Zakaria Alqodah - Academia.edu (original) (raw)

Papers by Zakaria Alqodah

Studies on the -amylase-producing thermophilic bacterium isolated and identified from a hot sprin... more Studies on the -amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. Thegrowth and enzyme production optimum conditions were pH 7 and 50oC. The kinetic study of cellular growth indicates max, Ks, d, Yx/s and kd were 0.53 h-1, 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h,respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant Ki 190 mg/l. The kinetic parameters of -amylase activation Vmax, and Km were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested

Chemical Engineering Research and Design, 2011

Natural convection in enclosures is of importance in many engineering applications. The stratific... more Natural convection in enclosures is of importance in many engineering applications. The stratification arising out of natural convection may be desirable/undesirable depending on applications. In order to control the degree of stratification, understanding of flow pattern and temperature profiles is required. In the present work, transient natural convection in a cylindrical enclosure has been investigated for water with CFD simulations and flow visualization [using particle image velocimetry (PIV) and hot film anemometry (HFA)] over a wide range of parameters namely Rayleigh number (1.08 × 10 11 ≤ Ra ≤ 3.76 × 10 13) and aspect ratio (1 ≤ H/R ≤ 2). The effect of various parameters like pressure, tube diameter and aspect ratio on the extent of stratification has been studied. PIV measurements have been performed to understand the transient flow behavior. Multiple thermocouples were used to measure the temperature profiles. CFD simulations have been performed using SST k-ω model and the results have been compared with the PIV measurements. The CFD simulations have been carried out for 2D axi-symmetric cases and the effect of boundary conditions (free-slip and no-slip) has been investigated. An excellent agreement was found between the CFD predictions and the experimental measurements of flow and temperature patterns. The extent of stratification has been quantified using dimensionless parameters like stratification number and stratification time. The kinetic energy profiles and kinetic energy dissipation profiles show that almost 75% of the enclosure is stratified (after different times depending on Ra number and the aspect ratio). The turbulence parameters were found to weaken with time in the stratified region and these predictions are corroborated with HFA measurements.

Journal of Macromolecular Science, Part A, 2008

The adsorption of Cu(II) ions onto the chitosan derived Schiff bases obtained from the condensati... more The adsorption of Cu(II) ions onto the chitosan derived Schiff bases obtained from the condensation of chitosan with salicyaldehyde (polymer I), 2,4-dihydroxybenzaldehyde (polymer II) and with 4-(diethylamino) salicyaldehyde (polymer III) in aqueous solutions was investigated. Batch adsorption experiments were carried out as a function of contact time, pH, and polymer mass. The amount of metal-ion uptake of the polymers was

Abstract—The hydrothermal behavior of a bed consisting of magnetic and shale oil particle admixtu... more Abstract—The hydrothermal behavior of a bed consisting of magnetic and shale oil particle admixtures under the effect of a transverse magnetic field is investigated. The phase diagram, bed void fraction are studied under wide range of the operating conditions i.e., gas velocity, magnetic field intensity and fraction of the magnetic particles. It is found that the range of the stabilized regime is reduced as the magnetic fraction decreases. In addition, the bed voidage at the onset of fluidization decreases as the magnetic fraction decreases. On the other hand, Nusselt number and consequently the heat transfer coefficient is found to increase as the magnetic fraction decreases. An empirical equation is investigated to relate the effect of the gas velocity, magnetic field intensity and fraction of the magnetic particles on the heat transfer behavior in the bed. Keywords—Magnetic stabilization; Magnetic stabilized fluidized beds; Gas-fluidized beds. I.

Heat transfer and flow behavior of gas–solid suspension flows in a vertical plexi-glass tube of 2... more Heat transfer and flow behavior of gas–solid suspension flows in a vertical plexi-glass tube of 28-mm inside diameter and of a uniform heat-flux boundary conditions was investigated. The measurement was performed using oil shale particles of a mean diameter of 972-μm. with different flow rates of air and solids loading ratio. The measured parameters were: inlet and outlet temperatures of the steam and air; exchanger wall and tube center temperatures at different axial locations; the differential pressure a cross an orifice manometer connected to the air blower; and pressure drop in the radial direction which was measured by L–type Pitot tube located at the end the test section. The results obtained showed that the average Nusselt number, defined in terms of the average local heat transfer coefficient, increases with increasing solids – loading ratio. Also a little deviation of the velocity profiles of solids and pure air were observed. The profiles tended to flatten in the center re...

Journal of Materials Science Research, 2015

This study investigates the effect of temperature and impregnation ratio on the physicochemical p... more This study investigates the effect of temperature and impregnation ratio on the physicochemical properties of activated carbon prepared from agricultural waste; desiccated coconut residue (DCR) by chemical activation using sodium hydroxide (NaOH). DCR sample was first carbonized at three different temperatures for 1 hour at 400°C, 500°C, and 600°C respectively. The resulting chars were impregnated with NaOH at three different impregnation ratio; 1:1, 1:2, and 1:3 respectively and activated under nitrogen atmosphere for 1 hour at three different temperatures based on its carbonization temperature. The specific surface area was strongly affected by impregnation ratio in which increased with impregnation ratio. The specific surface area also increased with temperature but then decreased at highest desired temperature.

Please cite this article as: Ngah, C.C.W., Yahya, M.A., Optimization of Digestion Method for Dete... more Please cite this article as: Ngah, C.C.W., Yahya, M.A., Optimization of Digestion Method for Determination of Arsenic in Shrimp Paste Sample using Atomic Absorption Spectrometry, Food Chemistry (2012), doi: 10.1016/ j.foodchem.2012.04.032 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Asian Journal of Chemistry, 2015

Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring... more Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. The growth and enzyme production optimum conditions were pH 7 and 50 o C. The kinetic study of cellular growth indicates max , K s , d , Y x/s and k d were 0.53 h-1 , 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h, respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant K i 190 mg/l. The kinetic parameters of-amylase activation V max , and K m were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested.

Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring... more Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. The growth and enzyme production optimum conditions were pH 7 and 50 o C. The kinetic study of cellular growth indicates max , K s , d , Y x/s and k d were 0.53 h-1 , 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h, respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant K i 190 mg/l. The kinetic parameters of-amylase activation V max , and K m were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested.

Journal of Water Supply: Research and Technology-Aqua

A series of batch and dynamic column experiments were carried out for adsorbing reactive dyes pre... more A series of batch and dynamic column experiments were carried out for adsorbing reactive dyes present in textile mill effluents under different conditions. Jordanian shale oil ash, produced by burning oil shale at 800°C, was used to adsorb these dyes in a fixed bed adsorber. The bed depth service time (BDST) model was applied to illustrate the bed performance. The experimental and predicted results are compared for various operating conditions. The effects of feed flow rate, inlet concentration, adsorbent article diameter and temperature on the bed service time and performance are considered. It was found that the rate at which the breakthrough point is achieved increases with increasing temperature and inlet concentration, and decreases as the particle size increases. The results indicate that a bed of 0.20 m in height and 0.025 m in diameter is adequate for full development of the adsorption zones in all experiments. The spent adsorbent was easily regenerated by burning at 600°C. The results obtained indicate that shale oil ash has potential as an adsorbent and could be easily used in continuous processes. In addition, the BDST model gave reasonable results in predicting the bed performance using the relationships proposed by previous researchers or proposed in this study.

Environmental Engineering and Management Journal

In this study, the reduction of phenolic compounds and other organic pollutants from greenish bla... more In this study, the reduction of phenolic compounds and other organic pollutants from greenish black (GB) and dark brown (DB) olive mill wastewater (OMW) was investigated. Ultrasonic irradiation in combination with aerobic biodegradation was adopted as the treatment technique. Operational parameters such as the duration of ultrasonic irradiation, ultrasonic power intensity and ultrasonic frequency were tested to determine their effects on phenol, BOD, and COD degradations. It was found that a time interval of 90 minutes of continuous exposure of OMW to ultrasonic field lead up to 81% degradation of the total phenol at 25°C. In addition, the results showed that ultrasonic field affects significantly BOD of OMW. In contrast, there was no significant dependency between COD degradation and ultrasound intensity. It was demonstrated that phenol degradation can be modelled adequately according to first-order kinetics model with rate constant, k, of around 0.0083 and 0.0077 min-1 for (GB) and (DB) OMW samples, respectively. In the aerobic degradation step, the COD was consumed according to Grau kinetic model. The order of COD degradation rate, is about n=1.13 and 1.27, whereas, the Grau kinetic constant, K=0.0218 and 0.0149 h-1 for GB and DB OMW, respectively. The maximum COD removal efficiency achieved was about 80%. It can be concluded that sonication energy plays a significant role on enhancement the efficiency of the biodegradation of OMW by contributing positively in the reduction of the toxic phenolic compounds.

Environmental Engineering and Management Journal

The aim of the present work was to investigate experimentally the reduction of Chemical Oxygen De... more The aim of the present work was to investigate experimentally the reduction of Chemical Oxygen Demand (COD) levels from baker's yeast wastewater (BYW) using batch electrocoagulation (EC) treatment process. An electrocoagulation unit with six iron electrodes was designed to achieve this treatment task. The effect of several operational parameters including pH, direct current (DC) density (I ρ), mixing speed (MS), and temperature (T) on the performance of EC process was studied. The results indicated that the maximum removal efficiency of the COD was up to 85%. The visual test showed that the electrocoagulation process was able to remove completely the dark brown color of baker's yeast wastewater. The corresponding electrical energy and electrode consumption per kg COD removed was around 0.493 kWh and 2.956 kg iron, respectively. In addition, it was demonstrated that the reduction rate of COD follows the first-order model whose kinetic parameter, k, depends strongly on the DC current density according to a power law relation.

Http Dx Doi Org 10 1080 01496395 2012 707729, 2013

ABSTRACT The present work studied experimentally the variations of some characteristics of the mi... more ABSTRACT The present work studied experimentally the variations of some characteristics of the mixed liquor solution in wastewater treatment plants (WWTPs) under the effect of electrocoagulation (EC) technique. Unlike conventional methods, electrocoagulation was performed using cylindrical perforated iron electrodes to achieve a good distribution of the applied DC field onto the municipal wastewater. Effects of electrocoagulation time, applied voltage gradient, and aeration on the mixed liquor characteristics were considered. The study figured out the dependency of the local pH and oxidation potential reduction (OPR) values, near anode and cathode on these operational conditions. It was found that electrocoagulation process reached steady state conditions in no more than 60 minutes. At high voltage gradient (6 V/cm), the steady removal efficiencies of COD and nutrients exceeded 89%. While aeration showed moderate influence on removal efficiencies and wastewater sludge filterability, it significantly affected the pH and ORP near the electrodes especially at the low voltage gradient. Results also indicated that the sludge filterability was improved notably by increasing the voltage gradient to have minimal levels of specific-resistance to filtration (SRF).

Renewable and Sustainable Energy Reviews, 2015

ABSTRACT A review on the preparation of the activated carbon from agricultural waste material is ... more ABSTRACT A review on the preparation of the activated carbon from agricultural waste material is presented. The physical properties such as proximate and ultimate analysis of agricultural waste material were reviewed. The chemical compositions such as cellulose, hemicelluloses and lignin contents were also discussed. The effects of various parameters on the preparation such as carbonization and activation temperature, time, types of activating agents and impregnation ratio were reviewed. Various physical and chemical processes for the activation of the agricultural residues and their effects on the textural properties such as surface area and pore volume were discussed. The low cost, renewable and relatively less expensive of the agricultural waste were found to be efficiently being converted into wealth. The uses of activated carbon derived from agricultural residues in many fields were evidently proven in the review. The reaction kinetic modelling on the pyrolysis and activation of agricultural wastes were also reviewed.

Asian Journal of Chemistry, 2015

Studies on the -amylase-producing thermophilic bacterium isolated and identified from a hot sprin... more Studies on the -amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. Thegrowth and enzyme production optimum conditions were pH 7 and 50oC. The kinetic study of cellular growth indicates max, Ks, d, Yx/s and kd were 0.53 h-1, 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h,respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant Ki 190 mg/l. The kinetic parameters of -amylase activation Vmax, and Km were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested

Chemical Engineering Research and Design, 2011

Natural convection in enclosures is of importance in many engineering applications. The stratific... more Natural convection in enclosures is of importance in many engineering applications. The stratification arising out of natural convection may be desirable/undesirable depending on applications. In order to control the degree of stratification, understanding of flow pattern and temperature profiles is required. In the present work, transient natural convection in a cylindrical enclosure has been investigated for water with CFD simulations and flow visualization [using particle image velocimetry (PIV) and hot film anemometry (HFA)] over a wide range of parameters namely Rayleigh number (1.08 × 10 11 ≤ Ra ≤ 3.76 × 10 13) and aspect ratio (1 ≤ H/R ≤ 2). The effect of various parameters like pressure, tube diameter and aspect ratio on the extent of stratification has been studied. PIV measurements have been performed to understand the transient flow behavior. Multiple thermocouples were used to measure the temperature profiles. CFD simulations have been performed using SST k-ω model and the results have been compared with the PIV measurements. The CFD simulations have been carried out for 2D axi-symmetric cases and the effect of boundary conditions (free-slip and no-slip) has been investigated. An excellent agreement was found between the CFD predictions and the experimental measurements of flow and temperature patterns. The extent of stratification has been quantified using dimensionless parameters like stratification number and stratification time. The kinetic energy profiles and kinetic energy dissipation profiles show that almost 75% of the enclosure is stratified (after different times depending on Ra number and the aspect ratio). The turbulence parameters were found to weaken with time in the stratified region and these predictions are corroborated with HFA measurements.

Journal of Macromolecular Science, Part A, 2008

The adsorption of Cu(II) ions onto the chitosan derived Schiff bases obtained from the condensati... more The adsorption of Cu(II) ions onto the chitosan derived Schiff bases obtained from the condensation of chitosan with salicyaldehyde (polymer I), 2,4-dihydroxybenzaldehyde (polymer II) and with 4-(diethylamino) salicyaldehyde (polymer III) in aqueous solutions was investigated. Batch adsorption experiments were carried out as a function of contact time, pH, and polymer mass. The amount of metal-ion uptake of the polymers was

Abstract—The hydrothermal behavior of a bed consisting of magnetic and shale oil particle admixtu... more Abstract—The hydrothermal behavior of a bed consisting of magnetic and shale oil particle admixtures under the effect of a transverse magnetic field is investigated. The phase diagram, bed void fraction are studied under wide range of the operating conditions i.e., gas velocity, magnetic field intensity and fraction of the magnetic particles. It is found that the range of the stabilized regime is reduced as the magnetic fraction decreases. In addition, the bed voidage at the onset of fluidization decreases as the magnetic fraction decreases. On the other hand, Nusselt number and consequently the heat transfer coefficient is found to increase as the magnetic fraction decreases. An empirical equation is investigated to relate the effect of the gas velocity, magnetic field intensity and fraction of the magnetic particles on the heat transfer behavior in the bed. Keywords—Magnetic stabilization; Magnetic stabilized fluidized beds; Gas-fluidized beds. I.

Heat transfer and flow behavior of gas–solid suspension flows in a vertical plexi-glass tube of 2... more Heat transfer and flow behavior of gas–solid suspension flows in a vertical plexi-glass tube of 28-mm inside diameter and of a uniform heat-flux boundary conditions was investigated. The measurement was performed using oil shale particles of a mean diameter of 972-μm. with different flow rates of air and solids loading ratio. The measured parameters were: inlet and outlet temperatures of the steam and air; exchanger wall and tube center temperatures at different axial locations; the differential pressure a cross an orifice manometer connected to the air blower; and pressure drop in the radial direction which was measured by L–type Pitot tube located at the end the test section. The results obtained showed that the average Nusselt number, defined in terms of the average local heat transfer coefficient, increases with increasing solids – loading ratio. Also a little deviation of the velocity profiles of solids and pure air were observed. The profiles tended to flatten in the center re...

Journal of Materials Science Research, 2015

This study investigates the effect of temperature and impregnation ratio on the physicochemical p... more This study investigates the effect of temperature and impregnation ratio on the physicochemical properties of activated carbon prepared from agricultural waste; desiccated coconut residue (DCR) by chemical activation using sodium hydroxide (NaOH). DCR sample was first carbonized at three different temperatures for 1 hour at 400°C, 500°C, and 600°C respectively. The resulting chars were impregnated with NaOH at three different impregnation ratio; 1:1, 1:2, and 1:3 respectively and activated under nitrogen atmosphere for 1 hour at three different temperatures based on its carbonization temperature. The specific surface area was strongly affected by impregnation ratio in which increased with impregnation ratio. The specific surface area also increased with temperature but then decreased at highest desired temperature.

Please cite this article as: Ngah, C.C.W., Yahya, M.A., Optimization of Digestion Method for Dete... more Please cite this article as: Ngah, C.C.W., Yahya, M.A., Optimization of Digestion Method for Determination of Arsenic in Shrimp Paste Sample using Atomic Absorption Spectrometry, Food Chemistry (2012), doi: 10.1016/ j.foodchem.2012.04.032 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Asian Journal of Chemistry, 2015

Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring... more Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. The growth and enzyme production optimum conditions were pH 7 and 50 o C. The kinetic study of cellular growth indicates max , K s , d , Y x/s and k d were 0.53 h-1 , 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h, respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant K i 190 mg/l. The kinetic parameters of-amylase activation V max , and K m were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested.

Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring... more Studies on the-amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Bacillus sphaericus were carried out in a laboratory scale fermenter. The growth and enzyme production optimum conditions were pH 7 and 50 o C. The kinetic study of cellular growth indicates max , K s , d , Y x/s and k d were 0.53 h-1 , 1.1 g/l, 1.98 h, 0.44 g cell/g starch and 0.4 g/l/h, respectively. The optimum starch concentration for the enzyme production was 32 g/l and higher concentrations show substrate inhibition with inhibition constant K i 190 mg/l. The kinetic parameters of-amylase activation V max , and K m were 263 mole mg-1 enzyme min-1 and 0.97 mg/ml, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested.

Journal of Water Supply: Research and Technology-Aqua

A series of batch and dynamic column experiments were carried out for adsorbing reactive dyes pre... more A series of batch and dynamic column experiments were carried out for adsorbing reactive dyes present in textile mill effluents under different conditions. Jordanian shale oil ash, produced by burning oil shale at 800°C, was used to adsorb these dyes in a fixed bed adsorber. The bed depth service time (BDST) model was applied to illustrate the bed performance. The experimental and predicted results are compared for various operating conditions. The effects of feed flow rate, inlet concentration, adsorbent article diameter and temperature on the bed service time and performance are considered. It was found that the rate at which the breakthrough point is achieved increases with increasing temperature and inlet concentration, and decreases as the particle size increases. The results indicate that a bed of 0.20 m in height and 0.025 m in diameter is adequate for full development of the adsorption zones in all experiments. The spent adsorbent was easily regenerated by burning at 600°C. The results obtained indicate that shale oil ash has potential as an adsorbent and could be easily used in continuous processes. In addition, the BDST model gave reasonable results in predicting the bed performance using the relationships proposed by previous researchers or proposed in this study.

Environmental Engineering and Management Journal

In this study, the reduction of phenolic compounds and other organic pollutants from greenish bla... more In this study, the reduction of phenolic compounds and other organic pollutants from greenish black (GB) and dark brown (DB) olive mill wastewater (OMW) was investigated. Ultrasonic irradiation in combination with aerobic biodegradation was adopted as the treatment technique. Operational parameters such as the duration of ultrasonic irradiation, ultrasonic power intensity and ultrasonic frequency were tested to determine their effects on phenol, BOD, and COD degradations. It was found that a time interval of 90 minutes of continuous exposure of OMW to ultrasonic field lead up to 81% degradation of the total phenol at 25°C. In addition, the results showed that ultrasonic field affects significantly BOD of OMW. In contrast, there was no significant dependency between COD degradation and ultrasound intensity. It was demonstrated that phenol degradation can be modelled adequately according to first-order kinetics model with rate constant, k, of around 0.0083 and 0.0077 min-1 for (GB) and (DB) OMW samples, respectively. In the aerobic degradation step, the COD was consumed according to Grau kinetic model. The order of COD degradation rate, is about n=1.13 and 1.27, whereas, the Grau kinetic constant, K=0.0218 and 0.0149 h-1 for GB and DB OMW, respectively. The maximum COD removal efficiency achieved was about 80%. It can be concluded that sonication energy plays a significant role on enhancement the efficiency of the biodegradation of OMW by contributing positively in the reduction of the toxic phenolic compounds.

Environmental Engineering and Management Journal

The aim of the present work was to investigate experimentally the reduction of Chemical Oxygen De... more The aim of the present work was to investigate experimentally the reduction of Chemical Oxygen Demand (COD) levels from baker's yeast wastewater (BYW) using batch electrocoagulation (EC) treatment process. An electrocoagulation unit with six iron electrodes was designed to achieve this treatment task. The effect of several operational parameters including pH, direct current (DC) density (I ρ), mixing speed (MS), and temperature (T) on the performance of EC process was studied. The results indicated that the maximum removal efficiency of the COD was up to 85%. The visual test showed that the electrocoagulation process was able to remove completely the dark brown color of baker's yeast wastewater. The corresponding electrical energy and electrode consumption per kg COD removed was around 0.493 kWh and 2.956 kg iron, respectively. In addition, it was demonstrated that the reduction rate of COD follows the first-order model whose kinetic parameter, k, depends strongly on the DC current density according to a power law relation.

Http Dx Doi Org 10 1080 01496395 2012 707729, 2013

ABSTRACT The present work studied experimentally the variations of some characteristics of the mi... more ABSTRACT The present work studied experimentally the variations of some characteristics of the mixed liquor solution in wastewater treatment plants (WWTPs) under the effect of electrocoagulation (EC) technique. Unlike conventional methods, electrocoagulation was performed using cylindrical perforated iron electrodes to achieve a good distribution of the applied DC field onto the municipal wastewater. Effects of electrocoagulation time, applied voltage gradient, and aeration on the mixed liquor characteristics were considered. The study figured out the dependency of the local pH and oxidation potential reduction (OPR) values, near anode and cathode on these operational conditions. It was found that electrocoagulation process reached steady state conditions in no more than 60 minutes. At high voltage gradient (6 V/cm), the steady removal efficiencies of COD and nutrients exceeded 89%. While aeration showed moderate influence on removal efficiencies and wastewater sludge filterability, it significantly affected the pH and ORP near the electrodes especially at the low voltage gradient. Results also indicated that the sludge filterability was improved notably by increasing the voltage gradient to have minimal levels of specific-resistance to filtration (SRF).

Renewable and Sustainable Energy Reviews, 2015

ABSTRACT A review on the preparation of the activated carbon from agricultural waste material is ... more ABSTRACT A review on the preparation of the activated carbon from agricultural waste material is presented. The physical properties such as proximate and ultimate analysis of agricultural waste material were reviewed. The chemical compositions such as cellulose, hemicelluloses and lignin contents were also discussed. The effects of various parameters on the preparation such as carbonization and activation temperature, time, types of activating agents and impregnation ratio were reviewed. Various physical and chemical processes for the activation of the agricultural residues and their effects on the textural properties such as surface area and pore volume were discussed. The low cost, renewable and relatively less expensive of the agricultural waste were found to be efficiently being converted into wealth. The uses of activated carbon derived from agricultural residues in many fields were evidently proven in the review. The reaction kinetic modelling on the pyrolysis and activation of agricultural wastes were also reviewed.

Asian Journal of Chemistry, 2015