of lead from wastewater by hazelnut shell: an experimental design methodology

International Journal of Environmental Science and Technology, 2018

The present work aimed to investigate the possibility to enhance Pb(II) removal from wastewater b... more The present work aimed to investigate the possibility to enhance Pb(II) removal from wastewater by ultrasound-assisted adsorption using unmodified hazelnut shell, as locally and readily available agricultural waste. The main objective was to optimize operational parameters, to allow efficient (fast and low-cost) lead removal. Thus, parameters as contact time, initial Pb(II) concentration and wastewater temperature were investigated in batch operation and optimized using response surface methodology. The obtained results indicated high adsorption efficiency, between 91.6 and 97.3%, even for very short contact time (4-10 min) and for relatively large particles of grounded shell (particle size between 0.5 and 0.63 mm). Furthermore, it was found that the initial Pb(II) concentration is the most important factor in this process: a higher initial concentration of Pb(II) determined a higher removal efficiency. The linear forms of Langmuir and Freundlich isotherms were applied for different values of temperature and initial Pb(II) concentration. In all cases, based on the obtained values of the correlation coefficient, Langmuir model fitted better the isotherms of ultrasound-assisted adsorption. Overall, this study can be regarded as positive background for ultrasound-assisted adsorption as industrial-scale application.

Research paper thumbnail of Removal of Hexavalent Chromium Ions from the Simulated Wastewater Using Electrocoagulation Process

SIMI 2018, 2018

The removal of hexavalent chromium (Cr +6) ions from simulated wastewater was investigated by usi... more The removal of hexavalent chromium (Cr +6) ions from simulated wastewater was investigated by using batch electrocoagulation. The influence of several variables on the removal process was studied such as a type of electrodes, initial pH, initial concentration of Cr +6 ions, electrolysis time, sodium chloride concentration and current density. The experimental results showed that the removal efficiency of Cr +6 ions was more effective when using iron electrode comparing with the aluminium electrodes. The maximum removal of Cr +6 ions was 96.58% at pH 6.0, initial ion concentration 40 mg/L, electrolysis time 15 min, sodium chloride concentration 2 g/L, and the current density 30 mA/cm 2 .

Research paper thumbnail of Comparison of an Artificial Neural Network and a Multiple Linear Regression in Predicting the Heat of Combustion of Diesel Fuel Based on Hydrocarbon Groups

Revista de Chimie

A comparison between artificial neural network (ANN) and multiple linear regression (MLR) models ... more A comparison between artificial neural network (ANN) and multiple linear regression (MLR) models was employed to predict the heat of combustion, and the gross and net heat values, of a diesel fuel engine, based on the chemical composition of the diesel fuel. One hundred and fifty samples of Iraqi diesel provided data from chromatographic analysis. Eight parameters were applied as inputs in order to predict the gross and net heat combustion of the diesel fuel. A trial-and-error method was used to determine the shape of the individual ANN. The results showed that the prediction accuracy of the ANN model was greater than that of the MLR model in predicting the gross heat value. The best neural network for predicting the gross heating value was a back-propagation network (8-8-1), using the Levenberg�Marquardt algorithm for the second step of network training. R = 0.98502 for the test data. In the same way, the best neural network for predicting the net heating value was a back-propagati...

Research paper thumbnail of Use of Artificial Neural Network for Modeling and Prediction of Reactive Red Dye Removal from Wastewater Using Banana Peels Bio-sorbent

Revista de Chimie

Bio-sorption of red dye from aqueous solutions onto banana peels was investigated. Effects of ini... more Bio-sorption of red dye from aqueous solutions onto banana peels was investigated. Effects of initial pH, bio-sorbent dose, initial concentration, contact time, and temperature were studied and they found of 3, 0.4 g/100 mL, 50 mg/L, 100 min and 298 K respectively with removal efficiency of 93.44%. Artificial neural network was used for prediction of adsorption efficiency and its outputs showed a better fit than other traditional isotherm models. The negative values of DG� and DH� indicate that the bio-sorption of red dye was favored and exothermic. The sensitivity analysis signified that the pH was the most influential variable.

Research paper thumbnail of Removal of Dyes from Wastewater by Ceramic Membrane

Revista de Chimie

The current study aimed to investigate the elimination of dyes from sewerage, using microfiltrati... more The current study aimed to investigate the elimination of dyes from sewerage, using microfiltration membrane mechanism. Three dyes were applied, acid yellow-23, disperse blue -79 and acid orange -7. Experiments were performed with feed concentration (40 -120) ppm, feed flow rate (25 -65) l/h and time (0.25 -1.5) h. The membrane used ceramic membrane, constructed as a candle. It was discovered that water flow diminishes with an elevation in running time, feeding oil concentration and enhancing with elevation in the feed flow rate. In addition, it was determined that the elimination (rejection) rate of dyes enhances with elevation in the flow rate, and the elimination (rejection) rate diminishes as time passes. In cross flow microfiltration, the rejection concentration (concentrate) goes up as time passes, with high feed concentration and flow rate. It was also discovered that the modal infusion concentration declines with high feed concentration and working time. In addition, it was ...

Research paper thumbnail of Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

Revista de Chimie

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the remova... more The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ...

Research paper thumbnail of Determination of Ethanol in Fermented Broth by Headspace Gas Chromatography using Capillary Column

Revista de Chimie

The gas chromatography (GC) method in analytical chemistry is a quick and accurate method to dete... more The gas chromatography (GC) method in analytical chemistry is a quick and accurate method to detect volatile components like ethanol. A method for determining volatile components known as Headspace chromatography (HS-GC) was developed along with an internal standard method (ISM) to identify ethanol in fermented broth in the laboratory. The aim of this research is determining the concentration of ethanol in fermented broth using capillary column (ZB-1). This method can analyze ethanol concentrations in the fermented medium broth ranging from 10 to 200 g/L. The validation of this method was done in order to obtain the results to be of high precision and the significant, precision was represented as the relative standard deviation (RSD) which was less than 5%, accuracy was less than 4 % and significance level was p [ 0.05. It was found that this method exhibited good reproducibility.

Research paper thumbnail of Isotherm and Kinetic Models for Bio-sorption of Cadmium Ions from Aqueous Solutions using Dry Peanut Shells and Hazelnut Shells

Revista de Chimie

This work is aiming to investigate the removal Cd(II) ions from the aqueous solution using two ty... more This work is aiming to investigate the removal Cd(II) ions from the aqueous solution using two types of biosorbent materials: peanut shells (PS) and hazelnut shells (HS). The effect of several variables on the batch bio-sorption was studied. The process was carried out at room temperature, shacking speed 200 rpm and using fixed adsorbent diameters of 0.75 mm. The highest removal efficiency of Cd(II) ions onto PS was 91.45% in the best conditions (pH=3, initial concentration of Cd(II) ions 50 mg/ L, amount adsorbent was 0.75 g, contact time was 120 min), while the highest removal efficiency when using HS was 85.62% at pH= 4, and contact time of 160 minutes using the same initial concentration of Cd(II) ions as well as the same amount of absorbent material. Isotherm was studied for bio-sorption of Cd(II) ions using these two adsorbents, and the pseudo- first and second order models were used to study bio-sorption kinetics. The results of the infrared spectroscopy (FTIR) of (PS) and (H...

Research paper thumbnail of Utilization of Waste of Enzymes Biomass as Biosorbent for the Removal of Dyes from Aqueous Solution in Batch and Fluidized Bed Column

Revista de Chimie

The biosorption performance of both batch and liquid-solid fluidized bed operations of dead funga... more The biosorption performance of both batch and liquid-solid fluidized bed operations of dead fungal biomass type (Agaricusbisporus ) for removal of methylene blue from aqueous solution was investigated. In batch system, the adsorption capacity and removal efficiency of dead fungal biomass were evaluated. In fluidized bed system, the experiments were conducted to study the effects of important parameters such as particle size (701-1400�m), initial dye concentration(10-100 mg/L), bed depth (5-15 cm) and solution flow rate (5-20 ml/min) on breakthrough curves. In batch method, the experimental data was modeled using several models (Langmuir,Freundlich, Temkin and Dubinin-Radushkviechmodels) to study equilibrium isotherms, the experimental data followed Langmuir model and the results showed that the maximum adsorption capacity obtained was (28.90, 24.15, 21.23 mg/g) at mean particle size (0.786, 0.935, 1.280 mm) respectively. In Fluidized-bed method, the results show that the total ion u...

Research paper thumbnail of Experimental and Theoretical Studies for Tobacco Leaf Extract as an Eco-friendly Inhibitor for Steel in Saline Water

Journal of Bio- and Tribo-Corrosion

Research paper thumbnail of Aqueous Phase Biosorption of Pb(II), Cu(II), and Cd(II) onto Cabbage Leaves Powder

International Journal of Chemical Reactor Engineering, 2016

In this study, the biosorption of lead (Pb(II)), copper (Cu(II)), and cadmium (Cd(II)) ions from ... more In this study, the biosorption of lead (Pb(II)), copper (Cu(II)), and cadmium (Cd(II)) ions from aqueous solution using waste of cabbage leaves powder (CLP) was investigated as a function of pH, shaking time, initial metal concentration, and biosorbent dose. The maximum removal efficiency at optimum condition in single biosorption system was 95.67, 92.42, and 88.92 % for Pb(II), Cu(II), and Cd(II) ions, respectively. These values reduced in ternary systems in the same sequence. Langmuir and extended Langmuir isotherm models were found to be the best fit of the isotherm data for single and ternary biosorption systems, respectively. The kinetic data of the three metals were better fit by the pseudo-second-order model with higher coefficient of determination and more closely predicted uptake. In addition, the results showed that the intraparticle diffusion was the dominating mechanism. Thermodynamic study showed that the biosorption of Pb(II), Cu(II), and Cd(II) onto CLP was a chemical...